Sharp Decrease Research Articles

Synthesizing Carbon Nanodots for Longer Wave Quantum Emission in Biological Applications

Carbon quantum dots are activated carbon particles with a size of 1–10 nm that have unique properties such as stable temperature, high stability in the environment, and special chemical properties. Their emission spectrum is always wide and towards long wavelengths with a sharp decrease in intensity. In this work, carbon quantum dots with long emission wavelengths and productivity improvements for biological applications are investigated. In order to reduce the experiments and obtain the best method, the experiment is designed with a mini fever and screened between different factors. In addition, complete factorial screening is performed between three factors (time, OPDA, and ALCL3) and the results demonstrated that time factor and OPDA are more effective. Using a UV–vis fluorescence device, the samples were examined and with the software (Origin Probe), the diagrams of each sample are drawn and their quantum efficiency is recorded. Quantum efficiency is evaluated at 575 nm and 618 nm. Then, the TEM test examined the synthesized nanoparticles’ size. The average particle size synthesized in this project is reported to be about 3 nm. The effect of synthesized carbon quantum dots on fibroblast cells is investigated and the results demonstrated that the survival of these cells after 24 h of incubation with synthesized carbon dots could be more than 90%. As a result, these nanoparticles can be used in biological applications such as bioimaging as a diagnostic sensor for methylene blue. On the other hand, it was found that the nanoparticles synthesized in the presence of HCL have higher strength and wavelength.

Experimental study on the spray characteristics of high-pressure liquid ammonia under different ambient conditions

As a promising carbon-free fuel, ammonia is expected to be widely applied in internal combustion engines. However, the physical properties of ammonia are quite different from those of conventional fuels, which leads to different spray characteristics. In this paper, the ammonia spray under injection pressure as high as 80 MPa was visualized by the diffused back-illumination imaging method, and the liquid ammonia spray characteristics under different ambient pressures and ambient temperatures were analyzed. The liquid spray penetration length, cone angle and tip velocity calculated from the spray images provide a reference database for numerical simulation. The results show that the development characteristics of liquid ammonia spray are significantly different under flare flash boiling, transitional flash boiling and non-flash boiling conditions. Flash boiling (especially flare flash boiling) inhibits the initial liquid spray penetration. The spray tip velocity increases first and then gradually decreases under flash boiling conditions. Ammonia spray has obvious radial expansion at the initial stage of flare flash boiling and the spray contour under flare flash boiling conditions is noticeably distorted, forming an obvious dilute region. With the increase of ambient pressure, the intensity of flash boiling reduces, the dilute region gradually disappears, and the distortion of the spray contour gradually weakens. Under non-flash boiling conditions, ammonia spray presents a dense and regular shape; there is no spray acceleration but a sharp decrease in spray tip velocity at the initial stage, and then the spray penetrates forward at a similar velocity. The spray penetration velocity decreases significantly with the increase of ambient pressure. The increase in ambient temperature accelerates the vaporization of ammonia spray. The liquid spray penetration length decreases and maintains with only slight fluctuations during the injection process as the ambient temperature increases from 300 K to 600 K because the vaporization rate and penetration velocity reach a balance.

A novel combining Raman-photoluminescence method to characterize the brittle and plastic states of fused silica based on nanoscale ring structures and atomic point defects

Fused silica has been widely used in many key technical domains. However, the inevitably induced micron-sized brittle fractures during manufacturing processes seriously affect its service performance. Scanning electron and atomic force microscopes are mainly employed to estimate the brittle and plastic states (BPS) of the precise fused silica components, which would put strict demands on the dimensions of detected components and damage the detected surfaces. Herein, the evolution rules of the D2 characteristic peak intensities in Raman spectra corresponding to three-fold rings with the BPS were explored. Interestingly, it is found that the D2 peak intensity first greatly increases in brittle-plastic mixing zones and then sharply decreases in brittle zones. The evolution mechanisms of the nanoscale rings with respect to the BPS were further revealed using the molecular dynamics modeling. The enveloping-space compression of rings and the ring conversion from large- to small rings are found to be the leading factors of the significant increase of the three-fold rings in brittle-plastic mixing zones. And the abrupt destruction of ring structures due to amounts of damaged Si-O bonds in brittle zones contributes to the sharp decrease of the three-fold rings. Based on the evolution rules of the nanoscale rings with the BPS, the brittle-plastic mixing zones could be distinguished from the brittle and plastic zones. It also implies that the rings, especially three-fold rings may dominate the BPS. Moreover, the change laws of the photoluminescence properties with BPS were also studied. It has been found that the photoluminescence envelope area sharply increases with the BPS. It indicates that the concentrations of the atomic point defects would sharply increase with the BPS. Based on the evolution rules of the atomic point defects with the BPS, the brittle and plastic zones could be distinguished. Therefore, a novel Raman-photoluminescence combined method was proposed to characterize the BPS. Finally, its wide applicability was also verified in various specific cases. To sum up, the investigation develops a novel spectral method to effectively characterize the BPS. It is significant for the early warning of the material brittle fractures and the nondestructive characterization of fused silica during the manufacturing processes, which could vigorously promote the further application of fused silica components in various fields.

Global Impact of COVID-19 Pandemic on Gastrointestinal Infections: A Scoping Review.

During the COVID-19 pandemic, nonpharmaceutical public health interventions (NPIs) were implemented worldwide to control the spread of severe acute respiratory syndrome coronavirus 2. However, the incidence of other pathogens, including gastrointestinal (GI) pathogens, was also affected. Here, we reviewed studies assessing the impact of NPIs during the COVID-19 pandemic on the incidence of GI infections, particularly foodborne infections. A systems literature search was conducted in May 2023, using Living Evidence on COVID-19 (COAP) and Scopus. Articles were identified and selected through a screening process with inclusion and exclusion criteria based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Data were extracted from each full-text article included in the review. Parameters included were GI viruses, GI bacteria, NPIs against the COVID-19 pandemic, and the associated impact of NPIs on GI pathogens. A total of 42 articles were included in the review, representing 18 countries. Overall, a larger reduction was observed for viral GI infections compared with bacterial GI infections during the COVID-19 pandemic, particularly for norovirus. For bacterial GI infections, Campylobacter and nontyphoidal Salmonella were the most frequently detected pathogens in the majority of the studies, with the largest reduction observed for Shigella and Shiga toxin-producing Escherichia coli infections. The sharp decrease in GI viral infections in most of the included countries is suggested to be related to the disruption of person-to-person transmission due to several implemented interventions (e.g., social distancing and hand hygiene). GI bacterial pathogens, more commonly transmitted via the foodborne route, were least impacted, and their reduction is associated with closure of food-providing settings and travel restrictions. However, the observed changes appear to be multifactorial; alterations in health-care-seeking behaviors and in routinary diagnostic testing have undeniably played a significant role, affecting national surveillance systems. Therefore, although NPIs likely had a substantial impact on the burden of GI infectious diseases, the extent of the true change cannot be fully assessed.

The eastward intrusion of the Lena River into the East Siberian Sea since the early Holocene

The sedimentary environments and material sources of the eastern and northeastern Lena Delta differ in coarse-grained components and garnet geochemistry, particularly in the Buor-Khaya Bay, where the material composition is primarily influenced by the Lena River, while the Yana Bay sediment is controlled by the Yana River. Analysis of detrital minerals in core LV83–32-3, located in northern Yana Bay, indicates dominant primarily fluvial input from the Yana River, with secondary contributions from the Lena River and minor inputs from coastal permafrost erosion since the early Holocene. During the sea-level rise period from 8.5 to 5 ka, four significant fluvial discharge events from the Yana River were identified, marked by high mica contents, associated with multiple climate warming events. From ∼5 to 1.6 ka, an increasing Lena River runoff transported coastal permafrost material via river flow or river ice, evident in a gradual rise in plagioclase content. After 1.6 ka, a sharp decrease in hypersthene and garnet contents suggests reduced Lena River discharge, coinciding with a similar decline in hypersthene content in the core of the East Siberian Sea since 1.8 ka. Two prominent Lena River fluvial events, dated to 7.1 and 3.7 ka, are identified by the event layers containing minerals typical of the Lena River, rich in hypersthene, garnet and zircon, along with substantial coarse-grained debris such as quartz, plagioclase, siderite and clayey tubes. These two events are also recorded in the East Siberian Sea. The 7.1 ka discharge event may coincide with the separation of the New Siberian Islands from the mainland, while the 3.7 ka event represents a widely distributed Lena River floodplain event.

Widely targeted metabolomics and SPME-GC-MS analysis revealed the quality characteristics of non-volatile/volatile compounds in Zheng'an Bai tea.

As albino tea under the geographical protection of agricultural products, Zheng'an Bai tea is not only rich in amino acids, polyphenols and other beneficial components for the human body, but also its leaf color will turn green as the temperature gradually rises, thus causing changes in the quality characteristics of tea leaves. However, these changing characteristics have not yet been revealed. In-depth quality analysis was carried out on the fresh leaves of Zheng'an Bai tea at four different developmental stages and four samples from the processing stage through extensive targeted metabolomics and SPME-GC-MS analysis. In this study, a total of 573 non-volatile metabolites were detected from the fresh leaves and processing samples of Zheng'an Bai tea, mainly including 96 flavonoids, 75 amino acids, 56 sugars and alcohols, 48 terpenoids, 46 organic acids, 44 alkaloids, and 39 polyphenols and their derivatives. In fresh leaves, the most significant differential metabolites (VIP > 1, p < 0.05) among different samples mainly include substances such as ethyl gallate, theaflavin, isovitexin and linalool, while the main differential metabolites of samples in the processing stage include alkaloids, polyphenols and flavonoids such as zarzissine, methyl L-Pyroglutamate, theaflavin 3,3'-digallate, euscaphic acid and ethyl gallate. Overall, substances such as sugars and alcohols, alkaloids and polyphenols show the greatest differences between fresh leaves and the processing process. Meanwhile, 97 kinds of volatile metabolites were detected in these samples, most of which had a higher content in the fresh leaves. Moderate spreading is conducive to the release of the aroma of tea leaves, but fixation causes a sharp decrease in the content of most volatile metabolites. Ultimately, 9 volatile substances including geraniol, linalool, nerolidol, jasmone, octanal, 1-Nonanal, heptaldehyde, methyl salicylate and 1-Octen-3-ol were identified as the key aroma components (OAV >1) of Zheng'an Bai tea. In conclusion, this study has for the first time comprehensively revealed the quality change characteristics of fresh leaves at different developmental stages and during the processing of Zheng'an Bai tea, and provided a foundation for further process improvement.

Effect of In Vitro Low-Impulse Laser Irradiation on Morphofunctional Properties of Human Platelets.

We studied morphofunctional features of human platelets exposed in vitro to low-pulse laser radiation (LPLR) with different wavelengths. Platelet-rich plasma (PRP) was irradiated at wavelengths of 635, 488, and 355 nm. LPLR with λ=635 nm and 1 W power after 10 min caused degranulation of many platelets, formation of small platelet conglomerates, and accelerated platelet adhesion on glass. LPLR with λ=635 nm and 2 mW and LPLR with λ=488 nm did not cause significant changes in the morphofunctional platelet status. LPLR with λ=355 nm induced massive platelets' deformation, sharp decrease in their morphofunctional status without activation.

Study on thermal damage characteristics and micromechanical behavior of structures induced by spontaneous combustion of low-rank coal

Thermal damage induced by coal spontaneous combustion (CSC) has a significant impact on its development. In this study, low-rank coals were heat-treated (25–500 °C). Experiments such as nuclear magnetic resonance, scanning electron microscopy, and uniaxial compression were used to visualize and quantify the evolution of pore structure and structural strength during CSC. A multi-component discrete-element model of coal thermal fracture was developed and a sensitivity analysis of the micromechanical behavior of CSC was carried out. The results showed that during CSC, the micropores in coal gradually evolved into mesopores or macropores, and the pore diameter, porosity and permeability can be increased to 5.51 μ m, 21.05 % and 1.51 mD respectively with the temperature. Significant thermal damage occurred in low-rank coal at 100 °C, leading to a sharp decrease in its load-bearing capacity, which made it easier to reach the damage condition and produce more cracks. And then the thermal damage was fluctuating with the increase of temperature. From 100 °C to 500 °C, the micromechanical behavior of low-rank coal is similar, and the variation of the critical value with temperature is small. The study results can serve as a reference for controlling coal fires.

Sharp Decrease of the Effective Cosmological Constant in the Poincare Gauge Theory of Gravity with Minimal Self-Acting Scalar Field

Sharp Decrease of the Effective Cosmological Constant in the Poincare Gauge Theory of Gravity with Minimal Self-Acting Scalar Field

Energy-efficient power summator of hydrogen fuel cell

The most important task after the end of the COVID-18 pandemic is to solve the problem of preserving the planet's climate and improving the environment in populated areas (metropolises, cities, towns). The most important principles contributing to the solution of this problem were set out in the Centenary Memorandum (A.L. Gusev, T.N. Veziroglu, J. Sheffield and other scientists, 2006). The most important element of hydrogen energy is the fuel cell. Fuel cells are produced in different modifications, they can be different in principle of operation, and different in size and DC generation power. Large consumers, both stationary and autonomous, at different times consume different amounts of power from the minimum value to the average and maximum. Obviously, if an object consumes minimal power over a given period of time, then there is no point in generating maximum power. Typically, fuel cells are designed for a specific power range. In connection with the above, in practice situations arise when it is necessary, depending on energy consumption, to connect hydrogen fuel cells of various powers.A new principle for constructing energy-efficient and small-sized summing step-up capacitor DC-DC converters (SSCC) capable of not only converting the level of output voltages, but also summing the powers of several sources in a common load is proposed. The sources are hydrogen fuel cells converted into constant voltage sources, different in output parameters and having a common grounded bus. The principle of multi-cycle construction of SSСС is proposed, which provides additional improvement of their weight and size characteristics under conditions of increased source power. It is shown that the effect is achieved by a multiple increase in the conversion frequency of individual SSСС modules and the practical elimination of a bulky output capacitor due to a sharp decrease and multiple increase in the frequency of the first harmonic of the total output current. Analytical expressions have been obtained that make it possible to calculate the parameters of the reactive elements of the SSСС, to analyze and quantify their efficiency.

Continuous Use During Disuse: Mechanisms and Effects of Spontaneous Activity of Unloaded Postural Muscle.

In most mammals, postural soleus muscles are involved in the maintenance of the stability of the body in the gravitational field of Earth. It is well established that immediately after a laboratory rat is exposed to conditions of weightlessness (parabolic flight) or simulated microgravity (hindlimb suspension/unloading), a sharp decrease in soleus muscle electrical activity occurs. However, starting from the 3rd day of mechanical unloading, soleus muscle electrical activity begins to increase and reaches baseline levels approximately by the 14th day of hindlimb suspension. This phenomenon, observed in the course of rat hindlimb suspension, was named the "spontaneous electrical activity of postural muscle". The present review discusses spinal mechanisms underlying the development of such spontaneous activity of rat soleus muscle and the effect of this activity on intracellular signaling in rat soleus muscle during mechanical unloading.

Magnetic structure and magnetic properties of Fe3BO5 and Mn3BO5 ludwigites

The magnetic ground state of transition metal ludwigites Fe3BO5and Mn3BO5was studied via the combination of representations analysis and the following DFT total energy calculations of possible magnetic configurations. The distinct in the magnetic properties of ludwigites was analyzed through estimation of exchange constants. The pressure evolution of manganese magnetic moments in Mn3BO5reveals the site-dependent behavior of magnetic moments. The manganese magnetic moments in 4-2-4 triads experience the sharp decrease above the pressure of 50 GPa, whereas magnetic moments in 3-1-3 triads have the weak dependence on pressure. The pressure-induced transition from half-metal state to metal state is also being found in Mn3BO5.

Effect of disorder on anomalous Hall effect and spin Hall magnetoresistance in the ferrimagnetic film

Ferrimagnets have attracted increasing attention in spintronics due to the possibility of easy manipulation by magnetic or electric fields. We report the anomalous Hall effect (AHE) and spin Hall magnetoresistance (SMR) in ferrimagnetic Mn1.77Co0.44V0.83Al0.96 (MCVA) films, which are sensitive to the disorder of the film. As the thickness of the film increases, the film gradually transitions from the disordered to the ordered state, resulting in the anomalous Hall resistivity changes from negative to positive. By separating their distinct the contributions to the AHE, we demonstrate that the thickness dependence originates from the competition between the skew scattering contribution and the sum of the side jump and intrinsic contributions. Moreover, under the effect of disorder, the dependence of the SMR ratio on thickness is more complex, and a critical level of disorder may lead to a sharp decrease in the SMR ratio. Our research reveals the impact of disorder on spin transport and provides a pathway for the design of ferrimagnetic Heusler alloy-based spintronic devices.

Can peer review accolade awards motivate reviewers? A large-scale quasi-natural experiment

The utilization of accolade awards to motivate reviewers is widespread, but their effectiveness remains uncertain. We aim to explore how receiving an accolade award affects reviewers’ subsequent number of reviews. In contrast to small-scale, unrepresentative experiments, we perform a large-scale, global, and all-disciplinary analysis based on quasi-natural experiments. By integrating the Publons, ORCID, MAG, SciSciNet, and OpenAlex databases, a large dataset that tracks the reviewers’ annual number of reviews and their bibliometric indicators is compiled, encompassing 179,794 individuals. Among them, 6605 individuals who receive the “Publons Global Peer Review Award” in 2018 are constituted as the experimental group. Those non-winners are then matched to form a control group. Using propensity score matching (PSM), 711 and 762 reviewers are matched as the experimental and control groups respectively. An analysis employing the difference-in-differences (DiD) method is conducted to examine the impact of an accolade award on reviewers’ subsequent number of reviews. It is found that, following the receipt of an accolade award, reviewers, on average, reviews about four fewer manuscripts, with the reduction exhibiting a V-shaped pattern. Additional analyses are conducted to examine how individual differences and socio-economic factors influence the awarding effects. Besides, we analyze the mechanisms underlying the awarding effect and propose strategies to motivate reviewers. In brief, the sharp decrease in marginal utility of accolades, the voluntary nature of peer review, and the unexpected properties of accolade awards are the potential mechanisms that generate the negative effect. The academic community should reassess the existing incentive strategies for reviewers.

Water-Vapor-Triggered Dual-Mode Optical Responses in Rare-Earth-Doped Hollow Nanospheres.

Multimode responsive optical materials are garnering ever-increasing attention due to their diverse applications. This work showcases a film assembled with rare-earth-doped CaF2 hollow nanospheres that exhibit water-vapor-triggered dual-mode optical responses. Upon exposure to flowing water vapor, the film rapidly (less than 1.5 s for a 7.7 μm thickness) transitions to a transparent state and simultaneously undergoes a sharp decrease in the photoluminescence intensity. Both of these changes fully reverse upon water evaporation, demonstrating an impressive reversibility over at least 200 cycles. The water-vapor-induced dual-mode responses are attributed to the altered incident light propagation path stemming from the similar refractive indices between CaF2 and water, coupled with the water-induced energy loss of the rare-earth ions. The fabrication of encryption patterns displaying separate signals in multiple channels, as well as the demonstration of noncontact sensing for water vapor distribution, underscore the promising application potential of this dual-mode responsive system.

Is the decline of war a delusion? The long peace phenomenon and the modernization peace – the explanation that refutes or subsumes all others

ABSTRACT The wars in Ukraine and the Middle East, and the China challenge, revive the question of whether the world is becoming more peaceful. Realists’ claim that we told you so compares oranges with cabbage. Today’s world is divided into a “zone of peace”, encompassing all the developed countries, and a “zone of war”, comprising less developed countries. Within the former, interstate wars, civil wars, and the “security dilemma” itself have all disappeared. The Long Peace since 1945 is widely attributed to nuclear deterrence. However, the sharp decrease in war had begun during the 19th century. The effect of industrialization is the greatest lacuna in IR theory. The Malthusian Trap that plagued premodern societies has been broken. Wealth is no longer finite and a zero-sum game. This transformation has made democracies as well as nondemocracies fight much less, and has sharply increased international trade. It underlies both the democratic/liberal and capitalist/trade interdependence peace.

Numerical study of dimpled structures on heat transfer deterioration mitigation with supercritical CO2 heated in vertical tube

To suppress heat transfer deterioration (HTD) in supercritical CO2 Rankine cycle, the flow and heat transfer characteristics of supercritical CO2 in elliptical dimple tubes (ET) are numerically investigated by the Shear-Stress Transport k-ω model in Fluent software. The ET based on a smooth tube with length of 2000 mm and diameter of 9 mm. The operating conditions consist of pressure 8 MPa, mass flux 100–700 kg/(m2∙s), and heat flux 70–300 kW/m2. The results indicate that dimples can prevent sharp decrease in radial density near-wall where HTD originally occurs, which mitigates buoyancy effect and improves heat transfer performance. Compared to staggered dimple, inline elliptical dimple tubes exhibit a better heat transfer. Reducing space (p = 10–30 mm) and increasing rows (n = 3–6) of dimples can further improve the effectiveness. At mass flux 300 kg/(m2∙s) and heat flux 70 kW/m2, the performance evaluation criterion (PEC) increases by 42.7 % and 34.7 % respectively, while the maximum buoyancy value (Bumax) decreases by 52.2 % and 28.7 % respectively. Additionally, the Bumax is highly influenced by ac, which represents the product of dimple width and depth. The optimal ET has a PEC of 2.45 and Bumax of 6.42 × 10-5, begin to be affected by buoyancy effect at Bu ≥ 2 × 10-5 and recovers heat transfer at Bu ≥ 2 × 10-4. A new heat transfer correlation is developed and over 95 % of data falls in a 30 % accuracy.

Abstract 4131486: Cardiovascular Mortality in Children and Young Adults: Trends and Demographic Differences in the United States, 1999 to 2021

Background: Cardiovascular disease (CVD) mortality in the U.S. younger population is on the rise. However, limited data is available on CVD-related mortality trends in this population. Aim: This study aimed to assess the temporal trends and demographic differences in CVD-related mortality among the U.S. youth. Methods: The CDC WONDER dataset was analyzed from 1999-2021 for CVD-related mortality in children and young adults (age &lt;25 years). Socio-demographic data including gender, race/ethnicity, urbanization status and census region was acquired. Age adjusted mortality rates (AAMR) per 100,000 persons and annual percent changes (APCs) with 95% confidence interval (CIs) were calculated. Results: Between 1999-2021, a total 54,283 CVD-related deaths occurred among the youth in the U.S. The overall AAMR declined from 1999-2008 (APC, -1.15 [-3.4 to 0.53]), followed by sharp decrease from 2008-2012 (APC, -3.28 [-4.68 to 0.86]). The AAMR continued to decrease steadily from 2012 to 2019 (APC: -1.20, [-3.76 to -0.06]), followed by a sharp increase in from 2019 to 2021, (APC, 3.03 [-0.66 to 5.12]). Males consistently had higher AAMRs than females from 1999 (AAMR males: 2.99 vs females: 2.3) to 2021 (AAMR males: 2.39 vs females: 1.74). Non-Hispanic (NH) Black or African Americans had the highest AAMR in 2020 (3.68), followed by NH Whites (1.71), Hispanic or Latinos (1.59), and Asian and Pacific Islanders (1.2). AAMRs also showed significant variations across different regions (overall AAMR West 1.81; Northeast 1.93; Midwest 2.3; South 2.69). Metropolitan areas (2.23) consistently had lower mortality rates than nonmetropolitan areas (2.59). Conclusion: Our analysis revealed that CVD-related mortality in the youth declined from 1999-2019, followed by an increase in 2020 to 2021. Highest mortality rates were seen in males, Black or African Americans, Western region of the U.S, and nonmetropolitan areas. Tailored interventions are necessitated to decrease the burden of CVD-related mortality in these demographics among children and young adults in the United States.

Abstract 4137878: Trends in Survival After Out-of-Hospital Cardiac Arrest Across Community Demographics Since the COVID-19 Pandemic

Background: The COVID-19 pandemic in 2020 was marked by a sharp decrease in out-of-hospital cardiac arrest (OHCA) survival. Whether OHCA survival has recovered to pre-pandemic levels, and whether changes in OHCA survival are similar across communities of different racial and ethnic composition, is unknown. Methods: We included adult patients with non-traumatic OHCA from 2015-2022 in the Cardiac Arrest Registry to Enhance Survival registry. Using hierarchical multivariable regression, we calculated risk-adjusted rates of survival to hospital discharge during 2015-2019 (reference period) and compared this to survival rates during 2020, 2021, and 2022. We also examined whether the trajectory of survival over this period differed based on the racial/ethnic composition of the community served by the emergency medical service (EMS) agency, defined as predominantly White (&gt;80% White residents), majority Black or Hispanic (&gt;50% Black or Hispanic residents), or integrated (neither). Results: Of 485,079 patients with OHCA, mean age was 61.9 years; 64% were male, and 22% were of Black race with 7% of Hispanic ethnicity. Overall, risk-adjusted survival rates to hospital discharge for OHCA decreased from 10.1% in 2015-2019 to 8.4% in 2020 (P&lt;0.0001). The relative decrease was similar at EMS agencies serving predominantly Black and Hispanic communities (-17.2%) as compared to predominantly White (-17.5%) or integrated communities (-16.8%). Risk-adjusted survival rates recovered partially in 2021 (8.7%) and 2022 (8.9%) but remained below the pre-pandemic period. As of 2022, OHCA survival in majority Black and Hispanic communities was still 9.7% lower, as compared to pre-pandemic years, whereas it was 10.9% lower in integrated communities and 13.6% lower in predominately White communities. Moreover, the survival disparity for OHCAs in Black/Hispanic vs. White communities narrowed to 0.4% (8.4% vs. 8.8%) in 2022, as compared to 1.0% (9.3% vs. 10.3%) prior to the pandemic. Conclusions: OHCA survival has improved in the U.S. since the initial pandemic year of 2020, but remains lower than the pre-pandemic years. The survival disparity for OHCAs occurring in majority Black and Hispanic relative to predominately White communities decreased since 2020, although absolute survival remained lower in majority Black and Hispanic communities throughout the study period.

High thermolectric properties of disordered Ge0.8-ySn0.2MnyTe semiconductor

For layered GeTe-based materials, the typical strategy to reduce the thermal conductivity of the crystal lattice is to introduce atomic disorder, increase the lattice non-harmonicity, and maximize the fluctuations of the quality/stress field in the sample. Since Sn/Mn can easily form solid solutions in the GeTe matrix, the degree of disorder in the sample is much higher than the level reported in IV-VI alloys in the past, which leads to a strong phonon scattering and a sharp decrease in the lattice thermal conductivity over the entire temperature range. In addition, Mn plays a significant role in changing the valence band structure of GeTe, i.e., Mn doping enhances the convergence of the light valence band and the heavy valence band and the change of the bandgap, significantly increasing the Seebeck coefficient of the GeTe matrix, resulting in a significant improvement in the thermoelectric performance of the Sn/Mn co-doped synthesized GeTe-based materials. Finally, we found that treating the sample with layered disorder is an effective method to improve the thermoelectric performance, and this study has certain reference value for the development of novel toxic-free, high-performance thermoelectric materials.