Burst firing in Output-Defined Parallel Habenula Circuit Underlies the Antidepressant Effects of Bright Light Treatment.

Research highlights the significance of increased bursting in lateral habenula (LHb) neurons in depression and as a focal point for bright light treatment (BLT). However, the precise spike patterns of LHb neurons projecting to different brain regions during depression, their roles in depression development, and BLT's therapeutic action remain elusive. Here, LHb neurons are found projecting to the dorsal raphe nucleus (DRN), ventral tegmental area (VTA), and median raphe nucleus (MnR) exhibit increased bursting following aversive stimuli exposure, correlating with distinct depressive symptoms. Enhanced bursting in DRN-projecting LHb neurons is pivotal for anhedonia and anxiety, while concurrent bursting in LHb neurons projecting to the DRN, VTA, and MnR is essential for despair. Remarkably, reducing bursting in distinct LHb neuron subpopulations underlies the therapeutic effects of BLT on specific depressive behaviors. These findings provide valuable insights into the mechanisms of depression and the antidepressant action of BLT.

Nanoscale Spatiotemporal Dynamics of Microbial Adhesion: Unveiling Stepwise Transitions with Plasmonic Imaging.

Understanding bacterial adhesion at the nanoscale is crucial for elucidating biofilm formation, enhancing biosensor performance, and designing advanced biomaterials. However, the dynamics of the critical transition from reversible to irreversible adhesion has remained elusive due to analytical constraints. Here, we probed this adhesion transition, unveiling nanoscale, step-like bacterial approaches to substrates using a plasmonic imaging technique. This method reveals the discontinuous nature of adhesion, emphasizing the complex interplay between bacterial extracellular polymeric substances (EPS) and substrates. Our findings not only deepen our understanding of bacterial adhesion but also have significant implications for the development of theoretical models for biofilm management. By elucidating these nanoscale step-like adhesion processes, our work provides avenues for the application of nanotechnology in biosensing, biofilm control, and the creation of biomimetic materials.

High-Throughput Identification of Single Nanoparticles via Electrochemically Assisted High-Resolution Plasmonic Scattering Interferometric Microscopy.

The identification of nanoparticles within heterogeneous mixtures poses significant challenges due to the similarity in physical properties among different nanomaterials. Here, we present electrochemically assisted high-resolution plasmonic scattering interferometric microscopy (HR-PSIM). This technique allows for the high-throughput identification of nanoparticles by accurately measuring the refractive index of individual nanoparticles without interference from background signals. Through elimination of parabolic scattering interference and employing electrochemical modulation, HR-PSIM demonstrates high spatial resolution and stability against background noise, enabling the differentiation of nanoparticles with closely matched refractive indices, such as Au and Ag nanoparticles. The efficacy of this method is demonstrated through its application in real-time, label-free imaging of nanoparticle electrochemical activity, providing a platform for the precise and high-throughput characterization of nanomaterials. The robustness of our approach against electrochemical interference and its high spatial resolution mark a significant advancement in the field of nanomaterial analysis, promising wide-ranging applications in nanoparticle research and beyond.

Factors Affecting Sustainability-Related Career Expectations among Engineering Undergraduates in China: An Empirical Study Based on a Modified College Impact Model.

The international engineering education community has reached a consensus regarding the need to enhance engineering students' awareness of and capability to provide sustainable services in their future careers. Based on a modified college impact model, this study analyzed the impacts of curricular emphasis, curricular instruction, and sustainability-related career self-efficacy on the sustainability-related career expectations of engineering students and investigated the moderating effects of gender on the relationships among the research variables. The results show that both curricular emphasis and curricular instruction have direct positive effects on the sustainability-related career expectations of engineering students; sustainability-related career self-efficacy plays a partial mediating role in this process; and gender significantly moderates the influence of curricular emphasis and curricular instruction on sustainability-related career expectations. The findings of this study provide empirical evidence that can be used by higher education institutions and engineering educators to enhance the belief of engineering students in their ability to solve sustainability-related issues in their future careers and promote the diversification of engineering education.

Prediction of microbial activity and abundance using interpretable machine learning models in the hyporheic zone of effluent-dominated receiving rivers.

Serving as a vital linkage between surface water and groundwater, the hyporheic zone (HZ) plays a fundamental role in improving water quality and maintaining ecological security. In arid or semi-arid areas, effluent discharge from wastewater treatment facilities could occupy a predominant proportion of the total base flow of receiving rivers. Nonetheless the relationship between microbial activity, abundance and environmental factors in the HZ of effluent-receiving rivers appear to be rarely addressed. In this study, a spatiotemporal field study was performed in two representative effluent-dominated receiving rivers in Xi'an, China. Land use data, physical and chemical water quality parameters of surface and subsurface water were used as predictive variables, while the microbial respiratory electron transport system activity (ETSA), the Chao1 and Shannon index of total microbial community, as well as the Chao1 and Shannon index of denitrifying bacteria community were used as response variables, while ETSA was used as response variables indicating ecological processes and Shannon and Chao1 were utilized as parameters indicating microbial diversity. Two machine learning models were utilized to provide evidence-based information on how environmental factors interact and drive microbial activity and abundance in the HZ at variable depths. The models with Chao1 and Shannon as response variables exhibited excellent predictive performances (R2: 0.754-0.81 and 0.783-0.839). Dissolved organic nitrogen (DON) was the most important factor affecting the microbial functions, and an obvious threshold value of ∼2 mg/L was observed. Credible predictions of models with Chao1 and Shannon index of denitrifying bacteria community as response variables were detected (R2: 0.484-0.624 and 0.567-0.638), with soluble reactive phosphorus (SRP) being the key influencing factor. Fe (Ⅱ) was favorable in predicting denitrifying bacteria community. The ESTA model highlighted the importance of total nitrogen in the ecological health monitoring in HZ. These findings provide novel insights in predicting microbial activity and abundance in highly-impacted areas such as the HZ of effluent-dominated receiving rivers.

Elevated dorsal medial prefrontal cortex to lateral habenula pathway activity mediates chronic stress-induced depressive and anxiety-like behaviors.

The medial prefrontal cortex (mPFC) sends projections to numerous brain regions and is believed to play a significant role in depression and anxiety. One of the key downstream targets of the mPFC, the lateral habenula (LHb), is essential for chronic stress (CS)-induced depressive and anxiety-like behaviors. Nevertheless, whether the mPFC-LHb pathway mediates the co-occurrence of depression and anxiety and the underlying mechanism remain incompletely understood. Here, using chemogenetics, we first determined that activation of LHb-projecting mPFC neurons is essential for the development of depressive and anxiety-like behaviors induced by CS. Subsequently, we identify the extent and distribution of LHb-projecting neurons originating from the mPFC subregion. Through circuit-specific in vivo fiber photometry, we found that Ca2+ activity in dorsal mPFC (dmPFC) axon terminals within the LHb was increased during exposure to stressful and anxiety-related stimuli, highlighting the potential role of LHb-projecting dmPFC neurons in conveying stressful and anxiety-related information to the LHb. Finally, we observed that activation of both LHb-projecting dmPFC neurons and their postsynaptic counterparts in the LHb was necessary for CS-induced depressive and anxiety-like behaviors. Overall, this study provides multiple lines of evidence demonstrating that activation of the dmPFC-LHb pathway is a crucial neural circuitry for CS-induced depressive and anxiety-like behaviors.

Deep-Learning Driven, High-Precision Plasmonic Scattering Interferometry for Single-Particle Identification.

Label-free probing of the material composition of (bio)nano-objects directly in solution at the single-particle level is crucial in various fields, including colloid analysis and medical diagnostics. However, it remains challenging to decipher the constituents of heterogeneous mixtures of nano-objects with high sensitivity and resolution. Here, we present deep-learning plasmonic scattering interferometric microscopy, which is capable of identifying the composition of nanoparticles automatically with high throughput at the single-particle level. By employing deep learning to decode the quantitative relationship between the interferometric scattering patterns of nanoparticles and their intrinsic material properties, this technique is capable of high-throughput, label-free identification of diverse nanoparticle types. We demonstrate its versatility in analyzing dynamic surface chemical reactions on single nanoparticles, revealing its potential as a universal platform for nanoparticle imaging and reaction analysis. This technique not only streamlines the process of nanoparticle characterization, but also proposes a methodology for a deeper understanding of nanoscale dynamics, holding great potential for addressing extensive fundamental questions in nanoscience and nanotechnology.

Differences in resting-state brain activity in first-episode drug-naïve major depressive disorder patients with and without suicidal ideation.

Despite altered brain activities being associated with suicidal ideation (SI), the neural correlates of SI in major depressive disorder (MDD) have remained elusive. We enrolled 82 first-episode drug-naïve MDD patients including 41 with SI and 41 without SI, as well as 41 healthy controls (HCs). Resting-state functional and structural MRI data were collected. The measures of fractional amplitude of low-frequency fluctuation (fALFF) and grey matter volume (GMV) were calculated and compared. Compared with HCs, patients with SI exhibited increased fALFF values in the right rectus gyrus and left medial superior frontal gyrus, middle frontal gyrus and precuneus. Decreased GMV in the right parahippocampal gyrus, insula and middle occipital gyrus and increased GMV in the left superior frontal gyrus were detected in patients with SI. In addition, patients without SI demonstrated increased fALFF values in the right superior frontal gyrus and decreased fALFF values in the right postcentral gyrus. Decreased GMV in the left superior frontal gyrus, right medial superior frontal gyrus, opercular part of inferior frontal gyrus, postcentral gyrus, fusiform gyrus and increased left supplementary motor area, superior occipital gyrus, right anterior cingulate gyrus and superior temporal gyrus were revealed in patients with SI. Moreover, in comparison with patients without SI, increased fALFF values were identified in the left precuneus of patients with SI. However, no significant differences were found in GMV between patients with and without SI. These findings might be helpful for finding neuroimaging markers predicting individual suicide risk and detecting targeted brain regions for effective early interventions.

Tuning the apparent hydrogen binding energy to achieve high-performance Ni-based hydrogen oxidation reaction catalyst.

High-performance platinum-group-metal-free alkaline hydrogen oxidation reaction catalysts are essential for the hydroxide exchange membrane fuel cells, which generally require high Pt loadings on the anode. Herein, we report a highly active hydrogen oxidation reaction catalyst, NiCuCr, indicated by the hydroxide exchange membrane fuel cell with a high peak power density of 577 mW cm-2 (18 times as high as the Ni/C anode) and a stability of more than 150 h (a degradation rate slower by 7 times than the Ni/C anode). The spectroscopies demonstrate that the alloy effect from Cu weakens the hydrogen binding, and the surface Cr2O3 species enhance the interfacial water binding. Both effects bring an optimized apparent hydrogen binding energy and thus lead to the high hydrogen oxidation reaction performance of NiCuCr. These results suggest that the apparent hydrogen binding energy determines the hydrogen oxidation reaction performance and that its tuning is beneficial toward high electrocatalytic performance.

Duodenal malignant melanoma: Primary and metastatic case series and literature review.

RATIONALE: Duodenal malignant melanoma is rare, and its early clinical symptoms are insidious, making it difficult to diagnose in its early stages. Combined with previous literature, We explored the clinicopathological characteristics and v-raf murine sarcoma viral oncogene homolog B1 mutations in primary and metastatic duodenal malignant melanoma, in order to provide some experience on its differential diagnosis and treatment. PATIENT CONCERNS: The 2 patients (a 63-year-old female [Patient 1] and a 54-year-old male [Patient 2]) experienced pain and discomfort in their upper abdomen. Additionally, one of them had a history of skin malignant melanoma. DIAGNOSES: Patient 1 was diagnosed with primary duodenal malignant melanoma; and Patient 2 was diagnosed with metastatic duodenal malignant melanoma. INTERVENTIONS: Patient 1 underwent pancreaticoduodenectomy; and patient 2 underwent complete surgical resection and lymph node dissection. OUTCOMES: After surgery, Patient 1 survived after 26 months follow-up, and Patient 2 died of systemic multi-organ circulatory failure after 1 month follow-up. LESSONS: Primary and metastatic cases should be diagnosed through previous medical history analysis and detailed physical and auxiliary examinations. This would enable a diagnosis based on characteristic histomorphology and immunohistochemical markers. An early diagnosis and surgical treatment can prolong patient survival and the molecular inspection of v-raf murine sarcoma viral oncogene homolog B1 mutations can guide follow-up treatment.

Effects of D-CAG chemotherapy regimen on cognitive function in patients with acute myeloid leukaemia: A resting-state functional magnetic resonance imaging study.

Post-chemotherapy cognitive impairment, also known as 'chemobrain', is a common neurotoxic complication induced by chemotherapy, which has been reported in many cancer survivors who have undergone chemotherapy. In this study, we aimed to explore the effects of D-neneneba dicitabine, C-nenenebb cytarabine, A-aclamycin, G-granulocyte colony-stimulating factor (D-CAG) chemotherapy on cognitive function in patients with acute myeloid leukaemia (AML) and its possible central mechanisms. Twenty patients with AML and 25 matched healthy controls (HC) were enrolled in this study. The cognitive function of patients before and after D-CAG chemotherapy was evaluated by the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog). The resting-state functional magnetic resonance imaging data were collected from all patients before and after chemotherapy intervention, as well as HC. Then, resting-state functional magnetic resonance imaging data were preprocessed using DPABI software package and regional homogeneity (ReHo) values of brain regions were calculated. Finally, ReHo values between groups were compared by Resting-State fMRI Data Analysis software package with t-tests and Alphasim method was performed for multiple comparison correction. Moreover, associations between ReHo values of altered brain regions and the scores of FACT-Cog were analysed by Pearson correlation. The total FACT-Cog scores and four factor scores of AML patients increased significantly after treatment. ReHo values showed no significant changes in patients before treatment when compared with HC. Compared with HC, ReHo values of the right middle frontal gyrus, inferior frontal gyrus (opercular part), middle occipital gyrus, and left praecuneus decreased significantly, while ReHo values of the left inferior temporal gyrus, right middle temporal gyrus, and hippocampus increased significantly in patients after treatment. Compared with patients before treatment, ReHo values decreased significantly in the right middle frontal gyrus, inferior frontal gyrus (opercular part), and middle and inferior occipital gyri of patients after treatment. In addition, ReHo values of the right inferior frontal gyrus (opercular part) were negatively correlated with the total scores of FACT-Cog and factor scores of perceived cognitive impairment in patients after treatment. There were also negative correlations between ReHo values of the right middle frontal gyrus and perceived cognitive impairment scores. The present study confirmed that D-CAG chemotherapy might cause impaired subjective self-reported cognitive functioning in AML patients, which might be related to the decreased function of certain regions in the right prefrontal lobe. These findings provided further understanding of the mechanisms involved in post-chemotherapy cognitive impairment and would help develop new therapeutic strategies for 'chemobrain' in AML patients.

Microbiome-functionality in anaerobic digesters: A critical review.

Microbially driven anaerobic digestion (AD) processes are of immense interest due to their role in the biovalorization of biowastes into renewable energy resources. The function-versatile microbiome, interspecies syntrophic interactions, and trophic-level metabolic pathways are important microbial components of AD. However, the lack of a comprehensive understanding of the process hampers efforts to improve AD efficiency. This study presents a holistic review of research on the microbial and metabolic "black box" of AD processes. Recent research on microbiology, functional traits, and metabolic pathways in AD, as well as the responses of functional microbiota and metabolic capabilities to optimization strategies are reviewed. The diverse ecophysiological traits and cooperation/competition interactions of the functional guilds and the biomanipulation of microbial ecology to generate valuable products other than methane during AD are outlined. The results show that AD communities prioritize cooperation to improve functional redundancy, and the dominance of specific microbes can be explained by thermodynamics, resource allocation models, and metabolic division of labor during cross-feeding. In addition, the multi-omics approaches used to decipher the ecological principles of AD consortia are summarized in detail. Lastly, future microbial research and engineering applications of AD are proposed. This review presents an in-depth understanding of microbiome-functionality mechanisms of AD and provides critical guidance for the directional and efficient bioconversion of biowastes into methane and other valuable products.

Plasmonic Probing of Deoxyribonucleic Acid Hybridization at the Single Base Pair Resolution.

Partial DNA duplex formation greatly impacts the quality of DNA hybridization and has been extensively studied due to its significance in many biological processes. However, traditional DNA sensing methods suffer from time-consuming amplification steps and hinder the acquisition of information about single-molecule behavior. In this work, we developed a plasmonic method to probe the hybridization process at a single base pair resolution and study the relationship between the complementarity of DNA analytes and DNA hybridization behaviors. We measured single-molecule hybridization events with Au NP-modified ssDNA probes in real time and found two hybridization adsorption events: stable and transient adsorption. The ratio of these two hybridization adsorption events was correlated with the length of the complementary sequences, distinguishing DNA analytes from different complementary sequences. By using dual incident angle excitation, we recognized different single-base complementary sequences. These results demonstrated that the plasmonic method can be applied to study partial DNA hybridization behavior and has the potential to be incorporated into the identification of similar DNA sequences, providing a sensitive and quantitative tool for DNA analysis.

Robustness of Quantitative Diffusion Metrics from Four Models: A Prospective Study on the Influence of Scan-Rescans, Voxel Size, Coils, and Observers.

BACKGROUND: Quantitative diffusion metrics provide additional microstructural information of diseases. The robustness of quantitative diffusion metrics should be established before clinical application. PURPOSE: To evaluate the variability and reproducibility of quantitative diffusion MRI metrics. STUDY TYPE: Prospective. POPULATION: 14 volunteers (7 men; median age, range, 28, 26-59 years). FIELD STRENGTH/SEQUENCE: 3.0-T/Diffusion spectrum imaging. ASSESSMENT: Brain MRI studies were performed four times per subject: involving different combinations of coil types and voxel sizes. Regions of interest of 13 brain anatomical sites were drawn by one observer twice and another observer once to allow interobserver and intraobserver reproducibility assessment. Twenty-five quantitative metrics were calculated using four diffusion models. STATISTICAL TESTS: The variability was evaluated with coefficients of variation (CV), and quartile coefficient of dispersion (QCD). The reproducibility was assessed with intraclass correlation coefficient (ICC), and concordance correlation coefficient (CCC). Wilcoxon signed rank test was used to compare the influence of factors on robustness of quantitative diffusion metrics. A two-tailed P < 0.05 was considered statistically significant. RESULTS: The variability of quantitative diffusion metrics showed CV of 2.4%-68.2%, and QCD of 0.6%-48.2%, respectively. The reproducibility of scans using 20-channel coils with voxels of 2 × 2 × 2 mm3 and 3 × 3 × 3 mm3 , respectively (ICC 0.03-0.84, CCC 0.03-0.84) was significantly worse than that of repeated scans using a 20-channel coil with a voxel size of 2 × 2 × 2 mm3 (ICC of 0.74-0.97, CCC 0.74-0.97) and that of scans using 20- and 64-channel coils, respectively, with a voxel size of 2 × 2 × 2 mm3 (ICC 0.59-0.95, CCC 0.59-0.95). The intraobserver reproducibility (ICC 0.49-0.94, CCC 0.49-0.94) was significantly better than the interobserver reproducibility (ICC 0.28-0.91, CCC 0.28-0.91). DATA CONCLUSION: Our study indicated that the voxel size has a greater influence on the reproducibility of quantitative diffusion metrics than scan-rescans and coils. The reproducibility within one observer was higher than that between two observers. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Exploring the Potential of Water-Soluble Squid Ink Melanin: Stability, Free Radical Scavenging, and Cd2+ Adsorption Abilities.

Squid ink melanin can be efficiently extracted from the byproduct ink sac generated during squid processing. As a natural food colorant, it possesses inherent antioxidant properties and the capability to adsorb heavy metals. This study aims to investigate the solubility of water-soluble squid ink melanin (WSSM) obtained from the ink sac, as well as its stability under various conditions including temperature, pH, salt, sugar, potassium sorbate, metal ions, sodium benzoate, sodium sulfite (reducing agent), and hydrogen peroxide (oxidizing agent). Moreover, it explores the scavenging effects of WSSM on free radicals and cadmium ions. The findings suggest that WSSM's stability is insignificantly affected by high temperature, sucrose, and salt. However, acidity, sodium benzoate, potassium sorbate, sodium sulfite (Na2SO3), and hydrogen peroxide (H2O2) significantly influence its stability. Most metal ions do not impact the stability of WSSM, except for Fe2+, Fe3+, Al3+, and Cu2+, which result in the precipitation of WSSM. Additionally, WSSM exhibits remarkable antioxidant activity with IC50 values of 0.91, 0.56, and 0.52 mg/mL for scavenging superoxide anion radicals (O2-·), hydroxyl radicals (·OH), and DPPH radicals, respectively. It also demonstrates the ability to adsorb the heavy metal Cd2+, with the adsorption rate gradually increasing with a higher temperature and larger amounts of WSSM added. Infrared spectroscopy analysis reveals the weakening of characteristic peaks (-COOH and -OH) during the process of Cd2+ adsorption by WSSM, while SEM confirms surface roughening and structural damage after Cd2+ adsorption. This study provides valuable insights for the utilization of squid melanin products as natural antioxidants and heavy metal adsorbents in the food industry.

Chaperonin co-expression and chemical modification enables production of active microbial transglutaminase from E. coli cytoplasm.

Microbial transglutaminase (MTG) is a usable enzyme for biomacromolecule modification. In the present study, a "molecular chaperonin" strategy was developed to produce MTG in E. coli cytoplasm with high expression level and a "small molecule-mediated chemical modification" strategy was adopted to strip propeptide chaperonin efficiently during purification. Propeptide (Pro) was expressed separately as a chaperonin to facilitate MTG expression in E. coli cytoplasm with a yield up to 300 mg or about 9 kU from 1 L fed-batch culture. Furthermore, small molecular chemicals were applied to interfere the interaction between MTG and Pro. Chemical acetylation was identified as a suitable method to strip Pro resulting in pure MTG with high specific activity up to 49.6 U/mg. The purified acetylated MTG was characterized by MS analysis. The deconvoluted mass and Peptide Sequence Tags analysis confirmed acetylation on amino groups of MTG protein. Finally, the applications of obtained MTG were demonstrated via protein polymerization of bovine serum albumin and PEGylation of human interferon-α2b. Our method provides MTG with high purity and specific activity as well as unique merit with masked amino groups thus avoiding self-polymerization and cross-linking between MTG and substrates.

A cytodiagnosis of adenoid cystic carcinoma of the tracheobronchial tree through a systematic clinical case comparison and analysis.

BACKGROUND: Primary adenoid cystic carcinoma (AdCC) of the tracheobronchial tree is very rare with a high risk for recurrence and metastasis. The diagnosis of AdCC by histologic and immunohistochemical means has been well studied clinically. However, the identification of AdCC by cytologic features remains elusive due to the atypical features the cancer presents. This study aimed to describe the cytologic features of AdCC by using bronchial brushing, which could aid in distinguishing AdCC from other pulmonary carcinomas. METHODS: The cytopathological features of bronchial brushing smears collected from seven cases were histologically diagnosed as AdCC. The defined cytologic features, which could potentially be diagnostic, were systemically analyzed. RESULTS: Four out of the seven cytologic cases were inconcordance with the histologic diagnosis and cytologically classified as positive for malignant cells, small cell carcinoma, or atypical cells. Three cases showed a characteristic adenoid structure and magenta stroma forming globule, which was distinguished from the four cases. Cytologically, the above mentioned three cases were uniform with relatively small bland nuclei and little cytoplasm. In this study, only one case showed atypical polygonal medium-sized cells with conspicuous nucleoli. CONCLUSIONS: Unlike fine-needle aspiration cytology, magenta stroma globules might offer an alternate clue for cytodiagnosis of AdCC clinically. Bronchial brushings cytology was more present in bland uniform cells with high nuclear to cytoplasmic ratios and background mucoid substance. More cases should be collected and confirmed using histopathology with careful film reading to reduce the rate of misdiagnosis.

Dynamic imaging of interfacial electrochemistry on single Ag nanowires by azimuth-modulated plasmonic scattering interferometry.

Direct visualization of surface chemical dynamics in solution is essential for understanding the mechanisms involved in nanocatalysis and electrochemistry; however, it is challenging to achieve high spatial and temporal resolution. Here, we present an azimuth-modulated plasmonic imaging technique capable of imaging dynamic interfacial changes. The method avoids strong interference from reflected light and consequently eliminates the parabolic-like interferometric patterns in the images, allowing for a 67-fold increase in the spatial resolution of plasmonic imaging. We demonstrate that this optical imaging approach enables comprehensive analyses of surface chemical dynamics and identification of previously unknown surface reaction heterogeneity by investigating electrochemical redox reactions over single silver nanowires as an example. This work provides a general strategy for high-resolution plasmonic imaging of surface electrochemical dynamics and other interfacial chemical reactions, complementing existing surface characterization methods.

Multiple spectroscopic insights into the interaction mechanisms between proteins and humic acid.

Proteins are important constituents of dissolved organic matter (DOM) in aqueous environments, and their interaction with humic acid (HA), another key component of DOM, substantially affects the environmental behaviors of DOM. In this work, the interaction mechanisms between tryptophan-containing proteins and HA were systematically investigated using multiple molecular spectroscopic approaches. The fluorescence quenching tests indicate that bovine serum albumin (BSA) was more readily quenched by HA and the coexisting phenolic, carboxyl, and quinone groups in HA contributed to this process significantly. By comparison, the fluorescence of L-tryptophan (L-Trp) was more stable under the same conditions. Furthermore, with multiple groups in HA, static quenching with the binding constants and the number of sites were calculated in the protein-HA and L-Trp-HA mixtures. In addition, the differential fluorescence spectra, UV‒Vis spectra, and two-dimensional correlation spectroscopy results confirmed that L-tryptophan amino acid could indeed form a complex with HA, while did not lead to fluorescence quenching. Finally, the molecular docking and density functional theory (DFT) simulations highlighted the contribution of multiple residues surrounding the HA groups to their interactions. The direct interaction between the tryptophan residue and HA might not be the prerequisite for the fluorescence response. Therefore, our work provides further insights into protein-HA interactions and implies other reasonable elucidations for further explanation.

Unenhanced CT-based predictive model to identify small bowel necrosis in patients with mechanical small bowel obstruction.

OBJECTIVES: To investigate the diagnostic value of unenhanced CT in mechanical small bowel obstruction (SBO) with small bowel necrosis, and to establish a predictive model. METHODS: From May 2017 to December 2021, the patients with mechanical SBO admitted to our hospital were retrospectively collected. Taking pathology-confirmed small bowel necrosis as the gold standard, the experimental group was composed of patients with small bowel necrosis confirmed by pathology, and the control group was composed of patients with no intestinal necrosis confirmed by surgery or successful conservative treatment with no recurrence of intestinal obstruction during 1-month followed-up. RESULTS: A total of 182 patients were enrolled in this study, 157 patients underwent surgery, of which 35 patients were accompanied with small bowel necrosis and 122 patients were not (33 patients with ischemic findings at surgery without necrosis). Finally, there were 35 patients in the experimental group and 147 patients in the control group. Multivariable logistic regression showed that increased attenuation of small bowel wall (P = 0.002), diffuse mesenteric haziness (P = 0.010), difference of CT value between mesenteric vessel and aorta (P = 0.025) and U-/C-shaped small bowel loop (P = 0.010) were independent risk factors for the diagnosis of mechanical SBO with small bowel necrosis. Through internal verification, the area under curve (AUC) of the predictive model reached 0.886 (95%CI: 0.824-0.947), and the calibration result was moderate. CONCLUSION: Multiple features (increased attenuation of small bowel wall; difference of CT values between mesenteric vessel and aorta; diffuse mesenteric haziness; and U-/C-shaped small bowel loop) of unenhanced CT have clinical value in the diagnosis of mechanical SBO with small bowel necrosis. The predictive model based on these four features could achieve satisfactory efficiency.