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1.
Platelets ; 34(1): 2136646, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36325604

RESUMO

Platelets are routinely stored at room temperature for 5-7 days before transfusion. Stored platelet quality is traditionally assessed by Kunicki's morphology score. This method requires extensive training, experience, and is highly subjective. Moreover, the number of laboratories familiar with this technique is decreasing. Cold storage of platelets has recently regained interest because of potential advantages such as reduced bacterial growth and preserved function. However, platelets exposed to cold temperatures change uniformly from a discoid to a spherical shape, reducing the morphology score outcomes to spheroid versus discoid during cooling. We developed a simpler, unbiased screening tool to measure temperature-induced platelet shape change using imaging flow cytometry. When reduced to two dimensions, spheres appear circular, while discs are detected on a spectrum from fusiform to circular. We defined circular events as having a transverse axis of >0.8 of the longitudinal axis and fusiform events ≤0.8 of the longitudinal axis. Using this assay, mouse and human platelets show a temperature and time-dependent, two-dimensional shape change from fusiform to circular, consistent with their three-dimensional change from discs to spheres. The method we describe here is a valuable tool for detecting shape change differences in response to agonists or temperature and will help screening for therapeutic measures to mitigate the cold-induced storage lesion.


What is the context? Platelets for transfusion are currently stored for 5­7 days at room temperature, increasing the risk for bacterial growthCold storage reduces the risk for bacterial growth but reduces circulation timeStored platelet quality can be assessed by the light microscopy-based Morphology Score, first described in the 1970sDownsides of the Morphology Score include subjectivity, extensive training, and reduced availability in platelet laboratories.What is new? In this study, we provide data showing that the Morphology score is reduced to a binary spheres versus discs response in cold-exposed plateletsWe developed an imaging flow cytometry-based approach to quantify platelets' response to cold based on the two-dimensional projection of the three-dimensional shapes, i.e., fusiform (discoid) versus circular (discoid and spherical)We provide validation of this approach in mouse and human plateletsWhat is the impact?This study provides an easy and unbiased tool for laboratories working on circumventing the cold-induced storage lesion or documenting spherical shape change in general.


Assuntos
Plaquetas , Criopreservação , Humanos , Camundongos , Animais , Citometria de Fluxo , Temperatura Baixa , Temperatura , Preservação de Sangue , Transfusão de Plaquetas
2.
Food Chem ; 400: 133996, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36055140

RESUMO

24-Epibrassinolide (EBR) may act as a modulator for chilling injury in peach fruit during cold storage. In this study, we screened a EBR-induced GATA-type zinc finger protein PpGATA12. The objective of this study was to investigate the potential roles of EBR treatment and transcriptional regulation of PpGATA12 in regulating chilling resistance of peaches. In the current study, we found that EBR treatment promoted the activities and transcriptions of energy and sucrose metabolism-related enzymes, maintained higher ATP content and energy status, improved the accumulation of sucrose and hexose. Furthermore, molecular biology assays suggested that PpGATA12 up-regulated transcriptions of sucrose metabolism-related genes including PpSS and PpNI, and energy metabolism-related genes including PpCCO, PpSDH and PpH+-ATPase. These results provided a new insight that the enhancement of chilling resistance in peach fruit by EBR treatment might be closely related to the regulatory role of PpGATA12 on sucrose and energy metabolisms.


Assuntos
Prunus persica , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Brassinosteroides , Temperatura Baixa , Metabolismo Energético , Frutas/genética , Frutas/metabolismo , Prunus persica/genética , Prunus persica/metabolismo , Esteroides Heterocíclicos , Sacarose/metabolismo
3.
Braz. j. biol ; 83: e242603, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1355852

RESUMO

Abstract Transcription factors (TF) are a wide class of genes in plants, and these can regulate the expression of other genes in response to various environmental stresses (biotic and abiotic). In the current study, transcription factor activity in sugarcane was examined during cold stress. Initially, RNA transcript reads of two sugarcane cultivars (ROC22 and GT08-1108) under cold stress were downloaded from SRA NCBI database. The reads were aligned into a reference genome and the differential expression analyses were performed with the R/Bioconductor edgeR package. Based on our analyses in the ROC22 cultivar, 963 TF genes were significantly upregulated under cold stress among a total of 5649 upregulated genes, while 293 TF genes were downregulated among a total of 3,289 downregulated genes. In the GT08-1108 cultivar, 974 TF genes were identified among 5,649 upregulated genes and 283 TF genes were found among 3,289 downregulated genes. Most transcription factors were annotated with GO categories related to protein binding, transcription factor binding, DNA-sequence-specific binding, transcription factor complex, transcription factor activity in RNA polymerase II, the activity of nucleic acid binding transcription factor, transcription corepressor activity, sequence-specific regulatory region, the activity of transcription factor of RNA polymerase II, transcription factor cofactor activity, transcription factor activity from plastid promoter, transcription factor activity from RNA polymerase I promoter, polymerase II and RNA polymerase III. The findings of above results will help to identify differentially expressed transcription factors during cold stress. It also provides a comprehensive analysis of the regulation of the transcription activity of many genes. Therefore, this study provides the molecular basis for improving cold tolerance in sugarcane and other economically important grasses.


Resumo Fatores de transcrição (FT) são uma ampla classe de genes em plantas e podem regular a expressão de outros genes em resposta a vários estresses ambientais (estresses bióticos e abióticos). No presente estudo, a atividade do fator de transcrição na cana-de-açúcar foi examinada durante o estresse pelo frio. Inicialmente, as leituras de transcrição de RNA de duas cultivares de cana-de-açúcar (ROC22 e GT08-1108) sob estresse frio foram baixadas do banco de dados SRA NCBI. As leituras foram alinhadas em um genoma de referência e as análises de expressão diferencial foram realizadas com o pacote R / Bioconductor edgeR. Com base em nossas análises no cultivar ROC22, 963 genes TF foram significativamente regulados positivamente sob estresse pelo frio entre um total de 5.649 genes regulados positivamente, enquanto 293 genes TF foram regulados negativamente entre um total de 3.289 genes regulados negativamente. No cultivar GT08-1108, 974 genes TF foram identificados entre 5.649 genes regulados positivamente e 283 genes TF foram encontrados entre 3.289 genes regulados negativamente. Os fatores de transcrição, em sua maioria, foram anotados com categorias GO relacionadas à ligação de proteína, ligação de fator de transcrição, ligação específica de sequência de DNA, complexo de fator de transcrição, atividade de fator de transcrição em RNA polimerase II, atividade de fator de transcrição de ligação de ácido nucleico, atividade de corepressor de transcrição, sequência específica da região reguladora, atividade do fator de transcrição da RNA polimerase II, atividade do cofator do fator de transcrição, atividade do fator de transcrição do promotor do plastídio, atividade do fator de transcrição do promotor da RNA polimerase I, polimerase II e RNA polimerase III. As descobertas dos resultados acima ajudarão a identificar fatores de transcrição expressos diferencialmente durante o estresse pelo frio. Ele também fornece uma análise abrangente da regulação da atividade de transcrição de muitos genes. Portanto, este estudo fornece base molecular para melhorar a tolerância ao frio em cana-de-açúcar e outras gramíneas economicamente importantes.


Assuntos
Saccharum/genética , Saccharum/metabolismo , Resposta ao Choque Frio/genética , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Temperatura Baixa , Regulação da Expressão Gênica de Plantas , Perfilação da Expressão Gênica
4.
Sci Total Environ ; 856(Pt 1): 158846, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36122719

RESUMO

Urban crime (UC) seriously affects the security and stability of the communities and society. However, the effects of external temperatures on the risk of UC are still confusing. We quantitatively estimated the effects of high and low temperatures on UC in Chicago. After controlling for the confounding factors, we found that high temperature has a positive promoting effect on UC, for non-domestic crime, the effect occurs at lag day 0 with a maximum risk of 1.40 (95%CI, 1.34-1.46) compared to a risk of 1 at temperature of -12.3 °C, and decreased as the lag day increased. The effect of low temperature is not significant for UC. Heat waves above the 99th percentile with a duration of 4.5-5.5 days exert a significant positive impact on non-domestic crime of UC. Our findings confirm the adverse promotion effect of high temperature on UC risk, and effective individual behavior guidance and administrative intervention are of great significance for reducing the risk of UC under specific high temperature environment.


Assuntos
Temperatura Baixa , Temperatura Alta , Temperatura , Chicago/epidemiologia , Crime
5.
Sci Rep ; 12(1): 18353, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36319720

RESUMO

Low-temperature plasmas have quickly emerged as alternative and unconventional types of radiation that offer great promise for various clinical modalities. As with other types of radiation, the therapeutic efficacy and safety of low-temperature plasmas are ubiquitous concerns, and assessing their dose rates is crucial in clinical settings. Unfortunately, assessing the dose rates by standard dosimetric techniques has been challenging. To overcome this difficulty, we proposed a dose-rate assessment framework that combined the predictive modeling of plasma-induced damage in DNA by machine learning with existing radiation dose-DNA damage correlations. Our results indicated that low-temperature plasmas have a remarkably high dose rate that can be tuned by various process parameters. This attribute is beneficial for inducing radiobiological effects in a more controllable manner.


Assuntos
Aprendizado de Máquina , Radiobiologia , Temperatura , Dano ao DNA , Temperatura Baixa
6.
Sensors (Basel) ; 22(21)2022 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-36366222

RESUMO

A low electromagnetic interference (EMI), precision temperature control system for sensitive piezoelectric sensors stabilization and their thermal characteristics research was proposed. Quartz crystal microbalance (QCM) was chosen as the device to be tested. Recently, QCMs found use in many fields of study such as biology, chemistry, and aerospace. They often operate in harsh environments and are exposed to many external factors including temperature fluctuations, to which QCMs are highly susceptible. Such disturbances can cause undesirable resonant frequency shifts resulting in measurement errors that are difficult to eliminate. The proposed solution enables measurements of QCMs thermal characteristics, effectiveness evaluation of temperature compensation methods, and testing of the frequency stability. As a part of the developed solution, two independent temperature regulators were used: first to maintain the QCM crystal at desired temperature, and second to keep the QCM oscillator circuit at fixed temperature. The single regulator consists of a thermoelectric module (TEC) used for both heating and cooling. Two considered TEC driving methods were compared in terms of EMI and their impact on the QCM signal quality. The proposed system was examined for its temperature stabilization capability showing high stability of 11 mKp-p for one hour and the setpoint accuracy of ±15 mK in the full temperature range.


Assuntos
Técnicas Biossensoriais , Técnicas de Microbalança de Cristal de Quartzo , Temperatura , Técnicas de Microbalança de Cristal de Quartzo/métodos , Temperatura Baixa , Técnicas Biossensoriais/métodos
7.
Glob Health Action ; 15(1): 2139340, 2022 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-36345977

RESUMO

We aimed to investigate a hypothesised association between daily mean temperature and the risk of surgery for acute type A aortic dissection (ATAAD). For the period of 1 January 2005 until 31 December 2019, we collected daily data on mean temperatures and date of 2995 operations for ATAAD at 10 Nordic cities included in the Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) collaboration. Using a two-stage time-series approach, we investigated the association between hot and cold temperatures relative to the optimal temperature and the rate of ATAAD repair in the selected cities. The relative risks (RRs) of cold temperatures (≤-5°C) and hot temperatures (≥21°C) compared to optimal temperature were 1.47 (95% CI: 0.72-2.99) and 1.43 (95% CI: 0.67-3.08), respectively. In line with previous studies, we observed increased risk at cold and hot temperatures. However, the observed associations were not statistically significant, thus only providing weak evidence of an association.


Assuntos
Aneurisma Dissecante , Aneurisma Aórtico , Humanos , Aneurisma Aórtico/epidemiologia , Aneurisma Aórtico/cirurgia , Incidência , Temperatura , Estudos Retrospectivos , Fatores de Risco , Doença Aguda , Resultado do Tratamento , Aneurisma Dissecante/epidemiologia , Aneurisma Dissecante/cirurgia , Temperatura Alta , Temperatura Baixa
9.
J Chem Phys ; 157(17): 171101, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36347666

RESUMO

The advent of ion traps as cooling devices has revolutionized ion spectroscopy as it is now possible to efficiently cool ions vibrationally and rotationally to levels where truly high-resolution experiments are now feasible. Here, we report the first results of a new experimental apparatus that couples a cryogenic 3D Paul trap with a laser vaporization cluster source for high-resolution photoelectron imaging of cold cluster anions. We have demonstrated the ability of the new apparatus to efficiently cool BiO- and BiO2 - to minimize vibrational hot bands and allow high-resolution photoelectron images to be obtained. The electron affinities of BiO and BiO2 are measured accurately for the first time to be 1.492(1) and 3.281(1) eV, respectively. Vibrational frequencies for the ground states of BiO and BiO2, as well as those for the anions determined from temperature-dependent studies, are reported.


Assuntos
Temperatura Baixa , Ânions/química , Íons , Temperatura , Transição de Fase
10.
Adv Appl Microbiol ; 121: 1-26, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36328730

RESUMO

Temperature-dependent composting is a challenging task but is worthy if it is done in the right manner. Cold composting has been known to be practiced since ancient times but there were not enough advancements to overcome the long mesophilic phase and bring the compost maturation to a short period. The composting processes that have been well practiced are discussed and the role of psychrotrophic bacteria that produce cold tolerant hydrolytic enzymes has been highlighted. In this chapter, the mechanism of substrate degradation has been elaborated to better understand the need of specific bacteria for a specific kind of substrate allowing fast and efficient decomposition. This chapter attempts to pave an appropriate way and suggest the best-suited method of composting for efficient production of compost by the conservation of heat in cold regions.


Assuntos
Compostagem , Solo , Bactérias/genética , Temperatura Baixa , Temperatura
11.
Sci Rep ; 12(1): 18474, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36323816

RESUMO

Epidemiological studies have reported the association between extreme temperatures and adverse reproductive effects. However, the susceptible period of exposure during pregnancy remains unclear. This study aimed to assess the impact of extreme temperature on the stillbirth rate. We performed a time-series analysis to explore the associations between temperature and stillbirth with a distributed lag nonlinear model. A total of 22,769 stillbirths in Taiwan between 2009 and 2018 were enrolled. The mean stillbirth rate was 11.3 ± 1.4 per 1000 births. The relative risk of stillbirth due to exposure to extreme heat temperature (> 29 °C) was 1.18 (95% CI 1.11, 1.25). Pregnant women in the third trimester were most susceptible to the effects of extreme cold and heat temperatures. At lag of 0-3 months, the cumulative relative risk (CRR) of stillbirth for exposure to extreme heat temperature (29.8 °C, 97.5th percentile of temperature) relative to the optimal temperature (21 °C) was 2.49 (95% CI: 1.24, 5.03), and the CRR of stillbirth for exposure to extreme low temperature (16.5 °C, 1st percentile) was 1.29 (95% CI: 0.93, 1.80). The stillbirth rate in Taiwan is on the rise. Our findings inform public health interventions to manage the health impacts of climate change.


Assuntos
Calor Extremo , Natimorto , Feminino , Humanos , Gravidez , Temperatura , Natimorto/epidemiologia , Terceiro Trimestre da Gravidez , Calor Extremo/efeitos adversos , Temperatura Baixa , Temperatura Alta
12.
Sci Rep ; 12(1): 19536, 2022 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-36376445

RESUMO

Cold stress is a critical environmental challenge that affects an organism's fitness-related traits. In Drosophila, increased resistance to specific environmental stress may lead to increased resistance to other kinds of stress. In the present study, we aimed to understand whether increased cold stress resistance in Drosophila melanogaster can facilitate their ability to tolerate other environmental stresses. For the current study, we used successfully selected replicate populations of D. melanogaster against cold shock and their control population. These selected populations have evolved several reproductive traits, including increased egg viability, mating frequency, male mating ability, ability to sire progenies, and faster recovery for mating latency under cold shock conditions. In the present work, we investigated egg viability and mating frequency with and without heat and cold shock conditions in the selected and their control populations. We also examined resistance to cold shock, heat shock, desiccation, starvation, and survival post-challenge with Staphylococcus succinus subsp. succinus PK-1 in the selected and their control populations. After cold-shock treatment, we found a 1.25 times increase in egg viability and a 1.57 times increase in mating frequency in the selected populations compared to control populations. Moreover, more males (0.87 times) and females (1.66 times) of the selected populations survived under cold shock conditions relative to their controls. After being subjected to heat shock, the selected population's egg viability and mating frequency increased by 0.30 times and 0.57 times, respectively, compared to control populations. Additionally, more selected males (0.31 times) and females (0.98 times) survived under heat shock conditions compared to the control populations. Desiccation resistance slightly increased in the females of the selected populations relative to their control, but we observed no change in the case of males. Starvation resistance decreased in males and females of the selected populations compared to their controls. Our findings suggest that the increased resistance to cold shock correlates with increased tolerance to heat stress, but this evolved resistance comes at a cost, with decreased tolerance to starvation.


Assuntos
Drosophila melanogaster , Inanição , Animais , Feminino , Masculino , Drosophila melanogaster/genética , Resposta ao Choque Frio , Adaptação Fisiológica , Evolução Biológica , Reprodução , Drosophila , Temperatura Baixa
13.
Int J Mol Sci ; 23(21)2022 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-36361995

RESUMO

Rice (Oryza sativa L.) is a chilling-sensitive staple food crop, and thus, low temperature significantly affects rice growth and yield. Many studies have focused on the cold shock of rice although chilling acclimation is more likely to happen in the field. In this paper, a genome-wide association study (GWAS) was used to identify the genes that participated in cold stress and chilling accumulation. A total of 235 significantly associated single-nucleotide polymorphisms (SNPs) were identified. Among them, we detected 120 and 88 SNPs for the relative shoot fresh weight under cold stress and chilling acclimation, respectively. Furthermore, 11 and 12 quantitative trait loci (QTLs) were identified for cold stress and chilling acclimation, respectively, by integrating the co-localized SNPs. Interestingly, we identified 10 and 15 candidate genes in 11 and 12 QTLs involved in cold stress and chilling acclimation, respectively, and two new candidate genes (LOC_Os01g62410, LOC_Os12g24490) were obviously up-regulated under chilling acclimation. Furthermore, OsMYB3R-2 (LOC_Os01g62410) that encodes a R1R2R3 MYB gene was associated with cold tolerance, while a new C3HC4-type zinc finger protein-encoding gene LOC_Os12g24490 was found to function as a putative E3 ubiquitin-protein ligase in rice. Moreover, haplotype, distribution, and Wright's fixation index (FST) of both genes showed that haplotype 3 of LOC_Os12g24490 is more stable in chilling acclimation, and the SNP (A > T) showed a difference in latitudinal distribution. FST analysis of SNPs in OsMYB3R-2 (LOC_Os01g62410) and LOC_Os12g24490 indicated that several SNPs were under selection in rice indica and japonica subspecies. This study provided new candidate genes in genetic improvement of chilling acclimation response in rice.


Assuntos
Oryza , Resposta ao Choque Frio/genética , Plântula/genética , Estudo de Associação Genômica Ampla , Temperatura Baixa , Aclimatação/genética
14.
Soc Sci Med ; 314: 115461, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36327633

RESUMO

Cold homes are associated with a range of serious health conditions as well as excess winter mortality. Despite a comparatively mild climate cold homes are a significant problem in the UK, with a recent estimate finding that over one-quarter of low-income households had been unable to adequately heat their home in winter 2022. The magnitude of cold housing in a country that benefits from a mild climate indicates indifference towards, or acceptance of, a significant minority of people living in inadequate conditions on the part of policy makers. Cold homes are therefore a source of social harm. Recent changes to the household energy price cap, the rising cost of living, the ongoing effects of the benefit cap, and below inflation uprating to social security benefits is likely to greatly exacerbate this issue. In this research we use data from the UK Household Longitudinal Study to explore whether living in a cold home causes mental health harm. We control for mental distress and housing temperature on entry to the survey in order to account for the potentially bi-directional relationship. Multilevel discrete-time event history models show that the transition into living in a home that is not suitably warm is associated with nearly double the odds of experiencing severe mental distress for those who had no mental distress at the beginning of the survey; and over three times the odds of severe mental distress for those previously on the borderline of severe mental distress. These results show the significant costs of failing to ensure that people are able to live in homes in which they are able to live comfortably by even the most basic standards. These costs will be felt not just individually, but also more broadly in terms of increased health spending and reduced working.


Assuntos
Temperatura Baixa , Saúde Mental , Humanos , Estudos Longitudinais , Análise Multinível , Reino Unido/epidemiologia
15.
Nat Commun ; 13(1): 6616, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36379936

RESUMO

El Niño-Southern Oscillation (ENSO) features strong warm events in the eastern equatorial Pacific (EP), or mild warm and strong cold events in the central Pacific (CP), with distinct impacts on global climates. Under transient greenhouse warming, models project increased sea surface temperature (SST) variability of both ENSO regimes, but the timing of emergence out of internal variability remains unknown for either regime. Here we find increased EP-ENSO SST variability emerging by around 2030 ± 6, more than a decade earlier than that of CP-ENSO, and approximately four decades earlier than that previously suggested without separating the two regimes. The earlier EP-ENSO emergence results from a stronger increase in EP-ENSO rainfall response, which boosts the signal of increased SST variability, and is enhanced by ENSO non-linear atmospheric feedback. Thus, increased ENSO SST variability under greenhouse warming is likely to emerge first in the eastern than central Pacific, and decades earlier than previously anticipated.


Assuntos
Temperatura Baixa , El Niño Oscilação Sul
16.
Crit Care ; 26(1): 356, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36380332

RESUMO

BACKGROUND: Targeted temperature management (TTM) is recommended following cardiac arrest; however, time to target temperature varies in clinical practice. We hypothesised the effects of a target temperature of 33 °C when compared to normothermia would differ based on average time to hypothermia and those patients achieving hypothermia fastest would have more favorable outcomes. METHODS: In this post-hoc analysis of the TTM-2 trial, patients after out of hospital cardiac arrest were randomized to targeted hypothermia (33 °C), followed by controlled re-warming, or normothermia with early treatment of fever (body temperature, ≥ 37.8 °C). The average temperature at 4 h (240 min) after return of spontaneous circulation (ROSC) was calculated for participating sites. Primary outcome was death from any cause at 6 months. Secondary outcome was poor functional outcome at 6 months (score of 4-6 on modified Rankin scale). RESULTS: A total of 1592 participants were evaluated for the primary outcome. We found no evidence of heterogeneity of intervention effect based on the average time to target temperature on mortality (p = 0.17). Of patients allocated to hypothermia at the fastest sites, 71 of 145 (49%) had died compared to 68 of 148 (46%) of the normothermia group (relative risk with hypothermia, 1.07; 95% confidence interval 0.84-1.36). Poor functional outcome was reported in 74/144 (51%) patients in the hypothermia group, and 75/147 (51%) patients in the normothermia group (relative risk with hypothermia 1.01 (95% CI 0.80-1.26). CONCLUSIONS: Using a hospital's average time to hypothermia did not significantly alter the effect of TTM of 33 °C compared to normothermia and early treatment of fever.


Assuntos
Reanimação Cardiopulmonar , Hipotermia Induzida , Hipotermia , Parada Cardíaca Extra-Hospitalar , Humanos , Parada Cardíaca Extra-Hospitalar/terapia , Temperatura Baixa , Febre/terapia , Resultado do Tratamento
17.
PLoS One ; 17(11): e0276748, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36383516

RESUMO

The present study assessed heat-escape/cold-seeking behavior during thermoregulation in mice and the influence of TRPV1 channels. Mice received subcutaneous injection of capsaicin (50 mg/kg; CAP group) for desensitization of TRPV1 channels or vehicle (control [CON] group). In Experiment 1, heat-escape/cold-seeking behavior was assessed using a newly developed system comprising five temperature-controlled boards placed in a cross-shape. Each mouse completed three 90-min trials. In the trials, the four boards, including the center board, were set at either 36˚C, 38˚C, or 40˚C, while one corner board was set at 32˚C, which was rotated every 5 min. In Experiment 2, mice were exposed to an ambient temperature of 37˚C for 30 min. cFos expression in the preoptic area of the hypothalamus (POA) was assessed. In Experiment 1, the CON group stayed on the 32˚C board for the longest duration relative to that on other boards, and intra-abdominal temperature (Tabd) was maintained. In the CAP group, no preference for the 32˚C board was observed, and Tabd increased. In Experiment 2, cFos expression in the POA decreased in the CAP group. Capsaicin-induced desensitization of TRPV1 channels suppressed heat-escape/cold-seeking behavior in mice during heat exposure, resulting in hyperthermia. In conclusion, our findings suggest that heat sensation from the body surface may be a key inducer of thermoregulatory behaviors in mice.


Assuntos
Capsaicina , Temperatura Alta , Camundongos , Animais , Capsaicina/farmacologia , Canais de Cátion TRPV/genética , Canais de Cátion TRPV/metabolismo , Regulação da Temperatura Corporal/fisiologia , Temperatura Baixa
18.
Int J Hyperthermia ; 39(1): 1421-1439, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36396127

RESUMO

BACKGROUND: A necessary precondition for a successful microwave hyperthermia (HT) treatment delivered by phased arrays is the ability of the HT applicator to selectively raise the temperature of the entire tumor volume. SAR-based treatment plan (HTP) optimization methods exploit the correlation between specific absorption rate (SAR) and temperature increase in order to determine the set of steering parameters for optimal focusing, while allowing for lower model complexity. Several cost functions have been suggested in the past for this optimization problem. However, their correlation with high and homogeneous tumor temperatures remains sub-optimal in many cases. Previously, we proposed the hot-to-cold spot quotient (HCQ) as a novel cost function for SAR-based HTP optimization and showed its potential to address these issues. MATERIALS AND METHODS: In this work, we validate the HCQ on a standard ESHO patient repository within single and multi-frequency contexts. We verify its correlation with clinical SAR and temperature indexes, and compare it to HTPs obtained using a commonly accepted cost-function for SAR-based HTP (hot-spot to target quotient, HTQ). RESULTS AND DISCUSSION: The results show that low HCQ values produce better SAR (TC50, TC75) and temperature metrics (T50, T90) than HTQ in most patient models and frequency settings. For the deep-seated tumors, the correlation between the clinical indicators and 1/HCQ is more favorable than the correlation exhibited by 1/HTQ. CONCLUSION: The validation confirms the ability of HCQ to promote target coverage and hot-spot suppression in SAR-based HTP optimization, resulting in higher SAR and temperature indexes for deep-seated tumors.


Assuntos
Hipertermia Induzida , Neoplasias , Humanos , Micro-Ondas/uso terapêutico , Hipertermia Induzida/métodos , Hipertermia , Temperatura Baixa , Neoplasias/terapia
19.
Phys Rev Lett ; 129(17): 178001, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36332249

RESUMO

We present the operational principle for a refrigerator that uses inertial effects in active Brownian particles to locally reduce their (kinetic) temperature by 2 orders of magnitude below the environmental temperature. This principle exploits the peculiar but so-far unknown shape of the phase diagram of inertial active Brownian particles to initiate motility-induced phase separation in the targeted cooling regime only. Remarkably, active refrigerators operate without requiring isolating walls opening the route toward using them to systematically absorb and trap, e.g., toxic substances from the environment.


Assuntos
Temperatura Baixa , Refrigeração , Temperatura
20.
Proc Natl Acad Sci U S A ; 119(48): e2215977119, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36409918

RESUMO

Recent advances in thermophotovoltaic (TPV) power generation have produced notable gains in efficiency, particularly at very high emitter temperatures. However, there remains substantial room for improving TPV conversion of waste, solar, and nuclear heat streams at temperatures below 1,100°C. Here, we demonstrate the concept of transmissive spectral control that enables efficient recuperation of below-bandgap photons by allowing them to transmit through the cell to be absorbed by a secondary emitter. We fabricate a semitransparent TPV cell consisting of a thin InGaAs-InP heterojunction membrane supported by an infrared-transparent heat-conducting substrate. The device absorbs less than 1% of below-bandgap radiation, resulting in a TPV efficiency of 32.5% at an emitter temperature of 1,036°C. To our knowledge, this represents an 8% absolute improvement (~33% relative) in efficiency relative to the best TPV devices at such low temperatures. By enabling near-zero photon loss, the semitransparent architecture facilitates high TPV efficiencies over a wide range of applications.


Assuntos
Temperatura Baixa , Temperatura Alta , Temperatura
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