Similar Temperature Sensitivity Research Articles

Nanothermometer Based on Polychlorinated Trityl Radicals Showing Two-Photon Excitation and Emission in the Biological Transparency Window: Temperature Monitoring of Biological Tissues.

Nanothermometers are emerging probes as biomedical diagnostic tools. Especially appealing are nanoprobes using NIR light in the range of biological transparency window (BTW) since they have the advantages of a deeper penetration into biological tissues, better contrast, reduced phototoxicity and photobleaching. This article reports the preparation and characterization of organic nanoparticles (ONPs) doped with two polychlorinated trityl radicals (TTM and PTM), as well as studies of their electronic and optical properties. Such ONPs having inside isolated radical molecules and dimeric excimers, can be two-photon excited showing optimal properties for temperature sensing. Remarkably, in TTM-based ONPs the emission intensity of the isolated radical species is unaltered increasing temperature, while the excimer emission intensity decreases strongly being thereby able to monitor temperature changes with an excellent thermal absolute sensitivity of 0.6-3.7%K-1 in the temperature range of 278-328K. The temperature dependence of the excimeric bands of ONPs are theoretically simulated by using electronic structure calculations and a vibronic Hamiltonian model. Finally, TTM-doped ONPs as ratiometric NIR-nanothermometers are tested with two-photon excitationwith enucleated pig eye sclera, as a real tissue model, obtaining a similar temperature sensitivity as in aqueous suspensions, demonstrating their potential as NIR nanothermometers for bio applications.

Do different vegetative organs exhibit a similar temperature sensitivity in growth?

Although phenology and growth traits of leaves or woods have been the focus of research on growth-climate relationships, more is needed regarding whether there is a consistent growth response of different organs to environmental change. However, such work is crucial to accurately assess the impact of climate change on tree growth. Here, the growth timing, duration, rate, and increment of Picea meyeri needles, shoots, and stems were examined, and the corresponding environmental effects were revealed along an altitudinal gradient (2040–2740 m a.s.l.) in North-Central China during 2016 and 2017. The three organs showed a consistent altitudinal variation in growth onset timing, but a different variation in other traits; the growth duration, rate, and increment of needles changed slightly while those of shoots and stems dropped markedly with altitude. The air temperature was the key environmental factor driving the altitudinal variation. For each 1 °C increase in air temperature, the onset timing of needle and shoot elongation and xylem cell production was synchronously advanced by 3.3–3.7 ± 0.2 days; the peak timing was advanced by 3.4 ± 0.2 days, 2.2 ± 0.1 days, and 0 days; and the cessation timing was delayed by −3.8 ± 0.0 days, 2.1 ± 0.3 days, and 2.4 ± 0.1 days. Meanwhile, the duration was lengthened by 0 days, 5.6 ± 0.3 days, and 6.4 ± 0.2 days, respectively; the average rate was improved by 0%, 7.0 ± 1.2%, and 6.5 ± 0.5%, respectively; the increment was increased by 1.3 ± 0.1%, 8.2 ± 0.4%, and 11.0 ± 0.4%, respectively. These findings suggested that the aboveground vegetative growth of P. meyeri exhibits different temperature sensitivities; stem growth will benefit more from future warming than shoot and needle growth. It adds a new clue to conducting growth-climate relationship studies, and the response difference of organ growth to temperature should be considered in revealing future climate warming on tree growth.

Laser micromachined 3D glass photonics platform demonstrated by temperature compensated strain sensor

A platform for integrated glass solutions with full 3D capabilities based on femtosecond laser micromachining is presented. The design and fabrication of different building blocks, such as optical waveguides, bragg gratings, V-grooves and (freestanding) microstructures are described. The capabilities of the platform are exemplified by designing a temperature compensated strain sensor composed of two Bragg grating sensors, where one Bragg grating sensor is mechanically isolated by means of a cantilever, while the other is embedded in the bulk of the glass. Both Bragg gratings exhibit a similar temperature sensitivity of about 10.5pm/°C. It is proven that the isolated Bragg grating does not experience strain, while the other one does with a sensitivity of 1.1 pm/μϵ; thus allowing temperature compensation. Integrated V-grooves allow for a fully fiber-packaged strain sensing solution, directly applicable in many structural health monitoring applications. The versatility of the platform is further illustrated by the widely varying building blocks.

A calibration-free fiber sensor based on CdZnSe/ZnSe/ZnS quantum dots for real-time monitoring of human thermal activities

A calibration-free fiber sensor based on CdZnSe/ZnSe/ZnS quantum dots (QDs) was proposed. The sensor was fabricated by filling fully a thick hollow core fiber (HCF) with QDs solutions and fused tapering to seal the micro-cavity subsequently. Results showed that sensors with different cavity lengths can provide a similar temperature sensitivity of 0.12 nm/°C with an excellent linearity. Compared with sensors based on the interference and grating, the temperature demodulation function is universal due to a fact that fluorescence wavelengths changed by temperatures are only related to QDs materials, independent of the cavity length and the excitation power, so the sensor can be calibration-free, providing an idea and the technology for the calibration-free work of optical fiber temperature sensor in the future. Furthermore, the sensor exhibiting an excellent stability and repeatability can monitor thermal signals generated by human activity in real-time.

The carbon-quality temperature hypothesis: Fact or artefact?

Climate warming can reduce global soil carbon stocks by enhancing microbial decomposition. However, the magnitude of this loss remains uncertain because the temperature sensitivity of the decomposition of the major fraction of soil carbon, namely resistant carbon, is not fully known. It is now believed that the resistance of soil carbon mostly depends on microbial accessibility of soil carbon with physical protection being the primary control of the decomposition of protected carbon, which is insensitive to temperature changes. However, it is still unclear whether the temperature sensitivity of the decomposition of unprotected carbon, for example, carbon that is not protected by the soil mineral matrix, may depend on the chemical recalcitrance of carbon compounds. In particular, the carbon-quality temperature (CQT) hypothesis asserts that recalcitrant low-quality carbon is more temperature-sensitive to decomposition than labile high-quality carbon. If the hypothesis is correct, climate warming could amplify the loss of unprotected, but chemically recalcitrant, carbon and the resultant CO2 release from soils to the atmosphere. Previous research has supported this hypothesis based on reported negative relationships between temperature sensitivity and carbon quality, defined as the decomposition rate at a reference temperature. Here we show that negative relationships can arise simply from the arbitrary choice of reference temperature, inherently invalidating those tests. To avoid this artefact, we defined the carbon quality of different compounds as their uncatalysed reaction rates in the absence of enzymes. Taking the uncatalysed rate as the carbon quality index, we found that the CQT hypothesis is not supported for enzyme-catalysed reactions, which showed no relationship between carbon quality and temperature sensitivity. The lack of correlation in enzyme-catalysed reactions implies similar temperature sensitivity for microbial decomposition of soil carbon, regardless of its quality, thereby allaying concerns of acceleration of warming-induced decomposition of recalcitrant carbon.

Delayed effect of low rearing temperature on gonadal DNA methylation in juvenile barramundi (Lates calcarifer)

Sex differentiation in many gonochoristic fish is highly responsive to temperature treatment. In some species, exposure to high or low temperatures during primary gonadal development induces phenotypic reversal of an otherwise genetically encoded sex. These changes in sexual phenotype occur in the absence of changes in genotype and are often accompanied by epigenetic modifications, such as DNA methylation. It is unknown if sequentially hermaphroditic fish exhibit similar temperature sensitivity to what has been shown in gonochoristic species; however, sex-specific differences in DNA methylation have been observed. The barramundi (Lates calcarifer) is a protandrous (male-first) sequential hermaphrodite that exhibits sex-specific DNA methylation patterns. To examine the effect of temperature on DNA methylation and primary gonadal differentiation in a sequential hermaphrodite, sexually immature barramundi were exposed to high (34 °C), control (29 °C) low (24 °C) and fluctuating (25–33 °C) temperatures from 10 to 90 days post hatch, and then on-reared at 29 °C for 12 months. At 6 months and 12 months, individuals were sampled, and their gonads examined for evidence of changes in DNA methylation and/or gonadal differentiation. Male-specific DNA methylation patterns and advanced testis development were observed at 12 months but were absent at 6 months, suggesting that low temperature treatment had a delayed effect on the gonads of juvenile barramundi. Additionally, there was an initial, but not lasting, negative effect of low temperature treatment on fish length and weight, indicating that compensatory growth may have occurred. This research provides the first evidence for an effect of temperature on gonadal DNA methylation and primary sexual development in a sequential hermaphrodite. A refinement of treatment timing and intensity could lead to the development of a hormone-free method of sex control for this widely cultured species.

Climate-induced shifts in composition and protection regulate temperature sensitivity of carbon decomposition through soil profile

Through soil profile, both chemical composition of soil organic carbon (SOC) and edaphic physiochemical properties present a vertical gradient, likely resulting in depth-specific SOC dynamics in response to climate change (e.g., global warming). We assessed temperature sensitivity of SOC decomposition (Q10) by incubating (128 days) soils sampled across five sequential layer depths (i.e., 0–10, 10–20, 20–30, 30–50, and 50–100 cm) at ten sites along a ∼2500 m elevational transect (from ∼2100 m to ∼4600 m) covering various vegetation types (from evergreen broadleaved forest to alpine meadow) in southeast Tibet, China. The Q10 of SOC decomposition was significantly affected by both soil depth and elevation. However, depth-induced variation of Q10 was much smaller than that induced by the elevation gradient. Across the ten sites and five soil depths, chemical composition of SOC and its physiochemical protection against decomposition contributed >80% to the explained variance of Q10 values. Path analysis suggested that climate indirectly affected Q10 via its regulation on chemical composition of SOC and their physiochemical stabilization. The results from a carbon model constrained by the collected data further revealed that fast, slow and passive SOC pools exhibited significant difference in their Q10, resulted from different involvement of chemical composition and physicochemical protection in their decomposition. Our findings demonstrate similar temperature sensitivity of SOC decomposition across soil depths, but spatially heterogeneous temperature sensitivity due to climate-induced variability of both chemical recalcitrance of SOC and its physiochemical protection against decomposition.

Experimental validation of a reflective long period grating design methodology

In this work, we present an experimental demonstration of our previously published modeling work on reflective long period grating (LPG). To provide the practical realization of the modeling work, we coat a long segment of fiber both in the tail length and the end facet beyond the gratings with silver to invert the transmission mode LPG to reflection mode LPG. We then measure the LPG characteristics in both the transmission and reflection mode and validate our findings from modeling work. We further build temperature and refractive index (RI) sensors and demonstrate temperature sensing from 21 °C to 191 °C with similar temperature sensitivity coefficients of 54.4 ± 2.9 pm/°C and 53.2 ± 2.6 pm/°C for transmission and reflection mode LPG, respectively whereas same RI sensitivity coefficient of 370 ± 2.2 nm/RIU.

When does temperature matter for ecosystem respiration?

The temperature response of ecosystem processes is key to understand and predict impacts of climate change. This is especially true for respiration, given its high temperature sensitivity and major role in the global carbon cycle. However, similar intrinsic temperature sensitivity for respiration does not mean comparable temperature effects across ecosystems and biomes because non-temperature factors can be more important. Here we analyzed soil and sediment respiration data and found that in temperature ranges corresponding to high latitude mean temperatures, absolute respiration rates are more sensitive to non-temperature factors than to projected direct temperature effects. However, at higher temperatures (>20 °C) the direct effect of temperature mediated by temperature sensitivity will likely be more important over changes in non-temperature factors in shaping how respiration change over time. This supports past suggestions that the relatively small projected temperature increase at low (tropical) latitudes may have a large direct impact on absolute respiration. In contrast, absolute respiration rates at high (boreal/arctic) latitudes will likely be more sensitive on the development of the non-temperature factors than on the direct effects of the large projected temperature increase there. Social media abstract. Respiration may be less dependent to changes in temperature at higher than lower latitudes.

Phylogeny, alkenone profiles and ecology of Isochrysidales subclades in saline lakes: Implications for paleosalinity and paleotemperature reconstructions

Long-chain alkenones (LCAs) produced by phylogenetically classified Groups 1 and 3 Isochrysidales are increasingly used for paleotemperature and/or paleosalinity reconstructions in oligohaline lakes and marine environments. However, there are considerable difficulties in the paleoenvironmental interpretation of LCAs from Group 2 Isochrysidales thriving in saline lakes. The biggest challenge lies in our poor understanding of the complexity and ecological niches of individual Group 2 subclades in saline lakes. Here, we perform comprehensive analysis of haptophyte-specific 18S rRNA sequences and distributions of LCAs, and long-chain alkenoates (LCEs) in surface sediments and suspended particulate matter (SPM) from 37 saline lakes in northern China. These lakes span a large salinity gradient from 0.5 to 308‰. Combined with published genomic data of Group 2 Isochrysidales, our phylogenetic analysis reveals three Group 2 subclades occupying distinct ecological niches: one ice-related bloomer Group 2i and two warm-season bloomers Groups 2w1 and 2w2. Group 2i, the earliest seasonal bloomer, frequently co-occurs with Group 2w1 in sediments from saline lakes with relatively low to intermediate salinity waters, whereas Group 2w2 blooms in hypersaline waters. Based on existing data, C39:4 methyl alkenone is a chemotaxonomic biomarker for Group 2i. %C37:4 (relative abundance of C37:4 to the total C37 alkenones) values in the three Group subclades follow the order: Group 2i > Group 2w2 > Group 2w1. The %C37:4 in sediment cores of saline lakes does not directly record past salinity changes, but instead reflects variable contributions in production by these three subclades. This could indirectly and partially reflect overall salinity changes in some lakes dominated by Groups 2i and 2w1, but can be more complicated in lakes dominated by other assemblages. For our sites, we also demonstrate that direct use of C37 alkenone unsaturation indices (U37K, U37K', and U37K'') for paleotemperature reconstructions in saline lakes is generally not feasible, except for cases where alkenone-producing Isochrysidales are dominated by one single species/subclade and seasonal production effects can be circumvented. We propose two possible alternative proxies for paleotemperature reconstructions in saline lakes: 1) unsaturation ratios of C41 and C42 alkenones, as these compounds are predominantly produced by a limited number of Group 2 species, such as Isochrysis nuda (Liao et al., 2020); 2) C38Et/C36OEt ratio (ratio of C38 ethyl alkenones and C36 ethyl alkenoates), which appears to have similar temperature sensitivity for Groups 2w1 and 2w2, in lakes with no Group 2i inputs. Our study provides new insights into the phylogenetic classifications of Group 2 Isochrysidales and their ecological/environmental niches, which are fundamental for more quantitative and rigorous applications of LCAs and LCEs in saline lakes as paleosalinity and paleotemperature proxies.

Resistance mechanisms and fitness of pyraclostrobin-resistant isolates of Lasiodiplodia theobromae from mango orchards.

BackgroundStem-end rot, caused by Lasiodiplodia theobromae (Pat.) Griffon & Maubl is a serious postharvest disease in mango. In China, a high prevalence of the QoI fungicides resistance has been reported in the last decade. The study aimed to discuss factors determining rapid development of pyraclostrobin-resistance and its resistance mechanisms.MethodsTo determine the resistance stability and fitness of pyraclostrobin resistance in L. theobromae, three phenotypes of pyraclostrobin resistance were compared and analyzed for the EC50 values, mycelial growth, virulence and temperature sensitivity and osmotic stress sensitivity. The relative conductivity and enzyme activities of different phenotypes were compared under fungicide stress to explore possible biochemical mechanisms of pyraclostrobin resistance in L. theobromae. The Cytb gene sequences of different phenotypes were analysed.ResultsAll isolates retained their original resistance phenotypes during the 10 subcultures on a fungicide-free PDA, factor of sensitivity change (FSC) was approximately equal to 1. The resistance-pyraclostrobin of the field isolates should be relatively stable. Two pyraclostrobin-resistant phenotypes shared similar mycelial growth, virulence and temperature sensitivity with pyraclostrobin-sensitive phenotype. After treated by pyraclostrobin, the relative conductivity of the sensitive phenotype was significantly increased. The time of Pyr-R and Pyr-HR reached the most conductivity was about 8–10 times than that of Pyr-S, the time for the maximum value appearance showed significant differences between sensitive and resistant phenotypes. The activities of Glutathione S-transferase (GST), catalase (CAT) and peroxidase (POD) of Pyr-HR were 1.78, 5.45 and 1.65 times respectively, significantly higher than that of Pyr-S after treated by 200 mg/l pyraclostrobin.ConclusionThe results showed that the pyraclostrobin-resistant phenotypes displayed high fitness and high-risk. The nucleotide sequences were identical among all pyraclostrobin-resistant and -sensitive isolates. The pyraclostrobin resistance was not attributable to Cytb gene alterations, there may be some of other resistance mechanisms. Differential response of enzyme activity and cell membrane permeability were observed in resistant- and sensitive-isolates suggesting a mechanism of metabolic resistance.

Identification and biochemical characterization of Asp t 36, a new fungal allergen from Aspergillus terreus

Aspergillus terreus is an allergenic fungus, in addition to causing infections in both humans and plants. However, the allergens in this fungus are still unknown, limiting the development of diagnostic and therapeutic strategies. We used a proteomic approach to search for allergens, identifying 16 allergens based on two-dimensional immunoblotting with A. terreus susceptible patient sera. We further characterized triose-phosphate isomerase (Asp t 36), one of the dominant IgE (IgE)-reactive proteins. The gene was cloned and expressed in Escherichia coli. Phylogenetic analysis showed Asp t 36 to be highly conserved with close similarity to the triose-phosphate isomerase protein sequence from Dermatophagoides farinae, an allergenic dust mite. We identified four immunodominant epitopes using synthetic peptides, and mapped them on a homology-based model of the tertiary structure of Asp t 36. Among these, two were found to create a continuous surface patch on the 3D structure, rendering it an IgE-binding hotspot. Biophysical analysis indicated that Asp t 36 shows similar secondary structure content and temperature sensitivity with other reported triose-phosphate isomerase allergens. In vivo studies using a murine model displayed that the recombinant Asp t 36 was able to stimulate airway inflammation, as demonstrated by an influx of eosinophils, goblet cell hyperplasia, elevated serum Igs, and induction of Th2 cytokines. Collectively, our results reveal the immunogenic property of Asp t 36, a major allergen from A. terreus, and define a new fungal allergen more broadly. This allergen could serve as a potent candidate for investigating component resolved diagnosis and immunotherapy.

Soil respiration in seven types of temperate forests exhibits similar temperature sensitivity

PurposeThe aim of the study was to compare the temperature sensitivity of soil respiration rate in two soil horizons of seven types of temperate forests.Materials and methodsSoil samples were collected in O and A horizons in seven types of temperate forests, each one represented by five independent stands distributed throughout Poland. Soil respiration rates were measured at standard moisture in five temperatures (4 °C, 10 °C, 16 °C, 22 °C and 28 °C), and the first-order Q10 values were calculated for each stand. General linear models (GLM) were fitted for respiration rate and for Q10 values separately using selected soil physical-chemical properties: C:N ratio, dissolved organic carbon (DOC) content and soil pH.Results and discussionThe soil respiration rate increased with temperature was the highest in O horizon of fresh mixed forest dominated by hornbeam and increased with C:N ratio, DOC content and soil pH (model p < 0.0001). In turn, model for Q10 was not significant meaning none of tested variables affected soil temperature sensitivity (p = 0.2886).ConclusionsDespite studied forest types exhibit substantial distinctness in many soil properties including respiration rate, they showed similar susceptibility to temperature increase (roughly to climate warming).

Environmental and biological controls on Na∕Ca ratios in scleractinian cold-water corals

Abstract. Here we present a comprehensive attempt to correlate aragonitic Na∕Ca ratios from Desmophyllum pertusum (formerly known as Lophelia pertusa), Madrepora oculata and a caryophylliid cold-water coral (CWC) species with different seawater parameters such as temperature, salinity and pH. Living CWC specimens were collected from 16 different locations and analyzed for their Na∕Ca ratios using solution-based inductively coupled plasma-optical emission spectrometry (ICP-OES) measurements. The results reveal no apparent correlation with salinity (30.1–40.57 g kg−1) but a significant inverse correlation with temperature (-0.31±0.04 mmolmol-1∘C-1). Other marine aragonitic organisms such as Mytilus edulis (inner aragonitic shell portion) and Porites sp. exhibit similar results highlighting the consistency of the calculated CWC regressions. Corresponding Na∕Mg ratios show a similar temperature sensitivity to Na∕Ca ratios, but the combination of two ratios appears to reduce the impact of vital effects and domain-dependent geochemical variation. The high degree of scatter and elemental heterogeneities between the different skeletal features in both Na∕Ca and Na∕Mg, however, limit the use of these ratios as a proxy and/or make a high number of samples necessary. Additionally, we explore two models to explain the observed temperature sensitivity of Na∕Ca ratios for an open and semi-enclosed calcifying space based on temperature-sensitive Na- and Ca-pumping enzymes and transport proteins that change the composition of the calcifying fluid and consequently the skeletal Na∕Ca ratio.

Similar temperature sensitivity of soil mineral-associated organic carbon regardless of age

Most of the carbon (C) stored in temperate arable soils is present in organic matter (OM) intimately associated with soil minerals and with slow turnover rates. The sensitivity of mineral-associated OM to changes in temperature is crucial for reliable predictions of the response of soil C turnover to global warming and the associated flux of carbon dioxide (CO2) from the soil to the atmosphere. We studied the temperature sensitivity of C in <63 μm fractions rich in mineral-associated organic matter (MOM) and of C in >63 μm fractions rich in particulate organic matter (POM). The fractions were isolated by physical separation of two light-textured arable soils where the C4-plant silage maize had replaced C3-crops 25 years ago. Differences in 13C abundance allowed for calculation of the age of C in the soil-size fractions (old C, C3–C > 25 years; recent C, C4–C < 25 years). We incubated bulk soils (<2 mm) and size fractions sequentially at 6, 18, 26 and 34 °C (ramping up and down the temperature scale) and calculated the temperature sensitivity of old and recent C from 12CO2 and 13CO2 evolution rates. The temperature sensitivity was similar or slightly higher for POM than for MOM. Within the POM fraction, old C3–C was more sensitive to changes in temperature than recent C4–C. For the MOM fraction, the temperature sensitivity was unrelated to the age of C. Quantitative PCR analysis indicated that the proportions of bacteria, archaea and fungi did not change during incubation. Our results suggest that while OM stabilizing mechanisms affect the temperature sensitivity of soil C, temperature sensitivity appears unrelated to the age of mineral-associated OM.

Simultaneous Distributed Sensing on Multiple MgO-Doped High Scattering Fibers by Means of Scattering-Level Multiplexing

We introduce a novel multiplexing technique applied to optical fiber distributed sensors, based on optical backscatter reflectometry (OBR) and high-scattering MgO-doped fibers. In this paper, we demonstrate the possibility of simultaneously detecting multiple fiber with a single scan using an OBR distributed sensor, and successfully discriminating each sensing region (with ~1 mm spatial resolution). The sensing element is a high-scattering fiber with MgO-based nanoparticles doping in the core, that emits a scattering signal more than 40 dB larger than a standard fiber, while having similar temperature and strain sensitivity. Multiplexing occurs as the scattered light from a sensing fiber overshadows the amount of scattering occurring in all the other channels. The setup has been validated for temperature sensing and implemented in an epidural catheter with multiple fibers fixed to the outer walls for strain sensing. The proposed solution goes beyond the multiplexing methods which exploit 1 × N switches, as the multiplexing is simultaneous and not rearranged in different time slots.

Plant Traits are Key Determinants in Buffering the Meteorological Sensitivity of Net Carbon Exchanges of Arctic Tundra

AbstractThe climate sensitivity of carbon (C) cycling in Arctic terrestrial ecosystems is a major unknown in the Earth system. There is a lack of knowledge about the mechanisms that drive the interactions between photosynthesis, respiration, and changes in C stocks across full annual cycles in Arctic tundra. We use a calibrated and validated model (soil‐plant‐atmosphere; SPA) to estimate net ecosystem exchange (NEE), gross primary production (GPP), ecosystem respiration (Reco), and internal C processing across eight full years. SPA's carbon flux estimates are validated with observational data obtained from the Greenland Ecosystem Monitoring program in West Greenland tundra. Overall, the model explained 73%, 73%, and 50% of the variance in NEE, GPP, and Reco, respectively, and 85% of the plant greenness variation. Flux data highlighted the insensitivity of growing season NEE to interannual meteorological variability, due to compensatory responses of photosynthesis and ecosystem respiration. In this modelling study, we show that this NEE buffering is the case also for full annual cycles. We show through a sensitivity analysis that plant traits related to nitrogen are likely key determinants in the compensatory response, through simulated links to photosynthesis and plant respiration. Interestingly, we found a similar temperature sensitivity of the trait‐flux couplings for GPP and Reco, suggesting that plant traits drive the stabilization of NEE. Further, model analysis indicated that wintertime periods decreased the C sink by 60%, mostly driven by litter heterotrophic respiration. This result emphasizes the importance of wintertime periods and allows a more comprehensive understanding of full annual C dynamics.

Comment on "The whole-soil carbon flux in response to warming".

In a compelling study, Hicks Pries et al (Reports, 31 March 2017, p. 1420) showed that 4°C warming enhanced soil CO2 production in the 1-meter soil profile, with all soil depths displaying similar temperature sensitivity (Q10). We argue that some caveats can be identified in their experimental approach and analysis, and that these critically undermine their conclusions and hence their claim that the strength of feedback between the whole-soil carbon and climate has been underestimated in terrestrial models.

Green Pea and Garlic Puree Model Food Development for Thermal Pasteurization Process Quality Evaluation.

Development and selection of model foods is a critical part of microwave thermal process development, simulation validation, and optimization. Previously developed model foods for pasteurization process evaluation utilized Maillard reaction products as the time-temperature integrators, which resulted in similar temperature sensitivity among the models. The aim of this research was to develop additional model foods based on different time-temperature integrators, determine their dielectric properties and color change kinetics, and validate the optimal model food in hot water and microwave-assisted pasteurization processes. Color, quantified using a* value, was selected as the time-temperature indicator for green pea and garlic puree model foods. Results showed 915 MHz microwaves had a greater penetration depth into the green pea model food than the garlic. a* value reaction rates for the green pea model were approximately 4 times slower than in the garlic model food; slower reaction rates were preferred for the application of model food in this study, that is quality evaluation for a target process of 90 °C for 10 min at the cold spot. Pasteurization validation used the green pea model food and results showed that there were quantifiable differences between the color of the unheated control, hot water pasteurization, and microwave-assisted thermal pasteurization system. Both model foods developed in this research could be utilized for quality assessment and optimization of various thermal pasteurization processes.

Phase sensitivity to temperature of the guiding mode in polarization-maintaining photonic crystal fiber.

The propagating phase changing of a polarization-maintaining photonic crystal fiber (PM-PCF) caused by temperature variation is theoretically studied, as well as compared with conventional PANDA fiber. As to verifying numerical analysis, a platform based on a Michelson interferometer for phase versus temperature measurement was built for both kinds of fiber. Experiments show that PM-PCF has similar temperature sensitivity with conventional polarization-maintaining fiber. With optimized PM-PCF design (thinner coating layer and coating material with smaller thermal expansion coefficient), the sensitivity could be further reduced to about 80% of the present level.