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1.
Artigo em Inglês | MEDLINE | ID: mdl-38773841

RESUMO

Pickleball is one of the fastest growing sports in the United States with millions of players nationwide. It is a relatively appealing sport because of its ease of access, low impact, and highly social atmosphere, allowing players of all ages to participate. As the number of players continues its dramatic increase, player injuries are certain to increase in turn. There is little to no orthopaedic research on pickleball-related injuries and a paucity of data regarding treatment and prevention strategies. This summary was designed to familiarize orthopaedic surgeons with the basics of the sport and highlight potential pickleball-related injuries they may encounter in practice.

2.
Head Neck Pathol ; 18(1): 39, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38727854

RESUMO

BACKGROUND: Columnar cell papillary thyroid carcinoma (CC-PTC) is a morphologic subtype of papillary thyroid carcinoma with a variable prognosis. It is characterized by neoplastic thyroid follicular-derived cells with pseudostratified columnar morphology arranged in papillary or follicular structures with supranuclear or subnuclear vacuoles. The molecular profile of this subtype has only recently come under scrutiny, with mixed results. The aim of this study is to further explore the morphologic, immunohistochemical, and genetic profile of CC-PTC, as well as to correlate these features with clinical outcomes. METHODS: CC-PTC cases were identified from 3 institutions. Immunohistochemistry (ER, CDX2) and molecular testing (DNA and RNA sequencing) were performed. Clinicopathologic parameters and patient outcomes were recorded. RESULTS: Twelve cases (2006-2023) were identified, all in adults (age 45-91). Two presented with disease outside the thyroid gland (neck and mediastinum) and two presented with distant metastasis. Four were high-grade differentiated thyroid carcinomas (necrosis or mitoses), one of which died of disease. Four were noninvasive or minimally invasive, one of which locally recurred. Three patients had lymph node metastases. ER and CDX2 were positive in 73% and 50%, respectively. Pathogenic mutations were found in TERT promoter (n = 3), RAS (n = 2), ATM, NOTCH1, APC, and ESR1, along with cases bearing AGK::BRAF fusion (n = 1), BRAF VE1 expression (n = 1), and NF2 loss (n = 1). CONCLUSIONS: This study represents the largest molecularly defined cohort of non-oncocytic thyroid carcinomas with columnar cell morphology. These tumors represent a genetically and behaviorally heterogeneous group of neoplasms, some of which have RAS-like or follicular neoplasm-like genetics, some of which have BRAF-p.V600E-like or classic papillary thyroid carcinoma-like genetics, and some of which remain unclear. Noninvasive or minimally invasive tumors showed an indolent course compared to those with angioinvasion, gross extrathyroidal growth, or high-grade morphology. Consideration could be given to reclassification of this neoplasm outside of the subtyping of papillary thyroid carcinoma in light of its genetic diversity, distinct morphology, and clinical behavior more closely aligned with follicular thyroid neoplasms.


Assuntos
Adenocarcinoma Folicular , Câncer Papilífero da Tireoide , Neoplasias da Glândula Tireoide , Humanos , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/genética , Masculino , Feminino , Pessoa de Meia-Idade , Câncer Papilífero da Tireoide/patologia , Câncer Papilífero da Tireoide/genética , Idoso , Idoso de 80 Anos ou mais , Adenocarcinoma Folicular/patologia , Adenocarcinoma Folicular/genética , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/genética
3.
MicroPubl Biol ; 20242024.
Artigo em Inglês | MEDLINE | ID: mdl-38741934

RESUMO

Antimicrobial resistance (AMR) in microorganisms is an ongoing threat to human health across the globe. To better characterize the AMR profiles of six strains of Staphylococcus aureus , we performed a secondary analysis that consisted of the following steps: 1) download fastq files from the Sequence Read Archive, 2) perform a de novo genome assembly from the sequencing reads, 3) annotate the assembled contigs, 4) predict the presence of antimicrobial resistance genes. We predicted the presence of 75 unique genes that conferred resistance against 22 unique antimicrobial compounds.

4.
Robot Rep ; 2(1): 15-28, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38584677

RESUMO

Soft robotics is a rapidly growing field that spans the fields of chemistry, materials science, and engineering. Due to the diverse background of the field, there have been contrasting naming schemes such as "intelligent," "smart," and "adaptive" materials, which add vagueness to the broad innovation among literature. Therefore, a clear, functional, and descriptive naming scheme is proposed in which a previously vague name-Soft Material for Soft Actuators-can remain clear and concise-Phase-Change Elastomers for Artificial Muscles. By synthesizing the working principle, material, and application into a naming scheme, the searchability of soft robotics can be enhanced and applied to other fields. The field of thermo-active soft actuators spans multiple domains and requires added clarity. Thermo-active actuators have potential for a variety of applications spanning virtual reality haptics to assistive devices. This review offers a comprehensive guide to selecting the type of thermo-active actuator when one has an application in mind. In addition, it discusses future directions and improvements that are necessary for implementation.

5.
Injury ; : 111540, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38622039

RESUMO

OBJECTIVES: In far-distal extra-articular tibia fracture "extreme" nailing, debate surrounds the relative biomechanical performance of plating the fibula compared with extra distal interlocks. This study aimed to evaluate several constructs for extreme nailing including one interlock (one medial-lateral interlock), one interlock + plate (one medial-lateral interlock with lateral fibula compression plating), and two interlocks (one medial-lateral interlock and one anterior-posterior interlock). METHODS: Fifteen pairs of fresh cadaver legs were instrumented with a tibial nail to the physeal scar. A 1 cm segment of bone was resected from the distal tibia 3.5 cm from the joint and an oblique osteotomy was made in the distal fibula. We loaded specimens with three different distal fixation constructs (one interlock, one interlock + plate, and two interlocks) through 10,000 cycles form 100N-700 N of axial loading. Load to failure (Newtons), angulation and displacement were also measured. RESULTS: Mean load to failure was 2092 N (one interlock), 1917 N (one interlock + plate), and 2545 N (two interlocks). Linear mixed effects modeling demonstrated that two interlocks had a load to failure 578 N higher than one interlock alone (95 % CI, 74N-1082 N; P = 0.02), but demonstrated no significant difference between one interlock and one interlock + plate. No statistically significant difference in rates or timing of displacement >2 mm or angulation >10° were demonstrated. CONCLUSIONS: When nailing far-distal extra-articular tibia and fibula fractures, adding a second interlock provides more stability than adding a fibular plate. Distal fibula plating may have minimal biomechanical effect in extreme nailing.

6.
Med Phys ; 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38642468

RESUMO

BACKGROUND: Minibeam represents a preclinical spatially fractionated radiotherapy modality with great translational potential. The advantage lies in its high therapeutic index (compared to GRID and LATTICE) and ability to treat at greater depth (compared to microbeam). Proton minibeam radiotherapy (pMBRT) is a synergy of proton and minibeam. While the single-gantry proton facility has gained popularity due to its affordability and compact design, it often has limited beam time available for research purposes. Conversely, given the current requirement of pMBRT on specific minibeam hardware collimators, necessitates a reproducible and fast setup to minimize pMBRT treatment time and streamline the switching time between pMBRT and conventional treatment for clinically translation. PURPOSE: The contribution of this work is the development and characterization of the first pMBRT system tailored for single-gantry proton facility. The system allows for efficient and reproducible plug-and-play setup, achievable within minutes. METHODS: The single room pMBRT system is constructed based on IBA ProteusONE proton machine. The end of nozzle is attached with beam modifying accessories though an accessory drawer. A small snout is attached to the accessory drawer and used to hold apertures and range shifters. The minibeam aperture consists of two components: a fitting ring and an aperture body. Three minibeam apertures were manufactured. The first-generation apertures underwent qualitatively analysis with film, and the second generation aperture underwent more comprehensive quantitative measurement. The reproducibility of the setup is accessed, and the film measurements are performed to characterize the pMBRT system in cross validation with Monte Carlo (MC) simulations. RESULTS: We presented initial results of large field pMBRT aperture and the film measurements indicates the effect of source-to-isocenter distance = 930 cm in Y proton scanning direction. Consistent with TOPAS MC simulation, the dose uniformity of pMBRT field <2 cm is demonstrated to be better than 2%, rendering its suitability for pre-clinical studies. Subsequently, we developed the second generation of aperture with five slits and characterized the aperture with film dosimetry studies and compared the results to the benchmark MC. Comprehensive film measurements were also performed to evaluate the effect of divergence, air gap and gantry-angle dependency and repeatability and revealing a consistent performance within 5%. Furthermore, the 2D gamma analysis indicated a passing rate exceeding 99% using 3% dose difference and 0.2 mm distance agreement criteria. We also establish the peak valley dose ratio and the depth dose profile measurements, and the results are within 10% from MC simulation. CONCLUSIONS: We have developed the first pMBRT system tailored for a single-gantry proton facility, which has demonstrated accuracy in benchmark with MC simulations, and allows for efficient plug-and-play setup, emphasizing efficiency.

7.
Adv Colloid Interface Sci ; 327: 103140, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38579462

RESUMO

This paper provides a comprehensive overview of recent advancements in membrane modification for fouling mitigation in various water treatment processes, employing carbon nanomaterials such as fullerenes, nanodiamonds, carbon quantum dots, carbon nanotubes, and graphene oxide. Currently, using different carbon nanomaterials for polymeric membrane fouling mitigation is at various stages: CNT-modified membranes have been studied for more than ten years and have already been tested in pilot-scale setups; tremendous attention has been paid to utilizing graphene oxide as a modifying agent, while the research on carbon quantum dots' influence on the membrane antifouling properties is in the early stages. Given the intricate nature of fouling as a colloidal phenomenon, the review initially delves into the factors influencing the fouling process and explores strategies to address it. The diverse chemistry and antibacterial properties of carbon nanomaterials make them valuable for mitigating scaling, colloidal, and biofouling. This review covers surface modification of existing membranes using different carbon materials, which can be implemented as a post-treatment procedure during membrane fabrication. Creating mixed-matrix membranes by incorporating carbon nanomaterials into the polymer matrix requires the development of new synthetic procedures. Additionally, it discusses promising strategies to actively suppress fouling through external influences on modified membranes. In the concluding section, the review compares the effectiveness of carbon materials of varying dimensions and identifies key characteristics influencing the antifouling properties of membranes modified with carbon nanomaterials.

8.
Front Sports Act Living ; 6: 1309991, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38469227

RESUMO

Esports research lacks game-based metrics platforms appropriate for adequately capturing esports performance. The aim of this pilot study was to assess the reliability of the KovaaK's first-person shooter (FPS) aim trainer as a metrics platform for assessing shooting proficiency in esports players. Ten FPS esports players completed two identical experimental trials (T) separated by three to five days. Each trial included four rounds (R) of testing, evaluating four shooting tasks: Micro Flicking, Macro Flicking, Strafe Tracking, and Wall Peeking. Reliability of performance outcomes (e.g., accuracy, headshot accuracy, hits per second, and total shots hit) were assessed using the intraclass correlation coefficient (ICC) and their 95% confidence intervals (CI), and significant differences were identified using repeated-measures analysis of variance (RM-ANOVA). Results indicated excellent, or good to excellent reliability for all outcome variables with the ICC estimates ranging between 0.947-0.995, with lower and upper bound 95% CIs ranging between 0.876-0.988, and 0.984-0.999, respectively. Significant improvements were seen between experimental trials in the Macro Flicking task for accuracy (p = .005) and hits per second (p = .009) only. Significant interactions between trial and round were identified in the Micro Flicking task for accuracy (p = .006), with post hoc analysis showing accuracy was significantly higher in T1R1 compared to T2R1 (87.74 ± 3.13 vs. 85.99 ± 3.05, respectively, p = .02), and in T2R4 compared to T2R2 (87.99 ± 2.89 vs. 84.70 ± 4.25, respectively, p = .049). Significant interactions were also identified in the Strafe Tracking task for headshot accuracy (p = .002), with post hoc analysis showing headshot accuracy was significantly higher in T1R2 compared to T2R2 (78.48 ± 8.15 vs. 76.79 ± 12.16, respectively, p = .003), and in T1R2 compared to T1R1 (78.48 ± 8.15 vs. 73.68 ± 17.94, respectively, p = .023). In summary, this study demonstrates that KovaaK's provides a reliable metrics platform for assessing shooting proficiency in esports, however, some variability in performance was observed.

9.
Spat Spatiotemporal Epidemiol ; 48: 100623, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38355253

RESUMO

This study compares two social vulnerability indices, the U.S. CDC SVI and SoVI (the Social Vulnerability Index developed at the Hazards Vulnerability & Resilience Institute at the University of South Carolina), on their ability to predict the risk of COVID-19 cases and deaths. We utilize COVID-19 cases and deaths data for the state of Indiana from the Regenstrief Institute in Indianapolis, Indiana, from March 1, 2020, to March 31, 2021. We then aggregate the COVID-19 data to the census tract level, obtain the input variables, domains (components), and composite measures of both CDC SVI and SoVI data to create a Bayesian spatial-temporal ecological regression model. We compare the resulting spatial-temporal patterns and relative risk (RR) of SARS-CoV-2 infection (COVID-19 cases) and associated death. Results show there are discernable spatial-temporal patterns for SARS-CoV-2 infections and deaths with the largest contiguous hotspot for SARS-CoV-2 infections found in the southwest of the Indianapolis metropolitan area. We also observed one large contiguous hotspot for deaths that stretches across Indiana from the Cincinnati area in the southeast to just east and north of Terre Haute (southeast to west central). The spatial-temporal Bayesian model shows that a 1-percentile increase in CDC SVI was significantly (p ≤ 0.05) associated with an increased risk of SARS-CoV-2 infection by 6 % (RR = 1.06, 95 %CI = 1.04 -1.08). Whereas a 1-percentile increase in SoVI was significantly predicted to increase the risk of COVID-19 death by 45 % (RR = 1.45, 95 %CI =1.38 - 1.53). Domain-specific variables related to socioeconomic status, age, and race/ethnicity were shown to increase the risk of SARS-CoV-2 infections and deaths. There were notable differences in the relative risk estimates for SARS-CoV-2 infections and deaths when each of the two indices were incorporated in the model. Observed differences between the two social vulnerability indices and infection and death are likely due to alternative methodologies of formation and differences in input variables. The findings add to the growing literature on the relationship between social vulnerability and COVID-19 and further the development of COVID-19-specific vulnerability indices by illustrating the utility of local spatial-temporal analysis.


Assuntos
COVID-19 , Vulnerabilidade Social , Humanos , Teorema de Bayes , COVID-19/epidemiologia , Incidência , SARS-CoV-2
10.
Nature ; 627(8004): 564-571, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38418889

RESUMO

Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species1,2, a phenomenon known as conspecific negative density dependence (CNDD)3. A long-held ecological hypothesis posits that CNDD is more pronounced in tropical than in temperate forests4,5, which increases community stabilization, species coexistence and the diversity of local tree species6,7. Previous analyses supporting such a latitudinal gradient in CNDD8,9 have suffered from methodological limitations related to the use of static data10-12. Here we present a comprehensive assessment of latitudinal CNDD patterns using dynamic mortality data to estimate species-site-specific CNDD across 23 sites. Averaged across species, we found that stabilizing CNDD was present at all except one site, but that average stabilizing CNDD was not stronger toward the tropics. However, in tropical tree communities, rare and intermediate abundant species experienced stronger stabilizing CNDD than did common species. This pattern was absent in temperate forests, which suggests that CNDD influences species abundances more strongly in tropical forests than it does in temperate ones13. We also found that interspecific variation in CNDD, which might attenuate its stabilizing effect on species diversity14,15, was high but not significantly different across latitudes. Although the consequences of these patterns for latitudinal diversity gradients are difficult to evaluate, we speculate that a more effective regulation of population abundances could translate into greater stabilization of tropical tree communities and thus contribute to the high local diversity of tropical forests.


Assuntos
Biodiversidade , Florestas , Mapeamento Geográfico , Árvores , Modelos Biológicos , Especificidade da Espécie , Árvores/classificação , Árvores/fisiologia , Clima Tropical
11.
Viruses ; 16(2)2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38400064

RESUMO

Enterobacteriaceae is a large family of Gram-negative bacteria composed of many pathogens, including Salmonella and Shigella. Here, we characterize six bacteriophages that infect Enterobacteriaceae, which were isolated from wastewater plants in the Wasatch front (Utah, United States). These phages are highly similar to the Kuttervirus vB_SenM_Vi01 (Vi01), which was isolated using wastewater from Kiel, Germany. The phages vary little in genome size and are between 157 kb and 164 kb, which is consistent with the sizes of other phages in the Vi01-like phage family. These six phages were characterized through genomic and proteomic comparison, mass spectrometry, and both laboratory and clinical host range studies. While their proteomes are largely unstudied, mass spectrometry analysis confirmed the production of five hypothetical proteins, several of which unveiled a potential operon that suggests a ferritin-mediated entry system on the Vi01-like phage family tail. However, no dependence on this pathway was observed for the single host tested herein. While unable to infect every genus of Enterobacteriaceae tested, these phages are extraordinarily broad ranged, with several demonstrating the ability to infect Salmonella enterica and Citrobacter freundii strains with generally high efficiency, as well as several clinical Salmonella enterica isolates, most likely due to their multiple tail fibers.


Assuntos
Bacteriófagos , Fagos de Salmonella , Bacteriófagos/genética , Proteômica , Glicoproteína da Espícula de Coronavírus/genética , Águas Residuárias , Genômica , Enterobacteriaceae , Genoma Viral , Especificidade de Hospedeiro , Fagos de Salmonella/genética
13.
J Gen Intern Med ; 39(6): 1058-1062, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38413538

RESUMO

BACKGROUND: Op-ed writing can be a powerful and accessible advocacy tool for physicians, but training is lacking in undergraduate medical education. AIM: To train and engage first-year medical students in op-ed writing. SETTING: Midwestern research-intensive medical school. PARTICIPANTS: All students in a required first-year health policy course in 2021 and 2022. PROGRAM DESCRIPTION: For their health policy course's final assignment, students could opt to write an op-ed on a healthcare issue of their choice. All students received written instruction on op-ed writing. Additionally, they could access a seminar, coaching and editing by peers and faculty, and publication guidance. PROGRAM EVALUATION: Of 179 students over 2 years, 105 chose to write op-eds. Fifty-one attended the seminar, 35 attended peer coaching sessions, 33 accessed structured peer editing, and 23 received faculty assistance. Thirty-eight students submitted a total of 42 op-eds for publication. Twenty-two pieces were published in major outlets and 17 in the university's health policy review. Of the 22 in major outlets, 21 received editing from either peers or faculty. DISCUSSION: An op-ed writing curriculum can be integrated into an existing medical school health policy course, resulting in a high level of engagement and in published op-eds by medical students.


Assuntos
Currículo , Educação de Graduação em Medicina , Estudantes de Medicina , Redação , Humanos , Educação de Graduação em Medicina/métodos , Política de Saúde , Defesa do Paciente/educação
14.
Cancer Med ; 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38164123

RESUMO

BACKGROUND: TP53 mutation is present in about 50.8% of lung adenocarcinomas, frequently in combination with other genetic alterations. However, a rare subset harbors the TP53 mutation alone. METHODS: Next-generation sequencing was performed in 840 lung adenocarcinomas diagnosed by fine needle aspiration. Fourteen cases (1.7%) showed isolated TP53 alteration and were subjected to a comprehensive analysis. RESULTS: The average age at diagnosis was 65 years (range 48-79); 9 males and 5 females. All were smokers with an average pack-year of 41 (range 10-70). Nine had metastases, mostly in the brain (n = 2) and pleura (n = 2). After a follow-up period of up to 102 months, 9 died, 4 were alive with disease, and 1 was lost to follow-up. The median survival was 13 months. Most tumors exhibited poor differentiation, composed of solid sheets with moderate to severe atypia, increased mitotic activity, and necrotic background. Half were positive for TTF-1 and showed p53 overexpression. PD-L1 was positive in 6 cases. Most alterations were missense mutations in exons 5-8, and this mutation type was associated with p53 overexpression. Tumors with combined missense mutation and truncated protein had higher PD-L1 expression and significantly shorter overall survival, along with a trend towards an increase in tumor mutational burden (TMB). CEBPA deletion of undetermined significance was the most common copy number alteration. CONCLUSION: Isolated TP53 mutation was seen in association with smoking, high-grade cytomorphologic features, adverse prognosis, and recurrent CEBPA deletions. These tumors tend to have strong PD-L1 expression and high TMB, suggesting potential benefit from immune checkpoint inhibitors. Hence, the recognition of this molecular group has prognostic and therapeutic implications.

15.
J Gen Intern Med ; 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38191972

RESUMO

The medical-legal partnership (MLP) model is emerging across the USA as a powerful tool to address the adverse social conditions underlying health injustice. MLPs embed legal experts into healthcare teams to address health-harming legal needs with civil legal remedies. We conducted a narrative review of peer-reviewed articles published between 2007 and 2022 to characterize the structure and impacts of US MLPs on patients, providers, and healthcare systems. We found that MLPs largely serve vulnerable patient populations by integrating legal experts into community-based clinical settings or children's hospitals, although patient populations and settings varied widely. In most models, healthcare providers were trained to screen patients for legal needs and refer them to legal experts. MLPs provided a wide range of services, such as assistance accessing public benefits (e.g., Social Security, Medicaid, cash assistance) and legal representation for immigration and family law matters. Patients and their families also benefited from increased knowledge about legal rights and systems. Though the evidence base remains nascent, available studies show MLPs to be associated with greater access to care, fewer hospitalizations, and improved physical and mental health outcomes. Medical and legal providers who were engaged in MLPs reported interdisciplinary learning, and healthcare systems often experienced high returns on investment through cost savings and increased Medicaid reimbursement. Many MLPs also conducted advocacy and education to effect broader policy changes related to population health and social needs. To optimize the MLP model, more rigorous research, systematic implementation practices, evaluation metrics, and sustainable funding mechanisms are recommended. Broader integration of MLPs into healthcare systems could help address root causes of health inequity among historically marginalized populations in the USA.

16.
Sci Justice ; 64(1): 28-37, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38182310

RESUMO

Application of isotope ratio mass spectrometry (IRMS) to skeletal remains has become an important tool to investigate human behavior and history. Isotopic variations in collagen, enamel, and keratin reflect variations in an individual's diet and drinking water. Since food and water sources typically are geographically linked, isotope testing can assist in forensic identification by classifying remains to a likely geographic or population origin. If remains are commingled, differences in diet or geographic origin also can support their separation. The usefulness of IRMS in forensic science is dependent on the underlying quality and surety of the isotope test results; in other words, we need to understand their reliability in interpretations. To take ownership of isotopic data quality, we recommend asking a series of questions:Here, we use data collected during the buildout and accreditation of an isotope testing program at the Defense POW/MIA Accounting Agency (DPAA) to answer the above questions for the forensic application of IRMS for human identification. While our primary focus is on the preparation and analysis of bone collagen, the questions above should be considered whenever isotope testing is used in forensic casework. Whether the populations of interest are drugs or humans, olives or explosives, users need to evaluate their isotopic data and interpretations to ensure they are scientifically sound and legally defensible.


Assuntos
Restos Mortais , Antropologia Forense , Humanos , Reprodutibilidade dos Testes , Isótopos , Colágeno
17.
Proc Natl Acad Sci U S A ; 121(4): e2311132121, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38227667

RESUMO

Forests are integral to the global land carbon sink, which has sequestered ~30% of anthropogenic carbon emissions over recent decades. The persistence of this sink depends on the balance of positive drivers that increase ecosystem carbon storage-e.g., CO2 fertilization-and negative drivers that decrease it-e.g., intensifying disturbances. The net response of forest productivity to these drivers is uncertain due to the challenge of separating their effects from background disturbance-regrowth dynamics. We fit non-linear models to US forest inventory data (113,806 plot remeasurements in non-plantation forests from ~1999 to 2020) to quantify productivity trends while accounting for stand age, tree mortality, and harvest. Productivity trends were generally positive in the eastern United States, where climate change has been mild, and negative in the western United States, where climate change has been more severe. Productivity declines in the western United States cannot be explained by increased mortality or harvest; these declines likely reflect adverse climate-change impacts on tree growth. In the eastern United States, where data were available to partition biomass change into age-dependent and age-independent components, forest maturation and increasing productivity (likely due, at least in part, to CO2 fertilization) contributed roughly equally to biomass carbon sinks. Thus, adverse effects of climate change appear to overwhelm any positive drivers in the water-limited forests of the western United States, whereas forest maturation and positive responses to age-independent drivers contribute to eastern US carbon sinks. The future land carbon balance of forests will likely depend on the geographic extent of drought and heat stress.


Assuntos
Mudança Climática , Ecossistema , Estados Unidos , Dióxido de Carbono , Florestas , Árvores , Biomassa , Carbono
20.
Heliyon ; 9(11): e21403, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38027919

RESUMO

Determination of solubility parameters by dissolution tests are difficult for some valuable molecules, such as proteins, where the quantities available are small, UV-vis spectroscopy can determine dissolved concentrations of even small amounts of material, but accurate determination of dissolution is difficult in relatively poor solvents, due to difficulty with constructing a reliable calibration curve. In this work we report a new simple procedure to determine the relative dissolution of proteins in various solvents using UV vis spectroscopy for the determination of Hansen solubility parameters (HSP) of proteins. This method allows qualitative determination of the amounts of BSA dissolved in various solvents. The amounts of BSA dissolved in each solvent, can then be used to rank solvents as good or bad for HSP calculation purpose, which gives more reliable ranking than observation alone in dissolution tests. To be able to evaluate the HSP of any solid material, the solubility of the tested material in a range of solvents needs to be determined. Solvents are then scored as good or bad based on observations and from the known properties of those solvents, the HSP of the solute molecule in question can be calculated. Here, bovine serum albumin (BSA) was used as a model protein, but the procedure reported here can be applied to any soluble protein or other macromolecule with a clear UV/vis adsorption peak. This procedure requires the tested material to be highly soluble in water, therefore eliminating the need for the preparation of many standard solutions of BSA in different solvents. Only a set of standard solutions of protein in water is required. UV-vis spectroscopy was used to analyze the remaining solid resuspended in water after centrifugation of solutions of BSA dissolved in other solvents to separate any undissolved protein. The HSP of BSA obtained via this procedure was compared to values previously obtained for BSA using other methods. A very good agreement between the HSP obtained in this work with the that reported by Houen et al. which used amino acid analysis for the estimation of the solubility of BSA in various organic solvents.

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