Range Of Environmental Temperatures Research Articles

Model of the brittle crack growth under the combined mode loading.

The modified model for dynamic crack growth in viscoelastic material has been proposed. The model based on the structural approach that includes Zhurkov’s thermokinetical concept and Neiber-Novozhilov’s criterion of brittle fracture. The structural approach describes the microstructure inhomogeneity of material and staging of crack propagation revealing by optical and electronic fractography as changing the scale of damage accumulation and fracture. The main parameters of the physical model approved by experimental data on the pulse hit action of striker to a notch of the permanently hardly loaded single edge-notched specimen in wide range of environment temperatures has been analyzed in the paper. The proposed model of brittle crack growth under the dynamic blow influence based on physical representations of the fluctuation nature of the fracture process and enables a description of the transition from discrete experimental data under combined loading to a set of continuous numerical data sufficient to calculate the values of the crack tip energy flow in a wide range of external loading and extreme environment, including the low temperatures.

Bioinspired Design of Vascular Artificial Muscle

AbstractRecently, liquid crystal elastomers (LCEs) have drawn much attention for its wide applications as artificial muscle in soft robotics, wearable devices, and biomedical engineering. One commonly adopted way to trigger deformation of LCEs is using embedded heating elements such as resistance heating wires and photothermal particles. To enable the material to recover to its unactuated state, passive and external cooling is often employed to lower the temperature, which is typically slow and environmentally sensitive. The slow and uncontrollable recovery speed of thermally driven artificial muscle often limits its applications when even moderate cyclic actuation rate is required. In this article, inspired by biology, a vascular LCE‐based artificial muscle (VLAM) is designed and fabricated with internal fluidic channel in which the hot or cool water is injected to heat up or cool down the material to achieve fast actuation as well as recovery. It is demonstrated that the actuation stress, strain, and cyclic response rate of the VLAM are comparable to mammalian skeletal muscle. Because of the internal heating and cooling mechanism, VLAM shows a very robust actuating performance within a wide range of environmental temperatures. The VLAM designed in this article may also provide a convenient way to harvest waste heat to conduct mechanical work.

Red muscle function and thermal acclimationto cold in rainbow smelt, Osmerus mordax, and rainbow trout, Oncorhynchus mykiss.

Climate change affects the thermal environment of aquatic organisms. Changes in the thermal environment may affect muscle function in the eurythermal rainbow smelt, Osmerus mordax, and relatively more stenothermal rainbow trout, Oncorhynchus mykiss. Literature suggests that the trout will be more sensitive to changes in environmental temperature, as they experience a more limited range of environmental temperatures. To examine the effects of thermal environment on red muscle function, both the smelt and trout were thermally acclimated to either a warm (12-15°C) or cold (4-5°C) temperature, after which studies of swimming performance and muscle mechanics were performed. The data on swimming performance and maximum muscle shortening velocity in rainbow smelt were previously published. In both species, cold-acclimated (CA) fish swam with a significantly faster maximum aerobic swimming speed than warm-acclimated fish, when tested at a common temperature of 10°C. Similarly, CA smelt and trout had faster red muscle contraction kinetics. However, smelt displayed a greater shift in contractile properties, such as having a significant shift in maximum muscle shortening velocity that was not observed in trout. The smelt red muscle outperformed trout, with twitch and tetanic times of relaxation being significantly faster for CA smelt compared with CA trout, especially when contraction kinetics were tested at 2°C. The smelt shows a greater thermal acclimation response compared with trout, with more robust increases in maximum swimming speed and faster muscle contractile properties. These differences in acclimation response may contribute to understanding how smelt and trout cope with climate change.

Empirical models to predict feed intake of growing-finishing pigs reared under high environmental temperatures

ABSTRACT Several empirical models were proposed to predict feed intake (FI) of growingfinishing pigs reared under high environmental temperatures. However, these models have not been evaluated under conditions different from those in which they were developed. Twelve empirical models were evaluated using a database built after systematic literature review (observed data: 28 studies in which the FI was evaluated in pigs under high environmental temperatures). Model accuracy was assessed using the mean squared of prediction error (MSPE). Analyses were performed considering two scenarios: (1) general population, where all observed data were used in the simulation; (2) reference population, where data were filtered in order to simulate only scenarios with environment (temperature range) and animals (body weight and sex) similar to that used in the model development. Six models estimated FI values similar (p >; 0.05) to those observed in the general population, while four models produced estimates similar to the observed values in the reference populations. Most models were more accurate when they were simulated using the reference population than when the simulation considered the general database. Moving the simulation from the general database to the reference population reduced up to 98 % of the MSPE, depending on the equation. Empirical models allow to accurately predict FI of growing-finishing pigs exposed to high environmental temperatures, especially in scenarios similar to the ones used for model development. Thus, population characteristics (body weight and sex) and environment (temperature range) must be considered in the model assessment.

Artificial neural network analysis of teachers’ performance against thermal comfort

PurposeThe impact of thermal comfort in educational buildings continues to be of major importance in both the design and construction phases. Given this, it is also equally important to understand and appreciate the impact of design decisions on post-occupancy performance, particularly on staff and students. This study aims to present the effect of IEQ on teachers’ performance. This study would provide thermal environment requirements to BIM-led school refurbishment projects.Design/methodology/approachThis paper presents a detailed investigation into the direct impact of thermal parameters (temperature, relative humidity and ventilation rates) on teacher performance. In doing so, the research methodological approach combines explicit mixed-methods using questionnaire surveys and physical measurements of thermal parameters to identify correlation and inference. This was conducted through a single case study using a technical college based in Saudi Arabia.FindingsFindings from this work were used to develop a model using an artificial neural network (ANN) to establish causal relationships. Research findings indicate an optimal temperature range between 23 and 25°C, with a 65% relative humidity and 0.4 m/s ventilation rate. This ratio delivered optimum results for both comfort and performance.Originality/valueThis paper presents a unique investigation into the effect of thermal comfort on teacher performance in Saudi Arabia using ANN to conduct data analysis that produced indoor environmental quality optimal temperature and relative humidity range.

Zebrafish as a model of mammalian cardiac function: Optically mapping the interplay of temperature and rate on voltage and calcium dynamics

The zebrafish (Danio rerio) heart is a viable model of mammalian cardiovascular function due to similarities in heart rate, ultrastructure, and action potential morphology. Zebrafish are able to tolerate a wide range of naturally occurring temperatures through altering chronotropic and inotropic properties of the heart. Optical mapping of cannulated zebrafish hearts can be used to assess the effect of temperature on excitation-contraction (EC) coupling and to explore the mechanisms underlying voltage (Vm) and calcium (Ca2+) transients.Applicability of zebrafish as a model of mammalian cardiac physiology should be understood in the context of numerous subtle differences in structure, ion channel expression, and Ca2+ handling. In contrast to mammalian systems, Ca2+ release from the sarcoplasmic reticulum (SR) plays a relatively small role in activating the contractile apparatus in teleosts, which may contribute to differences in restitution. The contractile function of the zebrafish heart is closely tied to extracellular Ca2+ which enters cardiomyocytes through L-type Ca2+ channel (LTCC), T-type Ca2+ channel (TTCC), and the sodium-calcium exchanger (NCX).Novel data found that despite large temperature effects on heart rate, Vm, and Ca2+ durations, the relationship between Vm and Ca2+ signals was only minimally altered in the face of acute temperature change. This suggests that zebrafish Vm and Ca2+ kinetics are largely rate-independent. In comparison to mammalian systems, zebrafish Ca2+ cycling is inherently more dependent on transsarcolemmal Ca2+ transport and less reliant on SR Ca2+ release. However, the compensatory actions of various components of the Ca2+ cycling machinery of the zebrafish cardiomyocytes, allow for maintenance of EC coupling over a wide range of environmental temperatures.

Origin, differentiation and functional ultrastructure of egg envelopes in the cestode Echinococcus multilocularis Leuckart, 1863 (Cyclophyllidea: Taeniidae)

The origin, differentiation and functional ultrastructure of oncospheral or egg envelopes in Echinococcus multilocularis Leuckart, 1863 were studied by transmission electron microscopy (TEM) and cytochemistry. The purpose of our study is to describe the formation of the four primary embryonic envelopes, namely vitelline capsule, outer envelope, inner envelope and oncospheral membrane, and their transformation into the oncospheral or egg envelopes surrounding the mature hexacanth. This transformation takes place in the preoncospheral phase of embryonic development. The vitelline capsule and oncospheral membrane are thin membranes, while the outer and inner envelopes are thick cytoplasmic layers formed by two specific types of blastomeres: the outer envelope by cytoplasmic fusion of two macromeres and the inner envelope by cytoplasmic fusion of three mesomeres. Both outer and inner envelopes are therefore cellular in origin and syncytial in nature. During the advanced phase of embryonic development, the outer and inner envelopes undergo great modifications. The outer envelope remains as a metabolically active layer involved in the storage of glycogen and lipids for the final stages of egg development and survival. The inner envelope is the most important protective layer because of its thick layer of embryophoric blocks that assures oncospheral protection and survival. This embryophore is the principal layer of mature eggs, affording physical and physiological protection for the differentiated embryo or oncosphere, since the outer envelope is stripped from the egg before it is liberated. The embryophore is very thick and impermeable, consisting of polygonal blocks of an inert keratin-like protein held together by a cementing substance. The embryophore therefore assures extreme resistance of eggs, enabling them to withstand a wide range of environmental temperatures and physicochemical conditions.

The contrasting effects of short-term climate change on the early recruitment of tree species.

Predictions of plant responses to climate change are frequently based on organisms' presence in warmer locations, which are then assumed to reflect future performance in cooler areas. However, as plant life stages may be affected differently by environmental changes, there is little empirical evidence that this approach provides reliable estimates of short-term responses to global warming. Under this premise, we analyzed 8years of early recruitment data, seed production and seedling establishment and survival, collected for two tree species at two latitudes. We quantified recruitment to a wide range of environmental conditions, temperature, soil moisture and light, and simulated recruitment under two forecasted climatic scenarios. Annual demographic transitions were affected by the particular conditions taking place during their onset, but the effects of similar environmental shifts differed among the recruitment stages; seed production was higher in warmer years, while seedling establishment and survival peaked during cold years. Within a species, these effects also varied between latitudes; increasing temperatures at the southern location will have stronger detrimental effects on recruitment than similar changes at the northern locations. Our simulations illustrate that warmer temperatures may increase seed production, but they will have a negative effect on establishment and survival. When the three early recruitment processes were simultaneously considered, simulations showed little change in recruitment dynamics at the northern site and a slight decrease at the southern site. It is only when we considered these three stages that we were able to assess likely changes in early recruitment under the predicted conditions.

Improved Reliability of FPGA-Based PUF Identification Generator Design

Physical unclonable functions (PUFs), a form of physical security primitive, enable digital identifiers to be extracted from devices, such as field programmable gate arrays (FPGAs). Many PUF implementations have been proposed to generate these unique n -bit binary strings. However, they often offer insufficient uniqueness and reliability when implemented on FPGAs and can consume excessive resources. To address these problems, in this article we present an efficient, lightweight, and scalable PUF identification (ID) generator circuit that offers a compact design with good uniqueness and reliability properties and is specifically designed for FPGAs. A novel post-characterisation methodology is also proposed that improves the reliability of a PUF without the need for any additional hardware resources. Moreover, the proposed post-characterisation method can be generally used for any FPGA-based PUF designs. The PUF ID generator consumes 8.95% of the hardware resources of a low-cost Xilinx Spartan-6 LX9 FPGA and 0.81% of a Xilinx Artix-7 FPGA. Experimental results show good uniqueness, reliability, and uniformity with no occurrence of bit-aliasing. In particular, the reliability of the PUF is close to 100% over an environmental temperature range of 25°C to 70°C with ± 10% variation in the supply voltage.

Comment on an analysis of endotherm thermal tolerances: systematic errors in data compilation undermine its credibility.

Understanding the vulnerability of animal populations and communities to rapid climate warming is a critically important endeavour and has recently been informed by a variety of meta-analyses (e.g. [1]). One current area of interest is the synthesis of thermoregulatory data from mammals and birds to examine geographical variation in thermal limits, by comparing thermoregulatory parameters such as thermoneutral zone (TNZ) breadth and variation in the upper and lower critical temperatures that bound the TNZ [2–5]. Here, we report wide-ranging errors in the dataset that is the foundation of Khaliq et al .'s [2] analysis. Khaliq et al . [2] presented a large meta-analysis that extracted data on thermoregulation in birds (161 species) and mammals (297 species) from the physiological literature, with the goal of examining the relationships between physiological capacities and geographical variation in climate. From these individual studies, they compiled data on the lower (LCT) and upper (UCT) critical temperatures, which represent the upper and lower boundaries of the TNZ, the range of environmental temperatures over which resting metabolic rate is constant in endothermic homeotherms. Our discovery that many unsuitable or non-existent data had been included in the dataset compiled by Khaliq et al . [2] was initially triggered by our surprise at the large number of mammal UCT data ( N = 297). At the time, we were conducting a comprehensive review of mammalian thermoregulation in the heat and had found far fewer studies (approx. 100) that contained data permitting the determination of a UCT. We then examined the methods section in the electronic supplementary material, figure S1 and accompanying text, which indicated that Khaliq et al . had indeed used the appropriate definitions of LCT and UCT. Given this disparity, we reviewed the source data from …

Effect of thermal stress on metabolic and oxidative stress biomarkers of Hoplosternum littorale (Teleostei, Callichthyidae)

The present study aimed to investigate in Hoplosternum littorale (Hancock, 1828) the effects of different water temperatures (10°C, 25°C-control group- and 33°C) on physiologic and metabolic traits following acute (1day) and chronic (21days) exposures. We analyzed several biomarker responses in order to achieve a comprehensive survey of fish physiology and metabolism under the effect of this natural stressor. We measured morphological indices, biochemical and hematological parameters as well as oxidative stress markers. To evaluate energy consumption, muscle and hepatic total lipid, protein and glycogen concentrations were also quantified. Extreme temperatures exposures clearly resulted in metabolic adjustments, being liver energy reserves and plasma metabolites the most sensitive parameters detecting those changes. We observed reduced hepatosomatic index after acute and chronic exposure to 33°C while glycogen levels decreased at both temperatures and time of exposure tested. Additionally, acute and chronic exposures to 10°C increased liver lipid content and plasma triglycerides. Total protein concentration was higher in liver and lower in plasma after chronic exposures to 10°C and 33°C. Acute exposition at both temperatures caused significant changes in antioxidant enzymes tested in the different tissues without oxidative damage to lipids. Antioxidant defenses in fish failed to protect them when they were exposed for 21days to 10°C, promoting higher lipid peroxidation in liver, kidney and gills. According to multivariate analysis, oxidative stress and metabolic biomarkers clearly differentiated fish exposed chronically to 10°C. Taken together, these results demonstrated that cold exposure was more stressful for H. littorale than heat stress. However, this species could cope with variations in temperature, allowing physiological processes and biochemical reactions to proceed efficiently at different temperatures and times of exposure. Our study showed the ability of H. littorale to resist a wide range of environmental temperatures and contributes for the understanding of how this species is adapted to environments with highly variable physicochemical conditions.

Evidences of non-linear short-term stress relaxation in polymers

Back in 1986, investigating the Space Shuttle Challenger disaster, famous physicist Richard Feynman clearly showed how viscoelastic behavior of a polymeric material is of paramount importance in practical engineering. At present day a definitive universal rheological law is not yet available for polymers, as a consequence both theoretical models and experimental investigations of viscoelastic behavior must be necessarily focused independently on each single polymer or, at least, on well-defined classes of polymers. Accurate experimental evidences are needed in order to properly evaluate the mechanical properties of a polymeric material, as a function of its particular applications. In this paper measurements of the stress relaxation behavior of six polymeric materials under uniaxial tension and uniaxial unconfined compression tests, are performed and experimental results are modelled using a stretched exponential function, known as Kohlraush-Williams-Watts time-decay function. In particular the short-term stress relaxation is investigated, as a function of typical environmental temperature range, in order to assess viscoelastic behavior of tested polymeric materials for peculiar industrial and biomedical applications.

Aspects of biology of Megalobulimus paranaguensis (Gastropoda, Acavoidea) in the coastal plain of the Brazilian southeast

ABSTRACT We studied the reproductive biology of Megalobulimus paranaguensis (Pilsbry & Ihering, 1900), a large and long-lived land gastropod from the Atlantic Rainforest of Brazil. The study was conducted at an urban park in the city of Santos, state of São Paulo. For 4 years, we counted the egg postures and annual eclosion rate of 32 captive snails and looked for associations between egg posture and the climatical variables of the period. The annual mean posture of 8.7 eggs per snail obtained in our results is a small number, but typical of Brazilian macromollusks. The annual eclosion rate was 31%. The beginning of the annual activity period of snails occurred in the middle of March, and lasted 33.97±3.02 weeks. The dormancy period started in the beginning of November, and lasted 18.39±3.11 weeks. There were two egg posture peaks, a minor peak between March and May, and a major peak between August and November, with greater values in September. Megalobulimus paranaguensis has a well-defined seasonal reproductive pattern influenced by environmental temperature and temperature range. Furthermore, in this snail, reproduction is negatively influenced by temperature increasing and temperature range.

Avian thermoregulation in the heat: evaporative cooling capacity of arid-zone Caprimulgiformes from two continents.

Birds in the order Caprimulgiformes (nightjars and allies) have a remarkable capacity for thermoregulation over a wide range of environmental temperatures, exhibiting pronounced heterothermy in cool conditions and extreme heat tolerance at high environmental temperatures. We measured thermoregulatory responses to acute heat stress in three species of Caprimulgiformes that nest in areas of extreme heat and aridity, the common poorwill (Phalaenoptilus nuttallii: Caprimulgidae) and lesser nighthawk (Chordeiles acutipennis: Caprimulgidae) in the Sonoran Desert of Arizona, and the Australian owlet-nightjar (Aegotheles cristatus: Aegothelidae) in the mallee woodlands of South Australia. We exposed wild-caught birds to progressively increasing air temperatures (Ta) and measured resting metabolic rate (RMR), evaporative water loss (EWL), body temperature (Tb) and heat tolerance limit (HTL; the maximum Ta reached). Comparatively low RMR values were observed in all species (0.35, 0.36 and 0.40 W for the poorwill, nighthawk and owlet-nightjar, respectively), with Tb approximating Ta at 40°C and mild hyperthermia occurring as Ta reached the HTL. Nighthawks and poorwills reached HTLs of 60 and 62°C, respectively, whereas the owlet-nightjar had a HTL of 52°C. RMR increased gradually above minima at Ta of 42, 42 and 35°C, and reached 1.7, 1.9 and 2.0 times minimum resting values at HTLs in the poorwill, nighthawk and owlet-nightjar, respectively. EWL increased rapidly and linearly as Ta exceeded Tb and resulted in maximum rates of evaporative heat dissipation equivalent to 237-424% of metabolic heat production. Bouts of gular flutter resulted in large transient increases in evaporative heat loss (50-123%) accompanied by only small increments in RMR (<5%). The cavity-nesting/roosting owlet-nightjar had a lower HTL and less efficient evaporative cooling compared with the species that nest and/or roost on open desert surfaces. The high efficiency of gular flutter for evaporative cooling, combined with mild hyperthermia, provides the physiological basis for defending Tb well below Ta in extreme heat and is comparable to the efficient cooling observed in arid-zone columbids in which cutaneous EWL is the predominant cooling pathway.

Structural and functional characteristics of photosynthetic apparatus of chlorophyll-containing grape vine tissue

Photosynthesis in tissues under periderm of woody stems and shoots of perennial plants occurs in environment that is very different from the internal environment of leaf chloroplasts. These tissues are characterized by high CO2 and low O2 concentrations, more acidic surroundings, besides that only light which have passed through periderm reaches photosynthetic antennas. In contrast to leaves of deciduous plants chlorenchyma tissues of wintering plant organs are exposed to temperature fluctuations during all seasons, that is why the photosynthetic apparatus of woody stems has to be able to adapt to a wide range of environmental temperatures. In order to reveal unique features, which enable photosynthetic apparatus of chlorenchyma cells in woody plant organs to implement biological functions under different light and temperature conditions, we studied photosynthetic tissues of stem cortex in grapevine (Vitis vinifera L.) under normal conditions and after exposure to suboptimal temperatures and high light intensity. Comparative analysis of photosynthetic pigment composition and low-temperature chlorophyll fluorescence emission spectrum of leaves, young shoots and chlorenchyma of lignified shoots revealed relatively high level of chlorophyll b and carotenoids, and high photosystem II (PSII) to photosystem I (PSI) ratio in woody shoots. Analysis of parameters of variable chlorophyll fluorescence revealed high PSII activity in grapevine shoot cortex and demonstrated improved freeze tolerance and higher sensitivity to light of photosynthetic apparatus in grape vine in comparison to leaves. It was shown for the first time that photosynthetic apparatus in chlorenchyma cells of vine undergoes so-called “state-transition”–fast rearrangements leading to redistribution of energy between photosystems. Analysis of fatty acid (FA) compositions of lipids in examined tissues showed that the FA unsaturation index in green tissue of vine is lower than in leaves. A distinct feature of FA compositions of lipids in vine cortex was relatively high level of linoleic acid.

SEALDH-II-An Autonomous, Holistically Controlled, First Principles TDLAS Hygrometer for Field and Airborne Applications: Design-Setup-Accuracy/Stability Stress Test.

Instrument operation in harsh environments often significantly impacts the trust level of measurement data. While commercial instrument manufacturers clearly define the deployment conditions to achieve trustworthy data in typical standard applications, it is frequently unavoidable in scientific field applications to operate instruments outside these commercial standard application specifications. Scientific instrumentation, however, is employing cutting-edge technology and often highly optimized but also lacks long-term field tests to assess the field vs. laboratory performance. Recently, we developed the Selective Extractive Laser Diode Hygrometer (SEALDH-II), which addresses field and especially airborne applications as well as metrological laboratory validations. SEALDH-II targets reducing deviations between airborne hygrometers (currently up to 20% between the most advanced hygrometers) with a new holistic, internal control and validation concept, which guarantees the transfer of the laboratory performance into a field scenario by capturing more than 80 instrument internal “housekeeping” data to nearly perfectly control SEALDH-II’s health status. SEALDH-II uses a calibration-free, first principles based, direct Tuneable Diode Laser Absorption Spectroscopy (dTDLAS) approach, to cover the entire atmospheric humidity measurement range from about 3 to 40,000 ppmv with a calculated maximum uncertainty of 4.3% ± 3 ppmv. This is achieved not only by innovations in internal instrument monitoring and design, but also by active control algorithms such as a high resolution spectral stabilization. This paper describes the setup, working principles, and instrument stabilization, as well as its precision validation and long-term stress tests in an environmental chamber over an environmental temperature and humidity range of ΔT = 50 K and ΔRH = 80% RH, respectively.

In situ photosynthetic yields of cave photoautotrophic biofilms using two different Pulse Amplitude Modulated fluorometers

In order to evaluate the photosynthetic efficiency of cave photoautotrophic biofilms, in vivo chlorophyll a fluorescence was measured using two different fluorometers, in two biofilms in the touristic karstic Nerja Cave (Spain). The study was done for entire days in summer and in winter during the first year and repeated for a second year, in order to cover the widest range of environmental conditions, i.e., atmospheric CO2, temperature, seeping water and relative humidity levels. Effective quantum yield and relative electron transport rate (rETR) were determined during periods of light whereas maximal quantum yield (Fv/Fm) was determined in situ during dark periods. On summer days, in situ photosynthetic yields in cyanobacterium biofilms (Chroococcidiopsis sp.) increased 7–16 times compared to that of winter days, whereas in biofilms comprised of green and red microalgae and various cyanobacterium species, no seasonal or yearly variations were observed. In contrast, maximal rETR in the two biofilms increased in the periods with the highest values of both CO2 and relative humidity. Positive correlations between all environmental variables and rETR were found. According to Redundancy Analysis, all environmental variables, mainly CO2 and relative humidity were related to photosynthetic variables. The effective quantum yields showed different values depending on the measuring light of the PAM. The values were higher with red light (Diving PAM) compared to blue light (Junior PAM) mainly in the site dominated by cyanobacteria. Nerja Cave is shown as an excellent place to study the effects of light and CO2, among other environmental variables of biofilm photosynthetic activity. The monitoring of photosynthetic activity by in vivo chlorophyll a fluorescence could be used to follow the effects of the treatments applied by the touristic cave managers to reduce the proliferation of biofilms composed of various species, and, consequently, the biodeterioration of speleothems could be reduced.

Effect of sublethal temperatures on pulsed light inactivation of bacteria

Abstract This study investigated the effect of sublethal temperatures on the efficacy of pulsed light (PL) treatment for the inactivation of Listeria innocua, Escherichia coli ATCC 25922, and Pseudomonas fluorescens. A thin layer of clear, liquid phosphate buffer inoculated with one of the challenge organisms, at a concentration of about 108 CFU/mL, was equilibrated to a temperature ranging from 5 °C to 50 °C and then treated with PL, at doses between 1.02 and 12.29 J/cm2. All treatments were performed in triplicate. In the temperature range of 5 °C to 40 °C, the average maximum reductions for L. innocua, E. coli, P. fluorescens were 6.27 ± 0.23 log CFU, 6.66 ± 0.36 log CFU, and 6.15 ± 0.19 log CFU, respectively. Temperature did not affect PL inactivation of E. coli or P. fluorescens, but a modest synergistic effect between PL and temperature was observed for L. innocua treated above 40 °C. Industrial relevance This study suggests that PL inactivation of bacteria is independent of temperature in the sublethal range 5 °C to 40 °C. The practical benefit of this finding is that PL treatments can be conducted in a wide range of environmental temperatures, without any change in the outcome of the treatment.

Long-Path Quantum Cascade Laser–Based Sensor for Methane Measurements

AbstractA long-path methane (CH4) sensor was developed and field deployed using an 8-μm quantum cascade laser. The high optical power (40 mW) of the laser allowed for path-integrated measurements of ambient CH4 at total pathlengths from 100 to 1200 m with the use of a retroreflector. Wavelength modulation spectroscopy was used to make high-precision measurements of atmospheric pressure–broadened CH4 absorption over these long distances. An in-line reference cell with higher harmonic detection provided metrics of system stability in rapidly changing and harsh environments. The system consumed less than 100 W of power and required no consumables. The measurements intercompared favorably (typically less than 5% difference) with a commercial in situ methane sensor when accounting for the different spatiotemporal scales of the measurements. The sensor was field deployed for 2 weeks at an arctic lake to examine the robustness of the approach in harsh field environments. Short-term precision over a 458-m pathlength was 10 ppbv at 1 Hz, equivalent to a signal from a methane enhancement above background of 5 ppmv in a 1-m length. The sensor performed well in a range of harsh environmental conditions, including snow, rain, wind, and changing temperatures. These field measurements demonstrate the capabilities of the approach for use in detecting large but highly variable emissions in arctic environments.

Evidence for physiological and pathological roles for sensory nerves in the microvasculature and skin

This review highlights the progress from the initial finding of neurogenic inflammation up to the most recent development in the field of sensory nerves research, focusing on their roles in the microvasculature and the skin. Recent discovery of Transient Receptor Potential (TRP) channels highlight their important roles in detecting a range of environmental stimuli, including chemical and temperature. This provides us novel mechanisms for driving neurogenic inflammation upstream of neuropeptide release in addition to promising potential therapeutic targets in various diseases, including pain, itching and skin inflammation.