692 research outputs found
An Effective Cold Start Recommendaton Method Using A Web Of Trust
Cold start recommendations are important because they help build user loyalty, which is the key to the success of e-services and e-commerce systems. Recommending useful information for new users generally creates a sense of belonging and loyalty, and encourages them to visit e-commerce systems frequently. However, as new users take time to become familiar with recommendation systems, the systems usually have limited information about newcomers and have difficulty providing appropriate recommendations. The cold start phenomenon has a serious impact on the performance of recommendation systems. To address the problem, we propose a cold start recommendation method that integrates a web of trust with a user model to identify trustworthy users. The suggestions of those users are then aggregated to provide useful recommendations for cold start users. Experiments based on the well-known Epinions dataset demonstrate that the proposed method is effective and efficient, and outperforms well-known recommendation methods by a significant margin
Spatially resolved MaNGA observations of the host galaxy of superluminous supernova 2017egm
Superluminous supernovae (SLSNe) are found predominantly in dwarf galaxies,
indicating that their progenitors have a low metallicity. However, the most
nearby SLSN to date, SN 2017egm, occurred in the spiral galaxy NGC 3191, which
has a relatively high stellar mass and correspondingly high metallicity. In
this paper, we present detailed analysis of the nearby environment of SN
2017egm using MaNGA IFU data, which provides spectral data on kiloparsec
scales. From the velocity map we find no evidence that SN 2017egm occurred
within some intervening satellite galaxy, and at the SN position most
metallicity diagnostics yield a solar and above solar metallicity (12 + log
(O/H) = 8.8-9.1). Additionally we measure a small H-alpha equivalent width (EW)
at the SN position of just 34 Angs, which is one of the lowest EWs measured at
any SLSN or Gamma-Ray Burst position, and indicative of the progenitor star
being comparatively old. We also compare the observed properties of NGC 3191
with other SLSN host galaxies. The solar-metallicity environment at the
position of SN 2017egm presents a challenge to our theoretical understanding,
and our spatially resolved spectral analysis provides further constraints on
the progenitors of SLSNe.Comment: Accepted version in ApJ Letter. Thank you for useful comment
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Functional Effects of let-7g Expression in Colon Cancer Metastasis.
MicroRNA regulation is crucial for gene expression and cell functions. It has been linked to tumorigenesis, development and metastasis in colorectal cancer (CRC). Recently, the let-7 family has been identified as a tumor suppressor in different types of cancers. However, the function of the let-7 family in CRC metastasis has not been fully investigated. Here, we focused on analyzing the role of let-7g in CRC. The Cancer Genome Atlas (TCGA) genomic datasets of CRC and detailed data from a Taiwanese CRC cohort were applied to study the expression pattern of let-7g. In addition, in vitro as well as in vivo studies have been performed to uncover the effects of let-7g on CRC. We found that the expression of let-7g was significantly lower in CRC specimens. Our results further supported the inhibitory effects of let-7g on CRC cell migration, invasion and extracellular calcium influx through store-operated calcium channels. We report a critical role for let-7g in the pathogenesis of CRC and suggest let-7g as a potential therapeutic target for CRC treatment
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All-trans retinoic acid ameliorates glycemic control in diabetic mice via modulating pancreatic islet production of vascular endothelial growth factor-A.
Patients with type 1 diabetes mellitus are associated with impairment in vitamin A metabolism. This study evaluated whether treatment with retinoic acid, the biologically active metabolite of vitamin A, can ameliorate diabetes. All-trans retinoic acid (atRA) was used to treat streptozotocin (STZ)-induced diabetic mice which revealed atRA administration ameliorated blood glucose levels of diabetic mice. This hyperglycemic amelioration was accompanied by an increase in the amount of β cells co-expressed Pdx1 and insulin and by restoration of the vascular laminin expression. The atRA-induced production of vascular endothelial growth factor-A from the pancreatic islets was possibly the key factor that mediated the restoration of islet vascularity and recovery of β-cell mass. Furthermore, the combination of islet transplantation and atRA administration significantly rescued hyperglycemia in diabetic mice. These findings suggest that vitamin A derivatives can potentially be used as a supplementary treatment to improve diabetes management and glycemic control
Identifying Epstein–Barr virus peptide sequences associated with differential IgG antibody response
Background: Epstein-Barr virus (EBV) infection contributes to cancers in a fraction of seropositive individuals, but much remains to be learned about variation in EBV-directed humoral immunity in cancer-free adults.
Methods: A protein microarray was used to probe serum from 175 Taiwanese and 141 Northern European adults for immunoglobulin G (IgG) antibody responses to 115 different peptide sequences, representing protein segments or protein variants, from 45 EBV proteins. It was posited that this antibody-based approach could identify EBV peptide sequences representing immunodominant regions relevant for B-cell immunity.
Results: Analyses of 45 EBV proteins with multiple protein segments or variants printed on the array identified eight EBV peptide sequences that appear to play a role in immunogenicity. This included: (1) three proteins with segments/regions associated with IgG reactivity (BALF5, LMP1, LMP2A); and (2) five proteins with sequence variants/amino acid changes associated with IgG reactivity (BDLF4, EBNA3A, EBNA3B, EBNA-LP, LF1).
Conclusion: This examination of IgG antibody responses against 115 EBV peptide sequences in 316 cancer-free adults represents an important step toward identifying specific EBV protein sequences that play a role in generating B-cell immunity in humans
Effects of Extract from Solid-State Fermented Cordyceps sinensis on Type 2 Diabetes Mellitus
Diabetes mellitus is the most common chronic disease in the world, and a wide range of drugs, including Chinese herbs, have been evaluated for the treatment of associated metabolic disorders. This study investigated the potential hypoglycemic and renoprotective effects of an extract from the solid-state fermented mycelium of Cordyceps sinensis (CS). We employed the KK/HIJ diabetic mouse model, in which the mice were provided with a high-fat diet for 8 weeks to induce hyperglycemia, followed by the administration of CS or rosiglitazone for 4 consecutive weeks. Several parameters were evaluated, including changes in body weight, plasma lipid profiles, oral glucose tolerance tests, insulin tolerance tests, and plasma insulin concentrations. Our results show that the CS extract significantly elevated HDL/LDL ratios at 4 weeks and decreased body weight gain at 8 weeks. Interestingly, CS treatment did not lead to obvious improvements in hyperglycemia or resistance to insulin, while in vitro MTT assays indicated that CS protects pancreatic beta cells against the toxic effects of STZ. CS also enhanced renal NKA activity and reduced the accumulation of mesangial matrix and collagen deposition. In conclusion, CS extract can potentially preserve β-cell function and offer renoprotection, which may afford a promising therapy for DM
Conductivity enhancement of multiwalled carbon nanotube thin film via thermal compression method
Variations in concerns reported on the Patient Concerns Inventory (PCI) in head and neck cancer patients from different health settings across the world
Background: The aim was to collate and contrast patient concerns from a range of different head and neck cancer follow-up clinics around the world. Also, we sought to explore the relationship, if any, between responses to the patient concerns inventory (PCI) and overall quality of life (QOL). Methods: Nineteen units participated with intention of including 100 patients per site as close to a consecutive series as possible in order to minimize selection bias. Results: There were 2136 patients with a median total number of PCI items selected of 5 (2-10). “Fear of the cancer returning” (39%) and “dry mouth” (37%) were most common. Twenty-five percent (524) reported less than good QOL. Conclusion: There was considerable variation between units in the number of items selected and in overall QOL, even after allowing for case-mix variables. There was a strong progressive association between the number of PCI items and QOL
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