Wide Range Of Light Intensities Research Articles

Chloroplast photoprotection: face the light or run and hide?

Light is both a source of energy and a potential harm for photosynthetic organisms because overexcitation causes photodamage (Mullineaux & Karpinski, 2002). In the highlighted publication, Zubik-Duda et al. focused on two mechanisms that plants have developed to avoid photodamage: chloroplast movement (Gotoh et al., 2018); and excitation quenching (Mullineaux & Karpinski, 2002). Under low light, chloroplasts accumulate along periclinal cell walls, perpendicular to the direction of the light, in order to absorb more photons. Under high light, chloroplasts move to the anticlinal cell walls that are parallel to the light beam direction, in order to avoid excess light (Gotoh et al., 2018). In the process of excitation quenching, excess excitation energy is dissipated either photochemically or non-photochemically. In non-photochemical quenching (NPQ), triplet-state chlorophyll excitation energy is transferred to carotenoids that dissipate the excess energy as heat during their return to a non-excited ground state (Mullineaux & Karpinski, 2002). This excitation quenching can be quantified in intact leaves by measuring chlorophyll a (Chla) fluorescence (Cazzaniga et al., 2013). However, both chloroplast movement and excitation quenching can act simultaneously and are both triggered by similar light intensities and wavelengths, therefore it is difficult to separate them on the basis of fluorescence intensity measurements. Monika Zubik-Duda, assistant professor in the Department of Biophysics, of the Maria Curie-Skłodowska University in Lublin, Poland, together with Wieslaw Gruszecki, head of the department, and their teams, raised the question of whether these parallel processes interfere with the results of the analyses of the individual mechanisms. They tackled the problem by using fluorescence lifetime imaging microscopy (FLIM) to measure both chloroplast movement and excitation quenching at the same time (Zubik-Duda et al., 2023). NPQ measurements based on the average fluorescent lifetime can be performed at very low light intensity, and have the advantage that Chla fluorescence lifetime is independent of the position of chloroplasts in the cell, whereas previous measurements quantified total Chla fluorescence intensity in a whole leaf, and were therefore subject to chloroplast position and orientation (Cazzaniga et al., 2013). For these measurements, Zubik-Duda et al. focused on spongy mesophyll cells in Arabidopsis leaves and used a pulsed blue laser to scan the images, activating excitation quenching and phototropins, the blue light photoreceptors that control chloroplast movements. Measurements of photosynthetic activity under different light intensities showed that at higher light, the photosynthesis rate measured by CO2 fixation increased and reached saturation. At the same time, photochemical quenching decreased and NPQ increased, probably as a mechanism to avoid photodamage due to high light intensities. Determination of the Chla fluorescence lifetime by FLIM and the relative chloroplast-free area deduced from the FLIM image showed that there were three distinguishable ranges of the blue light intensities based on different photoprotective responses (Figure 1a,b). The initial increase in light intensity to 100 μmol m−2 sec−1 led to movement of the chloroplasts to the central area of the cell, accompanied by an increase in the average lifetime of Chla fluorescence. This ensures greater absorption of light quanta combined with a relatively low rate of excitation quenching and therefore optimal conditions for photosynthesis. In the second light intensity range between 100 and 1000 μmol m−2 sec−1, the photosynthetic rate increased and the Chla excitation quenching followed the same trend, while no chloroplast movement was observed. In light intensities above 1000 μmol m−2 sec−1, the photosynthetic rate reached saturation and the chloroplasts moved toward the cell walls parallel to the light direction in a light avoidance response, while Chla lifetime decreased and enabled photoprotection via excitation quenching. Chloroplast movement and excitation quenching measured by fluorescence lifetime imaging microscopy (FLIM). (a) FLIM images of chloroplasts in Arabidopsis leaf cells under different light intensities. (b) Chloroplast movement quantified as chloroplast-free area and chlorophyll a (Chla) excitation quenching measured by the fluorescence lifetime of Chla under different light intensities. (c) Overview of chloroplast photoprotection measures (modified from Zubik-Duda et al., 2023). The authors then tested their system in different photosynthesis-related mutants. In the npq1 mutant that is impaired in excitation quenching, the Chla lifetime measurements showed that it was not possible to perform photoprotective excitation quenching at high light. However, a much greater chloroplast-free area suggested that the leaves could compensate for the lack of the excitation quenching by a stronger light avoidance response of chloroplasts. Mutants impaired in chloroplast movements showed that the lack of chloroplast relocation did not influence the Chla excitation quenching. Using fluorescence lifetime measurements of Chla, Zubik-Duda et al. have addressed the dilemma of which mechanism should be deployed for photoprotection – excitation quenching or chloroplast movement. It seems there may not be a dilemma after all: both photoprotective measures are able to operate effectively over a wide range of light intensities, and interplay to protect chloroplasts from photodamage. Chla excitation quenching steadily increases with photosynthetic activity, indicating that plants maintain a balance in the number of absorbed photons that is low enough to prevent photodamage, but high enough for efficient photosynthesis. When excitation quenching at high light intensities reaches saturation, chloroplast movement is facilitated to ensure maximal photoprotection (Figure 1c). If the photoprotective excitation quenching at high light intensities is blocked, the light avoidance movement of the chloroplasts is enhanced, suggesting a direct link between the level of excitation energy in the photosynthetic apparatus and chloroplast movement. Although the study was conducted in a single plant species (Arabidopsis), there is no reason to think that the results cannot be generalized and that these two photoprotective mechanisms may operate in parallel in other species.

Bicarbonate boosts flash response amplitude to augment absolute sensitivity and extend dynamic range in murine retinal rods.

Rod photoreceptors in the retina adjust their responsiveness and sensitivity so that they can continue to provide meaningful information over a wide range of light intensities. By stimulating membrane guanylate cyclases in the outer segment to synthesize cGMP at a faster rate in a Ca2+-dependent fashion, bicarbonate increases the circulating "dark" current and accelerates flash response kinetics in amphibian rods. Compared to amphibian rods, mammalian rods are smaller in size, operate at a higher temperature, and express visual cascade proteins with somewhat different biochemical properties. Here, we evaluated the role of bicarbonate in rods of cpfl3 mice. These mice are deficient in their expression of functional cone transducin, Gnat2, making cones very insensitive to light, so the rod response to light could be observed in isolation in electroretinogram recordings. Bicarbonate increased the dark current and absolute sensitivity and quickened flash response recovery in mouse rods to a greater extent than in amphibian rods. In addition, bicarbonate enabled mouse rods to respond over a range that extended to dimmer flashes. Larger flash responses may have resulted in part from a bicarbonate-induced elevation in intracellular pH. However, high pH alone had little effect on flash response recovery kinetics and even suppressed the accelerating effect of bicarbonate, consistent with a direct, modulatory action of bicarbonate on Ca2+- dependent, membrane guanylate cyclase activity.

Effects of monochromatic lights on the melanophores arrangement in the spotted snakehead fish Channa punctata (Bloch, 1793).

Some freshwater teleost fish have pigment cells whose arrangement and shape are affected by the environment. Natural light has a wide range of light intensity. Fish are sensitive to the background and exposed light colour. Fish body colour is a significant criterion in fixing its market value, whether it is ornamental or edible. Byfavourable light exposure, a culturist may get a good market value of fish on most ethical grounds. In this study, we recorded the changes in melanophore response with the changes in light colour on Channa punctata. Adult fish were treated with monochromatic lights (darkness, white, blue and red light) for 5 and 28 days. After treatment, their body colour and melanophore size, number, length and the number of dendrites were studied. The results showed a significant influence of monochromatic light on melanophore arrangement in fish skin. The data showed that blue light is appropriate for the overall species colour of photic C. punctata. Continuous black or white light caused severe damage to the fish's appearance.

The photoprotective dilemma of a chloroplast: To avoid high light or to quench the fire?

The safe and smooth functioning of photosynthesis in plants is ensured by the operation of numerous regulatory mechanisms that adjust the density of excitation resulting from photon absorption to the capabilities of the photosynthetic apparatus. Such mechanisms include the movement of chloroplasts inside cells and the quenching of electronic excitations in the pigment-protein complexes. Here we address the problem of a possible cause-and-effect relationship between these two mechanisms. Both the light-induced chloroplast movements and quenching of chlorophyll excitations were analyzed simultaneously with the application of fluorescence lifetime imaging microscopy of A. thaliana leaves, wild-type and impaired in chloroplast movements or photoprotective excitation quenching. The results show that both regulatory mechanisms operate over a relatively wide range of light intensities. In contrast, impaired chloroplast translocations have no effect on photoprotection at the molecular level, suggesting the direction of information flow in the coupling of these two regulatory mechanisms: from the photosynthetic apparatus to the cellular level. The results show also that the presence of the xanthophyll zeaxanthin is necessary and sufficient for the full development of photoprotective quenching of excessive chlorophyll excitations in plants.

The pattern of photosynthetic response and adaptation to changing light conditions in lichens is linked to their ecological range

Epiphytic lichens constitute an important component of biodiversity in both deforested and forest ecosystems. Widespread occurrence is the domain of generalist lichens or those that prefer open areas. While, many stenoecious lichens find shelter only in a shaded interior of forests. Light is one of the factors known to be responsible for lichen distribution. Nevertheless, the effect of light intensity on photosynthesis of lichen photobionts remain largely unknown. We investigated photosynthesis in lichens with different ecological properties in relation to light as the only parameter modified during the experiments. The aim was to find links between this parameter and habitat requirements of a given lichen. We applied the methods based on a saturating light pulse and modulated light to perform comprehensive analyses of fast and slow chlorophyll fluorescence transient (OJIP and PSMT) combined with quenching analysis. We also examined the rate of CO2 assimilation. Common or generalist lichens, i.e. Hypogymnia physodes, Flavoparmelia caperata and Parmelia sulcata, are able to adapt to a wide range of light intensity. Moreover, the latter species, which prefers open areas, dissipates the excess energy most efficiently. Conversely, Cetrelia cetrarioides considered an old-growth forest indicator, demonstrates definitely lower range of energy dissipation than other species, although it assimilates CO2 efficiently both at low and high light. We conclude that functional plasticity of the thylakoid membranes of photobionts largely determines the dispersal abilities of lichens and light intensity is one of the most important factors determining the specificity of a species to a given habitat.

MoTe2-Based Schottky Barrier Photodiode Enabled by Contact Engineering

Two-dimensional (2D) atomic crystalline materials have attracted the scientific community owing to their remarkable electrical and optical applications, such as solar cells, light-emitting diodes, and photodiodes. This study demonstrates a Schottky barrier photodiode (SPD) using different metal architectures in lateral and vertical contacts on n-type 2H phase semiconducting molybdenum ditelluride (MoTe2) synthesized by the self-flux crystal growth method. High-work-function palladium and low-work-function indium metals have been deposited on MoTe2 to fabricate a field-effect transistor confirming diode characteristics. The device shows an ideality factor of 1.09 and a rectification ratio of 102, indicating ideal diode characteristics based on a single MoTe2 channel. In addition, we measured the device in the dark and used the green laser to analyze the photodiode behavior of SPD in a wide range of light intensity. A single channel using contact architecture-based study is helpful to apply in other 2D materials to achieve the simplest fundamental diodes for future nanoelectrical and optoelectronic devices.

Analysis and Optimization of Signal Detection Noise of Single-Beam Modulated Atomic Magnetometer Array

Highly sensitive atomic magnetometers (AMs) have been wildly used to form magnetocardiography (MCG) or magnetoencephalography (MEG) devices recently. However, signal detection noise, including light noise due to pump light fluctuations and electrical noise introduced by the detection circuit, will inevitably affect the sensitivity of the AM. Therefore, this article proposes a novel method to suppress signal detection noise and improve the sensitivity of AM. We first propose a low-noise preamplifier circuit to suppress the electrical noise of the signal detection part. Then, based on the equivalent magnetic noise amplitude, a method to optimize the pump light intensity is proposed. The experimental setup has been established. Both the analysis and experimental results can be evaluated that the magnetometer sensitivity can always be maintained at a relatively high-sensitivity level (around 24 fT/Hz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2}$ </tex-math></inline-formula> ) over a wide range of light intensities. We hope that the method proposed in this article can contribute to the improvement of sensor sensitivity in array AM systems.

Operational stability, low light performance, and long-lived transients in mixed-halide perovskite solar cells with a monolayer-based hole extraction layer

Due to their tunable bandgap and low manufacturing cost, metal halide perovskite solar cells are attractive for ambient/indoor light-harvesting applications. In this work, we evaluate p-i-n perovskite solar cells fabricated with MeO-2PACz, a molecular monolayer hole extraction layer, as potential candidates for ambient light-harvesting applications. Two triple-cation mixed halide lead perovskite absorbers are compared, one with high bromide content (Br/I ratio 1:2, bandgap 1.72 eV, 16.1% power conversion efficiency) and one with low bromide content (Br/I ratio 1:11, bandgap 1.57 eV, 19.1% power conversion efficiency). Both materials demonstrated good stability while operating under simulated sunlight at the maximum power point for 100 h, a cumulative light dose comparable to over two years of ambient use. After 100 h operation, however, the measured device efficiency fell temporarily due to a transient loss of output current before returning to the nominal level after a long recovery period in the dark. These transient losses were more apparent in the wide bandgap device under strong light and were likely caused by light-induced halide segregation. After recovery, both devices retained good performance under a wide range of light intensities. Under a simulated ambient light source (835 lx white LED), the power conversion efficiency of the wide bandgap device reached 30.4%.

Spiral wave drift under optical feedback in cardiac tissue.

Spiral waves occur in various types of excitable media and their dynamics determine the spatial excitation patterns. An important type of spiral wave dynamics is drift, as it can control the position of a spiral wave or eliminate a spiral wave by forcing it to the boundary. In theoretical and experimental studies of the Belousov-Zhabotinsky reaction, it was shown that the most direct way to induce the controlled drift of spiral waves is by application of an external electric field. Mathematically such drift occurs due to the onset of additional gradient terms in the Laplacian operator describing excitable media. However, this approach does not work for cardiac excitable tissue, where an external electric field does not result in gradient terms. In this paper, we propose a method of how to induce a directed linear drift of spiral waves in cardiac tissue, which can be realized as an optical feedback control in tissue where photosensitive ion channels are expressed. We illustrate our method by using the FitzHugh-Nagumo model for cardiac tissue and the generic model of photosensitive ion channels. We show that our method works for continuous and discrete light sources and can effectively move spiral waves in cardiac tissue, or eliminate them by collisions with the boundary or with another spiral wave. We finally implement our method by using a biophysically motivated photosensitive ion channel model included to the Luo-Rudy model for cardiac cells and show that the proposed feedback control also induces directed linear drift of spiral waves in a wide range of light intensities.

Divergent outer retinal circuits drive image and non-image visual behaviors.

SUMMARYImage- and non-image-forming vision are essential for animal behavior. Here we use genetically modified mouse lines to examine retinal circuits driving image- and non-image-functions. We describe the outer retinal circuits underlying the pupillary light response (PLR) and circadian photoentrainment, two non-image-forming behaviors. Rods and cones signal light increments and decrements through the ON and OFF pathways, respectively. We find that the OFF pathway drives image-forming vision but cannot drive circadian photoentrainment or the PLR. Cone light responses drive image formation but fail to drive the PLR. At photopic levels, rods use the primary and secondary rod pathways to drive the PLR, whereas at the scotopic and mesopic levels, rods use the primary pathway to drive the PLR, and the secondary pathway is insufficient. Circuit dynamics allow rod ON pathways to drive two non-image-forming behaviors across a wide range of light intensities, whereas the OFF pathway is potentially restricted to image formation.

Highly Sensitive and Durable Organic Photodiodes Based on Long-Term Storable NiOx Nanoparticles.

Organic optoelectronic devices that can be fabricated at low cost have attracted considerable attention because they can absorb light over a wide frequency range and have high conversion efficiency, as well as being lightweight and flexible. Moreover, their performance can be significantly affected by the choice of the charge-selective interlayer material. Nonstoichiometric nickel oxide (NiOx) is an excellent material for the hole-transporting layer (HTL) of organic optoelectronic devices because of the good alignment of its valence band position with the highest occupied molecular orbital level of many p-type polymers. Herein, we report a simple low-temperature process for the synthesis of NiOx nanoparticles (NPs) that can be well dispersed in solution for long-term storage and easily used to form thin NiOx NP layers. NiOx NP-based organic photodiode (OPD) devices demonstrated high specific detectivity (D*) values of 1012-1013 jones under various light intensities and negative biases. The D* value of the NiOx NP-based OPD device was 4 times higher than that of a conventional poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based device, an enhancement that originated mainly from the 16 times decreased leakage current. The NiOx NP-based OPD device demonstrated better reliability over a wide range of light intensities and operational biases in comparison to a device with a conventional sol-gel-processed NiOx film. More importantly, the NiOx NP-based OPD showed long-term device stability superior to those of the PEDOT:PSS and sol-gel-processed NiOx-based devices. We highlight that our low-temperature solution-processable NiOx NP-based HTL could become a crucial component in the fabrication of stable high-performance OPDs.

Quantifying the long-term interplay between photoprotection and repair mechanisms sustaining photosystem II activity.

The photosystem II reaction centre (RCII) protein subunit D1 is the main target of light-induced damage in the thylakoid membrane. As such, it is constantly replaced with newly synthesised proteins, in a process dubbed the 'D1 repair cycle'. The mechanism of relief of excitation energy pressure on RCII, non-photochemical quenching (NPQ), is activated to prevent damage. The contribution of the D1 repair cycle and NPQ in preserving the photochemical efficiency of RCII is currently unclear. In this work, we seek to (1) quantify the relative long-term effectiveness of photoprotection offered by NPQ and the D1 repair cycle, and (2) determine the fraction of sustained decrease in RCII activity that is due to long-term protective processes. We found that while under short-term, sunfleck-mimicking illumination, NPQ is substantially more effective in preserving RCII activity than the D1 repair cycle (Plant. Cell Environ.41, 1098-1112, 2018). Under prolonged constant illumination, its contribution is less pronounced, accounting only for up to 30% of RCII protection, while D1 repair assumes a predominant role. Exposure to a wide range of light intensities yields comparable results, highlighting the crucial role of a constant and rapid D1 turnover for the maintenance of RCII efficiency. The interplay between NPQ and D1 repair cycle is crucial to grant complete phototolerance to plants under low and moderate light intensities, and limit damage to photosystem II under high light. Additionally, we disentangled and quantified the contribution of a slowly reversible NPQ component that does not impair RCII activity, and is therefore protective.

High-performance photodetector based on an interface engineering-assisted graphene/silicon Schottky junction

Graphene/silicon Schottky junctions have been proven efficient for photodetection, but the existing high dark current seriously restricts applications such as weak signal detection. In this paper, a thin layer of gadolinium iron garnet (Gd3Fe5O12, GdIG) film is introduced to engineer the interface of a graphene/silicon Schottky photodetector. The novel structure shows a significant decrease in dark current by 54 times at a −2 V bias. It also exhibits high performance in a self-powered mode in terms of an Ilight/Idark ratio up to 8.2 × 106 and a specific detectivity of 1.35 × 1013 Jones at 633 nm, showing appealing potential for weak-light detection. Practical suitability characterizations reveal a broadband absorption covering ultraviolet to near-infrared light and a large linear response with a wide range of light intensities. The device holds an operation speed of 0.15 ms, a stable response for 500 continuous working cycles, and long-term environmental stability after several months. Theoretical analysis shows that the interlayer increases the barrier height and passivates the contact surface so that the dark current is suppressed. This work demonstrates the good capacity of GdIG thin films as interlayer materials and provides a new solution for high-performance photodetectors.

Tunable dual-wavelength saturable absorber based on dual defective photonic crystal by MoS2 monolayer

Dual-wavelength Q-switched lasers have currently received extensive attention due to their wide applications in nonlinear optoelectronic devices. Their main mechanism can be based on the integration of laser with devices such as dual defective photonic crystals (DPCs). Nonetheless, DPCs with a high modulation depth is still demanding in this field. Toward this goal, in this paper, we have designed a dual DPC with MoS2 monolayers as defects in this structure. Defect modes helped adjust the wavelength by the distance between the two defects, and finally, a tunable wavelength was created by changing the intensity, incident angle, and polarization. Using the dual DPC, modulation depth was increased to 97% and 85% in the dual defect modes and a wide range of light intensities was achieved with over 80% of absorption, which helps accomplish a tunable dual Q-switching operation.

Abstracts

Scholars of childhood and youth have drawn our attention to the diverse ways Black and LGBTQ young people experience marginalization across intersections of race, class, gender, and sexuality. However, our understandings of how parental concerns affect access to resources for racial and gender minority young people deserve further attention. In my research with LGBTQ African Americans in Birmingham Alabama, I found that parents and Black communities often perceived “gayness” as an additional obstacle for young people already highly policed, educationally stereotyped, and economically disadvantaged. These findings are compelling in that they show how the hopes and aspirations of parents together with racial marginalization experienced by African Americans more broadly, can distance LGBTQ young people from support and resources. In this paper, I examine the coming out narratives of three individuals to show how parents and communities working to counteract racial marginalization may create spaces of resource scarcity for LGBTQ children and youth. Examining the meanings and politics of gender identity for Black parents and communities contributes key insights into how intersections of race and gender impact experiences of childhood and access to LGBTQ resources for Black LGBTQ young people and their communities.How did Ottoman influence lead to the emergence of entrepreneurship among elites in Transjordan during the late Ottoman period? During the late Ottoman period, Britain and the Ottomans practiced capitalism and influenced changes in Transjordan, such as introducing private land ownership through the Ottoman Land Code of 1858. During the late Ottoman period, there was an economic transition from subsistence farming to large, for-profit farms, privately owned by elites. My research is a case study tracking the arrival of capitalism in the Eastern Mediterranean, and Ottoman influence in opening space for entrepreneurship, focusing on Transjordan. To measure my dependent variable, entrepreneurship, I adapted Rostow's Stages of Economic Development to measure entrepreneur-friendly conditions. To track my independent variable, Ottoman influence, I created a scale to search for mentions of Ottoman government actions. I conducted a thematic analysis of two case studies from Raouf Sa'd Abujaber's book Pioneers Over Jordan. My hypothesis was that by prioritizing farming over nomadic living, the Ottoman government created conditions that allowed elites in Jordan to become entrepreneurs. My analysis supported and expanded on my hypothesis, demonstrating that government influence and traditional practices cooperated to produce economic change.Phillipe Descola revolutionized the field of anthropology with his classificatory ontology. Borrowing the name from the longstanding philosophic school, Descola's ontology revolves around the conception of being, however, its definition is refined to how a culture perceives its own being in comparison to nonhuman beings. Descola's four ontological categories are based on whether a culture believes it has a corporeal sameness or a cognitive sameness with nonhuman beings. The categories refer to whether a culture believes it has both types of sameness, neither, or only one or the other. The category representing western ontological beliefs, naturalism, maintains we have a corporeal sameness with other beings through Darwinian evolution, but not a cognitive sameness, as we believe we have different brains and therefore different cognition. However, from within this framework, an anomalous internet subculture exists, a community built on a shared feeling of being in some way animal. They call themselves therians and have existed online since 1993. This paper utilizes Descola's categorization to analyze therians because their unique connection to nonhuman beings is uncharacteristic of naturalist cultures. As such, my thesis question was simple: how and where do therians fit within Descola's ontological classifications?Historical markers are important because they create cultural narratives and memories to educate the public about achievements of historic people that embody ideal cultural values, to inspire modern people to aspire to such accomplishments and take pride in their history. This paper reports the results of a form of activist archaeology involved in conducting critical feminist intersectional research to promote social justice in representations of America's heritage on historical markers in Detroit, Michigan, USA. Existing historical markers are very predominantly for sites associated with white men, with far fewer sites associated with minorities or women. The dominance of white men is masked by only labelling nonwhites and women. The inclusion of some new information on existing historical markers, and some new markers, is proposed to educate the public about more of the important historical achievements of minorities and women. Materially inscribing the landscape with the important heritage of marginalized groups re-enfranchises them of their powerful pasts and identities that have been largely erased from mainstream history. Historical markers can educate the public about historic minorities and women who worked for social justice in the past, empowering marginalized groups who are working for social justice today.In this cognitive-anthropological report, I analyze the differing philosophical framework which constructed Eastern languages like Chinese compared to those used in Western intellectual history. Despite China's heavy involvement with the West in recent times, it is a fairly new era in Chinese history as many years of its existence were spent in isolation, separated from the world. Rulers came and went and China stayed alone, developing its ideas and perspective with sparse modica of ideological influence from what would become the West. As utilized in the literature and poetry of Classical China, Literary Chinese shows a fundamentally different understanding of the world seemingly free of the dualism pervading Western thought. Ideas taken for granted in the West such as subject and object do not seem to be separate entities in the macrocosm of Chinese philosophy. Therefore the ontology of the language sets up those speaking it as a necessary symptom of Nature, not as a violation of it. Through looking at its history and syntax, I apply the perceivably alien notions of Literary Chinese to the Sapir-Whorf hypothesis and study its implications for a more acute interpretation of its thoughtform and of those who intellectually utilized the language.Scutellaria barbata (SB) has been used in traditional Chinese medicine for treating liver, lung and colorectal cancers. We previously showed that SB inhibited pre-cancer foci formation in the colon of AOM-induced mice. Other researchers demonstrated their effects in regulation of various apoptotic enzymes and pathways. Glioblastoma is an aggressive and lethal tumor of the brain with few treatment options. In this study, the effects of aqueous extract of SB on the induction and modulation of apoptosis in glioblastoma U87-MG cells were assessed using the green/red/blue fluorescent Apoptosis/Necrosis Detection Kit and the Human Apoptosis Antibody Array - Membrane (43 Targets) test by the Abcam cooperation. Our data demonstrated that 3-hours of 4 mg/mL SB treatment induced a statistically higher percentage of apoptosis in U87-MG cells than 1 mg/mL of SB (74.0±2.0% &gt; 55.5±5.5%, p &lt; 0.05); while both were significantly different from the negative control with no apoptotic cells. Slightly less induction of apoptosis was obtained from 6-hours of 1 mg/mL and 4 mg/mL SB treatment with more necrotic cells (50.0±5%, 4.0±1.0% &lt; 59.5±7.5%, 5.0±3.0%), respectively. Modulation of various apoptosis markers such as up-regulation of Bax, Bad, Caspase 3, p53; and down-regulation of Bcl-2 was also observed. These results suggest that SB contains phytochemicals which induce apoptosis in glioblastoma U87-MG cells by modulating these apoptotic markers.Traumatic Brain Injury (TBI) is among the most prevalent causes of cerebrovascular and neurological damage worldwide. Premorbid conditions such as tobacco smoking (TS) may exacerbate post-TBI brain damage and impact recovery due to vascular endothelial dysfunction as a result of TS content of reactive oxygen species (ROS) and oxidative stress (OS) stimuli targeting the blood-brain barrier (BBB) endothelium. Herein, we validated the pathophysiological mechanisms underlying the exacerbation of TBI following chronic TS exposure by studying key pathological parameters leading to loss of BBB function and integrity. Experiments were conducted on TS-exposed mBMEC-P5 induced by a valid in vitro TBI model and in vivo study was performed on TS-exposed male C57BL/6J mice, age range 6–8 weeks, induced by weight drop TBI model. Immunofluorescence, western blotting, and RT-PCR analyses were applied to assess the expression of Nrf2 (critical antioxidant transcription factor) as well as tight junction proteins including, ZO-1, Occludin, and Claudin-5. Intracellular ROS generation and the levels of inflammatory markers including NF-kB, PECAM-1, VCAM-1, IL-6, IL-10, and TNF-? were also evaluated. The results revealed that TS significantly promoted increased inflammation, OS, and loss of BBB integrity in TBI when compared to TS-Free samples. BBB impairment and pro-inflammatory vascular responses induced by chronic TS exposure are likely responsible for the substantial exacerbation of post-TBI neurovascular and neurological damage.Carboxypeptidases are enzymes that remove C-terminal amino acids from proteins. Carboxypeptidase O (CPO) is a GPI-anchored enzyme that is found in the small intestine with a primary function to cleave C-terminal acidic amino acids. In mammals, CPO is found lacking a prodomain, in contrast to other closely related enzymes that require this. Four copies of the CPO gene have been found in Xenopus tropicalis, the tropical clawed frog. We wished to investigate the functionality of these four genes, and therefore gain insight into the role of CPO and the events following gene duplication. Bioinformatics analysis predicted that the proteins encoded by these X. tropicalis genes contained an ER signal peptide, a prodomain (in contrast to mammalian CPO), and three of the four were predicted to have a GPI anchor. Only one of these proteins was predicted to retain substrate specificity for acidic C-terminal amino acids. Western blotting analysis indicated that three of these genes were translated into protein in HEK293T cells. Enzyme activity was not detectable. In conclusion, only one of the four CPO genes in X. tropicalis maintains similar properties as mammalian CPO, although the functions of all await further analysis.Genes have been shown to impact drug performance and therefore it is essential to study this connection and apply it to personalized medicine. A single nucleotide polymorphism (SNP) is a common form of genetic variation which can impact patient response to drugs. SNPs vary by only one base pair which can be difficult to detect. We are developing a method to identify SNPs in the HFE gene. Alleles of the HFE gene have been shown to predict patient response to Humira treatment for Crohn's disease. One method to identify SNPs is high-resolution melt curve analysis. Theoretically, the alleles should melt at different rates and become distinguishable. To independently determine the SNP genotype, Sanger sequencing was used. We are investigating the impact of DNA fragment length, genomic DNA concentration and other factors in SNP determination by melt curve analysis. It is our goal that this experiment will become a course-based research experience for students in biology. We have concluded that longer fragments of amplified DNA (greater than 160 bp) produce melt curves that are indistinguishable for different genotypes.Scutellaria barbata (SB), a Chinese herb used in Traditional Chinese Medicine has been known to contain anti-cancer properties. SB has been investigated as a potential treatment for multiple types of cancer including colon cancer, glioblastoma, and ovarian cancer. Breast cancer cell lines MDA-MB-157, 93A, and 93B are drug-resistant APC-mutants. In this study, the effectiveness of SB in apoptotic modulation of breast cancer cell lines MDA-MB-157, 93A, and 93B was investigated. Assessments were performed using green/red/blue fluorescent Apoptosis/Necrosis Detection Kit and the Human Apoptosis Antibody Array - Membrane (43 Targets) test by the Abcam cooperation. Our data demonstrated that 1-hour treatment with 2 mg aqueous extract of SB induced a statistically significant percentage of apoptosis in MDA-MB- 157 (46.5 ± 7.5% &gt; 16%± 1.0% , p 0%, p 0%, p Modulation of various apoptosis markers such as pro-apoptotic Bad, Bax, p53; and anti-apoptotic markers BcL-2, p21, and FasL also observed. These results suggest that SB contains phytochemicals that induce apoptosis in MDA-MB-157, 93A, and 93B by modulating these pro-apoptotic and anti-apoptotic proteins.Characterized by a high energy manic phase and a low energy depressive phase, bipolar disorder affects more than 45 million people globally. Current pharmaceutical treatments, valproate (VPA) and lithium (Li), treat the manic phase of bipolar disorder in part by decreasing the inositol levels of the phosphatidylinositol (PI) signaling pathway according to the inositol depletion hypothesis. Support for this hypothesis is seen in the lower cortical inositol levels in patients in the depressive phase of bipolar disorder and suicide victims. Two genes, inositol monophosphatase 2 (IMPA2) and inositol-3phosphate synthase 1 (ISYNA1), involved in de novo inositol biosynthesis have been implicated in the pathophysiology of bipolar disorder. We seek to understand how inositol levels and the expression of IMPA2 and ISYNA1 differ between individuals with bipolar disorder types 1 and 2 compared with neurotypical. In this study, differences in inositol and IMPA2 and ISYNA1 gene expression levels in lymphocytes derived from subjects with bipolar disorder types 1, 2, and neurotypical were measured fluorometrically and by RT-qPCR respectively. Preliminary results suggest differential IMPA2 and ISYNA1 gene expression associated with bipolar disorder as well as differential IMPA2 and ISYNA1 gene expression between bipolar types 1 and 2.Intrinsically Disordered Proteins (IDPs) challenge the classic static conception of protein structure and function. Late Embryogenesis Abundant (LEA) proteins are IDPs that mediate water interactions in seeds. The interactions between a protein's amino acid sequence and its solvent drive its folding. LEA proteins have an unusual amino acid composition which we hypothesized might drive conformational change in response to salt concentration. To test whether individual amino acids differ in their solvent association as salt concentration changes, we calculated Half-Sphere Exposures (HSE) of each amino acid from NMR Protein Data Bank files and plotted them against solvent salt concentration. The HSE of all amino acids decreased as salt concentration increased (12 of them significantly), indicating an overall loosening of proteins in high salt concentrations. Prevalence of an amino acid in LEA proteins was not predictive of a greater tendency to change solvent exposure in response to salt. However, different segments of one LEA protein were comprised of amino acids with significantly different variances in salt-induced changes in HSE. Overall, our results suggest that uniformity in response to salt concentration may be important in LEA function and solvent salt concentration determines solvent exposure and hence protein structure.The SARS-CoV-2 virus was first detected in China in 2019 and spread across the world to cause the global pandemic known as COVID-19. SARS-CoV-2 is an RNA enveloped virus belonging to the Coronaviridae family. It is highly contagious and causes illness with symptoms ranging from mild fever and shortness of breath, to, in more serious cases, acute respiratory failure and death. SARS-CoV-2 can be detected in wastewater. The MDEGLE SARS-CoV-2 wastewater surveillance pilot project organized multiple institutions across Michigan, from colleges to health departments, to detect the circulation of the SARS-CoV-2 virus within specific communities more rapidly. Wastewater samples were collected from different locations, but for this work, we focused on college dormitories. The virus was first concentrated by precipitation with PEG and NaCl. The RNA was then extracted from the resuspended viral pellet using a QIAGEN Kit. Viral RNA was detected using digital droplet quantitative PCR, or ddPCR using primers and probes generated from viral RNA. We compared our results with those from clinical tests, where available, and found broad agreement between these two testing methods. Future directions could include adapting this protocol for early detection of other viruses and infectious diseases.Maintaining internal homeostasis is a priority of every organism throughout life. Unfavorable conditions such as nutrient deprivation, heat, toxins and hypoxic stress prompt the organism to adapt and reestablish homeostasis in order to survive. In this module, students will be using a roundworm C. elegans to detect environmental stressors. C. elegans is an excellent model organism for such an assay because responses to diverse threats are coordinated by a hub protein, DAF-16. DAF-16 is normally dispersed throughout cytoplasm of intestinal cells. However, following exposure to harmful conditions, DAF-16 moves to the nucleus. The DAF-16 expression is easily observable because the intestine is one of the major organs that runs along the entire length of the transparent body. To visualize DAF-16 response to potential stressors, students will use the DAF-16::GFP strain in which DAF-16 protein is tagged with green fluorescent protein (GFP). Thus, any harmful condition that prompts the organism to respond will be easily detected using a fluorescent microscope. The proposed assay will allow students to test stressors of interest, but also learn how biologists use GFP to track movement of proteins in an organism. The main goal of this module is to engage first-year students in discovery-based scientific research, enhance their learning experience and empower them to pursue more research opportunities.Multiflora rose (Rosa multiflora Thunb.) is a non-native invasive shrub broadly distributed throughout the greater Midwest. Like many invasive species, multiflora rose (MR) colonizes a variety of habitats where it competes with and replaces native species. The goal of this research was to compare the growth rate of MR with co-habiting native shrubs in a variety of habitats at Pierce Cedar Creek Institute. Photosynthesis rate, transpiration rate, and leaf chlorophyll content was measured for MR and two co-habiting native shrubs across a wide range of light intensities in meadow, old and young forests, to describe how effectively MR can compete compared with native shrubs. Our data shows the advantages MR has over both high light intensities with Black Cherry and low light intensities with Virginia Creeper, as well as its lack of advantage at very low light levels overall. These results indicate land managers might prioritize surveillance of high value landscapes with little or no MR infestation and higher incident light while first mitigating areas with less light where mitigation effort is more likely to be successful. Between regular burns, pesticide, and encouraging growth of overstory plants to shade MR to keep light levels low, mitigation of MR is possible.Trees are under strong selection to optimize water transport and self-support, particularly in crowded settings. However, tradeoffs exist between optimizing water transport or self-support, because one tissue (xylem) is responsible for both functions. Trees, therefore, need to optimize these functions while maintaining safety margins. One facet of this optimization is the architecture characteristic of each tree species that results from rates of taper and branching, and mass-dependent angle(s) of branching. These traits are plastic to varying degrees among species and hence responsive to environmental circumstance (e.g., crowding, wind, drought). All published research regarding tree architecture has involved destruction of trees or their limbs, a cumbersome if accurate approach that eliminates longitudinal study of a tree or forest stand. We studied tree architecture in a quarter-hectare plot in the GVSU Ravines in which 178 trees were mapped and photographed. Correlation and principle components analyses were used to investigate: (1) Does species dominance in the plot correspond to tree architecture or to a combination of architectural and anatomical traits? (2) Does architecture for the most common species in the plot differ in a consistent manner in response to crowding and architecture of neighbors?The woody component of a tree is a standing vascular system that must maximize growth through efficient conduction of water while supporting its mass. These abilities are determined by a species' architecture (rate and angles of branching and rate of taper) and microanatomy. How a species' anatomy and architecture integrate to determine its ecological distribution is poorly understood. One reason for this is that tree architecture has been studied exclusively through computer modeling and destructive studies in which one or numerous trees are injured or felled. Destructive methods generate precise data, but alter or destroy trees, eliminating the opportunity for long-term study. Thus, non-destructive approaches are needed. Towards that end, our lab has been using digital photography to study tree architecture for the past year. Here, we report on a destructive test of the precision of measurements acquired from digital photographs. A 73 ft (22.3m) red maple tree was photographed and felled in early January 2021. Correlations between photo-acquired and destructively-acquired measurements will be explored. Additionally, the architecture of the tree will be used to assess shifts in the optimization of hydraulic transport, ability to support vertical mass, and ability to support divergent branches, from trunk base to apex.How a tree species' anatomy dictates its architecture (i.e., rate and angle of branching and rate of branch taper) is poorly understood. Much is known about individual wood and leaf traits, however, study of how they integrate to determine a species' innate architecture and hence its generalized ability to compete through growth and tolerate stress from wind and snow is in its infancy. We investigated correspondence between anatomical and biophysical traits (e.g., vessel tube diameter and Young's Modulus of Elasticity, respectively) and the architectures of twelve species of trees occurring in Kent County, Michigan, including eleven native and one invasive species. Architectural data were collected from scaled photographs and anatomical and biophysical data was acquired from literature. Results from principle components analysis and correlation reveal ranked-trait combinations that correspond with - and thus likely dictate - tree architecture and species-specific abilities to compete through growth and tolerate stresses imposed by wind and drought. This study also provides a foundation for investigating the ability of these species to plastically respond to local conditions of competition and biophysical stresses.Attrition within the Management Information Systems (MIS) degree program continues to rise, despite the abundance of jobs in technical fields and reported 12% annual growth in computer and information systems positions, faster than the average for all other occupations. Many students who intend to major in MIS do not graduate from the program. This research addresses influences on student decisions to pursue, persist or leave the MIS program of study. Previous studies suggest self-efficacy, organizational culture, and other causal factors contribute to the attrition of MIS students. However, a general framework to explain the problem thoroughly has not been identified. A significant gap exists in theoretical framework utilizing qualitative methods to identify the influences on students with intent to study MIS. This study focuses on College of Business students with intention to study MIS at a public midwestern university. Fisher et al.'s model was modified to reflect four influences on student interest and confidence in MIS: role models, curriculum, learning environment, and ongoing reinforcement. The findings of this research assist in the development of the program and future students to decrease attrition and increase the number of students who persist through to graduation from the program.Starting a business based on technology licensed from a university can be a rewarding experience, both for the entrepreneur and for the faculty member on whose research the startup is based. To be successful, however, the startup will need to navigate and traverse many obstacles including: forming a founding team, licensing the technology, raising money, perfecting the technology and choosing a path to market. Startups are not only great vehicles for “transferring” research to the public—supporting a key mission of the university—but they can also employ former students and may generate substantial wealth for the researchers and for the university. But like most things, success is much harder than it appears. Most research professors lack the business experience to lead their companies. Often an experienced business person is hired as the founding CEO with the professors and graduate students as co-founders. The author has been a founder of several companies based on technologies licensed from Argonne National Laboratory and the University of Illinois. In this talk, he will provide a roadmap of the myriad issues and tasks one will need to manage to launch a business based on university research.We use a mathematical model based on a multiple linear regression to investigate the influence of different factors (Option Difference between Calls and Puts, Volatility Index, Interest Rate on Required Reserves, 10-Year Treasury Minus 2-Year Treasury Spread, ICE BofA Option- Adjusted Spreads [OASs], Gold Currency, and Trade Weighted United States Dollar Index) to explain the variance in the closing price of the SPX. In our regressions, we find statistically significant relationships linking our independent variables to the closing price of the SPX on a daily, weekly, and monthly basis. The forecast error evaluations of our models suggest that investors can accurately predict financial markets to a certain extent.Religion is known to provide a sense of purpose to adherents (Krause &amp; Hayward, 2012: Robbins &amp; Francis, 2000). Having such a sense of purpose may affect an individual's life in many ways. This paper explores whether having a sense of religious purpose may translate into an increased likelihood of attempting to start a business. Entering self-employment is risky, as the income earned may be uncertain and new ventures are subject to high failure rates (Hyytinen et al., 2015). However, religious people may view starting and operating their own business as part of their vocation or purpose (Rietveld et al., 2014; Silk, 2007). This sense of purpose may give them the initiative required to attempt to start a new business. However, the impact that religious purpose has on engagement in entrepreneurship may vary based on an individual's religious commitment and specific religious tradition, and thus these interactions are examined as well. In order to test the proposed hypotheses, data are used from wave 4 of the Baylor Religion Survey.The workforce is changing as new employees enter the labor pool. Over the next ten years, up to 61 million people in the U.S. born after 1995 (i.e, Gen Z) will enter the workforce. Gen Z have unique characteristics, and human resource managers (HRM) need to be prepared for possible new hiring and training approaches. One of the most important issues facing HRM is employee retention (RET). RET is defined as the intention of employees to stay employed. RET is critical for organizational success due to the costs associated with hiring and training new workers, the loss of business continuity when employees leave (i.e., turnover), and the loss of productivity when employees leave. One strategy to increase RET is employee engagement (EE), because employees who are engaged have high intention to stay with the organization. According to current estimates, only about one-third of U.S. employees are engaged, thus there may be opportunities for HR managers and organizational leaders to increase EE in their human talent. The purpose of this study is to address the following research question: “How does Gen Z define employee engagement?” This question is timely in today's highly competitive global business market, especially with a multi-generational workforce.Amid the shift of home becoming the office for many professionals, the likelihood of it continuing to serve as not only the epicenter for workspaces, but also for education, exercise, nourishment and technology-based socialization is heightened, as individuals search for balance in addressing personal safety measures and societal responsibility. According to an analysis by the U.S. Census and Bureau of Labor Statistics, since 2005, the number of jobs with remote work has increased 115% (Abrams, 2019). It has also been discovered that those who work from home tend to work more, with an average of an additional four hours of work logged per week. This is often a result of over-compensation to c

Features of the Duckweed Lemna That Support Rapid Growth under Extremes of Light Intensity.

This study addresses the unique functional features of duckweed via comparison of Lemna gibba grown under controlled conditions of 50 versus 1000 µmol photons m−2 s−1 and of a L. minor population in a local pond with a nearby population of the biennial weed Malva neglecta. Principal component analysis of foliar pigment composition revealed that Malva was similar to fast-growing annuals, while Lemna was similar to slow-growing evergreens. Overall, Lemna exhibited traits reminiscent of those of its close relatives in the family Araceae, with a remarkable ability to acclimate to both deep shade and full sunlight. Specific features contributing to duckweed’s shade tolerance included a foliar pigment composition indicative of large peripheral light-harvesting complexes. Conversely, features contributing to duckweed’s tolerance of high light included the ability to convert a large fraction of the xanthophyll cycle pool to zeaxanthin and dissipate a large fraction of absorbed light non-photochemically. Overall, duckweed exhibited a combination of traits of fast-growing annuals and slow-growing evergreens with foliar pigment features that represented an exaggerated version of that of terrestrial perennials combined with an unusually high growth rate. Duckweed’s ability to thrive under a wide range of light intensities can support success in a dynamic light environment with periodic cycles of rapid expansion.

A novel thylakoid-less isolate fills a billion-year gap in the evolution of Cyanobacteria

Cyanobacteria have played pivotal roles in Earth's geological history, especially during the rise of atmospheric oxygen. However, our ability to infer the early transitions in Cyanobacteria evolution has been limited by their extremely lopsided tree of life-the vast majority of extant diversity belongs to Phycobacteria (or "crown Cyanobacteria"), while its sister lineage, Gloeobacteria, is depauperate and contains only two closely related species of Gloeobacter and a metagenome-assembled genome. Here, we describe a new cultured member of Gloeobacteria, Anthocerotibacter panamensis, isolated from a tropical hornwort. Anthocerotibacter diverged from Gloeobacter over 1.4 Ga ago and has low 16S rDNA identities with environmental samples. Our ultrastructural, physiological, and genomic analyses revealed that this species possesses a unique combination of traits that are exclusively shared with either Gloeobacteria or Phycobacteria. For example, similar to Gloeobacter, it lacks thylakoids and circadian clock genes, but the carotenoid biosynthesis pathway is typical of Phycobacteria. Furthermore, Anthocerotibacter has one of the most reduced gene sets for photosystems and phycobilisomes among Cyanobacteria. Despite this, Anthocerotibacter is capable of oxygenic photosynthesis under a wide range of light intensities, albeit with much less efficiency. Given its key phylogenetic position, distinct trait combination, and availability as a culture, Anthocerotibacter opens a new window to further illuminate the dawn of oxygenic photosynthesis.

Nonfullerene Small Molecules‐Enabled High‐Performance Organic Photovoltaics for Indoor Energy Harvesting

Organic photovoltaics (OPVs) have attracted considerable attention as a power source of indoor electronic devices for the Internet of Things (IoT). Herein, high‐efficiency and stable nonfullerene OPVs for low‐intensity indoor applications are demonstrated while discussing the origin of high photovoltaic performance and the design fundamentals in an indoor environment. Nonfullerene OPVs exhibit higher performance over a wide range of light intensities compared with fullerene OPVs, in spite of relatively lower spectral matching with indoor light sources. To understand this discrepancy, advanced morphological analyses for the bulk‐heterojunction (BHJ) photoactive layers are proposed, which demonstrate efficient phase‐interpenetrating networks of a polymer donor and a nonfullerene acceptor. These clarify a suppression of trap sites in nonfullerene blends as a key factor to alleviate charge recombination, resulting in high photovoltaic operation under indoor environments. Combined with the morphological benefits for the high performance, the superior stability corroborates high practical usage of nonfullerene OPVs in a variety of application areas.

Design of the vanadium dioxide temperature self-regulator in the terahertz regime

A temperature self-regulator can keep the particle temperature almost constant over a wide range of light intensities. In this study, we propose a temperature self-regulator design under terahertz radiation. A key ingredient in this proposal is vanadium dioxide (VO$_2$), whose properties in the terahertz regime vary drastically around its phase transition temperature. One would expect that the particle temperature may be self-adjusted in the phase change process. To verify this notion, we employ the Mie theory for the theoretical analysis. The results show that the absorption exhibits nonlinear dependence with different parameters. At optimized sizes, the absorption of terahertz radiation can be significantly suppressed once the phase change occurs. Consequently, the temperature does not show a significant increment with increasing intensity. These results can facilitate the future development of temperature self-regulator using phase change materials in the terahertz regime.

Efficient Hybrid Amorphous Silicon/Organic Tandem Solar Cells Enabled by Near‐Infrared Absorbing Nonfullerene Acceptors

AbstractMonolithically stacked tandem solar cells present opportunities to absorb more of the sun's radiation while reducing the degree of energetic loss through thermalization. In these applications, the bandgap of the tandem's constituent subcells must be carefully adjusted so as to avoid competition for photons. Organic photovoltaics based on nonfullerene acceptors (NFAs) have recently exploded in popularity owing to the ease with which their electrical and optical properties can be tuned through chemistry. Here, highly complementary and efficient 2‐terminal tandem solar cells are reported based on a wide bandgap amorphous silicon absorber, and a narrow bandgap NFA bulk‐heterojunction with power conversion efficiencies (PCEs) exceeding 15%. Interface engineering of this tandem device allows for high PCEs across a wide range of light intensities both above and below “1 sun.” Furthermore, the addition of an inorganic silicon subcell enhances the operational stability of the tandem by reducing the light‐stress experienced by the bulk heterojunction, resolving a long‐standing stumbling block in organic photovoltaic research.