463 research outputs found
Investigating the effect of a stress-based uniaxial anisotropy on the magnetic behaviour of La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub> elements
We investigate the interplay between shape anisotropy and a stress-based uniaxial anisotropy on the magnetic domain structure of La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub> nanoelements as a function of aspect ratio, using micromagnetic simulations. We show that a direct competition between the anisotropies gives rise to high energy multi-domain flux closure configurations, whilst an alignment of the anisotropies can modify the effective element dimensions and act to stabilise a single domain configuration. Our results demonstrate the ability to control the spin state of La<sub>0.7</sub>Sr<sub>0.3</sub>MnO<sub>3</sub> elements in addition to tailoring the domain wall width by controlling the anisotropy of the material, which is key for spintronic applications that require a high spin-polarization and stable magnetic configurations
Microseminoprotein-Beta Expression in Different Stages of Prostate Cancer
Microseminoprotein-beta (MSMB, MSMB) is an abundant secretory protein contributed by the prostate, and is implicated as a prostate cancer (PC) biomarker based on observations of its lower expression in cancerous cells compared with benign prostate epithelium. However, as the current literature on MSMB is inconsistent, we assessed the expression of MSMB at the protein and mRNA levels in a comprehensive set of different clinical stages of PC. Immunohistochemistry using monoclonal and polyclonal antibodies against MSMB was used to study protein expression in tissue specimens representing prostatectomies (n = 261) and in diagnostic needle biopsies from patients treated with androgen deprivation therapy (ADT) (n = 100), and in locally recurrent castration-resistant PC (CRPC) (n = 105) and CRPC metastases (n = 113). The transcript levels of MSMB, nuclear receptor co-activator 4 (NCOA4) and MSMB-NCOA4 fusion were examined by qRT-PCR in prostatectomy samples and by RNA-sequencing in benign prostatic hyperplasia, PC, and CRPC samples. We also measured serum MSMB levels and genotyped the single nucleotide polymorphism rs10993994 using DNA from the blood of 369 PC patients and 903 controls. MSMB expression in PC (29% of prostatectomies and 21% of needle biopsies) was more frequent than in CRPC (9% of locally recurrent CRPCs and 9% of CRPC metastases) (p<0.0001). Detection of MSMB protein was inversely correlated with the Gleason score in prostatectomy specimens (p = 0.024). The read-through MSMB-NCOA4 transcript was detected at very low levels in PC. MSMB levels in serum were similar in cases of PC and controls but were significantly associated with PC risk when adjusted for age at diagnosis and levels of free or total PSA (p<0.001). Serum levels of MSMB in both PC patients and controls were significantly associated with the rs10993994 genotype (p<0.0001). In conclusion, decreased expression of MSMB parallels the clinical progression of PC and adjusted serum MSMB levels are associated with PC risk
Subclone eradication analysis identifies targets for enhanced cancer therapy and reveals L1 retrotransposition as a dynamic source of cancer heterogeneity
Treatment-eradicated cancer subclones have been reported in leukemia and have recently been detected in solid tumors. Here we introduce Differential Subclone Eradication and Resistance Analysis (DSER), a method developed to identify molecular targets for improved therapy by direct comparison of genomic features of eradicated and resistant subclones in pre- and post-treatment samples from a patient with BRCA2-deficient metastatic prostate cancer. FANCI and EYA4 were identified as candidate DNA repair-related targets for converting subclones from resistant to eradicable, and RNAi-mediated depletion of FANCI confirmed it as a potential target. The EYA4 alteration was associated with adjacent L1 transposon insertion during cancer evolution upon treatment, raising questions surrounding the role of therapy in L1 activation. Both carboplatin and enzalutamide turned on L1 transposon machinery in LNCaP and VCaP but not in PC-3 and 22Rv1 prostate cancer cell lines. L1 activation in LNCaP and VCaP was inhibited by the antiretroviral drug azidothymidine. L1 activation was also detected post-castration in LuCaP 77 and LuCaP 105 xenograft models and post-chemotherapy in previously published time-series transcriptomic data from SCC25 head and neck cancer cells. In conclusion DSER provides an informative intermediate step toward effective precision cancer medicine and should be tested in future studies, especially those including dramatic but temporary metastatic tumor regression. L1 transposon activation may be a modifiable source of cancer genomic heterogeneity, suggesting the potential of leveraging newly discovered triggers and blockers of L1 activity to overcome therapy resistance
Scalability of Incompressible Flow Computations on Multi-GPU Clusters Using Dual-Level and Tri-Level Parallelism
High performance computing using graphics processing units (GPUs) is gaining popularity in the scientific computing field, with many large compute clusters being augmented with multiple GPUs in each node. We investigate hybrid tri-level (MPI-OpenMP-CUDA) parallel implementations to explore the efficiency and scalability of incompressible flow computations on GPU clusters up to 128 GPUS. This work details some of the unique issues faced when merging fine-grain parallelism on the GPU using CUDA with coarse-grain parallelism using OpenMP for intra-node and MPI for inter-node communication. Comparisons between the tri-level MPI-OpenMP-CUDA and dual-level MPI-CUDA implementations are shown using computationally large computational fluid dynamics (CFD) simulations. Our results demonstrate that a tri-level parallel implementation does not provide a significant advantage in performance over the dual-level implementation, however further research is needed to justify our conclusion for a cluster with a high GPU per node density or when using software that can utilize OpenMP’s fine-grain parallelism more effectively
A mouse model for oral squamous cell carcinoma
Despite recent advances, the prognosis of oral squamous cell carcinoma is still poor. Therapeutic options such as radiotherapy, chemotherapy, surgery and the novel treatment option gene therapy are being investigated in animal models. Diverse models have been studied to induce oral squamous cell carcinomas. The carcinogenic 4-nitroquinoline-1-oxide (4NQO) model has proven to be successful although until now it is unknown at what time point the established tumor is a representative squamous cell carcinoma and has a suitable volume for scientific treatment. For this end we applied 4NQO 3 times a week during 16 weeks and measured the volume of tumor tissue each week until the end of the experiment at 40 weeks. Concurrent histopathology at different time points up to the end of the experiment revealed that all mice bearing oral tumors were diagnosed with squamous cell carcinoma. Immunohistochemistry with markers cyclin D1 and E-cadherin revealed that the generated mouse oral tumors showed strong similarities with the described immunopathology in human oral tumors. The 4NQO model is a suitable alternative for preclinical gene therapy experiments with primary oral tumors. Future survey of therapeutic options in the carcinogenic 4NQO model should be conducted around 40 weeks after the start of the treatment
Behavioral Defects in Chaperone-Deficient Alzheimer's Disease Model Mice
Molecular chaperones protect cells from the deleterious effects of protein misfolding and aggregation. Neurotoxicity of amyloid-beta (Aβ) aggregates and their deposition in senile plaques are hallmarks of Alzheimer's disease (AD). We observed that the overall content of αB-crystallin, a small heat shock protein molecular chaperone, decreased in AD model mice in an age-dependent manner. We hypothesized that αB-crystallin protects cells against Aβ toxicity. To test this, we crossed αB-crystallin/HspB2 deficient (CRYAB-/-HSPB2-/-) mice with AD model transgenic mice expressing mutant human amyloid precursor protein. Transgenic and non-transgenic mice in chaperone-sufficient or deficient backgrounds were examined for representative behavioral paradigms for locomotion and memory network functions: (i) spatial orientation and locomotion was monitored by open field test; (ii) sequential organization and associative learning was monitored by fear conditioning; and (iii) evoked behavioral response was tested by hot plate method. Interestingly, αB-crystallin/HspB2 deficient transgenic mice were severely impaired in locomotion compared to each genetic model separately. Our results highlight a synergistic effect of combining chaperone deficiency in a transgenic mouse model for AD underscoring an important role for chaperones in protein misfolding diseases
Exchange Rate and Inflation Dynamics in a Resource Rich Setting: The Case of Zambia
This paper investigates the relationship between copper prices, the exchange rate and consumer price inflation in Zambia using a structural vector autoregression with quarterly data for 1995–2014 and a combination of sign and zero restrictions to identify relevant global and domestic shocks. The paper makes two contributions. First, it provides new measures of exchange rate pass through (ERPT), based on less restrictive assumptions than previous estimates, to show how changes in the value of the kwacha are reflected in changes in consumer prices (distinguishing food and non‐food inflation). Second, the ERPT is disaggregated to demonstrate that measured ERPT depends on the nature of the shock, with implications for policy responses. Although the price of copper is the most important driver of the exchange rate, the fluctuations it caused are associated with a low pass‐through of about 7% (consistent with a period of relatively low inflation). Exchange rate fluctuations caused by monetary shocks, in contrast, come with a pass‐through of up to 25% (and even more for food prices). A fast response by monetary authorities can mitigate the adverse effects of exchange rate shocks
Association of homocysteine and methylene tetrahydrofolate reductase (MTHFR C677T) gene polymorphism with coronary artery disease (CAD) in the population of North India
The implications of the methylene tetrahydrofolate reductase (MTHFR) gene and the level of homocysteine in the pathogenesis of coronary artery disease (CAD) have been extensively studied in various ethnic groups. Our aim was to discover the association of MTHFR (C677T) polymorphism and homocysteine level with CAD in north Indian subjects. The study group consisted of 329 angiographically proven CAD patients, and 331 age and sex matched healthy individuals as controls. MTHFR (C677T) gene polymorphism was detected based on the polymerase chain reaction and restriction digestion with HinfI. Total homocysteine plasma concentration was measured using immunoassay. T allele frequency was found to be significantly higher in patients than in the control group. We found significantly elevated levels of mean homocysteine in the patient group when compared to the control group (p = 0.00). Traditional risk factors such as diabetes, hypertension, smoking habits, a positive family history and lipid profiles (triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol), were found significantly associated through univariate analysis. Furthermore, multivariable logistics regression analysis revealed that CAD is significantly and variably associated with diabetes, hypertension, smoking, triglycerides and HDL-cholesterol. Our findings showed that MTHFR C677T polymorphism and homocysteine levels were associated with coronary artery disease in the selected population
The FUSE binding proteins FBP1 and FBP3 are potential c-myc regulators in renal, but not in prostate and bladder cancer
BACKGROUND: The three far-upstream element (FUSE) binding proteins (FBP1, FBP2, and FBP3) belong to an ancient family of single-stranded DNA binding proteins which are required for proper regulation of the c-myc proto-oncogene. Whereas it is known that c-myc alterations play a completely different role in various carcinomas of the urogenital tract, the relevance of FBPs is unclear. Methods: FBP1, FBP3 and c-myc expression was studied in 105 renal cell, 95 prostate and 112 urinary bladder carcinomas by immunohistochemistry using tissue microarrays. High rates of FBP1 and FBP3 expression were observed in all cancer types. RESULTS: There was a concomitant up-regulation of FBP1 and FBP3 in renal cell and prostate carcinomas (p<0.001 both). C-myc expression was detectable in 21% of prostate, 30% of renal and 34% of urothelial carcinomas. Interestingly, strong FBP1 and FBP3 expression was associated with c-myc up-regulation in clear cell renal cell carcinomas (p<0.001 and 0.05 resp.), but not in bladder or prostate cancer. CONCLUSIONS: The correlation between FBP1/FBP3, c-myc and high proliferation rate in renal cell carcinoma provides strong in vivo support for the suggested role of FBP1 and FBP3 as activators of c-myc. The frequent up-regulation of FBP1 and FBP3 in urothelial and prostate carcinoma suggests that FBPs also have an important function in gene regulation of these tumors
Examining assumptions regarding valid electronic monitoring of medication therapy: development of a validation framework and its application on a European sample of kidney transplant patients
BACKGROUND: Electronic monitoring (EM) is used increasingly to measure medication non-adherence. Unbiased EM assessment requires fulfillment of assumptions. The purpose of this study was to determine assumptions needed for internal and external validity of EM measurement. To test internal validity, we examined if (1) EM equipment functioned correctly, (2) if all EM bottle openings corresponded to actual drug intake, and (3) if EM did not influence a patient's normal adherence behavior. To assess external validity, we examined if there were indications that using EM affected the sample representativeness. METHODS: We used data from the Supporting Medication Adherence in Renal Transplantation (SMART) study, which included 250 adult renal transplant patients whose adherence to immunosuppressive drugs was measured during 3 months with the Medication Event Monitoring System (MEMS). Internal validity was determined by assessing the prevalence of nonfunctioning EM systems, the prevalence of patient-reported discrepancies between cap openings and actual intakes (using contemporaneous notes and interview at the end of the study), and by exploring whether adherence was initially uncharacteristically high and decreased over time (an indication of a possible EM intervention effect). Sample representativeness was examined by screening for differences between participants and non-participants or drop outs on non-adherence. RESULTS: Our analysis revealed that some assumptions were not fulfilled: 1) one cap malfunctioned (0.4%), 2) self-reported mismatches between bottle openings and actual drug intake occurred in 62% of the patients (n = 155), and 3) adherence decreased over the first 5 weeks of the monitoring, indicating that EM had a waning intervention effect. CONCLUSION: The validity assumptions presented in this article should be checked in future studies using EM as a measure of medication non-adherence
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