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Oligocene-Pliocene shale reservoirs in the Western Qaidam Depression represent typical mixed shale deposits characterized by moderate organic matter (OM) abundance and sufficient OM maturity, indicating substantial shale-oil resource potential. Here, a comprehensive study was conducted to analyze the reservoir characteristics of different shale types, including the Upper Xiaganchaigou (late Oligocene), Shangganchaigou (Miocene), and Xiayoushashan (early Pliocene) Formations in the Western Qaidam Depression. Our analysis focused on the pore structural characteristics of shale reservoirs, employing X-ray diffraction, casting thin sections, scanning electron microscopy, low-temperature nitrogen adsorption, and nuclear magnetic resonance (NMR) as investigative techniques. Our results show that (1) the study area comprises five typical shale types: lime shale, argillaceous shale, limestone, argillaceous limestone, and mudstone. The best hydrocarbon source rock conditions are found in the lime shale and argillaceous shale. (2) Inorganic pores, including dissolution pores, intergranular pores, bedding fractures, structural fractures, and intraparticle pores in clay minerals, are the main pore types found in the studied samples and constitute the primary reservoir space for shale oil. On the basis of fractal dimensions obtained through NMR, the pores can be classified as micropores (<100 nm), mesopores (100-1000 nm), or macropores (>1000 nm). Mesopores are the main contributors to porosity. (3) The development of micropores is positively correlated with clay mineral content. The development of mesopores and macropores is influenced by the quartz, feldspar, dolomite, and calcite contents. Calcite content exhibits a negative correlation with porosity, suggesting that later-stage pore cementation hinders shale reservoir development. (4) The five typical shale reservoirs in the study area can be categorized into three types. Type I reservoir lithologies include lime shale and argillaceous shale; type II reservoir lithologies include limestone and argillaceous limestone; and type III reservoirs comprise mudstone. Type I and II reservoirs are of better quality than type III.
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Layered transition metal oxides are extensively considered as appealing cathode candidates for potassium-ion batteries (PIBs) due to their abundant raw materials and low cost, but their further implementations are limited by slow dynamics and impoverished structural stability. Herein, a layered composite having a P2 and P3 symbiotic structure is designed and synthesized to realize PIBs with large energy density and long-term cycling stability. The unique intergrowth of P2 and P3 phases in the obtained layered oxide is plainly characterized by X-ray diffraction refinement, high-angle annular dark field and annular bright field-scanning transmission electron microscopy at atomic resolution, and Fourier transformation images. The synergistic effect of the two phases of this layered P2/P3 composite is well demonstrated in K+ intercalation/extraction process. The as-prepared layered composite can present a large discharge capacity with the remarkable energy density of 321â Wh kg-1 and also manifest excellent capacity preservation after 600â cycles of K+ uptake/removal.
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BACKGROUND: Necrotizing enterocolitis (NEC) is the most common severe gastrointestinal emergency in neonates. We designed this study to identify the pathogenic microorganisms of NEC in the microbiota of the small intestine of neonates. METHODS: Using the 16S ribosomal DNA (rDNA) sequencing method, we compared and analyzed the structure and diversity of microbiotas in the intestinal feces of different groups of neonates: patients undergoing jejunostomy to treat NEC (NP group), neonates undergoing jejunostomy to treat other conditions (NN group), and neonates with NEC undergoing conservative treatment (NC group). We took intestinal feces and saliva samples from patients at different time points. RESULTS: The beta diversities of the NP, NN, and NC groups were all similar. When comparing the beta diversities between different time points in the NP group, we found similar beta diversities at time points E1 to E3 but significant differences between the E2-E3 and E4 time points: the abundances of Klebsiella and Enterococcus (Proteobacteria) were higher at the E1-E3 time points; the abundance of Escherichia-Shigella (Proteobacteria) increased at the E2 time point, and the abundance of Klebsiella decreased significantly, whereas that of Streptococcus increased significantly at the E4 time point. CONCLUSIONS: Our results suggest that the pathological changes of intestinal necrosis in the small intestine of infants with NEC are not directly caused by excessive proliferation of pathogenic bacteria in the small intestine. The sources of microbiota in the small intestine of neonates, especially in premature infants, may be affected by multiple factors.
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Enterocolite Necrosante , Doenças Fetais , Doenças do Recém-Nascido , Lactente , Feminino , Recém-Nascido , Humanos , RNA Ribossômico 16S/genética , Recém-Nascido Prematuro , Intestinos/microbiologia , Intestino DelgadoRESUMO
The change in larval body length of necrophagous flies during their development is a key indicator for estimating larval age. However, existing forensic entomological models have limitations in this regard. In this study, a logistic algorithm was used to establish a general model for estimating the minimum postmortem interval (PMImin) using larval body length. The new model was used to simulate the relationship between larval body length and developmental time of eight species of necrophagous flies. The model parameters of body length variation with developmental time of the different species were calculated. Computer software was developed based on the established logistic model. The advantage of the new model is that each parameter has a biological meaning and can be used to estimate the age of larvae at any temperature and any larval body length. Cross-validation of the model showed that the overall mean accuracy of the fitted growth curves for the eight necrophagous fly larvae was 82.7%, the mean accuracy of age extrapolations for seven necrophagous fly species ranged from 76.8% to 92.9%, while the accuracy of age extrapolations for only one species was lower (i.e., 63.3%). This study provides a new method to estimate the PMImin based on larval body length, and the developed computer software will facilitate its application in forensic entomology.
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Dípteros , Ciências Forenses , Animais , Entomologia , Mudanças Depois da Morte , Comportamento Alimentar , Larva , Modelos Logísticos , SoftwareRESUMO
Wheat pests and diseases are one of the main factors affecting wheat yield. According to the characteristics of four common pests and diseases, an identification method based on improved convolution neural network is proposed. VGGNet16 is selected as the basic network model, but the problem of small dataset size is common in specific fields such as smart agriculture, which limits the research and application of artificial intelligence methods based on deep learning technology in the field. Data expansion and transfer learning technology are introduced to improve the training mode, and then attention mechanism is introduced for further improvement. The experimental results show that the transfer learning scheme of fine-tuning source model is better than that of freezing source model, and the VGGNet16 based on fine-tuning all layers has the best recognition effect, with an accuracy of 96.02%. The CBAM-VGGNet16 and NLCBAM-VGGNet16 models are designed and implemented. The experimental results show that the recognition accuracy of the test set of CBAM-VGGNet16 and NLCBAM-VGGNet16 is higher than that of VGGNet16. The recognition accuracy of CBAM-VGGNet16 and NLCBAM-VGGNet16 is 96.60 and 97.57%, respectively, achieving high precision recognition of common pests and diseases of winter wheat.
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Forensic entomology case reports are the product of rapid development in the field, the widespread acceptance of the science and the application of forensic entomological knowledge. In this study, we retrospectively summarized information derived from 307 forensic entomology case reports from 1935 to 2022 from a global perspective. Our checklist of relevant information included insect species, specific indoor or outdoor preferences, preferred temperatures, and stages of body decomposition. Finally, a concept and calculation method for postmortem interval (PMI) estimation accuracy was proposed. There were 232 cases using insect developmental data and 28 cases using succession patterns to estimate PMI. A total of 146 species of insects were involved in the cases, of which 62.3% were Diptera and 37.7% were Coleoptera. Postmortem intervals were estimated from eggs in 4 cases, larvae in 180 cases, pupae in 45 cases, and puparia in 38 cases. The majority of cases were from June to October, and the average number of species mentioned in the cases was more at 15-30 °C. Considering the standardization of application, in the majority of cases, insect evidence was collected by other personnel and sent to forensic entomologists, there was a delay in the sampling, and the scene or meteorological data were directly used without correcting. Our data shows that there are still many shortcomings in the universality and standardization of forensic entomology in its practical application.
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Autoantibodies are associated with neuroimmune diseases that affect the central and peripheral nervous systems. There are many methods for detecting autoantibodies, among which cell-based assay (CBA) is a relatively novel and important technology that is widely used. CBAs, as novel indirect immunofluorescence assays with known antigen epitopes, have revolutionized the identification of autoantibodies compared with the traditional immunoassays, such as the radioimmunoprecipitation and enzyme-linked immunosorbent assays, as well as the tissue-based assays (TBAs). However, the results of the same sample might exhibit obvious differences between different laboratories, or among repeated testing in the same laboratory, which influence the sensitivity and specificity in the diagnostic performance for a specific neuroimmune disease. In this paper, we review the establishment of CBA technology, and discuss potential interfering factors in CBA methods on its sensitivity and specificity for the autoantibodies associated with neuroimmune diseases.
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INTRODUCTION/AIMS: Descriptions of the clinical characteristics of anti-AChR-MuSK-LRP4 antibody-negative myasthenia gravis (triple-negative myasthenia gravis, TNMG) are lacking in the current literature. Therefore, we investigated the clinical characteristics of TNMG in Chinese patients. METHODS: We retrospectively analyzed 925 patients with MG registered in the Department of Neuroimmunology, Henan Institute of Medical and Pharmaceutical Sciences from January 2015 to March 2021. RESULTS: One hundred six patients diagnosed with TNMG were included in the study. The average age of onset was 32.4 y, with a male-to-female ratio of 1:1. The age of onset showed a bimodal distribution: 0-9 y and 40-49 y. Adult patients were more likely to have weakness of limb and bulbar muscles (p < .05). Thymic hyperplasia was found in 20.2% of the patients. Younger patients were more likely to relapse. The rate of adult early-onset myasthenia gravis reaching complete stable remission and pharmacological remission was 47.6%, and the prognosis was better than that in juvenile-onset myasthenia gravis (p = .019). Older age of onset was the only risk factor for the development of generalized TNMG from ocular TNMG (R = 1.046, p = .002, 95% confidence interval 1.017-1.077). DISCUSSION: This study showed that the clinical characteristics of patients with TNMG varied among the different age groups. Significant findings included a bimodal distribution of onset age, coexisting thymic hyperplasia, and a generally favorable prognosis.
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Miastenia Gravis , Hiperplasia do Timo , Adulto , Humanos , Masculino , Feminino , Receptores Colinérgicos , Estudos Retrospectivos , Receptores Proteína Tirosina Quinases , Autoanticorpos , Recidiva Local de Neoplasia , Miastenia Gravis/diagnóstico , Miastenia Gravis/epidemiologia , China/epidemiologia , Proteínas Relacionadas a Receptor de LDLRESUMO
Purpose: This study aimed to clarify the effect of early glucocorticoid (GC) application on achieving minimal manifestation (MM) status or better in the treatment of myasthenia gravis (MG) in the early clinical phase. Methods: A retrospective analysis was performed using data from 336 patients with MG who received GC therapy from January 2015 to September 2022 in the Zhengzhou University Henan Institute of Medical and Pharmaceutical Sciences Myasthenia Gravis Biobank (ZMB). Patients were divided into two groups: the early mono-GC group (treated with GC within 6 months of MG onset) and the delayed mono-GC group. Results: Kaplan-Meier analysis showed that the early mono-GC group achieved MM status earlier and more frequently than the delayed mono-GC group (log-rank test, p = 0.0082; hazard ratio [HR], 1.66; p = 0.011). The early mono-GC group had a lower maintenance oral GC dose than the delayed mono-GC group. In multivariate Cox regression analysis, early mono-GC (HR, 1.50; p = 0.043), early-onset MG (EOMG) (HR, 1.74; p = 0.034), and ocular MG (OMG) (HR, 1.90; p = 0.007) were associated with MM status or better. In conclusion, early mono-GC, EOMG, and OMG were positive predictors of treatment goals. In EOMG, OMG, and acetylcholine receptor antibody-positive MG (AChR-MG) subgroups, the maintenance oral GC doses in the early mono-GC group were significantly lower than the doses in the delayed mono-GC group (p < 0.05). Conclusion: Early intervention with GC led to better long-term outcomes and reduced the necessary maintenance dose of oral GC for patients with MG. EOMG and OMG were positive predictors of MM status or better with mono-GC.
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Myasthenia gravis (MG) is characterized by autoimmune damage to the postsynaptic membrane of the neuromuscular junction (NMJ) with impaired postsynaptic acetylcholine receptor (AChR) aggregation. Low-density lipoprotein receptor-related protein 4 (LRP4) plays an important role in AChR aggregation at endplate membranes via the Agrin-LRP4-muscle-specific receptor tyrosine kinase (MuSK) cascade. Sorting nexin 17 (SNX17) regulates the degradation and recycling of various internalized membrane proteins. However, whether SNX17 regulates LRP4 remains unclear. Therefore, we examined the regulatory effects of SNX17 on LRP4 and its influence on AChR aggregation in MG. We selected C2C12 myotubes and induced LRP4 internalization via stimulation with anti-LRP4 antibody and confirmed intracellular interaction between SNX17 and LRP4. SNX17 knockdown and overexpression confirmed that SNX17 promoted MuSK phosphorylation and AChR aggregation by increasing cell surface LRP4 expression. By establishing experimental autoimmune MG (EAMG) mouse models, we identified that SNX17 upregulation improved fragmentation of the AChR structure at the NMJ and alleviated leg weakness in EAMG mice. Thus, these results reveal that SNX17 may be a novel target for future MG therapy.
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Miastenia Gravis Autoimune Experimental , Receptores Colinérgicos , Animais , Camundongos , Acetilcolina , Proteínas Relacionadas a Receptor de LDL , Lipoproteínas LDL , Receptores Proteína Tirosina Quinases , Nexinas de Classificação/genéticaRESUMO
In this paper, a D-A polymer (PIB) containing carbazole as the donor group in the main chain and benzimidazole benzisoindolinone as the acceptor group was synthesized by Suzuki reaction. The Suzuki reaction, also known as the Suzuki coupling reaction, is a relatively new organic coupling reaction in which aryl or alkenyl boronic acids or boronic acid esters react with chlorine, bromine, iodoaromatic hydrocarbons or alkenes under the catalysis of zerovalent palladium complexes cross-coupling. A series of devices were fabricated by a spin-coating approach, and the devices all exhibited ternary resistance switching storage behavior. Among them, the composite device with the mass fraction of SnO2 NPs of 5 wt% has the best storage performance, with a threshold voltage of -0.4 V and a switching current ratio of 1:101.5:104.5. At the same time, the current of the device remained stable after a 3-h test. Furthermore, after 103 cycles, the current has no obvious attenuation. The device has good stability and continuity. Moreover, the conduction mechanism is further revealed. Inorganic nanoparticle composite devices have splendid memory performances and exhibit underlying application significance in storing data.
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Recently, attention has been focused on the central role of TREM2 in diverse pathologies. However, the role of TREM2 signaling in the tumor microenvironment of hepatocellular carcinoma (HCC) remains poorly understood. Herein, we systematically investigated the single-cell transcriptomes of human HCC tissues and found that TREM2 was predominantly expressed by a macrophage subpopulation enriched in tumor tissues that resemble lipid-associated macrophages (LAMs). The accumulation of TREM2+ LAM-like cells in HCC was confirmed in two additional cohorts using scRNA-seq analysis and immunohistochemistry. High expression of TREM2 correlated with high infiltrating macrophage abundance and poor prognosis. Based on systematic interrogations of transcriptional profiles and cellular interactions, TREM2+ LAM-like cells were identified to mainly originate from S100A8+ monocytes and represented an immunosuppressive state. TREM2+ LAM-like cells recruited suppressive Treg cells, facilitating microenvironment remodeling. Furthermore, gene regulatory analysis and in vitro functional assays indicated that activation of LXR signaling could promote the reprogramming of TREM2+ LAM-like cells. Correlation analysis of bulk RNA-sequencing data demonstrated that the enrichment of TREM2+ LAM-like cells was an independent indicator of adverse clinical outcomes in HCC patients. Our comprehensive analyses provide deeper insights into the immunosuppressive role of TREM2+ LAM-like cells in HCC.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Macrófagos/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Monócitos/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Microambiente Tumoral/genéticaRESUMO
Growing evidence has demonstrated the functional relevance of long intergenic noncoding RNAs (lincRNAs) to tumorigenesis and immune response. However, immune-related lincRNAs and their value in predicting the clinical outcomes of patients with liver cancer remain largely unexplored. Herein, we utilized the strategy of iterative gene pairing to construct a tumor-specific immune-related lincRNA pairs signature (IRLPS), which did not require specific expression levels, as an indicator of patient outcomes. The 18-IRLPS we developed was associated with overall survival, tumor progression, and recurrence in liver cancer patients. Multivariate analysis revealed that the risk model was an independent predictive factor. A high IRLPS risk was correlated suppressive immune microenvironment, and IRLPS-high patients might benefit more from CD276 blockade or TMIGD2 agonist. Patients in the high-risk group were associated with elevated tumor mutation, increased sensitivity to dopamine receptor antagonists, cisplatin, doxorubicin, and mitomycin but more resistance to vinblastine. Mechanistically, IRLPS high scores might lead to poor prognosis by promoting cell proliferation and metabolic reprogramming. The prognostic significance of the 18-IRLPS was confirmed in independent cancer datasets. These findings highlighted the robust predictive performances of the 18-IRLPS for prognosis and personalized treatment.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , RNA Longo não Codificante , Antígenos B7/genética , Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Prognóstico , RNA Longo não Codificante/genética , Microambiente TumoralRESUMO
This study aimed to establish a cell-based assay (CBA) for the detection of agrin antibodies (Agrin-Ab) to explore the clinical features of agrin antibody-positive Chinese patients with myasthenia gravis (Agrin-MG). We developed a CBA based on the human full-length agrin protein expressed in HEK293T cells for the reliable and efficient detection of Agrin-Ab. Clinical data and serum samples were collected from 1948 MG patients in 26 provinces in China. The demographic and clinical features of Agrin-MG patients were compared with those of other MG patient subsets. Eighteen Agrin-MG cases were identified from 1948 MG patients. Nine patients were Agrin-Ab positive, and nine were AChR-Ab and Agrin-Ab double-positive (Agrin/AChR-MG). Eleven (61.11%) patients were males older than 40 years of age. The initial symptom in 13 (81.25%) cases was ocular weakness. Occasionally, the initial symptom was limb-girdle weakness (two cases) or bulbar muscle weakness (one case). Agrin-MG patients demonstrated slight improvement following treatment with either acetylcholinesterase inhibitor or prednisone; however, the combination of the two drugs could effectively relieve MG symptoms. In China, Agrin-MG demonstrated seropositivity rates of 0.92%. These patients were commonly middle-aged or elderly men. The patients usually presented weakness in the ocular, bulbar, and limb muscles, which may be combined with thymoma. These patients have more severe diseases, although the combination of pyridostigmine and prednisone was usually effective in relieving symptoms.
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Agrina/imunologia , Autoanticorpos/sangue , Autoantígenos/imunologia , Miastenia Gravis/imunologia , Prednisona , Idade de Início , Idoso , Agrina/química , Agrina/genética , Autoantígenos/química , Autoantígenos/genética , China/epidemiologia , Inibidores da Colinesterase/uso terapêutico , Feminino , Geografia Médica , Células HEK293 , Humanos , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/etiologia , Miastenia Gravis/etnologia , Miastenia Gravis/etiologia , Prednisona/uso terapêutico , Proteínas Recombinantes/imunologia , Timoma/complicações , Neoplasias do Timo/complicaçõesRESUMO
OBJECTIVE: To investigate the correlation between acetylcholine receptor antibodies (AChR-Ab) concentration levels and individualized clinical symptoms in patients with AChR myasthenia gravis (AChR-MG) in China. METHODS: ELISA was used to determine the concentration of AChR-Ab in patients with MG. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification, Quantitative Myasthenia Gravis (QMG) score, and MG-specific activities of daily living (MG-ADL) scoring systems were used to evaluate the clinical status of patients. Spearman correlation analysis was used to determine the correlation between the AChR-Ab concentration and clinical score. The changes in the antibody concentration and clinical score are shown in MGFA-antibody concentration-treatment plots. RESULTS: Autoantibody detection tests were performed in 67 patients, and their clinical scores were recorded. Forty-nine patients received immunosuppressive therapy, 17 patients received pyridostigmine only, and 1 patient under thymectomy without any medication. The AChR-Ab concentration correlated with the MGFA Classification in 5 (29.4%) patients in the pyridostigmine-only group and 15 (30.6%) patients in the immunosuppressive drug group. The changes in the MGFA Classification preceded the changes in the AChR-Ab concentration in 4 (23.5%) patients treated with pyridostigmine and 10 (20.4%) patients on immunosuppressive drugs. In patients on oral non-steroidal immunosuppressants, the AChR-Ab concentration changed by more than 50%, whereas the MGFA Classification did not increase. The AChR-Ab concentration decreased in 17/32 (53.1%) patients after thymectomy, and then increased, whereas the AChR-Ab concentration increased in 15/32 (46.9%) patients and the MGFA Classification decreased in 27/32 (81.8%) patients after thymectomy. The AChR-Ab concentration presented a slight correlation with the corresponding MGFA, QMG, and MG-ADL in patients with thymoma. DISCUSSION: In the Chinese AChR-MG population, the Changes in the AChR-Ab concentration in individuals with AChR-MG did not consistently correlate with the severity of clinical symptoms.
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Atividades Cotidianas , Miastenia Gravis , Autoanticorpos , Humanos , Miastenia Gravis/tratamento farmacológico , Receptores Colinérgicos , Estudos RetrospectivosRESUMO
In this study, the potential of specific Circular RNAs (circRNAs) as novel peripheral blood biomarkers for myasthenia gravis (MG) was explored. We analyzed circRNAs in the peripheral blood of three normal controls and three MG patients using RNA microarray. Candidate circRNAs were validated in three independent cohorts by Quantitative Real-time polymerase chain reaction (qPCR). Eleven differentially expressed circRNAs were initially identified and four were confirmed in the first independent cohort. Hsa_circ_0076490 and hsa-circ_5333-4 had the largest areas under the curve (AUCs) of the receiver operating characteristics (ROC) and were validated in the second cohort. In the third cohort, hsa-circRNA5333-4 had a larger AUC: 0.864 (95% confidence interval [CI] = 0.801-0.928, P < 0.001), a stronger correlation with the Quantitative Myasthenia Gravis Score (qMG): r = 0.505 (P < 0.001) and was correlated with gender and acetylcholine receptor antibody levels (P < 0.05). So hsa-circRNA5333-4 represents a novel biomarker for the diagnosis and monitoring of MG.
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RNA Circular/sangue , RNA Circular/química , Albumina Sérica Humana/química , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Miastenia Gravis/sangue , Miastenia Gravis/genética , Curva ROC , Reprodutibilidade dos Testes , Adulto JovemRESUMO
Hydrotaea spinigera Stein is a necrophagous species, widely distributed in Oriental and Australasian regions. Considering that the postfeeding larvae or puparia of this species can still be found in abundance at the advanced decomposition stage or even the skeleton stage of remains, it can serve as a good supplementary indicator for estimating the minimum postmortem interval (PMImin). This could also extend the range of PMImin when the primary colonizers are no longer associated with the corpse or have emerged as adults. This study investigated the development duration, accumulated degree hours, and larval body length changes of H. spinigera at seven constant temperatures ranging from 16 to 34°C, and established three development models for estimating PMImin, including isomorphen diagram, isomegalen diagram, and thermal summation model. At 16, 19, 22, 25, 28, 31, and 34°C, the development durations of H. spinigera from egg to adult stage were 1,412.6 ± 62.9, 867.4 ± 14.9, 657.1 ± 22.9, 532.3 ± 10.1, 418.8 ± 21.3, 379.8 ± 16.6, and 340.0 ± 20.3 h, respectively. The lower developmental threshold L0 was estimated as 10.50 ± 0.20°C, and the thermal summation constant K was 7,648.83 ± 146.74 degree hours. Using regression analysis, equations were obtained modeling the change of larval body length with time after hatching at different temperatures. This study provided basic data based on the growth and development of H. spinigera for the estimation of PMImin in forensic science.
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Entomologia Forense/métodos , Muscidae/crescimento & desenvolvimento , Animais , Cadáver , Larva/crescimento & desenvolvimento , Características de História de Vida , Modelos Teóricos , Mudanças Depois da Morte , Pupa/crescimento & desenvolvimento , Análise de Regressão , TemperaturaRESUMO
Megaselia spiracularis Schmitz, 1938 (Diptera: Phoridae) is a pest that often appears in human living areas where it can spread pathogens. Besides, the species is of forensic value. Currently, studies focusing on the development of this species are limited. Understanding the developmental patterns of M. spiracularis, therefore, is important for controlling populations of this pest and for estimating the minimum postmortem interval (PMImin). Here, we studied the development of M. spiracularis exposed to seven constant temperatures ranging from 16 to 34 °C. The developmental durations, accumulated degree hours and larval body length changes were measured. Three kinds of development models that can be used to estimate the PMImin were established, including isomorphen diagram, isomegalen diagram and thermal summation model. The duration of M. spiracularis development at 16, 19, 22, 25, 28, 31 and 34 °C from egg to adult stage were 1131.1 ± 34.5, 807.3 ± 9.3, 529.6 ± 1.8, 367.0 ± 8.8, 302.4 ± 7.0, 250.0 ± 2.1 and 232.6 ± 1.9 h, respectively. The developmental threshold temperature and the thermal summation constant were estimated as 12.0 ± 0.5 °C and 4989.7 ± 308.9° hours, respectively. A general model represented by a logistic equation describing how larval body length will change with the time after hatching was fit to data. The present study provides basic developmental data of M. spiracularis, which can be used for achieving better control of this noxious insect as well as for estimation of its PMImin at different temperatures.
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Dípteros/crescimento & desenvolvimento , Entomologia Forense/métodos , Temperatura , Animais , Larva/crescimento & desenvolvimentoRESUMO
After the death of humans or animals, the odors released at different stages of decay attract various insects, and other arthropods, to the corpses. Therefore, the development of insects, and other arthropods present on corpses, can be assessed to estimate the minimum postmortem interval since death. In general, necrophagous blow flies are the insects that first colonize corpses. With progressing decay, other necrophagous and predatory insects arrive at the corpses, which will develop on or around these either by feeding directly on the corpses or by prey on other immature insects. Beetles (Coleoptera) mainly arrive at the corpses during the later stages of decay, and play important roles in cases with longer postmortem intervals. Necrobia rufipes (De Geer, 1755) (Coleoptera: Cleridae) is an important stored-product species with world-wide distribution. Moreover, it is also a forensically important insect species. At temperatures of 22, 25, 28, 31, 34, and 36°C (±0.5°C), the developmental periods from egg to adult were 113.20±2.96, 66.16±3.22, 50.61±1.95, 38.26±2.48, 37.97±2.40, and 31.20±2.11 days, respectively. In vivo measurements obtained the morphological indexes of larvae. The growth curve and the equation of the relationship between development time, body lengths, and mesonotum widths were simulated. The isomorphen diagram model, the isomegalen diagram model, and the thermal summation model were established. In addition, the widths of head capsules and pronota of larvae at different instars were determined by cluster analysis. Classifiers were created and validated by linear discriminant analysis.