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1.
Respir Res ; 25(1): 307, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39138486

RESUMO

OBJECTIVE: To develop and evaluate the predictive value of a simplified lung ultrasound (LUS) method for forecasting respiratory support in term infants. METHODS: This observational, prospective, diagnostic accuracy study was conducted in a tertiary academic hospital between June and December 2023. A total of 361 neonates underwent LUS examination within 1 h of birth. The proportion of each LUS sign was utilized to predict their respiratory outcomes and compared with the LUS score model. After identifying the best predictive LUS sign, simplified models were created based on different scan regions. The optimal simplified model was selected by comparing its accuracy with both the full model and the LUS score model. RESULTS: After three days of follow-up, 91 infants required respiratory support, while 270 remained healthy. The proportion of confluent B-lines demonstrated high predictive accuracy for respiratory support, with an area under the curve (AUC) of 89.1% (95% confidence interval [CI]: 84.5-93.7%). The optimal simplified model involved scanning the R/L 1-4 region, yielding an AUC of 87.5% (95% CI: 82.6-92.3%). Both the full model and the optimal simplified model exhibited higher predictive accuracy compared to the LUS score model. The optimal cut-off value for the simplified model was determined to be 15.9%, with a sensitivity of 76.9% and specificity of 91.9%. CONCLUSIONS: The proportion of confluent B-lines in LUS can effectively predict the need for respiratory support in term infants shortly after birth and offers greater reliability than the LUS score model.


Assuntos
Pulmão , Valor Preditivo dos Testes , Ultrassonografia , Humanos , Recém-Nascido , Feminino , Estudos Prospectivos , Masculino , Pulmão/diagnóstico por imagem , Ultrassonografia/métodos , Respiração Artificial/métodos , Nascimento a Termo/fisiologia , Seguimentos
2.
Heliyon ; 10(15): e34755, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39144971

RESUMO

Ossification of the ligamentum flavum (OLF) is the primary etiology of thoracic spinal stenosis. The functional properties of epidural fat (EF), an adipose tissue located in close proximity to ligamentum flavum (LF), have been scarcely investigated. The metabolic state of adipocytes significantly influences their functionality, and exosomes play a pivotal role in intercellular communication. This study aimed to investigate the role of EF-derived exosomes in OLF and characterize their protein profile by proteomics analysis. Our findings demonstrate that exosomes obtained from EF adjacent to OLF possess the ability to enhance osteogenesis of fibroblasts in vitro. Furthermore, proteomics analysis revealed metabolic dysfunction in EF adipocytes and identified lactate dehydrogenase A (LDHA) as a potential mediator involved in the development of OLF. This study provides new insights into the pathogenic mechanism underlying OLF and offers a theoretical basis for preventing and treating ligament ossification.

3.
Opt Lett ; 49(16): 4493-4496, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39146086

RESUMO

Recent advancements have brought significant attention to photonic terahertz (THz)-integrated sensing and communication (ISAC) systems. In this work, we present an adaptive frequency offset (FO) compensation method for dual-chirp-based ISAC waveforms, using the fractional Fourier transform (FrFT) method. The proposed scheme can enable frequency synchronization without a need for training preambles and exhibit robustness against system noise. We validate this approach through an experimental demonstration in a 300 GHz photonic THz-ISAC system with 20 Gbps quadrature-phase shift keying (QPSK) data transmission and 1.5 cm range resolution. The experiment successfully compensates for frequency offsets ranging from -5 to 5 GHz, achieving an estimation error of less than 0.08% and a chirp-pilot power overhead of 0.5%.

4.
Fish Shellfish Immunol ; : 109833, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39147178

RESUMO

C-type lectins (CTLs) are a kind of Ca2+-dependent immunoreactive factors, which participated in pathogens recognition and defense. The present study identified a new CTL from hard clam Meretrix meretrix (designated as MmCTL4). The full-length of MmCTL4 cDNA was 608 bp, encoding a presumed signal peptide of 19 bp and a carbohydrate recognition domain (CRD) of 131 bp. The tertiary structure of recombinant MmCTL4 protein (rMmCTL4) was the typical long double-ring structure with three conserved disulfide bonds, and the motifs in Ca2+-binding sites of MmCTL4 were QPN and WSD. The SYBR Green real-time PCR analysis indicated that MmCTL4 was widely expressed in the hemocytes, hepatopancreas and mantle of healthy clams. After Vibrio splendidus stimulation, the temporal expression profile of MmCTL4 mRNA in hemocytes and hepatopancreas increased by 7.8-fold at 6 hpi and 3.9-fold at 12 hpi, respectively. The cDNA fragments encoding MmCTL4 were recombined into pET-32a (+) vectors, and transformed into Escherichia coli BL21 (DE3). The rMmCTL4 with the presence of Ca2+ performed obvious hemagglutination activity, and could agglutinate E. coli, Bacillus subtilis, and Staphylococcus aureus, while it only weakly agglutinate Vibrio parahaemolyticus and fungi P. pastoris. The agglutination activity of rMmCTL4 were significantly inhibited by D-mannose, D-xylose, D-lactose, maltose and lipopolysaccharides. These results indicated that MmCTL4, as a class of typical pattern recognition receptors (PRRs), could protect the host against pathogen invasion in the innate immunity of clams.

5.
J Colloid Interface Sci ; 677(Pt B): 221-231, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39142162

RESUMO

Facile synthesis of high-efficiency and stable bifunctional electrocatalyst is essential for producing clean hydrogen in energy storage systems. Herein, low Rh-doped flower-like Ni3S2/Co3S4 heterostructures were facilely prepared on porous nickel foam (labeled Rh-Ni3S2/Co3S4/NF) by a hydrothermal method. The correlation of the precursors types with the morphological structures and catalytic properties were rigorously investigated for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the control groups. The low Rh doping within the catalyst played important role in boosting the catalytic characteristics. The resulting catalyst showed the smaller overpotentials of 197 and 78 mV to drive a current density of 10 mA cm-2 for the OER and HER in alkaline electrolyte, respectively. And the potential only required 1.71 V to drive a current density of 100 mA cm-2 in a water splitting device. It reflects excellent overall water splitting of the home-made Rh-Ni3S2/Co3S4/NF. This strategy shed some constructive light for preparing transition metal sulfide-based electrocatalysts in water splitting devices.

7.
NPJ Precis Oncol ; 8(1): 181, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39152182

RESUMO

Deep learning models have been developed for various predictions in glioma; yet, they were constrained by manual segmentation, task-specific design, or a lack of biological interpretation. Herein, we aimed to develop an end-to-end multi-task deep learning (MDL) pipeline that can simultaneously predict molecular alterations and histological grade (auxiliary tasks), as well as prognosis (primary task) in gliomas. Further, we aimed to provide the biological mechanisms underlying the model's predictions. We collected multiscale data including baseline MRI images from 2776 glioma patients across two private (FAHZU and HPPH, n = 1931) and three public datasets (TCGA, n = 213; UCSF, n = 410; and EGD, n = 222). We trained and internally validated the MDL model using our private datasets, and externally validated it using the three public datasets. We used the model-predicted deep prognosis score (DPS) to stratify patients into low-DPS and high-DPS subtypes. Additionally, a radio-multiomics analysis was conducted to elucidate the biological basis of the DPS. In the external validation cohorts, the MDL model achieved average areas under the curve of 0.892-0.903, 0.710-0.894, and 0.850-0.879 for predicting IDH mutation status, 1p/19q co-deletion status, and tumor grade, respectively. Moreover, the MDL model yielded a C-index of 0.723 in the TCGA and 0.671 in the UCSF for the prediction of overall survival. The DPS exhibits significant correlations with activated oncogenic pathways, immune infiltration patterns, specific protein expression, DNA methylation, tumor mutation burden, and tumor-stroma ratio. Accordingly, our work presents an accurate and biologically meaningful tool for predicting molecular subtypes, tumor grade, and survival outcomes in gliomas, which provides personalized clinical decision-making in a global and non-invasive manner.

8.
Trials ; 25(1): 542, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39152492

RESUMO

BACKGROUND: To explore the feasibility and effectiveness of a segmented sodium citrate solution anticoagulation strategy in patients receiving CRRT. METHODS: A prospective, randomized controlled study was conducted. RESULTS: According to the inclusion and exclusion criteria, 80 patients were included and randomly divided into two groups. Moreover, coagulation indices, liver function indices, renal function indices, and SOFA and APACHE II scores did not significantly differ between the two groups (P > 0.05). The coagulation grade of the venous ports in the experimental group was lower than that in the control group and the two groups of filters, but the difference was not statistically significant (P = 0.337). Both sodium citrate solution infusion methods maintained a low blood calcium concentration (0.25-0.45 mmol/L) in the peripheral circulation pathway, and no patient developed hypocalcaemia (< 1.0 mmol/L). The lifespans of the extracorporeal circulation tube in the experimental group and the control group were 69.43 ± 1.49 h and 49.39 ± 2.44 h, respectively (t = 13.316, P = 0.001). CONCLUSION: The segmented citrate solution anticoagulation strategy could extend the lifespan of the extracorporeal circulation tube and improve CRRT efficacy. TRIAL REGISTRATION: The Chinese Clinical Trial Registry number is ChiCTR2200057272. Registered on March 5, 2022.


Assuntos
Anticoagulantes , Estado Terminal , Citrato de Sódio , Humanos , Estudos Prospectivos , Anticoagulantes/administração & dosagem , Citrato de Sódio/administração & dosagem , Masculino , Pessoa de Meia-Idade , Feminino , Idoso , Coagulação Sanguínea/efeitos dos fármacos , Resultado do Tratamento , Terapia de Substituição Renal Contínua/métodos , Estudos de Viabilidade , China , Terapia de Substituição Renal/métodos
9.
Food Chem X ; 23: 101662, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39148526

RESUMO

This study aimed to employed the effects of five thermal processing methods, namely steaming (SM), boiling (BO), frying (FY), roasting (RO), and vacuum sealing (SV), on the sensory, physicochemical properties, and microbial composition of grass carp meat during refrigerated storage, alongside unheated raw meat (RW) as control. The results showed that thermal treatment improved the sensory quality and shelf life of refrigerated grass carp meat, and their shelf life was RW < BO

10.
Mod Rheumatol ; 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39119677

RESUMO

OBJECTIVES: Baker's cyst (BC) is a complex complication of rheumatoid arthritis (RA), with a poor prognosis. This paper aimed to analyze the clinical features and risk factors for BC in patients with RA to assist clinicians in early warning and appropriate action. METHODS: The Clinical features of hospitalized RA patients with knee affected were analyzed retrospectively. The R software was used for the statistical analysis, while logistic regression analyses were used to determine independent risk factors. RESULTS: A total of 367 RA patients with knee affected were studied, and BC was diagnosis in 15.3% of them. The BC group exhibited a higher proportion of knee-only affected than the non-BC group (p < 0.05), while the attributes linked to disease activity exhibited no disparity. Logistic regression analyses selected two independent risk factors for BC: knee-only affected and anemia. 26.8% of patients with BC developed rupture, exhibiting a higher proportion of knee-only affected (p < 0.05), compared to those unruptured. CONCLUSIONS: The occurrence and rupture of BC in RA patients were significantly related to local inflammation, but not to systemic one. Incorporating local treatment may be a more advantageous option compared to solely relying on systemic therapy.

11.
Nucleic Acids Res ; 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39106166

RESUMO

Heterochromatin is a key feature of eukaryotic genomes and is crucial for maintaining genomic stability. In fission yeast, heterochromatin nucleation is mainly mediated by DNA-binding proteins or the RNA interference (RNAi) pathway. In the filamentous fungus Neurospora crassa, however, the mechanism that causes the initiation of heterochromatin at the relics of repeat-induced point mutation is unknown and independent of the classical RNAi pathway. Here, we show that casein kinase II (CKII) and its kinase activity are required for heterochromatin formation at the well-defined 5-kb heterochromatin of the 5H-cat-3 region and transcriptional repression of its adjacent cat-3 gene. Similarly, mutation of the histone H3 phosphorylation site T11 also impairs heterochromatin formation at the same locus. The catalytic subunit CKA colocalizes with H3T11 phosphorylation (H3pT11) within the 5H-cat-3 domain and the deletion of cka results in a significant decrease in H3T11 phosphorylation. Furthermore, the loss of kinase activity of CKII results in a significant reduction of H3pT11, H3K9me3 (histone H3 lysine 9 trimethylation) and DNA methylation levels, suggesting that CKII regulates heterochromatin formation by promoting H3T11 phosphorylation. Together, our results establish that histone H3 phosphorylation by CKII is a critical event required for heterochromatin formation.

12.
JMIR Med Inform ; 12: e59273, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39106482

RESUMO

BACKGROUND: Recent advancements in artificial intelligence (AI) and large language models (LLMs) have shown potential in medical fields, including dermatology. With the introduction of image analysis capabilities in LLMs, their application in dermatological diagnostics has garnered significant interest. These capabilities are enabled by the integration of computer vision techniques into the underlying architecture of LLMs. OBJECTIVE: This study aimed to compare the diagnostic performance of Claude 3 Opus and ChatGPT with GPT-4 in analyzing dermoscopic images for melanoma detection, providing insights into their strengths and limitations. METHODS: We randomly selected 100 histopathology-confirmed dermoscopic images (50 malignant, 50 benign) from the International Skin Imaging Collaboration (ISIC) archive using a computer-generated randomization process. The ISIC archive was chosen due to its comprehensive and well-annotated collection of dermoscopic images, ensuring a diverse and representative sample. Images were included if they were dermoscopic images of melanocytic lesions with histopathologically confirmed diagnoses. Each model was given the same prompt, instructing it to provide the top 3 differential diagnoses for each image, ranked by likelihood. Primary diagnosis accuracy, accuracy of the top 3 differential diagnoses, and malignancy discrimination ability were assessed. The McNemar test was chosen to compare the diagnostic performance of the 2 models, as it is suitable for analyzing paired nominal data. RESULTS: In the primary diagnosis, Claude 3 Opus achieved 54.9% sensitivity (95% CI 44.08%-65.37%), 57.14% specificity (95% CI 46.31%-67.46%), and 56% accuracy (95% CI 46.22%-65.42%), while ChatGPT demonstrated 56.86% sensitivity (95% CI 45.99%-67.21%), 38.78% specificity (95% CI 28.77%-49.59%), and 48% accuracy (95% CI 38.37%-57.75%). The McNemar test showed no significant difference between the 2 models (P=.17). For the top 3 differential diagnoses, Claude 3 Opus and ChatGPT included the correct diagnosis in 76% (95% CI 66.33%-83.77%) and 78% (95% CI 68.46%-85.45%) of cases, respectively. The McNemar test showed no significant difference (P=.56). In malignancy discrimination, Claude 3 Opus outperformed ChatGPT with 47.06% sensitivity, 81.63% specificity, and 64% accuracy, compared to 45.1%, 42.86%, and 44%, respectively. The McNemar test showed a significant difference (P<.001). Claude 3 Opus had an odds ratio of 3.951 (95% CI 1.685-9.263) in discriminating malignancy, while ChatGPT-4 had an odds ratio of 0.616 (95% CI 0.297-1.278). CONCLUSIONS: Our study highlights the potential of LLMs in assisting dermatologists but also reveals their limitations. Both models made errors in diagnosing melanoma and benign lesions. These findings underscore the need for developing robust, transparent, and clinically validated AI models through collaborative efforts between AI researchers, dermatologists, and other health care professionals. While AI can provide valuable insights, it cannot yet replace the expertise of trained clinicians.

13.
Cell Host Microbe ; 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39106870

RESUMO

Identification of potential bacterial players in colorectal tumorigenesis has been a focus of intense research. Herein, we find that Clostridium symbiosum (C. symbiosum) is selectively enriched in tumor tissues of patients with colorectal cancer (CRC) and associated with higher colorectal adenoma recurrence after endoscopic polypectomy. The tumorigenic effect of C. symbiosum is observed in multiple murine models. Single-cell transcriptome profiling along with functional assays demonstrates that C. symbiosum promotes the proliferation of colonic stem cells and enhances cancer stemness. Mechanistically, C. symbiosum intensifies cellular cholesterol synthesis by producing branched-chain amino acids (BCAAs), which sequentially activates Sonic hedgehog signaling. Low dietary BCAA intake or blockade of cholesterol synthesis by statins could partially abrogate the C. symbiosum-induced cell proliferation in vivo and in vitro. Collectively, we reveal C. symbiosum as a bacterial driver of colorectal tumorigenesis, thus identifying a potential target in CRC prediction, prevention, and treatment.

14.
Artigo em Inglês | MEDLINE | ID: mdl-39110285

RESUMO

Heat stress (HS) causes severe economic losses in sheep industry worldwide. The objective of the present study was to investigate the effects of a herbal formula (HF) supplement on growth, digestibility, antioxidant capacity, and rumen microbes in fattening lambs under HS. The HF composed of four herbs was prepared based on the theory of compatibility of Chinese medicine "Jun-Chen-Zuo-Shi". Two-hundred forty 3-month weaned lambs (initial weight 36.61 ± 0.73 kg) were randomly allocated into four groups, supplemented 0% (Control), 0.5%, 1.0%, and 1.5% HF in diets. All lambs were exposed to HS conditions with 79.7 of average temperature-humidity index throughout an experimental period of 35 days. Growth performance, apparent digestibility, and antioxidant activities, involving antioxidant enzymes and heat shock proteins (HSPs), were measured at the end of trial, as well as microbial communities in bacteria and archaea. Results showed that 0.5% HF increased (P = 0.02) average daily gain by 13.80% and decreased feed-to-gain ratio (P = 0.03) by 14.68%, compared to control. With increasing HF doses, the digestibility of ether extract and acid detergent fiber demonstrated a cubical (P < 0.01) and quadratic (P = 0.03) relation, respectively; moreover, glutathione peroxidase and catalase activities demonstrated a quadratic increase (P < 0.01). Serum levels of HSP60, HSP70, and HSP90 for 0.5% HF were lower than that in control (P < 0.05). On the other hand, total volatile fatty acid, acetic acid, butyric acid, valeric acid, and isovaleric acid levels exhibited quadratic increases (P ≤ 0.01) with HF doses. From rumen microbes, the abundance and diversity of bacterial community were improved by HF supplements. Particularly for 0.5% HF group, the operational taxonomic units were the greatest among all groups. Compared to control, Prevotella abundance for HF supplements from 0.5 to 1.5% increased by 35.57 to 60.15%, and Succiniclasticum abundance demonstrated a quadratic pattern (P = 0.02) with doses. Additionally, Methanosphaera abundance in archaeal community raised by 0.2 to 3.3-folds when lambs were fed the HF additions of 0.5 to 1.5%. In summary, dietary HF supplements would contribute to alleviating HS in lambs, and our results suggest the optimal dose of 0.5% HF supplement in diet.

15.
World J Gastrointest Surg ; 16(7): 2135-2144, 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39087125

RESUMO

BACKGROUND: Colorectal cancer (CRC) is a prevalent cancer type in clinical settings; its early signs can be difficult to detect, which often results in late-stage diagnoses in many patients. The early detection and diagnosis of CRC are crucial for improving treatment success and patient survival rates. Recently, imaging techniques have been hypothesized to be essential in managing CRC, with magnetic resonance imaging (MRI) and spiral computed tomography (SCT) playing a significant role in enhancing diagnostic and treatment approaches. AIM: To explore the effectiveness of MRI and SCT in the preoperative staging of CRC and the prognosis of laparoscopic treatment. METHODS: Ninety-five individuals admitted to Zhongshan Hospital Xiamen University underwent MRI and SCT and were diagnosed with CRC. The precision of MRI and SCT for the presurgical classification of CRC was assessed, and pathological staging was used as a reference. Receiver operating characteristic curves were used to evaluate the diagnostic efficacy of blood volume, blood flow, time to peak, permeability surface, blood reflux constant, volume transfer constant, and extracellular extravascular space volume fraction on the prognosis of patients with CRC. RESULTS: Pathological biopsies confirmed the following CRC stages: 23, 23, 32, and 17 at T1, T2, T3, and T4, respectively. There were 39 cases at the N0 stage, 22 at N1, 34 at N2, 44 at M0 stage, and 51 at M1. Using pathological findings as the benchmark, the combined use of MRI and SCT for preoperative TNM staging in patients with CRC demonstrated superior sensitivity, specificity, and accuracy compared with either modality alone, with a statistically significant difference in accuracy (P < 0.05). Receiver operating characteristic curve analysis revealed the predictive values for laparoscopic treatment prognosis, as indicated by the areas under the curve for blood volume, blood flow, time to peak, and permeability surface, blood reflux constant, volume transfer constant, and extracellular extravascular space volume fraction were 0.750, 0.683, 0.772, 0.761, 0.709, 0.719, and 0.910, respectively. The corresponding sensitivity and specificity values were also obtained (P < 0.05). CONCLUSION: MRI with SCT is effective in the clinical diagnosis of patients with CRC and is worthy of clinical promotion.

16.
Int J Gynecol Cancer ; 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39089729

RESUMO

OBJECTIVE: To investigate the high-risk factors associated with concurrent cervical intra-epithelial neoplasia (CIN) and vaginal intra-epithelial neoplasia (VaIN) in patients with high-grade lesions. METHODS: This retrospective study at the Obstetrics and Gynecology Hospital of Fudan University included patients diagnosed with concurrent CIN2/3 and VaIN2/3 (concurrent group) over the period from January 1, 2019, to December 31, 2019. Patients with only CIN2/3 during the corresponding period were selected chronologically on a 1:2 basis (CIN group). Demographic data, human papillomavirus (HPV) infection rates, genotypes, and cytology results were compared between the groups. RESULTS: A total of 128 patients were included. The median age in the concurrent group was 50 years (range 20-79), which was significantly higher than the median age of 38 (range 23-72) in the CIN group (p<0.001). The cytological sensitivity for identifying high-grade lesions was markedly higher in the concurrent group at 83.1% (103 out of 124) compared with 68.4% (175 out of 256) in the CIN-only group (p=0.002). The prevalence of HPV 16 was 62.8% in the concurrent group, significantly higher than 51.6% in the CIN group (p=0.04). CONCLUSIONS: The risk of concurrent VaIN2/3 increases with age among women with CIN2/3. Cytology screening is effective for detecting concurrent VaIN2/3, with a sensitivity of 83.1%.

17.
Angew Chem Int Ed Engl ; : e202413753, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39138131

RESUMO

Silacycles have exhibited significant potential for application in the fields of medicinal chemistry, agrochemistry, and materials science. Accordingly, the development of effective methods for synthesizing these compounds has attracted increasing attention. Here, we report an efficient Cu-catalyzed enantioselective hydrosilylation of arylmethylenecyclopropanes with hydrosilanes, that allows the rapid assembly of various enantioenriched carbon- and silicon-stereogenic silacyclopentanes in good yields with excellent enantioselectivities and diastereoselectivities under mild conditions. Further stereospecific transformation of the Si-H bond on the chiral silicon center expands the diversity of these C- and Si-stereogenic silacyclopentanes.

18.
Sci Total Environ ; 950: 175197, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39094654

RESUMO

East African lakes, especially soda lakes, are home habitats for massive numbers of wildlife such as flamingos, mammals, and fishes. These lakes are known for their high primary production due to local high temperatures, light intensities, and alkalinity (inorganic carbon). However, these lakes, normally within remote areas, receive low nutrient inputs. Ammonium (NH4+) recycling and/or nitrogen fixation can become the major N supply mechanisms for phytoplankton. However, the driving forces on microbial N nutrition in lakes with minimal anthropogenic disturbance remain poorly understood. Using stable isotope tracer techniques, NH4+ recycling rates were measured in 18 lakes and reservoirs in East Africa (Tanzania and Kenya) during the dry season in early 2020. Three functional genes (nifH, gdh, and ureC) relating to microbial N nutrition were also measured. The regeneration of NH4+ supported up to 71 % of the NH4+ uptake. Positive community biological NH4+ demands (CBAD) for all lakes and reservoirs indicate an obvious N demand from microbial community. Our study provides clear evidence that microbial NH4+ uptake rates linked closely to the dissolved organic matter (DOM) properties (e.g., the absorption coefficient at 254 nm, percents of total fluorescence intensity contributed by microbial humic-like and protein-like components) and that water residence time drives microbial NH4+ recycling by regulating the duration of in-lake DOM processing and influencing algal growth. Phytoplankton, especially those of Cyanophyceae, showed maximum biomass and higher NH4+ recycling rates at a certain range of water residence time (e.g., 5-8 years). However, CBAD showed a decreasing trend with longer water residence time, which may be influenced by changes in the algal community composition (e.g., % Cyanophyceae vs. % Bacillariophyceae). These results indicate that DOM dynamics and the water residence time have the potential to facilitate the understanding of microbial nitrogen supply status in East African lakes.

19.
Animals (Basel) ; 14(15)2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39123754

RESUMO

A suitable feed size has a positive effect on animal feeding. For aquatic larvae, the correct feed size is very important for their growth. This experiment analyzed and compared the effect of different particle sizes of feed for larval stages on the growth performance, whole body composition, and muscle amino acid and fatty acid composition of crayfish. Five larval crayfish diets of different particle sizes, namely < 0.40 mm (Group A, control group), 0.40-0.50 mm (Group B), 0.71-0.85 mm (Group C), 0.90-1.00 mm (Group D) and 1.5 mm (Group E), were fed to 2000 crayfish (initial weight 0.0786 ± 0.0031 g) for 100 d. The results showed that as the particle size increased, final weight, weight gain (WG, p = 0.001) and specific growth rate (SGR, p = 0.000) of the crayfish tended to increase and then leveled off, with the control group being the lowest. The feed conversion ratio (FCR, p = 0.000) showed a decreasing and then equalizing trend with increasing particle size, but there was no significant difference between the groups except the control group. Broken-line regression analysis showed that the critical values for the appropriate particle feed size for crayfish larvae were 0.55 mm and 0.537 mm using SGR and FCR as indicators. Groups B, C and D had the highest crude protein content and were significantly higher than the control group (p = 0.001). Group E had the highest umami amino acid (UAA) and was significantly higher than the control group (p = 0.026). The content of isoleucine (Ile, p = 0.038) and phenylalanine (Phe, p = 0.038) was highest in group C and significantly higher than in the control group. Through principal component analysis, groups C and D were shown to contain leucine (Leu), glutamic (Glu), methionine (Met), valine (Val), histidine (His), Phe, and Ile levels significantly induced. The content of linoleic acid (C18:2n6, p = 0.000), linolenic acid (C18:3n3, p = 0.000), saturated fatty acid (SFA, p = 0.000), monounsaturated fatty acid (MUFA, p = 0.001), polyunsaturated fatty acid (PUFA, p = 0.000) and n-6 PUFA (p = 0.000) in group C was the highest and significantly higher than the control group. Principal component analysis showed that group C significantly induced the levels of C18:2n6, C18:3n3, DHA, EPA, n-3 PUFA and n-6 PUFA in muscle. Therefore, our results suggest that appropriate feed particle size can improve the growth performance and nutrient composition of crayfish. Based on the broken-line regression analysis of SGR and FCR, the critical values of optimal particle size for crayfish are 0.55 mm and 0.537 mm, and when the particle size exceeds these critical values (not more than 1.5 mm commercial feed), growth performance and FCR of the crayfish are no longer changed. Nevertheless, group C has high protein and low lipid content, as well as better nutrition with amino acids and fatty acids. Overall, combined with growth performance and nutrient composition, it is recommended that the particle size of the diet at the larval stage for crayfish is between 0.71 and 0.85 mm.

20.
Sensors (Basel) ; 24(15)2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39123870

RESUMO

This study proposes a dual-functional terahertz device based on the Dirac semimetal, serving as both a sensing element and a band-pass filter. The device's operating mode can switch between these two functions by utilizing the phase transition property of vanadium dioxide (VO2). When VO2 is in the insulating state, the device functions as a sensing element. The simulation results demonstrate an impressive refractive index sensitivity of 374.40 GHz/RIU (Refractive Index Unit). When VO2 is in the metallic state, the device functions as a band-pass filter, exhibiting a center frequency of 2.01 THz and a 3 dB fractional bandwidth of 0.91 THz. The integration of these dual functionalities within a single terahertz device enhances its utility in both sensing and filtering applications.

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