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1.
Phys Rev Lett ; 132(17): 176703, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38728713

RESUMO

We report the picosecond spin current generation from the interface between a heavy metal and a vicinal antiferromagnet insulator Cr_{2}O_{3} by laser pulses at room temperature and zero magnetic field. It is converted into a detectable terahertz emission in the heavy metal via the inverse spin Hall effect. The vicinal interfaces are apparently the source of the picosecond spin current, as evidenced by the proportional terahertz signals to the vicinal angle. We attribute the origin of the spin current to the transient magnetic moment generated by an interfacial nonlinear magnetic-dipole difference-frequency generation. We propose a model based on the in-plane inversion symmetry breaking to quantitatively explain the terahertz intensity with respect to the angles of the laser polarization and the film azimuth. Our work opens new opportunities in antiferromagnetic and ultrafast spintronics by considering symmetry breaking.

2.
Eur Rev Med Pharmacol Sci ; 28(8): 3073-3084, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38708466

RESUMO

OBJECTIVE: The aim of this study was to investigate and evaluate the risk of dyspepsia and anorexia in patients with type 2 diabetes mellitus (T2DM) induced by glucagon-like peptide 1 receptor agonist (GLP-1 RA) hypoglycemic drugs. MATERIALS AND METHODS: We searched papers in PubMed, Web of Science, Cochrane Library, Google Scholar, CNKI, Wanfang, Embase, and VIP databases, and the retrieval time limit was set from the establishment of the database to May 2023. Randomized Controlled Trials (RCTs) were collected in which the subjects were T2DM patients, the intervention was GLP-1RA compared with placebo or traditional hypoglycemic drugs, and the outcome indicators included dyspepsia and anorexia. A meta-analysis and a network meta-analysis were performed. RESULTS: The results of the traditional meta-analysis showed that the risk of dyspepsia and anorexia of total GLP-1 RA was 3.01 and 2.56 times that of placebo, respectively. All types of GLP-1RA were compared with placebo and the results also showed a trend towards increased risk of digestive system adverse events (DSAEs). Among all interventions included, liraglutide was the one with the highest risk of dyspepsia in patients with T2DM, and dulaglutide was the one with the highest risk of anorexia. CONCLUSIONS: The results of the two meta-analyses are consistent, and both clearly show that GLP-1RA can increase the risk of dyspepsia and anorexia in T2DM patients.


Assuntos
Anorexia , Diabetes Mellitus Tipo 2 , Dispepsia , Receptor do Peptídeo Semelhante ao Glucagon 1 , Hipoglicemiantes , Humanos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/complicações , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Dispepsia/tratamento farmacológico , Dispepsia/induzido quimicamente , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/uso terapêutico , Anorexia/induzido quimicamente , Anorexia/tratamento farmacológico , Metanálise em Rede , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
J Dent Res ; 103(5): 546-554, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38619065

RESUMO

The intricate formation of the palate involves a series of complex events, yet its mechanistic basis remains uncertain. To explore major cell populations in the palate and their roles during development, we constructed a spatiotemporal transcription landscape of palatal cells. Palate samples from C57BL/6 J mice at embryonic days 12.5 (E12.5), 14.5 (E14.5), and 16.5 (E16.5) underwent single-cell RNA sequencing (scRNA-seq) to identify distinct cell subsets. In addition, spatial enhanced resolution omics-sequencing (stereo-seq) was used to characterize the spatial distribution of these subsets. Integrating scRNA-seq and stereo-seq with CellTrek annotated mesenchymal and epithelial cellular components of the palate during development. Furthermore, cellular communication networks between these cell subpopulations were analyzed to discover intercellular signaling during palate development. From the analysis of the middle palate, both mesenchymal and epithelial populations were spatially segregated into 3 domains. The middle palate mesenchymal subpopulations were associated with tooth formation, ossification, and tissue remodeling, with initial state cell populations located proximal to the dental lamina. The nasal epithelium of the palatal shelf exhibited richer humoral immune responses than the oral side. Specific enrichment of Tgfß3 and Pthlh signals in the midline epithelial seam at E14.5 suggested a role in epithelial-mesenchymal transition. In summary, this study provides high-resolution transcriptomic information, contributing to a deeper mechanistic understanding of palate biology and pathophysiology.


Assuntos
Camundongos Endogâmicos C57BL , Palato , Animais , Camundongos , Palato/embriologia , Fator de Crescimento Transformador beta3/genética , Análise de Célula Única , Células Epiteliais , Análise de Sequência de RNA , Regulação da Expressão Gênica no Desenvolvimento , Feminino
4.
Artigo em Chinês | MEDLINE | ID: mdl-38677995

RESUMO

Dinitrogen tetroxide is often used as an oxidant in rocket propellant and has strong irritant and corrosive properties. This paper analyzes the clinical data of a patient with dinitrogen tetroxide poisoning admitted in the 63710 Army Hospital of Chinese People's Liberation Army, so as to further explore the poisoning mechanism, clinical characteristics and key points of acute inhaled dinitrogen tetroxide poisoning.


Assuntos
Humanos , Masculino , Adulto
5.
Zhonghua Liu Xing Bing Xue Za Zhi ; 45(4): 513-519, 2024 Apr 10.
Artigo em Chinês | MEDLINE | ID: mdl-38678346

RESUMO

Objective: To analyze the spatial-temporal distribution of etiologically positive pulmonary tuberculosis (PTB) at the county (city, district) unit in Jiangsu Province from 2011 to 2021 to provide evidence for the implementation and adjustment of prevention and control strategies of PTB in Jiangsu Province. Methods: The registration data of etiologically positive PTB patients in Jiangsu Province from 2011 to 2021 were collected from the Tuberculosis Management Information System in the China Information System of Disease Control and Prevention. Data on the permanent population were from the statistical yearbook of each county (city, district) in Jiangsu Province. Geoda 1.18.0 software was used to analyze the global and local spatial autocorrelation and explore the spatial clustering. SaTScan 10.1 software was used to analyze the spatial-temporal clusters, and ArcGIS 10.7 software was used to visualize the spatial-temporal clusters. Results: A total of 128 240 etiological positive PTB cases were registered in Jiangsu Province from 2011 to 2021, with an average annual registration rate of 13.99/100 000. The registration rate showed an overall upward trend (trend χ2=63.49, P<0.001) after 2017, and the etiologically positive rate showed an overall upward trend (trend χ2=3 710.86, P<0.001). The annual Moran's I values ranged from 0.107 to 0.343, which showed a spatial clustering distribution. The results of local spatial autocorrelation analysis showed that there were "high-high" clustering areas in Jiangsu Province each year, showing a dynamic distribution, and most of the areas were distributed in the central and southern regions of Jiangsu Province, with the largest number (7) in 2015 and the smallest number (1) in 2011. A total of 4 spatial-temporal clustering areas were explored by spatial-temporal scanning analysis (all P<0.001), among which the first-level clustering area covered 3 counties (cities, districts), namely Changshu, Taicang, and Xiangcheng District of Suzhou, and the clustering time was from 2011 to 2015. The secondary clustering areas covered 24 counties (cities, districts), mainly covering Jiangsu's central and northern regions, such as Huai'an, Suqian, and Yancheng. The third-level clustering areas covered 26 counties (cities, districts); the fourth-level clustering area was the Gaochun District of Nanjing, with the clustering period from 2017 to 2021. Conclusions: From 2011 to 2021, the etiologically positive PTB registration rate at the county (city, district) level in Jiangsu Province had obvious spatial-temporal clustering characteristics. The clustering areas included the northern areas with relatively backward economies and the southern areas with better economic development. Multiple measures should be taken to prevent and control PTB according to the specific situation in different regions.


Assuntos
Análise Espaço-Temporal , Tuberculose Pulmonar , Humanos , China/epidemiologia , Tuberculose Pulmonar/epidemiologia , Análise por Conglomerados , Sistemas de Informação Geográfica
8.
Zhonghua Nei Ke Za Zhi ; 63(4): 394-400, 2024 Apr 01.
Artigo em Chinês | MEDLINE | ID: mdl-38561285

RESUMO

Objective: To deepen understanding of IgG4-related diseases (RDs), we analyzed the associated lymphocyte subtypes, and explored the pathogenesis and potential immunotherapeutic targets. Methods: Eighty-six patients with IgG4-RDs were enrolled, and their clinical characteristics, peripheral lymphocyte subtypes, and disease course were analyzed. Results: The mean age of the participants was 36-87(62±11) years; 51 were male (59.3%) and 35 were women (40.7%); and 34.9% had a history of allergy. Follow-up lasted 4.8 (0.4, 14.1) months. The most common symptoms were abdominal pain, and submandibular gland and lacrimal gland swelling (each 20.9%). Sixty-five (75.6%) participants had multiple organ involvement, and the most frequently affected organs were the pancreas (52.3%), submandibular gland (51.2%), and lacrimal gland (34.9%). A high eosinophil count; high IgE, IgG, IgG1, and IgG4 concentrations; and low complement C3 and C4 concentrations were present in 18.8% (16/85), 30.0% (24/80), 72.9% (62/85), 58.3% (28/48), 89.5% (77/86), 61.2% (52/85), and 50.0% (42/84), respectively, of the participants. In addition, 64.7% (55/85) were positive for autoantibodies, and the most frequent was anti-nuclear antibody (63.5%). The proportion of CD4+T lymphocytes increased in 25.7% (9/35) of the participants, which was accompanied by an increase in the ratio of CD4+/CD8+T lymphocytes (22.9%, 8/35). Importantly, most participants (90.0%, 18/20) had a high proportion of regulatory T (Treg) cells. High interleukin (IL)-2, IL-6, and IL-10 concentrations were present in 50.0% (11/22), 33.3% (10/30), and 16.7% (5/30), respectively, of the participants. Substantial lymphoplasmacytic infiltration, fibrosis, IgG4-positive plasma cell infiltration, and lymphoid follicle hyperplasia or ectopic formation were present in 79.2% (42/53), 67.9%(36/53), 35.8%(19/53) and 30.2% (16/53), respectively, of the participants. Fifty-three participants with detailed pathologic data were also further evaluated, of whom 24.5% (13/53), 3.8% (2/53), and 67.9% (36/53) had definite, probable, and possible diagnoses; and 3.8% (2/53) could not be diagnosed. Compared with baseline, the percentage of eosinophils and the IgE, IgG, and IgG4 concentrations decreased significantly; and the complement C3 and C4 concentrations had increased significantly after 6 months of treatment (all P<0.05). The IgG4 concentration after 6 months of treatment negatively correlated with that of C4, and positively correlated with the baseline concentration of IgE and the IgG4/IgG ratio. Conclusion: IgG4-RDs are a group of diseases characterized by male predisposition; multiple organ involvement; a high eosinophil count; high IgE, IgG, IgG1, and IgG4 concentrations; and a low C3 concentration. Peripheral CD4+T cells and Treg cells are also more abundant. The diseases can be controlled with glucocorticoids and immunosuppressive drugs in the majority of instances. The IgG4 concentration after 6 months of treatment negatively correlates with the baseline complement C4 concentration and positively correlates with the IgE concentration and IgG4/IgG ratio, which suggests that IgG4/IgG, IgE, and complement should be closely monitored to evaluate disease activity and the efficacy of treatment in such patients.


Assuntos
Complemento C3 , Imunoglobulina G , Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Glucocorticoides/uso terapêutico , Linfócitos , Imunoglobulina E
9.
eNeuro ; 11(4)2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38569920

RESUMO

Most neuroeconomic research seeks to understand how value influences decision-making. The influence of reward type is less well understood. We used functional magnetic resonance imaging (fMRI) to investigate delay discounting of primary (i.e., food) and secondary rewards (i.e., money) in 28 healthy, normal-weighted participants (mean age = 26.77; 18 females). To decipher differences in discounting behavior between reward types, we compared how well-different option-based statistical models (exponential, hyperbolic discounting) and attribute-wise heuristic choice models (intertemporal choice heuristic, dual reasoning and implicit framework theory, trade-off model) captured the reward-specific discounting behavior. Contrary to our hypothesis of different strategies for different rewards, we observed comparable discounting behavior for money and food (i.e., exponential discounting). Higher k values for food discounting suggest that individuals decide more impulsive if confronted with food. The fMRI revealed that money discounting was associated with enhanced activity in the right dorsolateral prefrontal cortex, involved in executive control; the right dorsal striatum, associated with reward processing; and the left hippocampus, involved in memory encoding/retrieval. Food discounting, instead, was associated with higher activity in the left temporoparietal junction suggesting social reinforcement of food decisions. Although our findings do not confirm our hypothesis of different discounting strategies for different reward types, they are in line with the notion that reward types have a significant influence on impulsivity with primary rewards leading to more impulsive choices.


Assuntos
Desvalorização pelo Atraso , Feminino , Humanos , Adulto , Desvalorização pelo Atraso/fisiologia , Recompensa , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Comportamento Impulsivo/fisiologia , Hipocampo , Imageamento por Ressonância Magnética/métodos , Comportamento de Escolha/fisiologia
10.
Zhonghua Fu Chan Ke Za Zhi ; 59(4): 299-306, 2024 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-38644276

RESUMO

Objective: To explore the value of optical coherence tomography (OCT) imaging system in evaluating cervical lesions in vivo. Methods: A total of 1 214 patients with cervical lesions were collected from January 2020 to December 2021 in the Third Affiliated Hospital of Zhengzhou University, Maternal and Chlid Heaith Hospital of Gushi County, Xinyang City, Henan Province, and Maternal and Chlid Heaith Hospital of Sui County, Shangqiu City, Henan Province. The age of the patients was (38.9±10.5) years (range: 16-77 years). All patients underwent in vivo cervical OCT examination and cervical biopsy pathology examination, and summarized the OCT image features of in vivo cervical lesions. Using the pathological diagnosis as the "gold standard", the accuracy, specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) of OCT image interpretation results were evaluated, as well as the consistency of OCT image diagnosis and pathological diagnosis. At the same time, the in vivo cervical OCT imaging system, as a newly developed screening tool, was compared with the traditional combined screening of human papillomavirus (HPV) and Thinprep cytologic test (TCT), to assess the screening effect. Results: By comparing the OCT images of the cervix in vivo with the corresponding HE images, the OCT image characteristics of the normal cervix and various types of cervical lesions in vivo were summarized. The accuracy, sensitivity, specificity, PPV and NPV of OCT image in the diagnosis of high-grade squamous intraepithelial lesion (HSIL) and above (HSIL+) were 93.4%, 88.5%, 95.0%, 85.0% and 96.2%, respectively. The accuracy, sensitivity, specificity, PPV and NPV of OCT for low-grade squamous intraepithelial lesion (LSIL) were 84.7%, 61.7%, 96.3%, 89.3% and 83.2%, respectively. The consistency between OCT image diagnosis and pathological diagnosis was strong (Kappa value was 0.701).The accuracy, sensitivity and specificity of OCT screening, HPV and TCT combined screening were 83.7% vs 64.9% (χ²=128.82, P<0.001), 77.8% vs 64.5% (χ²=39.01, P<0.001), 91.8% vs 65.4% (χ²=98.12, P<0.001), respectively. The differences were statistically significant. Conclusions: OCT imaging system has high sensitivity and specificity in the evaluation of cervical lesions in vivo, and has the characteristics of non-invasive, real-time and high efficiency. OCT examination is expected to become an effective method for the diagnosis of cervical lesions and cervical cancer screening.


Assuntos
Colo do Útero , Sensibilidade e Especificidade , Tomografia de Coerência Óptica , Neoplasias do Colo do Útero , Humanos , Feminino , Tomografia de Coerência Óptica/métodos , Adulto , Neoplasias do Colo do Útero/diagnóstico por imagem , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/diagnóstico , Pessoa de Meia-Idade , Colo do Útero/diagnóstico por imagem , Colo do Útero/patologia , Adolescente , Idoso , Displasia do Colo do Útero/diagnóstico por imagem , Displasia do Colo do Útero/patologia , Displasia do Colo do Útero/diagnóstico , Infecções por Papillomavirus/diagnóstico , Adulto Jovem , Esfregaço Vaginal , Biópsia , Valor Preditivo dos Testes , Detecção Precoce de Câncer/métodos
13.
Zhonghua Xue Ye Xue Za Zhi ; 45(1): 74-81, 2024 Jan 14.
Artigo em Chinês | MEDLINE | ID: mdl-38527842

RESUMO

Objective: To investigated the safety and efficacy of donor-derived CD19+ or sequential CD19+ CD22+ chimeric antigen receptor T-cell (CAR-T) therapy in patients with B-cell acute lymphoblastic leukemia (B-ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: The data of 22 patients with B-ALL who relapsed after allo-HSCT and who underwent donor-derived CAR-T therapy at the Zhujiang Hospital of Southern Medical University and the 920th Hospital of Joint Logistics Support Force of the People's Liberation Army of China from September 2015 to December 2022 were retrospectively analyzed. The primary endpoint was overall survival (OS), and the secondary endpoints were event-free survival (EFS), complete remission (CR) rate, and Grade 3-4 adverse events. Results: A total of 81.82% (n=18) of the 22 patients achieved minimal residual disease-negative CR after CAR-T infusion. The median follow-up time was 1037 (95% CI 546-1509) days, and the median OS and EFS were 287 (95% CI 132-441) days and 212 (95% CI 120-303) days, respectively. The 6-month OS and EFS rates were 67.90% (95% CI 48.30%-84.50%) and 58.70% (95% CI 37.92%-79.48%), respectively, and the 1-year OS and EFS rates were 41.10% (95% CI 19.15%-63.05%) and 34.30% (95% CI 13.92%-54.68%), respectively. Grade 1-2 cytokine release syndrome occurred in 36.36% (n=8) of the patients, and grade 3-4 occurred in 13.64% of the patients (n=3). Grade 2 and 4 graft-versus-host disease occurred in two patients. Conclusion: Donor-derived CAR-T therapy is safe and effective in patients with relapsed B-ALL after allo-HSCT.


Assuntos
Linfoma de Burkitt , Transplante de Células-Tronco Hematopoéticas , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Leucemia-Linfoma Linfoblástico de Células Precursoras , Receptores de Antígenos Quiméricos , Humanos , Estudos Retrospectivos , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Imunoterapia Adotiva/efeitos adversos , Antígenos CD19 , Resposta Patológica Completa , Síndrome da Liberação de Citocina/etiologia
14.
Zhonghua Yu Fang Yi Xue Za Zhi ; 58: 1-7, 2024 Feb 23.
Artigo em Chinês | MEDLINE | ID: mdl-38403282

RESUMO

Objective: To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023. Methods: The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed. Results: A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M (Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant (P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age (P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion: Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

15.
Rep Prog Phys ; 87(3)2024 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-38306662

RESUMO

The interaction between dark matter and dark energy (DE) can be incorporated into field theory models of DE that have proved successful in alleviating the coincidence problem. We review recent advances in this field, including new models and constraints from different astronomical data sets. We show that interactions are allowed by observations and can reduce the current tensions among different measurements of cosmological parameters. We extend our discussion to include constraints from non-linear effects and results from cosmological simulations. Finally, we discuss forthcoming multi-messenger data from current and future observational facilities that will help to improve our understanding of the interactions within the dark sector.

16.
Zhonghua Yu Fang Yi Xue Za Zhi ; 58(2): 177-182, 2024 Feb 06.
Artigo em Chinês | MEDLINE | ID: mdl-38387947

RESUMO

Many childhood cancer survivors are suffering serious and long-lasting complications or sequelae, taking a significant toll on their health. Adequate physical activity can be effective in mitigating the negative effects of these complications or sequelae. However, low levels of physical activity are prevalent among childhood cancer survivors. Due to the lack of guidelines on physical activity for childhood cancer survivors, there are many difficulties in correctly guiding childhood cancer survivors to participate in physical activity. Therefore, it is necessary to summarize the relevant studies on the physical activity of childhood cancer survivors. This article provides a review of the concept and measurement of physical activity, recommended amount, and the participation of childhood cancer survivors both domestically and internationally, in order to provide a reference for promoting the physical activity level of Chinese childhood cancer survivors.


Assuntos
Sobreviventes de Câncer , Neoplasias , Humanos , Criança , Sobreviventes , Exercício Físico
17.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 59(1): 110-115, 2024 Jan 09.
Artigo em Chinês | MEDLINE | ID: mdl-38172071

RESUMO

Cleft palate is one of the most common maxillofacial birth defects, which can occur alone or accompany with many known deformities. Palatal selves need to complete the process of vertical growth, elevation, adhesion and fusion in a specific time window of embryo development. Any abnormality in this process will lead to cleft palate. Although previous studies have identified many molecular networks that regulate the growth, location and fusion of palatal selves, there are still many unknown mechanisms for palatal development. The pathogenesis of cleft palate has not been clarified so far. In recent years, the molecular research on palate development has been deepened continuously. Here we summarize major recent advances and integrate the genes and molecular pathways with the cellular and morphogenetic processes of palatal shelf growth, patterning, elevation, adhesion, and fusion, in order to comprehensively understand the genotype-phenotype functional relationship and provide assistance in formulating effective prevention strategies for cleft palate disease.


Assuntos
Fissura Palatina , Humanos , Fissura Palatina/genética , Palato , Morfogênese/genética
19.
bioRxiv ; 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38260539

RESUMO

Recent studies in mice have indicated that the gut microbiome can regulate bone tissue strength. However, prior work involved modifications to the gut microbiome in growing animals and it is unclear if the same changes in the microbiome, applied later in life, would change matrix strength. Here we changed the composition of the gut microbiome before and/or after skeletal maturity (16 weeks of age) using oral antibiotics (ampicillin + neomycin). Male and female mice (n=143 total, n=12-17/group/sex) were allocated into five study groups:1) Unaltered, 2) Continuous (dosing 4-24 weeks of age), 3) Delayed (dosing only 16-24 weeks of age), 4) Initial (dosing 4-16 weeks of age, suspended at 16 weeks), and 5) Reconstituted (dosing from 4-16 weeks following by fecal microbiota transplant from Unaltered donors). Animals were euthanized at 24 weeks of age. In males, bone matrix strength in the femur was 25-35% less than expected from geometry in mice from the Continuous (p= 0.001), Delayed (p= 0.005), and Initial (p=0.040) groups as compared to Unaltered. Reconstitution of the gut microbiota, however, led to a bone matrix strength similar to Unaltered animals (p=0.929). In females, microbiome-induced changes in bone matrix strength followed the same trend as males but were not significantly different, demonstrating sex-related differences in the response of bone matrix to the gut microbiota. Minor differences in chemical composition of bone matrix were observed (Raman spectroscopy). Our findings indicate that microbiome-induced impairment of bone matrix in males can be initiated and/or reversed after skeletal maturity. The portion of the femoral cortical bone formed after skeletal maturity (16 weeks) is small; however, this suggests that microbiome-induced changes in bone matrix occur without osteoblast/osteoclast turnover using an, as of yet unidentified mechanism. These findings add to evidence that the mechanical properties of bone matrix can be altered in the adult skeleton.

20.
J Environ Manage ; 351: 119726, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38052142

RESUMO

Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland-forest stabilized by vegetation-fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation-fire feedbacks; in forest, vegetation-fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation-fire feedbacks that suppress wildfire.


Assuntos
Incêndios , Incêndios Florestais , Ecossistema , Retroalimentação , Florestas , Árvores
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