128 research outputs found
Wait-for-change Strategy: A Dynamic Analysis Of Chinese Maternity Histories
This study is an attempt to understand how Chinese women carried out China\u27s fertility decline with an unprecedented speed since the mid-1970s. Based on China\u27s large-scale In-Depth Fertility Surveys in Shaanxi (1985) and Guangdong (1987), this study tries to explain the fertility revolution with a dynamic theoretical framework which concerns not only the socio-political institutional impact on Chinese women\u27s compliance with the birth control policy from the top down but also the effect of a supposedly all-embracing individual environment which includes socio-economic foundations and cultural mentality from the bottom up. Considering such a two-way interactive dynamic, a wait-for-change strategy analysis is developed to examine the spacing pattern of contraceptive use in the birth interval. The present study has characterized patterns of wait-for-change strategy fertility behaviour among Chinese couples in Shaanxi and Guangdong who were exposed to the risk of having out-of-quota births during the wan xi shao (later (marriage), longer (intervals between births), fewer (children)) and one-child-family national birth control campaigns, respectively. The findings reveal that Chinese couples were largely willing to comply with the birth control policy by using contraception to space birth at lower parity regardless of differences in educational level, age at marriage, and gender composition of children. However, as they arrived at the contraceptive stage, the situation changed. Generally, the socio-economic factors, gender composition of children, and age at marriage do have significant effect on women\u27s waiting time for parity change. These findings indicate that socio-economic and son preference cultural effects from the bottom up on Chinese women\u27s fertility behaviour were indeed profound and enduring, despite powerful constraints of political institutional settings from the top down
A New Classification Network for Diagnosing Alzheimer’s Disease in class-imbalance MRI datasets
Automatic identification of Alzheimer’s Disease (AD) through magnetic resonance imaging (MRI) data can eectively assist to doctors diagnose and treat Alzheimer’s. Current methods improve the accuracy of AD recognition, but they are insufficient to address the challenge of small interclass and large intraclass dierences. Some studies attempt to embed patch-level structure in neural networks which enhance pathologic details, but the enormous size and time complexity render these methods unfavorable. Furthermore, several self-attention mechanisms fail to provide contextual information to represent discriminative regions, which limits the performance of these classifiers. In addition, the current loss function is adversely aected by outliers of class imbalance and may fall into local optimal values. Therefore, we propose a 3D Residual RepVGG Attention network (ResRepANet) stacked with several lightweight blocks to identify the MRI of brain disease, which can also trade o accuracy and flexibility. Specifically, we propose a Non-local Context Spatial Attention block (NCSA) and embed it in our proposed ResRepANet, which aggregates global contextual information in spatial features to improve semantic relevance in discriminative regions. In addition, in order to reduce the influence of outliers, we propose a Gradient Density Multiple-weighting Mechanism (GDMM) to automatically adjust the weights of each MRI image via a normalizing gradient norm. Experiments are conducted on datasets from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) and Australian Imaging, Biomarker and Lifestyle Flagship Study of Aging (AIBL). Experiments on both datasets show that the accuracy, sensitivity, specificity, and Area Under the Curve are consistently better than for state-of-the-art methods
6,6-Dimethyl-2H,5H,6H,7H-1,3-dithiolo[4,5-f][1,5,3]dithiasilepin-2-one
In the structure of the title compound, C7H10OS4Si, the carbonyl O atom lies in the plane of the five-membered dithiole ring with a deviation of only 0.022 (2) Å. The seven-membered ring adopts a chair conformation. The crystal packing is stabilized by S⋯O [3.096 (4) Å] and S⋯S [3.620 (4) Å] contacts, together with C—H⋯S interactions
Effect of concrete stress states on carbonation depth of concrete
Carbonation can lead to reduction of alkalinity of concrete and initiation of steel reinforcement corrosion. In durability design of concrete structures, the carbonation depth should be duly considered. However, the concrete stress state would influence the carbonation depth, and there has been inadequate research on such effect. In this study, it is proposed to introduce a stress influence coefficient to the concrete carbonation depth model. With reference to the experimental data from eleven research studies in the literature encompassing both tensile and compressive stress states, the relationship between stress influence coefficient and concrete stress ratio is quantitatively investigated, and mathematical equations relating the stress influence coefficient with the concrete stress ratio are established. Comparative study with three typical existing groups of equations shows that the proposed equations of stress influence coefficient are more reasonable and have a higher reliability. The effects of carbonation time, mix proportions of concrete on stress influence coefficient are also analysed, and the magnitudes of the effects are found to be approximately within ±10%. Finally, the modified carbonation depth models are proposed and verified by the experimental data, which suggests that the proposed models are of desirable accuracy. Adoption of the proposed equations as the modified formula of stress influence coefficient in the concrete carbonation depth model for practical applications is recommended
Applications of various range shifters for proton pencil beam scanning radiotherapy
Background A range pull-back device, such as a machine-related range shifter (MRS) or a universal patient-related range shifter (UPRS), is needed in pencil beam scanning technique to treat shallow tumors. Methods Three UPRS made by QFix (Avondale, PA, USA) allow treating targets across the body: U-shaped bolus (UB), anterior lateral bolus (ALB), and couch top bolus. Head-and-neck (HN) patients who used the UPRS were tested. The in-air spot sizes were measured and compared in this study at air gaps: 6 cm, 16 cm, and 26 cm. Measurements were performed in a solid water phantom using a single-field optimization pencil beam scanning field with the ALB placed at 0, 10, and 20 cm air gaps. The two-dimensional dose maps at the middle of the spread-out Bragg peak were measured using ion chamber array MatriXX PT (IBA-Dosimetry, Schwarzenbruck, Germany) located at isocenter and compared with the treatment planning system. Results A UPRS can be consistently placed close to the patient and maintains a relatively small spot size resulting in improved dose distributions. However, when a UPRS is non-removable (e.g. thick couch top), the quality of volumetric imaging is degraded due to their high Z material construction, hindering the value of Image-Guided Radiation Therapy (IGRT). Limitations of using UPRS with small air gaps include reduced couch weight limit, potential collision with patient or immobilization devices, and challenges using non-coplanar fields with certain UPRS. Our experience showed the combination of a U-shaped bolus exclusively for an HN target and an MRS as the complimentary device for head-and-neck targets as well as for all other treatment sites may be ideal to preserve the dosimetric advantages of pencil beam scanning proton treatments across the body. Conclusion We have described how to implement UPRS and MRS for various clinical indications using the PBS technique, and comprehensively reviewed the advantage and disadvantages of UPRS and MRS. We recommend the removable UB only to be employed for the brain and HN treatments while an automated MRS is used for all proton beams that require RS but not convenient or feasible to use UB
Current status and focus of breast reconstruction research in China and abroad: a bibliometric study
Background and purpose: According to the 2020 global cancer burden data of the International Agency for Research on Cancer (IARC), breast cancer has replaced lung cancer as the most common type of cancer worldwide. The aim of this study was to conduct a bibliometric and visual analysis of breast reconstruction related research in China and abroad published in the past 5 years, to understand the research status and development trend in this field, to discuss the focus of research in different countries and different disciplines, and to provide reference for other researchers. Methods: Relevant literatures about breast reconstruction were retrieved from the Web of Science Core Collection. The VOS viewer 1.6.15 software was used to extract the authors, countries, institutions and keywords to generate network maps of high-yield authors, institutions and high-frequency keywords clustering network. Results: A total of 4 815 documents meeting the requirements were retrieved, which showed an upward trend in the past five years. Regarding the discipline, 838 documents (17.40%) were published by breast surgery and Cancer Surgery, 3 308 (68.70%) were published by plastic surgery, and 669 (13.90%) were jointly published by both types of researchers. There were differences in the disciplines of the main authors between China and abroad. In China, authors from breast surgery published a larger proportion of documents (138, 44.52%), while the number of documents published by authors of plastic surgery (129, 44.52%) and the joint publication of both types of authors (43, 13.87%) was relatively small. However, foreign documents mainly came from authors of plastic surgery (74.74%). There were more cooperative groups (155) formed by major foreign authors, and more frequent joint publishing between groups, while Chinese authors formed only 16 cooperative groups with less cooperation. Authors from breast surgery focused more on oncology-related issues in breast reconstruction, while in plastic surgery, more attentions were paid on autologous tissue reconstruction. Conclusion: Breast reconstruction has gradually attracted the attention of Chinese and foreign researchers. Compared with foreign countries, there were problems such as lack of high-quality research and less cooperative research in China. There were differences in the research focus of breast reconstruction between China and abroad, which was mainly related to the differences in the disciplines of researchers
Latissimus dorsi flap – the main force in breast reconstruction for breast tumor in Chinese population
BackgroundThe latissimus dorsi flap (LDF) is the most commonly used autologous flap for breast reconstruction (BR) in China. We conducted this study to explore the current status of BR using LDF with/without implants.MethodsThis study was a single-center retrospective study that included breast tumor patients who underwent LDF breast reconstruction at Fudan University Shanghai Cancer Center (FUSCC) between 2000 and 2021.ResultsWe analyzed 4918 patients who underwent postmastectomy BR, including 1730 patients (35.2%) with autologous flaps. LDF was used for BR in 1093 (22.2%) patients, and an abdominal flap was used in 637 (13.0%) patients. The proportion of LDFs used in autologous BR patients decreased each year and dropped to approximately 65.0% after 2013 due to the increased use of abdominal flaps. Among these patients, 609 underwent extended LDF (ELDF) BR, 455 underwent LDF BR with implants, and 30 received a LDF as a salvage flap due to previous flap or implant failure. Patients who underwent ELDF reconstruction were older and had a higher BMI than those who received a LDF with implants. There was no significant difference in the mean postoperative hospital stay, neoadjuvant chemotherapy rates, or adjuvant radiotherapy rates between the two groups. Major complications requiring surgical intervention occurred in 25 patients (2.29%). There was no significant difference in the incidence of major complications between the two groups (P=0.542).ConclusionsLDF breast reconstruction is a well-developed and safe procedure. The duration of postoperative hospitalization nor the incidence of major complications was affected by implant use
Random Forest in Clinical Metabolomics for Phenotypic Discrimination and Biomarker Selection
Metabolomic data analysis becomes increasingly challenging when dealing with clinical samples with diverse demographic and genetic backgrounds and various pathological conditions or treatments. Although many classification tools, such as projection to latent structures (PLS), support vector machine (SVM), linear discriminant analysis (LDA), and random forest (RF), have been successfully used in metabolomics, their performance including strengths and limitations in clinical data analysis has not been clear to researchers due to the lack of systematic evaluation of these tools. In this paper we comparatively evaluated the four classifiers, PLS, SVM, LDA, and RF, in the analysis of clinical metabolomic data derived from gas chromatography mass spectrometry platform of healthy subjects and patients diagnosed with colorectal cancer, where cross-validation, R2/Q2 plot, receiver operating characteristic curve, variable reduction, and Pearson correlation were performed. RF outperforms the other three classifiers in the given clinical data sets, highlighting its comparative advantages as a suitable classification and biomarker selection tool for clinical metabolomic data analysis
Impacts of systemic inflammation response index on the prognosis of patients with ischemic heart failure after percutaneous coronary intervention
BackgroundAtherosclerosis and cardiovascular diseases are significantly affected by low-grade chronic inflammation. As a new inflammatory marker, the systemic inflammation response index (SIRI) has been demonstrated to be associated with several cardiovascular disease prognoses. This study aimed to investigate the prognostic impact of SIRI in individuals having ischemic heart failure (IHF) following percutaneous coronary intervention (PCI).MethodsThis observational, retrospective cohort study was conducted at a single site. Finally, the research involved 1,963 individuals with IHF who underwent PCI, with a 36-month follow-up duration. Based on the SIRI quartiles, all patients were classified into four groups. Major adverse cardiovascular events (MACEs) were the primary outcomes. Every element of the main endpoint appeared in the secondary endpoints: all-cause mortality, non-fatal myocardial infarction (MI), and any revascularization. Kaplan–Meier survival analysis was conducted to assess the incidence of endpoints across the four groups. Multivariate Cox proportional hazards analysis confirmed the independent impact of SIRI on both the primary and secondary endpoints. The restricted cubic spline (RCS) was used to assess the nonlinear association between the SIRI and endpoints. Subgroup analysis was performed to confirm the implications of SIRI on MACE in the different subgroups.ResultsThe main outcome was much more common in patients with a higher SIRI. The Kaplan–Meier curve was another tool that was used to confirm the favorable connection between SIRI and MACE. SIRI was individually connected to a higher chance of the main outcome according to multivariate analyses, whether or not SIRI was a constant [SIRI, per one−unit increase, hazard ratio (HR) 1.04, 95% confidence interval (95% CI) 1.01–1.07, p = 0.003] or categorical variable [quartile of SIRI, the HR (95% CI) values for quartile 4 were 1.88 (1.47–2.42), p <0.001, with quartile 1 as a reference]. RCS demonstrated that the hazard of the primary and secondary endpoints generally increased as SIRI increased. A non-linear association of SIRI with the risk of MACE and any revascularization (Non-linear P <0.001) was observed. Subgroup analysis confirmed the increased risk of MACE with elevated SIRI in New York Heart Association (NYHA) class III–IV (P for interaction = 0.005).ConclusionIn patients with IHF undergoing PCI, increased SIRI was a risk factor for MACE independent of other factors. SIRI may represent a novel, promising, and low-grade inflammatory marker for the prognosis of patients with IHF undergoing PCI
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