A digestive phospholipase a2 in Midguts of worker honey bees, Apis mellifera : significance in lipid nutrition and health

Phospholipase A2 (PLA2) catalyzes hydrolysis of the fatty acid moiety from the sn-2 position of phospholipids. At least 16 groups of PLA2s are known in mammals. In insects, PLA2s occur in several tissues, where they act in a variety of biological functions, such as digestion, immune signaling, development and reproduction. However, other than the venom PLA2s, characterization of their physiological functions has not been reported in Hymenoptera, particularly in honey bees (Apis mellifera). Among many studies on honey bee nutrition and physiology, the enzymes acting in digesting dietary lipids remain understudied. This is an important lacuna because it bears directly on meeting essential dietary fatty acid requirements, which I addressed by characterizing a digestive PLA2 in midgut preparations of honey bee workers. The honey bee midgut PLA2 is sensitive to reaction conditions, including incubation time, substrate and enzyme concentrations, reaction temperature and pH. It is Ca2+- independent and susceptible to specific PLA2 inhibitors. Through a cryopreservation study of this PLA2 in honey bee midgut preparations, I confirmed that the honey bee digestive PLA2 preparations are physically stable, with high activity after storage at -80[degrees]C for at least three months. These findings open a new corridor of research into honey bee dietary lipid digestion and nutrition. I used classical molecular tools to identify genes encoding honey bee midgut PLA2s, to clone the genes from midgut tissue preparations and express one of the identified genes in competent E. coli cells. Although the enriched PLA2 from E. coli cultures was not biologically active, this work is a meaningful aspect of my training and education, on which I offer my thoughts in Chapter 4.Includes bibliographical reference

An Analysis of Factors Influencing Consumers\u27 Continued Purchase Intention Based on Online Shopping Pre-sale Mode

Online shopping pre-sale has great commercial value, and the key is to realize its commercial value,which is shown by the continuous purchase made by consumers. However, in China, there is a lack of relevant research on the factors affecting consumers\u27 continued purchase intention. Based on the expectation confirmation theory, this paper constructs a model to explore the influential factors of the consumer\u27s continued purchase intention. This study employed the Structural Equation Model (SEM) to perform empirical analysis. The results showed that the main influential factors of consumer’s continued purchase intention include perceived usefulness, perceived ease of use, expectation confirmation, and satisfaction. Among which, satisfaction had relatively high influence while perceived usefulness had a relatively low influence. Perceived usefulness and perceived ease of use had an indirect effect on the continued purchase intention through satisfaction

A Study On Influential Factors of Residential Rental Prices Based On Hedonic Price Model ——Evidence From Central Urban Districts Of Chengdu

With the government\u27s efforts to regulate housing prices, the trend of excessive housing price increases has been suppressed to some extent. Meanwhile, the government introduced a policy of renting and selling have the same rights, stimulating the development of the housing leasing market, increasing the market demand for residential leasing, and having an important impact on the formation of housing rental prices. This paper analyzes the influential factors of the formation of housing rental prices in Chengdu, selects the key variables of the residential rental characteristic price index, and constructs the model of the influential factors of the characteristic price of housing rental in Chengdu. The empirical study using residential sample data from three central urban districts in Chengdu. The data analysis showed that the 12 variables of residential building characteristics, neighborhood characteristics, location characteristics, and regional characteristics affected the residential rental price to varying degrees. The conclusions of this paper provide a theoretical basis for the pricing and management of residential leasing in Chengdu

Estimating Large Language Model Capabilities without Labeled Test Data

Large Language Models (LLMs) have exhibited an impressive ability to perform in-context learning (ICL) from only a few examples, but the success of ICL varies widely from task to task. Thus, it is important to quickly determine whether ICL is applicable to a new task, but directly evaluating ICL accuracy can be expensive in situations where test data is expensive to annotate -- the exact situations where ICL is most appealing. In this paper, we propose the task of ICL accuracy estimation, in which we predict the accuracy of an LLM when doing in-context learning on a new task given only unlabeled data for that task. To perform ICL accuracy estimation, we propose a method that trains a meta-model using LLM confidence scores as features. We compare our method to several strong accuracy estimation baselines on a new benchmark that covers 4 LLMs and 3 task collections. On average, the meta-model improves over all baselines and achieves the same estimation performance as directly evaluating on 40 labeled test examples per task, across the total 12 settings. We encourage future work to improve on our methods and evaluate on our ICL accuracy estimation benchmark to deepen our understanding of when ICL works.Comment: 14 pages, 4 figure

Cerebral metabolism in major depressive disorder:A voxel-based meta-analysis of positron emission tomography studies

BACKGROUND: Major depressive disorder (MDD) is a common mental illness with high lifetime prevalence close to 20%. Positron emission tomography (PET) studies have reported decreased prefrontal, insular and limbic cerebral glucose metabolism in depressed patients compared with healthy controls. However, the literature has not always been consistent. To evaluate current evidence from PET studies, we conducted a voxel-based meta-analysis of cerebral metabolism in MDD. METHOD: Data were collected from databases including PubMed and Web of Science, with the last report up to April 2013. Voxel-based meta-analyses were performed using the revised activation likelihood estimation (ALE) software. RESULTS: Ten whole-brain-based FDG-PET studies in MDD were included in the meta-analysis, comprising 188 MDD patients and 169 healthy controls. ALE analyses showed the brain metabolism in bilateral insula, left lentiform nucleus putamen and extra-nuclear, right caudate and cingulate gyrus were significantly decreased. However, the brain activity in right thalamus pulvinar and declive of posterior lobe, left culmen of vermis in anterior lobe were significantly increased in MDD patients. CONCLUSION: Our meta-analysis demonstrates the specific brain regions where possible dysfunctions are more consistently reported in MDD patients. Altered metabolism in insula, limbic system, basal ganglia, thalamus, and cerebellum and thus these regions are likely to play a key role in the pathophysiology of depression

Efficiency of different annuloplasty in treating functional tricuspid regurgitation and risk factors for recurrence

AbstractBackgroundFunctional tricuspid regurgitation (FTR) is frequent in patients with mitral valve disease. Untreated tricuspid regurgitation (TR) may cause poor clinical outcomes. The surgical factors involved in annuloplasty for FTR remain controversial. Our objective was to compare effectiveness of different tricuspid annuloplasty (TVP), and reveal the risk factors of recurrence.MethodsWe analyzed the clinical details of 399 consecutive patients who underwent mitral surgery with concomitant TVP, from 2006 to 2011, in two Chinese single-centers. Three methods were used for TVP: De Vega surgery was completed in 242 patients; annuloplasty using a flexible band was completed in 98 patients; and surgery with a rigid ring was performed in 59 patients.ResultsThe operative mortality rate was 2.3%. After surgery, the TR grade of all patients decreased significantly. At three years postoperatively, 13.7% of patients were diagnosed with recurrent FTR. At the three year time point, severe TR in the De Vega group was 18%, which was higher than those in the flexible (8.4%) and rigid planner ring groups (5.2%). During follow-up, the recurrent rates in the rigid group were significantly lower than in the flexible group. Multivariate analysis revealed that pre-operative atrial fibrillation, severe TR, large left atrial, ejection fraction (EF)<40%, De Vega annuloplasty, and postoperative permanent pacemaker installation were independent risk factors for severe recurrent TR.ConclusionsRigid ring annuloplasty efficaciously improved post-operative tricuspid valve function in patients with FTR. Atrial fibrillation, a large left atrium, low EF and postoperative permanent pacemaker installation were independent risk factors for severe recurrent TR

Anti-DKK1 Enhances the Early Osteogenic Differentiation of Human Adipose-Derived Stem/Stromal Cells

: Adipose-derived stem/stromal cells (ASCs) have been previously used for bone repair. However, significant cell heterogeneity exists within the ASC population, which has the potential to result in unreliable bone tissue formation and/or low efficacy. Although the use of cell sorting to lower cell heterogeneity is one method to improve bone formation, this is a technically sophisticated and costly process. In this study, we tried to find a simpler and more deployable solution-blocking antiosteogenic molecule Dickkopf-1 (DKK1) to improve osteogenic differentiation. Human adipose-derived stem cells were derived from = 5 samples of human lipoaspirate. In vitro, anti-DKK1 treatment, but not anti-sclerostin (SOST), promoted ASC osteogenic differentiation, assessed by alizarin red staining and real-time polymerase chain reaction (qPCR). Increased canonical Wnt signaling was confirmed after anti-DKK1 treatment. Expression levels of DKK1 peaked during early osteogenic differentiation (day 3). Concordantly, anti-DKK1 supplemented early (day 3 or before), but not later (day 7) during osteogenic differentiation positively regulated osteoblast formation. Finally, anti-DKK1 led to increased transcript abundance of the Wnt inhibitor SOST, potentially representing a compensatory cellular mechanism. In sum, DKK1 represents a targetable "molecular brake" on the osteogenic differentiation of human ASC. Moreover, release of this brake by neutralizing anti-DKK1 antibody treatment at least partially rescues the poor bone-forming efficacy of ASC

The diagnostic value of four-dimensional ultrasound examination of perineum in the diagnosis of postpartum pelvic floor dysfunction

Objective to explore the diagnostic value of perineal four-dimensional ultrasound (4D-US) in postpartum pelvic floor dysfunction (PFD) disease. 328 postpartum PFD patients diagnosed by clinical pelvic floor palpation from June 2018 to December 2020 were selected as the PFD group, and 328 patients without PFD were selected as the control group. All participants underwent perineal 4D-US, the indicators were statistically analyzed. The results showed that the LAT of left and right, LHLR, LHAP, LHA, resting state and holding the breath in the PFD group were higher than those in the control group, and the difference was statistically significant (P<0.05). From cervix to lower margin of pubic symphysis, bladder to lower margin of pubic symphysis of the pubic symphysis, and from the ampulla of the rectum to the lower margin of the pubic symphysis, the PFD group was larger than the control group, but the result of urethral rotation was reversed, and the difference was statistically significant (P<0.05). The morphologic features of the levator ani muscle and pelvic fissure can be detected early using 4D-US, which is a reliable technique that can be learned in a short period of time

Bone-forming perivascular cells: Cellular heterogeneity and use for tissue repair

: Mesenchymal progenitor cells are broadly distributed across perivascular niches-an observation conserved between species. One common histologic zone with a high frequency of mesenchymal progenitor cells within mammalian tissues is the tunica adventitia, the outer layer of blood vessel walls populated by cells with a fibroblastic morphology. The diversity and functions of (re)generative cells present in this outermost perivascular niche are under intense investigation; we have reviewed herein our current knowledge of adventitial cell potential with a somewhat narrow focus on bone formation. Antigens of interest to functionally segregate adventicytes are discussed, including CD10, CD107a, aldehyde dehydrogenase isoforms, and CD140a, among others. Purified adventicytes (such as CD10+ , CD107alow , and CD140a+ cells) have stronger osteogenic potential and promote bone formation in vivo. Recent bone tissue engineering applications of adventitial cells are also presented. A better understanding of perivascular progenitor cell subsets may represent a beneficial advance for future efforts in tissue repair and bioengineering

PDGFRα reporter activity identifies periosteal progenitor cells critical for bone formation and fracture repair

The outer coverings of the skeleton, which is also known as the periosteum, are arranged in concentric layers and act as a reservoir for tissue-specific bone progenitors. The cellular heterogeneity within this tissue depot is being increasingly recognized. Here, inducible PDGFR alpha reporter animals were found to mark a population of cells within the periosteum that act as a stem cell reservoir for periosteal appositional bone formation and fracture repair. During these processes, PDGFR alpha reporter(+) progenitors give rise to Nestin(+) periosteal cells before becoming osteoblasts and osteocytes. The diphtheria toxin-mediated ablation of PDGFR alpha reporter(+) cells led to deficits in cortical bone formation during homeostasis and a diminutive hard callus during fracture repair. After ossicle transplantation, both mouse PDGFR alpha reporter(+) periosteal cells and human Pdgfr alpha(+) periosteal progenitors expand, ossify, and recruit marrow to a greater extent than their counterpart periosteal cells, whereas PDGFR alpha reporter(-) periosteal cells exhibit a predisposition to chondrogenesis in vitro. Total RNA sequencing identified enrichment of the secreted factors Fermt3 and Ptpn6 within PDGFR alpha reporter(+) periosteal cells, which partly underlie the osteoblastogenic features of this cell population