22 research outputs found
Spectroscopic Observation and Analysis of HII regions in M33 with MMT: Temperatures and Oxygen Abundances
The spectra of 413 star-forming (or HII) regions in M33 (NGC 598) were
observed by using the multifiber spectrograph of Hectospec at the 6.5-m
Multiple Mirror Telescope (MMT). By using this homogeneous spectra sample, we
measured the intensities of emission lines and some physical parameters, such
as electron temperatures, electron densities, and metallicities. Oxygen
abundances were derived via the direct method (when available) and two
empirical strong-line methods, namely, O3N2 and N2. In the high-metallicity
end, oxygen abundances derived from O3N2 calibration were higher than those
derived from N2 index, indicating an inconsistency between O3N2 and N2
calibrations. We presented a detailed analysis of the spatial distribution of
gas-phase oxygen abundances in M33 and confirmed the existence of the
axisymmetric global metallicity distribution widely assumed in literature.
Local variations were also observed and subsequently associated with spiral
structures to provide evidence of radial migration driven by arms. Our O/H
gradient fitted out to 1.1 resulted in slopes of ,
, and dex utilizing abundances from
O3N2, N2 diagnostics, and direct method, respectively.Comment: Accepted for publication in Ap
Duplication of the transverse colon in adults: a case report and literature review
BackgroundDuplication of the transverse colon is a rare gastrointestinal malformation. Its pathogenesis is still unclear, and it is extremely rare in adults. Patients often present with symptoms of tumor compression such as abdominal mass, abdominal pain, and constipation as the first manifestation.Methods and resultA patient with a duplication of the transverse colon was admitted to the Department of General Surgery of our hospital. Laparoscopic exploration found a mass at the rear of the transverse colon near the splenic flexure, and the root was connected to the middle portion of the transverse colon.ConclusionSurgery is a radical treatment and reduces the possibility of perforation, bleeding, obstruction, and cancer
A Comparative Study of Information-Based Source Number Estimation Methods and Experimental Validations on Mechanical Systems
This paper investigates one eigenvalue decomposition-based source number estimation method, and three information-based source number estimation methods, namely the Akaike Information Criterion (AIC), Minimum Description Length (MDL) and Bayesian Information Criterion (BIC), and improves BIC as Improved BIC (IBIC) to make it more efficient and easier for calculation. The performances of the abovementioned source number estimation methods are studied comparatively with numerical case studies, which contain a linear superposition case and a both linear superposition and nonlinear modulation mixing case. A test bed with three sound sources is constructed to test the performances of these methods on mechanical systems, and source separation is carried out to validate the effectiveness of the experimental studies. This work can benefit model order selection, complexity analysis of a system, and applications of source separation to mechanical systems for condition monitoring and fault diagnosis purposes
Clinical efficacy of laparoscopic subtotal colectomy in adult megacolon
ObjectiveTo observe the clinical efficacy and safety of laparoscopic subtotal colectomy + loop colostomy in adult patients with megacolon. MethodsRetrospective analysis was performed on the clinical data of 22 adult megacolon patients treated by laparoscopic subtotal colectomy + loop colostomy in Affiliated Hospital of Nanjing University of Chinese Medicine from October 2016 to October 2020. All patients underwent preoperative CT, barium enema, anorectal manometry, and postoperative pathological examination to diagnose megacolon. The symptoms of abdominal pain and abdominal distension, gastrointestinal quality of life score index(GIQLI), Wexner constipation score and surgical complications were analyzed and compared before and after surgery. ResultsThe incidence of preoperative abdominal distension symptoms of 22 patients was 100%, and all improved after surgery. The incidence of abdominal distension at 12 months after surgery was 4.5% (1/22). The Wexner constipation scores at the 6th and 12th months after surgery were 6.27±2.16 and 4.77±1.11, respectively, significantly better than the preoperative score (20.41±2.48, P<0.05). The GIQLI at the 6th and 12th months after surgery were 104.05±12.09 and 102.23±8.20, respectively, significantly better than the preoperative score (68.64±6.04, P<0.05). The postoperative complications included 1 infection at the operation site (4.5%), 1 case of anastomotic fistula (4.5%), 1 case of abdominal bleeding (4.5%). ConclusionLaparoscopic subtotal colectomy + loop colostomy is a safe and effective operation for the treatment of adult megacolon, which is worthy of further exploration and application
Effect of Connection Resistance between Cyclones and Backpass on Furnace Solids Suspension Density Profile and Circulation Rates in CFB
The connection section between cyclones and backpass is an important configuration in multi-cyclone circulating fluidized bed boilers (CFB). In this work, the resistance coefficient of different connection modes, and connection resistance distribution from each cyclone outlet to backpass (connection branch) in one mode are defined and calculated, in order to investigate their effects on furnace solids suspension density distribution and circulation rates. Three connection modes with different overall resistance coefficients were tested experimentally and analyzed by a 1.5-dimensional model in a four-cyclone scaling CFB apparatus. Both experimental and theoretical results show that, with larger overall resistance of a connection, there are more solids suspended in the furnace bottom and fewer in the top section. The investigation of the C-type connection has revealed that when the branch resistance of the connection decreases from branch No. 1–4, the solids suspension density and circulation rate from corresponding solids recycle loops (No. 1–4) increase. Moreover, the non-uniformity of connection branch resistance distribution will lead to uneven lateral solids suspension density distribution and circulation rates allocation. This effect is enhanced by growing superficial velocity
Preliminary Study on High-Energy and Low-Energy Microfracture Event Evolution Characteristics in the Development Process of Rock Failure
The evolution characteristics of high-energy and low-energy microfracture events play an important role in the brittle failure mechanism of rock and reasonable microseismic (MS) monitoring and acoustic emission (AE) monitoring. The bimodal distribution (BMD) model is commonly used to observe the evolution characteristics of high-energy and low-energy MS events; however, its precise mechanism remains unclear. The evolution characteristics of high-energy and low-energy microfracture events are assessed in this study based on a BMD model. MS monitoring results from the No. 22517 working face of the Dongjiahe Coal Mine are studied, and AE monitoring results of a biaxial compression experiment of a granite specimen are analyzed. High-energy MS events in the No. 22517 working face are found to be generated by an increase in the failure scale of the overlying rock mass upon exiting the insufficient mining stage and entering the sufficient mining stage. The change characteristics of the high-energy AE hits are positively correlated with crack evolution characteristics in the granite specimen and negatively correlated with changes in the Gutenberg-Richter b value. A precise high-energy and low-energy AE hit evolution mechanism is analyzed based on the microscopic structure of the granite specimen. Similarities and differences between high-energy MS events and low-energy AE hits are determined based on these results. Both are found to have bimodal characteristics; an increase in the failure scale is identified as the root cause of the high-energy component. The bimodal distribution of AE hits is far less obvious than that of MS events
Evaluation of operation and management of Luocheng small municipal wastewater treatment plant
Operation efficiency, effect and operation energy consumption are the main basis for the evaluation of the operation and management level of wastewater treatment plant. The statistics of the operation data of the small municipal wastewater treatment plant in Luocheng County show that the operation rate of the facility is high, and the treated effluent reaches the Level A standard of the “Discharge standard of pollutants for municipal wastewater treatment plant” (GB18918-2002), and the various evaluation indicators of the urban wastewater treatment plant basically normal. However, the average operating load of some municipal wastewater treatment plant has not reached the index requirement for the operation period of production, and the load rates of CODCr and NH4+-N are mostly below 60%, and wastewater treatment plant unit wastewater volume, unit CODCr and NH4+-N load energy consumption is high. The reason is that the water quality of the design of the micro-municipal wastewater treatment plant is not reasonable, the construction scale is too large, and the operation fails to adopt effective management and control technology measures
Metabolic heterogeneity in clear cell renal cell carcinoma revealed by single-cell RNA sequencing and spatial transcriptomics
Abstract Background Clear cell renal cell carcinoma is a prototypical tumor characterized by metabolic reprogramming, which extends beyond tumor cells to encompass diverse cell types within the tumor microenvironment. Nonetheless, current research on metabolic reprogramming in renal cell carcinoma mostly focuses on either tumor cells alone or conducts analyses of all cells within the tumor microenvironment as a mixture, thereby failing to precisely identify metabolic changes in different cell types within the tumor microenvironment. Methods Gathering 9 major single-cell RNA sequencing databases of clear cell renal cell carcinoma, encompassing 195 samples. Spatial transcriptomics data were selected to conduct metabolic activity analysis with spatial localization. Developing scMet program to convert RNA-seq data into scRNA-seq data for downstream analysis. Results Diverse cellular entities within the tumor microenvironment exhibit distinct infiltration preferences across varying histological grades and tissue origins. Higher-grade tumors manifest pronounced immunosuppressive traits. The identification of tumor cells in the RNA splicing state reveals an association between the enrichment of this particular cellular population and an unfavorable prognostic outcome. The energy metabolism of CD8+ T cells is pivotal not only for their cytotoxic effector functions but also as a marker of impending cellular exhaustion. Sphingolipid metabolism evinces a correlation with diverse macrophage-specific traits, particularly M2 polarization. The tumor epicenter is characterized by heightened metabolic activity, prominently marked by elevated tricarboxylic acid cycle and glycolysis while the pericapsular milieu showcases a conspicuous enrichment of attributes associated with vasculogenesis, inflammatory responses, and epithelial–mesenchymal transition. The scMet facilitates the transformation of RNA sequencing datasets sourced from TCGA into scRNA sequencing data, maintaining a substantial degree of correlation. Conclusions The tumor microenvironment of clear cell renal cell carcinoma demonstrates significant metabolic heterogeneity across various cell types and spatial dimensions. scMet exhibits a notable capability to transform RNA sequencing data into scRNA sequencing data with a high degree of correlation