Higher Light Use Research Articles

Costs and Limitations of Marine Synechococcus Blue-Green Chromatic Acclimation

Benefits and trade-offs of blue/green chromatic acclimation (CA4) have received limited study. We investigated the energetic costs associated with executing chromatic acclimation using a fluorescence-based calculation of light use efficiency. Using laboratory cultures and artificial light environments, we show that the delayed response to acclimation known to occur in marine Synechococcus acclimating strains (generalists) in green light do not reduce light use efficiency in green light, but that only one generalist, RCC307, with a much smaller range of acclimation, had higher light use efficiency than blue and green light specialist strains. Generalists with a wider acclimation range either had the same or >30% lower light use efficiencies in blue and green light environments. From this work, we propose that advantages from CA4 may not be geared at direct competition with other Synechococcus specialists with fixed pigment types, but may serve to expand the ecological range of Synechococcus in spectral competition with other genera. As all eight Synechococcus strains tested had higher light use efficiency in green light, regardless of a fixed or flexible light harvesting strategy, we add evidence to the suitability of the Synechococcus genus to greener ocean niches, whether stable, or variable.

Thin mini-LED backlight using reflective mirror dots with high luminance uniformity for mobile LCDs.

A new mini light-emitting diode (mini-LED) backlight with reflective dots is proposed for high luminance uniformity, high contrast ratio, and low power consumption for use in mobile liquid crystal displays. The proposed backlight, comprising a small number of mini-LEDs, was verified as having high luminance uniformity and high light use efficiency, due to the optimized reflective dots, backlight thickness and light distribution of the mini-LEDs. Moreover, the light leakage to adjacent segments was reduced by cutting a slit between each segment, improving the light use efficiency per segment and suppressing halo artifacts.

Is the use of high correlated color temperature light at night related to delay of sleep timing in university students? A cross-country study in Japan and China

BackgroundBlue-enriched white light at night has the potential to delay the circadian rhythm in daily life. This study was conducted to determine whether the use of high correlated color temperature (CCT) light at home at night is associated with delay of sleep timing in university students.MethodsThe survey was conducted in 2014–2015 in 447 university students in Japan and 327 students in China. Habitual sleep timing and type of CCT light at home were investigated by using a self-administered questionnaire. The Japanese students were significantly later than the Chinese students in bedtime, wake time, and midpoint of sleep. They were asked whether the lighting in the room where they spend most of their time at night was closer to warm color (low CCT) or daylight color (high CCT). The amount of light exposure level during daily life was measured for at least 1 week by the use of a light sensor in 60 students in each country.ResultsThe percentages of participants who used high CCT lighting at night were 61.6% for Japanese students and 80.8% for Chinese students. Bedtime and sleep onset time on school days and free days were significantly later in the high CCT group than in the low CCT group in Japan. The midpoint of sleep in the high CCT group was significantly later than that in the low CCT group on free days but not on school days. On the other hand, none of the sleep measurements on school days and free days were significantly different between the high CCT and low CCT groups in China. Illuminance level of light exposure during the night was significantly higher in Japanese than in Chinese, but that in the morning was significantly higher in China than in Japan.ConclusionsThe use of high CCT light at night is associated with delay of sleep timing in Japanese university students but not in Chinese university students. The effects of light at night on sleep timing and circadian rhythm may be complicated by other lifestyle factors depending on the country.

GYMEE: A Global Field-Scale Crop Yield and ET Mapper in Google Earth Engine Based on Landsat, Weather, and Soil Data

In this study, we used Landsat Earth observations and gridded weather data along with global soil datasets available in Google Earth Engine (GEE) to estimate crop yield at 30 m resolution. We implemented a remote sensing and evapotranspiration-based light use efficiency model globally and integrated abiotic environmental stressors (temperature, soil moisture, and vapor deficit stressors). The operational model (Global Yield Mapper in Earth Engine (GYMEE)) was validated against actual yield data for three agricultural schemes with different climatic, soil, and management conditions located in Lebanon, Brazil, and Spain. Field-level crop yield data on wheat, potato, and corn for 2015–2020 were used for assessment. The performance of GYMEE was statistically evaluated through root-mean-square error (RMSE), mean absolute error (MAE), mean bias error (MBE), relative error (RE), and index of agreement (d). The results showed that the absolute difference between the modeled and predicted field-level yield was within ±16% for the analyzed crops in both Brazil and Lebanon study sites and within ±15% in the Spain site (except for two fields). GYMEE performed best for wheat crop in Lebanon with a low RMSE (0.6 t/ha), MAE (0.5 t/ha), MBE (−0.06 t/ha), and RE (0.83%). A very good agreement was observed for all analyzed crop yields, with an index of agreement (d) averaging at 0.8 in all studied sites. GYMEE shows potential in providing yield estimates for potato, wheat, and corn yields at a relative error of ±6%. We also quantified and spatialized the soil moisture stress constraint and its impact on reducing biomass production. A showcasing of moisture stress impact on two emphasized fields from the Lebanon site revealed that a 12% difference in soil moisture stress can decrease yield by 17%. A comparison between the 2017 and 2018 seasons for the potato culture of Lebanon showed that the 2017 season with lower abiotic stresses had higher light use efficiency, above-ground biomass, and yield by 5%, 10%, and 9%, respectively. The results show that the model is of high value for assessing global food production.

Changes of Light Components and Impacts on Interannual Variations of Photosynthesis in China Over 2000–2017 by Using a Two‐Leaf Light Use Efficiency Model

AbstractDiffuse radiation produces a higher light use efficiency (LUE) than does direct radiation. However, light components and their impacts on interannual variations of photosynthesis in China have not been intensively studied. We estimated gross primary production (GPP) from a two‐leaf LUE model that incorporates a diffuse radiation effect and compared it with a big‐leaf LUE model that ignores the diffuse radiation impact. The results show that a dimming occurred in China—the estimated annual photosynthetically active radiation (PAR) declined by −1.79 MJ m−2 yr−1. However, the diffuse fraction and diffuse PAR increased over this interval. Both GPP models simulated an increasing trend of GPP in China from 2000 to 2017. The big‐leaf GPP model underestimated the increasing trend of GPP from the two‐leaf GPP model by 6.4%. The diffuse fraction change during the dimming exerted an embedded positive impact relative to the big‐leaf GPP trend in China.To evaluate the impact of total PAR versus its components on GPP, annual anomaly percentage (Ap) of GPP shows that the big‐leaf GPP model had a positive correlation between Ap of GPP and PAR across China. Considering the diffuse radiation impact, Ap of two‐leaf GPP was negatively correlated with PAR in southern China, which had a higher leaf area index (2.02) and a greater diffuse fraction (0.63). Strong diffuse radiation effects in southern China produced GPP anomalies in opposition to the direction of the PAR changes. These findings highlight the distinctive impact of light components on interannual variations of plant photosynthesis.

Indoor Farming Marjoram Production—Quality, Resource Efficiency, and Potential of Application

Indoor vertical farming offers great opportunities regarding a sustainable and consistent production of high-quality herbs and raw materials all year round for the perfume, chemical, or food industry. Cultivation takes place in an enclosed structure, operating predominantly independent from external conditions in multi-layer systems equipped with artificial lighting, enabling extremely high resource use efficiencies with a simultaneous increase in yield. On the other hand, field production in terms of plant quality and harvesting times is highly influenced by environmental conditions, making it difficult to maintain homogenous raw material qualities throughout the year. To show how different light qualities affect the overall efficiency and quality of Origanum majorana grown in an indoor farm, the resource consumption, yield, and cultivation time as well as the essential oil quantity was analyzed, and the efficiencies in terms of energy and land use efficiency calculated. The experimental setup clearly demonstrated that the yield regarding fresh as well as dry matter and oil content was comparable to one square meter of open field production. Based on this, the multi-layer system and the noticeable lowered growth period result in a significantly higher area efficiency compared to the open field, leading to a potential increase of annual yields of dried leave weight and oil contents by up to 21 times. It was also shown that a white spectrum (W) showed similar influence on plant growth and yield as a spectrum consisting of blue and red (B/R). Nevertheless, the LED treatment W did show higher light use efficiencies as well as a better working conditions inside the cultivation chamber. By an integration of indoor vertical farming into existing industrial processes, new and innovative opportunities for a flexible and low-risk supply chain seem feasible and according to German food industry meet the interests of existing stakeholders.

Photosynthetic characteristics of Tamarix chinensis under different groundwater depths in freshwater habitats

Groundwater is the major source of water for Tamarix chinensis growth in the Yellow River Delta (YRD) region, and the groundwater depth (GWD) dramatically influences the physiological activities of T. chinensis. The quantitative response of the photosynthetic physiological process of T. chinensis to the GWD in freshwater habitats remains unclear. In this study, the response characteristics of gas exchange parameters in the leaves of three-year-old T. chinensis seedlings were measured and analyzed at a graded series of seven GWDs (0 m, 0.3 m, 0.6 m, 0.9 m, 1.2 m, 1.5 m and 1.8 m). The GWD thresholds corresponding to drastic changes in the photosynthetic efficiency and the GWDs of several levels of photosynthetic productivity and efficiency were also determined. In the freshwater habitats of the YRD, variations in GWD significantly altered the relative soil water content (RSWC) and thus influenced the photosynthetic efficiency of T. chinensis. RSWC at 0 ≤ GWD ≤ 0.9 m and GWD at 1.2 m ≤ GWD ≤ 1.8 m directly influenced the photosynthetic physiology of T. chinensis. When the GWD was 1.2 m, net photosynthetic rate (Pn), apparent quantum efficiency and water use efficiency (WUE) values all peaked. Thus, T. chinensis exhibited a high light and water use efficiency, wide ecological amplitude in terms of light, and high photosynthetic capacity. The optimum GWD for photosynthetic carbon assimilation and WUE in T. chinensis was determined to be 1.2 m. At a deep (≥1.64 m) or shallow (≤0.53 m) GWD, both Pn and WUE in T. chinensis clearly decreased below the corresponding mean values. The main causes for the reduction in Pn in these two GWD ranges (≤0.53 m, ≥1.64 m) were stomatal and nonstomatal limitations, respectively. Additionally, a moderate GWD of 1.09–1.25 m corresponded to the “high-productivity and high-efficiency GWD” range, in which T. chinensis displayed a high photosynthetic yield and WUE. Overall, the photosynthetic capacity of T. chinensis shows characteristics of high tolerance to moderate GWDs from 1.09 m to 1.25 m but intolerance at both shallow (≤0.53 m) and deep (≥1.64 m) GWDs in freshwater habitats.

Visible-Light-Enabled Paternò-Büchi Reaction via Triplet Energy Transfer for the Synthesis of Oxetanes.

One of the most efficient ways to synthesize oxetanes is the light-enabled [2 + 2] cycloaddition reaction of carbonyls and alkenes, referred to as the Paternò-Büchi reaction. The reaction conditions for this transformation typically require the use of high energy UV light to excite the carbonyl, limiting the applications, safety, and scalability. We herein report the development of a visible-light-mediated Paternò-Büchi reaction protocol that relies on triplet energy transfer from an iridium-based photocatalyst to the carbonyl substrates. This mode of activation is demonstrated for a variety of aryl glyoxylates and negates the need for both visible-light-absorbing carbonyl starting materials and UV light to enable access to a variety of functionalized oxetanes in up to 99% yield.

A Review: A Framework for Yield Improvement in Kharif/Rainy Season Potato in the Low Land Tropics

Abstract Potato is a temperate crop greately adapted to tropical climate as evidenced by the greater share of production by the tropical countries in recent years. It is grown mainly during rainy seasons coupled with long summers in majority of potato growing countries. However, the sub-tropics country like India, kharif (or) rainy season potatoes is still an underexploited segment which is mainly restricted to hills and plateaus, but not plains. Unlike short day crops grown during winter, the yield of kharif potato is far lower. However, the simulation model estimated the attainable yield could be enhanced substantially by extending canopy cover (100%) duration from 10 to and 40 days over the existing window of favourable growing period at various kharif growing areas. Accordingly, the yield could be enhanced from 25.4 to 34.7 t.ha−1 in plateaus (Dharwad), and from 31.9 to 42.0 t.ha−1 in Northern HH (Shimla). The South and Northern HH locations (Ooty and Shimla respectively) registered a higher attainable yield (45.1 and 42.0 t.ha−1, respectively) which strongly indicates the necessity of trait specific improvement program for developing better phenotype combination having high water, radiation and light use efficiency for enhanced yield potential.

H+ Transport by K+ EXCHANGE ANTIPORTER3 Promotes Photosynthesis and Growth in Chloroplast ATP Synthase Mutants.

The composition of the thylakoid proton motive force (pmf) is regulated by thylakoid ion transport. Passive ion channels in the thylakoid membrane dissipate the membrane potential (Δψ) component to allow for a higher fraction of pmf stored as a proton concentration gradient (ΔpH). K+/H+ antiport across the thylakoid membrane via K+ EXCHANGE ANTIPORTER3 (KEA3) instead reduces the ΔpH fraction of the pmf. Thereby, KEA3 decreases nonphotochemical quenching (NPQ), thus allowing for higher light use efficiency, which is particularly important during transitions from high to low light. Here, we show that in the background of the Arabidopsis (Arabidopsis thaliana) chloroplast (cp)ATP synthase assembly mutant cgl160, with decreased cpATP synthase activity and increased pmf amplitude, KEA3 plays an important role for photosynthesis and plant growth under steady-state conditions. By comparing cgl160 single with cgl160 kea3 double mutants, we demonstrate that in the cgl160 background loss of KEA3 causes a strong growth penalty. This is due to a reduced photosynthetic capacity of cgl160 kea3 mutants, as these plants have a lower lumenal pH than cgl160 mutants, and thus show substantially increased pH-dependent NPQ and decreased electron transport through the cytochrome b 6 f complex. Overexpression of KEA3 in the cgl160 background reduces pH-dependent NPQ and increases photosystem II efficiency. Taken together, our data provide evidence that under conditions where cpATP synthase activity is low, a KEA3-dependent reduction of ΔpH benefits photosynthesis and growth.

Nationalism, nationalized cultures, and English Language Teaching (ELT): what teacher interviews reveal about culture teaching as vehicle for ideological reproduction/transformation

ABSTRACT This study explores the interplay of nationalism and English Language Teaching (ELT) classroom practices, as reported in 11 interviews with ELT educators in various locations (e.g., United States, Serbia, France, and Saudi Arabia). The study approach is informed by theories of discursive nationalism which interpret nations and nationalized things (e.g., nationalized cultures) as social constructions maintained and managed through discourse. Qualitative analysis of interview data identified teacher-reported practices reflective of national reproduction (e.g., analogy-making and neutral stance-taking) and of national transformation (e.g., recasting nationalized things to global levels and engaging students with cultural and linguistic diversity within an otherwise coherent nationalized culture). The data reporting national reproduction are consistent with the existing literature, and the teacher reports of national transformation offer something new to the existing literature on nationalism in ELT. The analysis further highlighted teacher-reported use of assimilation/dissimilation discursive strategies in representing nationalized things to their students. The study findings contribute to a comprehensive understanding of how the ideology of nationalism intersects with ELT classroom practices. Such an understanding is valuable to the critical project of raising teacher sensitivity to the implications national representations have for social relations of power and privilege outside the classroom.

Study on screening of canola varieties with high light use efficiency and evaluation of selecting indices

High light use efficiency is an important factor for yield improvement during the growing season for winter canola. This study explored the evaluation method of high light use efficiency during the whole growth period in order to screen high light use coefficient of crop genotypes in canola producing areas of Southwest China. The pot experiment was conducted with sixty canola cultivars which had already been planted in the crops planting areas of the middle and upper reaches of Yangtze River. The plant height, root neck diameter, number of pods per main inflorescence, pods per plant, dry weight of shoots, seed weight per plant, pericarp weight per plant, ratio of pericarps to seeds weight per plant, seeds number per pod and 1000-grain weight were investigated under the shading treatment of reducing the incoming solar light by 20%. The high light use coefficient of canola cultivars was evaluated comprehensively by principal component analysis, membership function, cluster analysis and stepwise regression analysis. With these analyses, the original twelve indices related to light use efficiency could be synthesized into the four independent indices which represented 86.4% of all the investigated information of canola with high photosynthetic efficiency. Sixty varieties were classified into three groups by cluster analysis, and ZS12, GYZ6, FY792, RHY6, CZY3 and ZYZ19 displayed higher light use efficiency; such 18 varieties as XDZY9, XY1, YY50 and so on, were medium light efficient ones; and the rest 36 varieties such as LY9, ZYZ781, SG127 and so on, fell to the relatively lower light use efficiency categories. The comprehensive evaluation in this study had screened such four indicators as the stem dry weight per plant, the pod number per plant, the seed number per pod and the 1000-seed weight, which could be regarded as identification indicators for high light use efficiency of canola.

Reactor Technology Concepts for Flow Photochemistry

AbstractSynthetic organic photochemistry has been intensively carried out in the 20th century and paved the way to the preparation of complex organic molecules, which were not yet accessible via thermal chemistry. Several photochemical synthesis routes have found their way into industrial applications for the production of everyday commodities, but photochemistry was still underutilized until recently as a synthesis method in organic chemistry. With the advent of novel photocatalytic and photophysical concepts for the use of high power visible light, the research field of synthetic organic photochemistry has evolved to become a vivid and highly recognized technique in the last years. Fortunately, continuous flow technology has also become an increasingly accepted tool and has proved to be an excellent key player for the advancement of photochemistry in academic and industrial research settings. This Review provides an overview on the recent developments of continuous flow photoreactors and their application to photochemical syntheses under mild and defined process conditions.

Leaf Energy Balance Requires Mitochondrial Respiration and Export of Chloroplast NADPH in the Light.

Key aspects of leaf mitochondrial metabolism in the light remain unresolved. For example, there is debate about the relative importance of exporting reducing equivalents from mitochondria for the peroxisomal steps of photorespiration versus oxidation of NADH to generate ATP by oxidative phosphorylation. Here, we address this and explore energetic coupling between organelles in the light using a diel flux balance analysis model. The model included more than 600 reactions of central metabolism with full stoichiometric accounting of energy production and consumption. Different scenarios of energy availability (light intensity) and demand (source leaf versus a growing leaf) were considered, and the model was constrained by the nonlinear relationship between light and CO2 assimilation rate. The analysis demonstrated that the chloroplast can theoretically generate sufficient ATP to satisfy the energy requirements of the rest of the cell in addition to its own. However, this requires unrealistic high light use efficiency and, in practice, the availability of chloroplast-derived ATP is limited by chloroplast energy dissipation systems, such as nonphotochemical quenching, and the capacity of the chloroplast ATP export shuttles. Given these limitations, substantial mitochondrial ATP synthesis is required to fulfill cytosolic ATP requirements, with only minimal, or zero, export of mitochondrial reducing equivalents. The analysis also revealed the importance of exporting reducing equivalents from chloroplasts to sustain photorespiration. Hence, the chloroplast malate valve and triose phosphate-3-phosphoglycerate shuttle are predicted to have important metabolic roles, in addition to their more commonly discussed contribution to the avoidance of photooxidative stress.

Possible deviations from AM1.5 illumination in coherent light simulations on plasmonic nanostructures in Perovskite solar cells

The use of plasmonic nanostructures for light management in solar cells has been explored for conventional materials and is currently topic of interest for the perovskite solar cell. Often these studies make use of finite difference time domain (FDTD) simulations in which high intensity coherent light is used, which simultaneously generates multiple plasmon excitations in the plasmonic nanostructures in agreement with the quantum mechanical view . However, because of the relatively small photon flux of real sun light, in the classical view only one plasmon excitation can be generated at a time in real plasmonic nanostructured devices. In this work we demonstrate that the use of high intensity coherent light in simulations causes significant optical absorption variations due to surface plasmon polariton (SPP) interference, depending on incident light phase difference between neighboring plasmonic nanostructures. Because this is not possible under real sun light conditions in the classical view, this could constrain such FDTD simulations. The question therefore arises if a quantum mechanical view is more appropriate. In this case study the plasmonic nanostructures are embedded in Perovskite, which has a strong optical absorption from silver surface plasmon polaritons and is therefore sensitive to SPP interference. This study raises the question whether to mimic real sun light, SPPs should be separately generated at each individual plasmonic nanostructure, or that the quantum mechanical view leads to a better agreement with the experimental solar cell.

Synergistic Effect of Binary Mixed-Pluronic Systems on Temperature Dependent Self-assembly Process and Drug Solubility.

Mixed Pluronic micelles from very hydrophobic and very hydrophilic copolymers were selected to scrutinize the synergistic effect on the self-assembly process as well as the solubilization capacity of ibuprofen. The tendency of mixing behavior between parent copolymers was systematically examined from two perspectives: different block chain lengths at same hydrophilicity (L92 + F108, +F98, +F88, and +F68), as well as various hydrophobicities at the same PPO moiety (L92 + F88, +F87, and +P84). Temperature-dependent micellization in these binary systems was clearly inspected by the combined use of high sensitivity differential scanning calorimeter (HSDSC) and dynamic light scattering (DLS). Changes in heat capacity and size of aggregates at different temperatures during the whole micellization process were simultaneously observed and examined. While distinction of block chain length between parent copolymers increases, the monodispersity of the binary Pluronic systems decreases. However, parent copolymers with distinct PPO moieties do not affirmatively lead to non-cooperative binding, such as the L92 + P84 system. The addition of ibuprofen promotes micellization as well as stabilizes aggregates in the solution. The partial replacement of the hydrophilic Pluronic by a more hydrophobic Pluronic L92 would increase the total hydrophobicity of mixed Pluronics used in the system to substantially enhance the solubility of ibuprofen. The solubility of ibuprofen in the 0.5 wt % L92 + 0.368 wt % P84 system is as high as 4.29 mg/mL, which is 1.4 times more than that of the 0.868 wt % P84 system and 147 times more than that in pure water at 37 °C.

High light bio-fortification stimulates de novo synthesis of resveratrol in Diplotaxis tenuifolia (wild rocket) micro-greens

Background: Brassica vegetables and leafy greens are consumed globally due to their health promoting phytochemicals. Diplotaxis tenuifolia (wild rocket or arugula) is a popular Brassica leafy green, with a diverse range of phytochemicals (in mature plants). Immature plants (micro-greens, 2-4 true leaves) accumulate phytochemicals up to 10 times more than plants grown to maturity. Although plants accumulate phytochemicals ubiquitously, environmental stimuli can further enhance this phenomenon of accumulation, which is part of a global stress mechanism in plants. In this study, we describe a simple method toward the bio-fortification of a wild rocket micro-green system, via environmental manipulation (using high light). Objective: To establish a high light-induced bio-fortification strategy to augment the accumulation of bio-active compounds in Brassica micro-greens (wild rocket), with the purpose of developing a ‘designer’ micro-green melange (functional food product) containing a diverse range of bio-active (disease preventative) compounds.Results: High light stimulated wild rocket micro-greens to achieve a significant increase of known phytochemicals (documented in relevant Brassica leafy greens). Furthermore, undocumented phytochemicals (resveratrol, catechin, epicatechin, and kaempferol, among others) also accumulated to adequate concentrations. Plant extracts from bio-fortified micro-greens displayed increased anti-oxidant capacity (up to 3-fold, when compared to control), a key component in future cancer cell research.Conclusion: The use of high light resulted in successful bio-fortification of wild rocket micro-greens, evidenced by the accumulation of previously undocumented polyphenols (such as resveratrol, catechin and epicatechin) and improved anti-oxidant capacity.Key Words: anti-oxidant, high light, micro-greens, resveratrol, wild rocket

Refreshing Rubbers as Customized Photothermal Conversion Materials through Post-Darkening Modeling Production.

Organic conjugated polymers with low energy bandgaps are emerging as a particular class of near-infrared (NIR) photothermal conversion materials. However, these polymers routinely possess high phase transition temperatures due to the rigid skeleton and strong intermolecular interactions. Conjugated polymers can rarely be thermally processed at low temperature, especially below 100 °C. This work formulates a concept of post-darkening modeling production (p-DMP) by which the thermoplastic non-conjugated trans-polyisoprene (TPI) is refreshed into a photothermal conversion material with high light use efficiency. Two steps, including the customizable shaping at low temperature and iodine vapor-tailored "darkening", ensure the ease of preparing photothermal conversion devices with desirable topologies. A few characterizations, with the combination of density functional theory (DFT) calculations, provide reasonable explanations for understanding the "darkening" process of TPI in iodine atmosphere. In particular, the p-DMP is successfully extended to three-dimension (3D) printing, opening an avenue to fabricate personalized photothermal products, for example, a sunlight-directed physiotherapy device for healthcare of articular tissues.

Non-Directive Pregnancy Options Counseling: Online Instructional Module, Objective Structured Clinical Exam, and Rater and Standardized Patient Training Materials.

Many patients receiving news of an unplanned pregnancy need not only a test result, but also the initiation of pregnancy options counseling. Thus, this online instructional module and objective structured clinical examination (OSCE) aim to provide foundational training for medical students in nondirective pregnancy options counseling. To further the validity of a previously published OSCE, we reconsidered content, revised the checklist, and produced videos for rater training. We also developed a 30-minute preparatory module outlining a stepwise approach and providing a structured opportunity for values clarification. The 10-minute OSCE scenario involves a 24-year-old woman presenting to an urgent care center with persistent nausea who receives the diagnosis of an early, unplanned pregnancy. She responds to the news with shock and emotional silence, asking for guidance. We conducted the OSCE with 46 third-year medical students on the family medicine clerkship. Immediately after the OSCE, students completed a survey and self-assessment, followed by an individualized feedback session with a faculty member. In the self-assessment phase, students reflected on how successfully they utilized methods in the online module for handling emotional silence and presenting options. Student self-identified areas for improvement highlighted use of terminology and their response to difficult emotional encounters in the future. This online module and validated OSCE provide a valued opportunity for learners to practice nondirective pregnancy options counseling skills, including screening for intimate partner violence and reproductive coercion, engagement in self-assessment and receiving feedback, and engaging in personal values clarification.

Highly selective and efficient photocatalytic reduction of nitrate in water by a tandem reaction system consisting of Pt/TiO2 and SnPd/Al2O3: A comparative study of the tandem reaction system with a typical semiconductor photocatalyst, SnPd/TiO2

A tandem reaction system consisting of a photocatalyst (Pt/TiO2) and a nonphotocatalyst (SnPd/Al2O3) promoted the reduction of NO3− into gaseous products (mainly N2) under light irradiation (λ>300nm) in the presence of glucose as a hole scavenger. Photocatalytic H2 evolution (2H++2e−→H2) proceeded over Pt/TiO2, and conventional catalytic reduction of NO3− with H2 (NO3−+5/2H2→1/2N2+2H2O+OH−) occurred over SnPd/Al2O3. We optimized the loading amount of Pt on TiO2, the Sn/Pd ratio, the loading amount of SnPd on Al2O3, and the two catalyst dosages. The optimized tandem system gave a high reduction rate of NO3− and a high selectivity for gas (94%) from the photocatalytic reduction of NO3− in water. On the other hand, a typical semiconductor photocatalyst SnPd/TiO2 with an optimized Sn/Pd ratio and an optimized loading amount of SnPd bimetal on TiO2 reduced NO3− about two-thirds as fast as the tandem system and was less selective for gas (70%). The tandem system suppressed the wasted H2 formation, resulting in high light use efficiency for the NO3− reduction (95%), which is defined as the ratio of the number of electrons consumed for NO3− reduction to the total number of electrons consumed for both NO3− reduction and photocatalytic H2 evolution, though the tandem and SnPd/TiO2 systems consumed about the same total number of electrons. The tandem system has two advantages: (i) the Pt/TiO2 and SnPd/Al2O3 subsystems can be separately designed to give highly efficient photocatalytic and catalytic reactions, respectively; and (ii) the reaction rates of photocatalytic and catalytic reactions can be easily controlled by changing the catalyst dosage in the reactor. Those advantages brought about a high reduction rate for NO3−, high selectivity for gas, and high light use efficiency for NO3− reduction in the photocatalytic reduction of NO3− in water.