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Prophylaxis is commonly used to prevent central nervous sy stem (CNS) relapse in diffuse large B-cell lymphoma (DLBCL), with no clear standard of care. We retrospectively evaluated 1162 adult patients across 21 US academic centers with DLBCL or similar histologies who received single-route CNS prophylaxis as part of frontline therapy between 2013 and 2019. Prophylaxis was administered intrathecally(IT) in 894 (77%) and using systemic high-dose methotrexate (HD-MTX) in 236 (20%); 32 patients (3%) switched route due to toxicity and were assessed separately. By CNS-International Prognostic Index (IPI), 18% were considered low-risk, 51% moderate, and 30% high. Double-hit lymphoma (DHL) was confirmed in 243 of 866 evaluable patients (21%). Sixty-four patients (5.7%) had CNS relapse after median 7.1 months from diagnosis, including 15 of 64 (23%) within the first 6 months. There was no significant difference in CNS relapse between IT and HD-MTX recipients (5.4% vs 6.8%, P = .4), including after propensity score matching to account for differences between respective recipient groups. Weighting by CNS-IPI, expected vs observed CNS relapse rates were nearly identical (5.8% vs 5.7%). Testicular involvement was associated with high risk of CNS relapse (11.3%) despite most having lower CNS-IPI scores. DHL did not significantly predict for CNS relapse after single-route prophylaxis, including with adjustment for treatment regimen and other factors. This large study of CNS prophylaxis recipients with DLBCL found no significant difference in CNS relapse rates between routes of administration. Relapse rates among high-risk subgroups remain elevated, and reconsideration of prophylaxis strategies in DLBCL is of critical need.
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Antimetabolitos Antineoplásicos/uso terapéutico , Neoplasias del Sistema Nervioso Central/prevención & control , Linfoma de Células B Grandes Difuso/prevención & control , Metotrexato/uso terapéutico , Recurrencia Local de Neoplasia/prevención & control , Adulto , Anciano , Anciano de 80 o más Años , Antimetabolitos Antineoplásicos/administración & dosificación , Antimetabolitos Antineoplásicos/efectos adversos , Femenino , Humanos , Inyecciones Espinales , Masculino , Metotrexato/administración & dosificación , Metotrexato/efectos adversos , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Adulto JovenRESUMEN
Foodborne infections with antimicrobial-resistant Campylobacter spp. remain an important public health concern. Publicly available data collected by the National Antimicrobial Resistance Monitoring System for Enteric Bacteria related to antimicrobial resistance (AMR) in Campylobacter spp. isolated from broiler chickens and turkeys at the slaughterhouse level across the United States between 2013 and 2021 were analysed. A total of 1,899 chicken-origin (1,031 Campylobacter coli (C. coli) and 868 Campylobacter jejuni (C. jejuni)) and 798 turkey-origin (673 C. coli and 123 C. jejuni) isolates were assessed. Chicken isolates exhibited high resistance to tetracycline (43.65%), moderate resistance to ciprofloxacin (19.5%), and low resistance to clindamycin (4.32%) and azithromycin (3.84%). Turkey isolates exhibited very high resistance to tetracycline (69%) and high resistance to ciprofloxacin (39%). The probability of resistance to all tested antimicrobials, except for tetracycline, significantly decreased during the latter part of the study period. Turkey-origin Campylobacter isolates had higher odds of resistance to all antimicrobials than isolates from chickens. Compared to C. jejuni isolates, C. coli isolates had higher odds of resistance to all antimicrobials, except for ciprofloxacin. The study findings emphasize the need for poultry-type-specific strategies to address differences in AMR among Campylobacter isolates.
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Antiinfecciosos , Infecciones por Campylobacter , Campylobacter coli , Campylobacter jejuni , Campylobacter , Animales , Estados Unidos/epidemiología , Antibacterianos/farmacología , Pollos/microbiología , Pavos/microbiología , Farmacorresistencia Bacteriana , Pruebas de Sensibilidad Microbiana , Ciprofloxacina/farmacología , Tetraciclina/farmacología , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/veterinaria , Infecciones por Campylobacter/microbiologíaRESUMEN
In the quest for advanced materials with diverse applications in optoelectronics and energy storage, we delve into the fascinating world of halide perovskites, focusing on SiAuF3 and SiCuF3. Employing density functional theory (DFT) as our guiding light, we conduct a comprehensive comparative study of these two compounds, unearthing their unique structural, electronic, elastic, and optical attributes. Structurally, SiAuF3 and SiCuF3 reveal their cubic nature, with SiCuF3 demonstrating superior stability and a higher bulk modulus. Electronic investigations shed light on their metallic behavior, with Fermi energy levels marking the boundary between valence and conduction bands. The band structures and density of states provide deeper insights into the contributions of electronic states in both compounds. Elastic properties unveil the mechanical stability of these materials, with SiCuF3 exhibiting increased anisotropy compared to SiAuF3. Our analysis of optical properties unravels distinct characteristics. SiCuF3 boasts a higher refractive index at lower energies, indicating enhanced transparency in specific ranges, while SiAuF3 exhibits heightened reflectivity in select energy intervals. Further, both compounds exhibit remarkable absorption coefficients, showcasing their ability to absorb light at defined energy thresholds. The energy loss function (ELF) analysis uncovers differential absorption behavior, with SiAuF3 absorbing maximum energy at 6.9 eV and SiCuF3 at 7.2 eV. Our study not only enriches the fundamental understanding of SiAuF3 and SiCuF3 but also illuminates their potential in optoelectronic applications. These findings open doors to innovative technologies harnessing the distinctive qualities of these halide perovskite materials. As researchers seek materials that push the boundaries of optoelectronics and energy storage, SiAuF3 and SiCuF3 stand out as promising candidates, ready to shape the future of these fields.
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This research is being conducted to learn more about various compounds and their potential uses in various fields such as renewable energy, electrical conductivity, the study of optoelectronic properties, the use of light-absorbing materials in photovoltaic device thin-film LEDs, and field effect transistors (FETs). AgZF3 (Z = Sb, Bi) compounds, which are simple, cubic, ternary fluoro-perovskites, are studied using the FP-LAPW and low orbital algorithm, both of which are based on DFT. Structure, elasticity and electrical and optical properties are only some of the many features that can be predicted. The TB-mBJ method is used to analyze several property types. An important finding of this study is an increase in the bulk modulus value after switching Sb to Bi as the metallic cation designated as "Z" demonstrates the stiffness characteristic of a material. The anisotropy and mechanical balance of the underexplored compounds are also revealed. Our compounds are ductile, as evidenced by the calculated Poisson ratio, Cauchy pressure, and Pugh ratio values. Both compounds exhibit indirect band gaps (X-M), with the lowest points of the conduction bands located at the evenness point X and the highest points of the valence bands located at the symmetry point M. The principal peaks in the optical spectrum can be understood in light of the observed electronic structure.
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Algoritmos , Compuestos de Calcio , Anisotropía , ElectrónicaRESUMEN
This work describes an ab initio principle computational examination of the optical, structural, elastic, electronic and mechanical characteristics of aluminum-based compounds AlRF3 (R = N, P) halide-perovskites. For optimization purposes, we used the Birch-Murnaghan equation of state and discovered that the compounds AlNF3 and AlPF3 are both structurally stable. The IRelast software was used to compute elastic constants (ECs) of the elastic properties. The aforementioned compounds are stable mechanically. They exhibit strong resistance to plastic strain, possess ductile nature and anisotropic behavior and are scratch-resistant. The modified Becke-Johnson (Tb-mBJ) approximation was adopted to compute various physical properties, revealing that AlNF3 and AlPF3 are both metals in nature. From the density of states, the support of various electronic states in the band structures are explained. Other various optical characteristics have been calculated from the investigations of the band gap energy of the aforementioned compounds. These compounds absorb a significant amount of energy at high levels. At low energy levels, the compound AlNF3 is transparent to incoming photons, whereas the compound AlPF3 is somewhat opaque. The examination of the visual details led us to the deduction that the compounds AlNF3 and AlPF3 may be used in making ultraviolet devices based on high frequency. This computational effort is being made for the first time in order to investigate the aforementioned properties of these chemicals, which have yet to be confirmed experimentally.
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Zero Budget Natural Farming (ZBNF) is a grassroot agrarian movement and a state backed extension in Andhra Pradesh, and has been claimed to potentially meet the twin goals of global food security and environmental conservation. However, there is a lack of statistically evaluated data to support assertions of yield benefits of ZBNF compared to organic or conventional alternatives, or to mechanistically account for them. In order to fill this gap, controlled field experiments were established in twenty-eight farms across six districts, spanning over 800 km, over three cropping seasons. In these experiments, we compared ZBNF (no synthetic pesticides or fertilisers, home-made inputs comprising desi cow dung and urine with mulch) to conventional (synthetic fertilisers and pesticides) and organic (no synthetic pesticides or fertilisers, no mulch, purchased organic inputs, e.g. farmyard manure and vermicompost) treatments, all with no tillage. Comparisons were made in terms of yield, soil pH, temperature, moisture content, nutrient content and earthworm abundance. Our data shows that yield was significantly higher in the ZBNF treatment (z score = 0.58 ± 0.08), than the organic (z= -0.34 ± 0.06) or conventional (-0.24 ± 0.07) treatment when all farm experiments were analysed together. However, the efficacy of the ZBNF treatment was context specific and varied according to district and the crop in question. The ZBNF yield benefit is likely attributed to mulching, generating a cooler soil, with a higher moisture content and a larger earthworm population. There were no significant differences between ZBNF and the conventional treatment in the majority of nutrients. This is a particularly important observation, as intensive use of synthetic pesticides and fertilisers comes with a number of associated risks to farmers' finances, human health, greenhouse gas emissions, biodiversity loss and environmental pollution. However, long-term field and landscape scale trials are needed to corroborate these initial observations. Supplementary Information: The online version contains supplementary material available at 10.1007/s13593-023-00884-x.
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This paper explains our first-principle computational investigation regarding the structural, optical, elastic, and electrical characteristics of gallium-based GaMF3 (M = Be and Ge) perovskite-type (halide-perovskite) compounds. Our current computation is based on density functional theory (DFT) and is achieved with the help of the WIEN2k code. We used the Birch-Murnaghan equation for optimization; in both compounds, we found that both GaBeF3 and GaGeF3 compounds are structurally stable. For the computation of elastic characteristics, the IRelast package for calculating elastic constants (ECs) is utilized. These compounds are mechanically ductile, scratch-resistant, anisotropic, and mechanically stable, showing huge opposition to plastic strain. The modified Becke-Johnson (TB-mBJ) potential approximation method is used to calculate different physical characteristics and shows that GaGeF3 behaves as a metal, whereas the GaBeF3 compound is insulating in nature. The involvement of various electronic states in band structures is calculated using the theory of the density of states. The different optical properties of these compounds can be studied easily using their band gap energy. At high energy ranges, these substances demonstrate strong absorption. At low energies, the GaGeF3 compound is transparent, while the GaBeF3 compound is opaque to incoming photons. Investigation of the optical characteristics has led us to the conclusion that both GaGeF3 and GaBeF3 compounds can be used for high-frequency ultraviolet device applications. This computational work is considered to be the first time that we can study these compounds, which to our knowledge have not previously been experimentally validated.
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PURPOSE OF REVIEW: Hand osteoarthritis (hand OA), the most common peripheral arthritis in the world, is less studied than osteoarthritis (OA) of the knee and hip. However, it is uniquely situated to offer novel insight into OA as a disease process by removing weight-bearing as a confounder of systemic disease mechanisms. Here we review the epidemiology of hand OA and key risk factors for its development. RECENT FINDINGS: Mounting evidence points to obesity as an important risk factor for hand OA development, with new evidence implicating a role for leptin and serum fatty acids. Disease progression in hand OA and specifically the erosive OA subtype may be associated with diabetes. New evidence supports an association between cardiovascular disease progression and symptomatic hand OA. Alcohol use may be associated with increased synovitis and erosive hand OA. Differences in ethnical distributions of hand OA have become more apparent, with a lower prevalence in Black patients compared to White patients. Novel genetic insights implicating the WNT gene pathway and IL-1ß have led to novel potential targets in hand OA pathogenesis. Hand OA is a heterogeneous disease with many modifiable and non-modifiable risk factors that can determine disease severity and shed light on disease pathogenesis.
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Osteoartritis de la Rodilla , Osteoartritis , Mano , Humanos , Articulación de la Rodilla , Osteoartritis/epidemiología , Osteoartritis/etiología , Prevalencia , Factores de RiesgoRESUMEN
The present study aims to assess the arsenic (As) levels into dust samples and its implications for human health, of four ecological zones of Pakistan, which included northern frozen mountains (FMZ), lower Himalyian wet mountains (WMZ), alluvial riverine plains (ARZ), and low lying agricultural areas (LLZ). Human nail samples (N=180) of general population were also collected from the similar areas and all the samples were analysed by using ICP-MS. In general the higher levels (p<0.05) in paired dust and human nail samples were observed from ARZ and LLZ than those of other mountainous areas (i.e., WMZ and FMZ), respectively. Current results suggested that elevated As concentrations were associated to both natural, (e.g. geogenic influences) and anthropogenic sources. Linear regression model values indicated that As levels into dust samples were associated with altitude (r(2)=0.23), soil carbonate carbon density (SCC; r(2)=0.33), and population density (PD; r(2)=0.25). The relationship of paired dust and nail samples was also investigated and associations were found for As-nail and soil organic carbon density (SOC; r(2)=0.49) and SCC (r(2)=0.19) in each studied zone, evidencing the dust exposure as an important source of arsenic contamination in Pakistan. Risk estimation reflected higher hazard index (HI) values of non-carcinogenic risk (HI>1) for children populations in all areas (except FMZ), and for adults in LLZ (0.74) and ARZ (0.55), suggesting that caution should be paid about the dust exposure. Similarly, carcinogenic risk assessment also highlighted potential threats to the residents of LLZ and ARZ, as in few cases (5-10%) the values exceeded the range of US-EPA threshold limits (10(-6)-10(-4)).
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Arsénico/análisis , Carcinógenos/análisis , Polvo/análisis , Exposición a Riesgos Ambientales , Adulto , Niño , Fenómenos Ecológicos y Ambientales , Femenino , Humanos , Masculino , Uñas/química , Pakistán , Medición de Riesgo , Suelo/químicaRESUMEN
Saliva from arthropod vectors facilitates blood feeding by altering host inflammation. Whether arthropod saliva counters inflammasome signaling, a protein scaffold that regulates the activity of caspase-1 and cleavage of interleukin-1ß (IL-1ß) and IL-18 into mature molecules, remains elusive. In this study, we provide evidence that a tick salivary protein, sialostatin L2, inhibits inflammasome formation during pathogen infection. We show that sialostatin L2 targets caspase-1 activity during host stimulation with the rickettsial agent Anaplasma phagocytophilum. A. phagocytophilum causes macrophage activation and hemophagocytic syndrome features. The effect of sialostatin L2 in macrophages was not due to direct caspase-1 enzymatic inhibition, and it did not rely on nuclear factor κB or cathepsin L signaling. Reactive oxygen species from NADPH oxidase and the Loop2 domain of sialostatin L2 were important for the regulatory process. Altogether, our data expand the knowledge of immunoregulatory pathways of tick salivary proteins and unveil an important finding in inflammasome biology.
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Anaplasma phagocytophilum/fisiología , Caspasa 1/metabolismo , Ehrlichiosis/microbiología , Cistatinas Salivales/fisiología , Análisis de Varianza , Animales , Células Cultivadas , Citocinas/metabolismo , Modelos Animales de Enfermedad , Ehrlichiosis/metabolismo , Ehrlichiosis/patología , Inflamasomas/metabolismo , Inflamación/fisiopatología , Macrófagos/metabolismo , Macrófagos/microbiología , Ratones , Ratones Endogámicos C57BL , Especies Reactivas de OxígenoRESUMEN
Neuromorphic computing is a new field of information technology, which is inspired by the biomimetic properties of the memristor as an electronic synapse and neuron. If there are electronic receptors that can transmit exterior impulses to the internal nervous system, then the use of memristors can be expanded to artificial nerves. In this study, a layer type memristor is used to build an artificial nociceptor in a very feasible and straightforward manner. An artificial nociceptor is demonstrated here through the fabrication and characterization of a cobalt-doped zinc oxide (CZO)/Au based memristor. In order to increase threshold switching performance, the surface effects of the CZO layer are eliminated by adding cobalt cobalt-doped zinc oxide (CZO) layer between the P++-Si and Au electrodes. Allodynia, hyperalgesia, threshold, and relaxation are the four distinct nociceptive behaviours that the device displays based on the strength, rate of relapse, and duration of the external stimuli. The electrons that are trapped in or released from the CZO layer's traps are responsible for these nociceptive behaviours. A multipurpose nociceptor performance is produced by this type of CZO-based device, which is crucial for artificial intelligence system applications such as neural integrated devices with nanometer-sized characteristics.
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One possible result of low-level characteristics in the traditional von Neumann formulation system is brain-inspired photonics technology based on human brain idea. Optoelectronic neural devices, which are accustomed to imitating the sensory role of biological synapses by adjusting connection measures, can be used to fabricate highly reliable neurologically calculating devices. In this case, nanosized materials and device designs are attracting attention since they provide numerous potential benefits in terms of limited cool contact, rapid transfer fluidity, and the capture of photocarriers. In addition, the combination of classic nanosized photodetectors with recently generated digital synapses offers promising results in a variety of practical applications, such as data processing and computation. Herein, we present the progress in constructing improved optoelectronic synaptic devices that rely on nanomaterials, for example, 0-dimensional (quantum dots), 1-dimensional, and 2-dimensional composites, besides the continuously developing mixed heterostructures. Furthermore, the challenges and potential prospects linked with this field of study are discussed in this paper.
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Fluoro-perovskites compounds based on the Tl element TlMF3 (M = Au, Ga) were examined computationally, and their different aspects, studied utilizing TB-mBJ potential approximations, can be used for the generation of energy because of their ever-increasing power conversion efficiency. Birch Murnaghan's graph and tolerance factor show that these composites are structurally cubic and stable. The optimum volume of the compounds corresponding to the optimum energies and the optimized lattice constants were computed. The algorithm IRelast was used to predict the elastic information, and these results demonstrated that the presented compounds are stable mechanically and show anisotropic and ductile properties. TlAuF3 and TlGaF3 have an indirect band energy gap at (M-X) positions, with a forbidden energy gap of -0.55 eV for TlAuF3 and 0.46 eV for TlGaF3. The compounds show a metallic nature due to a small indirect band gap. Different component states corresponding to the upper and lower bands of the Fermi energy level are influenced by the total density in the different states and the density in various directions (TDOS & PDOS). These composites exhibit strong absorption, conductivity, and reflective coefficients at higher energy series together with a low refractive index, given by an inquiry into optical properties. The applications of these composites are thought to be good for conduction purposes in industries due to the indirect band gap. For the first time, computational analysis of these novel compounds offers a thorough understanding of their many characteristics.
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The topical route is the most appropriate route for the targeted delivery of drugs to skin tissues for the treatment of local skin diseases; however, the stratum corneum (SC), the foremost layer of the skin, acts as a major barrier. Numerous passive and active drug delivery techniques have been exploited to overcome this barrier; however, these modalities are associated with several detrimental effects which restrict their clinical applicability. Alternatively, nanotechnology-aided interventions have been extensively investigated for the topical administration of a wide range of therapeutics. In this review, we have mainly focused on the biopharmaceutical significance of polymeric nanoparticles (PNPs) (made from natural polymers) for the treatment of various topical skin diseases such as psoriasis, atopic dermatitis (AD), skin infection, skin cancer, acute-to-chronic wounds, and acne. The encapsulation of drug(s) into the inner core or adsorption onto the shell of PNPs has shown a marked improvement in their physicochemical properties, avoiding premature degradation and controlling the release kinetics, permeation through the SC, and retention in the skin layers. Furthermore, functionalization techniques such as PEGylation, conjugation with targeting ligand, and pH/thermo-responsiveness have shown further success in optimizing the therapeutic efficacy of PNPs for the treatment of skin diseases. Despite enormous progress in the development of PNPs, their clinical translation is still lacking, which could be a potential future perspective for researchers working in this field.
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Background: Numerous reviews of the epidemiology and risk factors for breast cancer have been published previously which heighted different directions of breast cancer. Aim: The present review examined the likelihood that incidence, prevalence, and particular risk factors might vary by geographic region and possibly by food and cultural practices as well. Methods: A systematic review (2017-2022) was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, reporting on epidemiological and risk factor reports from different world regions. Medical Subject Heading (MeSH) terms: "Breast neoplasm" "AND" country terms such as "Pakistan/epidemiology", "India/epidemiology", "North America/epidemiology", "South Africa/epidemiology" were used to retrieve 2068 articles from PubMed. After applying inclusion and exclusion terms, 49 papers were selected for systematic review. Results: Results of selected articles were summarized based on risk factors, world regions and study type. Risk factors were classified into five categories: demographic, genetic and lifestyle risk factors varied among countries. This review article covers a variety of topics, including regions, main findings, and associated risk factors such as genetic factors, and lifestyle. Several studies revealed that lifestyle choices including diet and exercise could affect a person's chance of developing breast cancer. Breast cancer risk has also been linked to genetic variables, including DNA repair gene polymorphisms and mutations in the breast cancer gene (BRCA). It has been found that most of the genetic variability links to the population of Asia while the cause of breast cancer due to lifestyle modifications has been found in American and British people, indicating that demographic, genetic, and, lifestyle risk factors varied among countries. Conclusion: There are many risk factors for breast cancer, which vary in their importance depending on the world region. However, further investigation is required to better comprehend the particular causes of breast cancer in these areas as well as to create efficient prevention and treatment plans that cater to the local population.
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Importance: Optimal blood product transfusion strategies before tunneled central venous catheter (CVC) placement are required in critically ill coagulopathic patients with liver disease to reduce exposure to allogeneic blood products and mitigate bleeding and thrombotic complications. Objectives: This study evaluated the safety and efficacy of a thromboelastography-guided transfusion strategy for the correction of coagulopathy in patients with liver disease compared with a conventional transfusion strategy (using international normalized ratio, platelet count, and fibrinogen) before tunneled CVC insertion. Design Setting and Participants: A retrospective propensity score-matched single-center cohort study was conducted at a quaternary care academic medical center involving 364 patients with liver disease (cirrhosis and acute liver failure) who underwent tunneled CVC insertion in the ICU. Patients were stratified into two groups based on whether they received blood product transfusions based on a thromboelastography-guided or conventional transfusion strategy. Main Outcomes and Measures: Primary outcomes that were evaluated included the volume, units and cost of blood products (fresh frozen plasma, cryoprecipitate, and platelets) when using a thromboelastography-guided or conventional approach to blood transfusions. Secondary outcomes included the frequency of procedure-related bleeding and thrombotic complications. Results: The total number of units/volume/cost of fresh frozen plasma (12 U/3,000 mL/$684 vs. 32 U/7,500 mL/$1,824 [p = 0.019]), cryoprecipitate (60 U/1,500 mL/$3,240 vs. 250 U/6,250 mL/$13,500 [p < 0.001]), and platelets (5 U/1,500 mL/$2,610 vs. 13 units/3,900 mL/$6,786 [p = 0.046]) transfused were significantly lower in the thromboelastography-guided transfusion group than in the conventional transfusion group. No differences in the frequency of bleeding/thrombotic events were observed between the two groups. Conclusions and Relevance: A thromboelastography-guided transfusion strategy for correction of coagulopathy in critically ill patients with liver disease before tunneled CVC insertion, compared with a conventional transfusion strategy, reduces unnecessary exposure to allogeneic blood products and associated costs without increasing the risk for peri-procedural bleeding and thrombotic complications.
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To enhance the effectiveness of materials, we are motivated to investigate lithium-based halide perovskites LiRCl3 (where R = Be and Mg) using first-principles techniques based on density functional theory (DFT), implemented in the WIEN2K code. In this study, the research makes use of the WIEN2K simulation code, employing the plane-wave and self-consistent (PWSCF) approach. The cut-off energy, responsible for distinguishing core and valence states, is established at -6.0 Ry. To guarantee well-converged solutions with 2000 K points, parameters of RMT × Kmax = 7.0 are selected, where RMT represents the smallest muffin-tin radius and Kmax denotes the plane wave cut-off. Convergence is determined to be attained when the overall energy of the system remains unchanged during self-consistent calculations, reaching a threshold of 0.001 Ry. We observe structural stability of these materials using the Birch-Murnaghan fit, tolerance factor and formation energy. The tolerance factor for LiMgCl3 and LiBeCl3 are 1.03 and 0.857, while the formation energy for LiMgCl3 and LiBeCl3 are -7.39 eV and -8.92 eV respectively, confirming these to be stable structurally. We evaluate the electronic properties of the current materials, shedding light on their nature, by using the suggested modified Becke-Johnson potential. It turns out that they are indirect insulators, with calculated band gaps of 4.02 and 4.07 eV for LiMgCl3 and LiBeCl3, respectively. For both materials, we also calculate the density of states (DOS), and our findings regarding the band gap energies are consistent with the band structure. It is observed that both materials exhibit transparency to low-energy photons, with absorption and optical conduction occurring in the UV range. These compounds are mechanically stable, according to the elastic investigation, however LiBeCl3 shows higher resistance to compressive and shear loads as well as resistance to shape change. On the other hand, LiMgCl3 exhibits weaker resistance to changes in volume. Furthermore, we discovered that none of the compounds are entirely isotropic, and specifically, LiMgCl3 and LiBeCl3 are brittle in nature. These materials appear to be potential candidates for use in optoelectronic devices based on our analysis of their optical properties. Our findings may provide comprehensive insight, invoking experimental studies for further investigations.
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We investigated the physical behavior of SrMO3 (M = Hf and Pt) compounds, which are strontium-based oxide perovskites. We utilized the WIEN2k software to simulate and investigate their physical properties. The structural stability of SrHfO3 and SrPtO3 was verified using the Birch-Murnaghan equation of states for optimization. We also checked the elastic stability through the computation of elastic constants using the IRelast software. Our results indicate the stability of these compounds and showed their anisotropic, ductility, scratch-resistive, and plastic strain-resistant characteristics. Using the TB-mBJ potential approach, we determined that SrHfO3 is an insulator, whereas SrPtO3 is a metal in nature. The density of states computations was used to find the band structure as well as the contribution of different electronic states. Optical property research was conducted using the band gap energies of these substances. Our findings suggest that these crystals have low energy absorption and reflectivity of up to 65%, making them suitable for use in high-frequency UV devices. Specifically, SrHfO3 is more transparent before the energy point 2.80 eV, while the compound SrPtO3 after 6.50 eV to 12.0 eV and SrHfO3 from 12.0 and 14.0 eV. This study represents the first DFT-based investigation of these discussed crystals according to the best of our knowledge.
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[This corrects the article DOI: 10.1039/D3RA02640J.].
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Herein, the optoelectronic, structural, thermoelectric, and elastic characteristics of M2LiCeF6 (M = Rb and Cs) double perovskite compounds were investigated using ab initio modeling in the DFT framework. The Birch-Murnaghan fitting curve used for the optimization showed that these two compounds are structurally stable. The elastic properties of the M2LiCeF6 (M = Rb and Cs) double perovskite compounds were examined using the IRelast code. The results showed that these two compounds possess mechanical stability, anisotropy, and toughness, and offer resistance to plastic deformation. The precise and accurate determination of their electronic properties was achieved via the Trans-Blaha-modified Becke-Johnson (TB-mBJ) approximation. The Rb2LiCeF6 and Cs2LiCeF6 compounds are narrow band gap semiconductors with band gaps of 0.6 eV and 0.8 eV at the high symmetrical points from (Γ-M), respectively, exhibiting an indirect nature. To further understand how the various states contribute to the different band structures, total and partial density of state (DOS) computations were performed. The optical properties in the energy range of 0-40 eV for Rb2LiCeF6 and Cs2LiCeF6 were explored. The selected materials show transparency in the low incident photon energy range and have large light absorption and transmission at higher photon energies. Thus, it can be concluded that Rb2LiCeF6 and Cs2LiCeF6 can be used in high-frequency UV devices based on their optical characteristics. Both materials exhibit high electrical conductivity, power factors, and figures of merit (ZT) and act as effective thermoelectric resources. To the best of our knowledge, this is the first theoretical research on the optoelectronic, structural, thermoelectric, and elastic features of M2LiCeF6 (M = Rb and Cs).