978 research outputs found
Effect of doping and oxygen vacancies on the octahedral tilt transitions in the BaCeO3 perovskite
We present a systematic study of the effect of Y doping and hydration level
on the structural transformations of BaCeO3 based on anelastic spectroscopy
experiments. The temperature of the intermediate transformation between
rhombohedral and orthorhombic Imma phases rises with increasing the molar
fraction x of Y roughly as (500 K)x in the hydrated state, and is depressed of
more than twice that amount after complete dehydration. This is explained in
terms of the effect of doping on the average (Ce/Y)-O and Ba-O bond lengths,
and of lattice relaxation from O vacancies. The different behavior of the
transition to the lower temperature Pnma orthorhombic phase is tentatively
explained in terms of progressive flattening of the effective shape of the OH
ion and ordering of the O vacancies during cooling.Comment: 8 pages, 5 figure
Hydrogen tunneling in the perovskite ionic conductor BaCe(1-x)Y(x)O(3-d)
We present low-temperature anelastic and dielectric spectroscopy measurements
on the perovskite ionic conductor BaCe(1-x)Y(x)O(3-x/2) in the protonated,
deuterated and outgassed states. Three main relaxation processes are ascribed
to proton migration, reorientation about an Y dopant and tunneling around a
same O atom. An additional relaxation maximum appears only in the dielectric
spectrum around 60 K, and does not involve H motion, but may be of electronic
origin, e.g. small polaron hopping. The peak at the lowest temperature,
assigned to H tunneling, has been fitted with a relaxation rate presenting
crossovers from one-phonon transitions, nearly independent of temperature, to
two-phonon processes, varying as T^7, to Arrhenius-like. Substituting H with D
lowers the overall rate by 8 times. The corresponding peak in the dielectric
loss has an intensity nearly 40 times smaller than expected from the classical
reorientation of the electric dipole associated with the OH complex. This fact
is discussed in terms of coherent tunneling states of H in a cubic and
orthorhombically distorted lattice, possibly indicating that only H in the
symmetric regions of twin boundaries exhibit tunneling, and in terms of
reduction of the effective dipole due to lattice polarization.Comment: submitted to Phys. Rev.
The role of weighing-bathing sequence and postmenstrual age in eliciting adaptive/maladaptive responses in very low birth weight preterm infants
Purpose: In the neonatal intensive care unit, preterm infants are exposed to several stressful stimuli. Inappropriate stimulation led to high risk for short- and long-term neurocognitive disabilities. This study aimed to evaluate whether the sequence of execution of weighing/bathing nursing procedures and postmenstrual age (PMA) have any effect on preterm infants' stress responses. Design and Methods: Prospective cross-sectional study on a sample of 21 preterm infants. Responses to the procedures were assessed using an observational sheet based on Als's Synactive Theory of Development. Autonomic and motor responses were scored according to five-point Likert scales. The order of execution of weighing/bathing nursing procedures and PMA were documented. Effects of weighing/bathing execution sequence and PMA on autonomic and motor response scores were analyzed by linear multiple regression analysis. Results: The sequence of execution had a significant effect on the autonomic score during weighing (p =.035), evidencing more stress when weighing was executed first. A higher level of stress response on the autonomic score during both weighing (p =.015) and bathing (p =.018) procedure was independently associated with a lower infant PMA. Conclusions and Practice Implications: The real-time recognition of adaptive/maladaptive responses allows nurses to personalize their approach to preterm infants, taking into account PMA and adjusting the appropriate sequence of execution of weighing/bathing nursing procedures
Prevalence of nursing diagnoses as a measure of nursing complexity in a hospital setting
Aims: To describe the prevalence of nursing diagnoses on admission among inpatient units and medical diagnoses and to analyse the relationship of nursing diagnoses to patient characteristics and hospital outcomes. Background: Nursing diagnoses classify patients according to nursing dependency and can be a measure of nursing complexity. Knowledge regarding the prevalence of nursing diagnoses on admission and their relationship with hospital outcomes is lacking. Design: Prospective observational study. Methods: Data were collected for 6 months in 2014 in four inpatient units of an Italian hospital using a nursing information system and the hospital discharge register. Nursing diagnoses with prevalence higher or equal to 20% were considered as \u2018high frequency.\u2019 Nursing diagnoses with statistically significant relationships with either higher mortality or length of stay were considered as \u2018high risk.\u2019 The high-frequency/high-risk category of nursing diagnoses was identified. Results: The sample included 2283 patients. A mean of 4\ub75 nursing diagnoses per patient was identified; this number showed a statistically significant difference among inpatient units and medical diagnoses. Six nursing diagnoses were classified as high frequency/high risk. Nursing diagnoses were not correlated with patient gender and age. A statistically significant perfect linear association (Spearman's correlation coefficient) was observed between the number of nursing diagnoses and both the length of stay and the mortality rate. Conclusion: Nursing complexity, as described by nursing diagnoses, was shown to be associated with length of stay and mortality. These results should be confirmed after considering other variables through multivariate analyses. The concept of high-frequency/high-risk nursing diagnoses should be expanded in further studies
Cholesterol metabolism is a potential therapeutic target in Duchenne muscular dystrophy
Background: Duchenne muscular dystrophy (DMD) is a lethal muscle disease detected in approximately 1:5000 male births. DMD is caused by mutations in the DMD gene, encoding a critical protein that links the cytoskeleton and the extracellular matrix in skeletal and cardiac muscles. The primary consequence of the disrupted link between the extracellular matrix and the myofibre actin cytoskeleton is thought to involve sarcolemma destabilization, perturbation of Ca homeostasis, activation of proteases, mitochondrial damage, and tissue degeneration. A recently emphasized secondary aspect of the dystrophic process is a progressive metabolic change of the dystrophic tissue; however, the mechanism and nature of the metabolic dysregulation are yet poorly understood. In this study, we characterized a molecular mechanism of metabolic perturbation in DMD. Methods: We sequenced plasma miRNA in a DMD cohort, comprising 54 DMD patients treated or not by glucocorticoid, compared with 27 healthy controls, in three groups of the ages of 4–8, 8–12, and 12–20 years. We developed an original approach for the biological interpretation of miRNA dysregulation and produced a novel hypothesis concerning metabolic perturbation in DMD. We used the mdx mouse model for DMD for the investigation of this hypothesis. Results: We identified 96 dysregulated miRNAs (adjusted P-value <0.1), of which 74 were up-regulated and 22 were down-regulated in DMD. We confirmed the dysregulation in DMD of Dystro-miRs, Cardio-miRs, and a large number of the DLK1-DIO3 miRNAs. We also identified numerous dysregulated miRNAs yet unreported in DMD. Bioinformatics analysis of both target and host genes for dysregulated miRNAs predicted that lipid metabolism might be a critical metabolic perturbation in DMD. Investigation of skeletal muscles of the mdx mouse uncovered dysregulation of transcription factors of cholesterol and fatty acid metabolism (SREBP-1 and SREBP-2), perturbation of the mevalonate pathway, and the accumulation of cholesterol in the dystrophic muscles. Elevated cholesterol level was also found in muscle biopsies of DMD patients. Treatment of mdx mice with Simvastatin, a cholesterol-reducing agent, normalized these perturbations and partially restored the dystrophic parameters. Conclusions: This investigation supports that cholesterol metabolism and the mevalonate pathway are potential therapeutic targets in DMD. 2
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Menage a trois : an evolutionary interplay between human papilloma virus, a tumor and a woman
Cervical cancer is the third most common cancer in women with Human papillomavirus (HPV) being a key etiologic factor of this devastating disease. In this article, we describe modern advances in the genomics and transcriptomics of cervical cancer that led to uncovering the key gene drivers. We also introduce, herein, a Model of Cervical Carcinogenesis that explains how the interplay between virus, tumor and woman results in the selection of clones that simultaneously harbor genomic amplifications for genes that drive cell cycle, antiviral response, and inhibit cell differentiation. The new model may help understanding controversies in antiviral therapy and immunogenetics of this cancer and may provide a basis for future research directions in early diagnostics and personalization of therapy.Keywords: gene expression, immune response, genomic aberrations, network analysis, cervical cancer, human papillomavirus, driver gene
Improving adherence to surveillance and screening recommendations for people with colorectal cancer and their first degree relatives: a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Colorectal cancer (CRC) is among the leading causes of cancer-related morbidity and mortality worldwide. Despite clinical practice guidelines to guide surveillance care for those who have completed treatment for this disease as well as screening for first degree relatives of people with CRC, the level of uptake of these recommendations remains uncertain. If outcomes for both patients and their families are to be improved, it is important to establish systematic and cost-effective interventions to improve adherence to guideline recommendations for CRC surveillance and screening.</p> <p>Methods/Design</p> <p>A randomized controlled trial will be used to test the effectiveness of a print-based intervention to improve adherence to colonoscopy surveillance among people with CRC and adherence to CRC screening recommendations among their first degree relatives (FDRs). People diagnosed with CRC in the past 10 months will be recruited through a population-based cancer registry. Consenting participants will be asked if their first degree relatives might also be willing to participate in the trial. Information on family history of CRC will be obtained from patients at baseline. Patients and their families will be randomized to either minimal ethical care or the print-based intervention. The print-based intervention for FDRs will be tailored to the participant's level of risk of CRC as determined by the self-reported family history assessment. Follow up data on surveillance and screening participation will be collected from patients and their FDRs respectively at 12, 24 and 36 months' post recruitment. The primary analyses will relate to comparing levels of guideline adherence in usual care group versus print-based group in the patient sample and the FDR sample respectively.</p> <p>Discussion</p> <p>Results of this study will provide contribute to the evidence base about effective strategies to a) improve adherence to surveillance recommendation for people with CRC; and b) improve adherence to screening recommendation for FDRs of people with CRC. The use of a population-based cancer registry to access the target population may have significant advantages in increasing the reach of the intervention.</p> <p>Trial registration</p> <p>This trial is registered with the Australian and New Zealand Clinical Trials Registry Registration Number (ACTRN): <a href="http://www.anzctr.org.au/ACTRN12609000628246">ACTRN12609000628246</a>.</p
Melanocortin Receptor-4 Gene Polymorphisms in Glioblastoma Patients Treated with Concomitant Radio-Chemotherapy.
Melanocortins are peptides with well-recognized antiinflammatory and neuroprotective activity. No data are currently available on melanocortin receptor-4 (MC4R) gene polymorphisms and tumors, including glioblastomas (GBMs), or their relationship with radiotherapy or chemotherapy. The aim of this study was to evaluate the possible predictive/prognostic role of the MC4R SNPs on GBM patients. Fifty-five patients with a proven diagnosis of GBM, treated with radiotherapy and temozolomide, were consecutively enrolled. MC4R gene SNPs (rs17782313, rs489693, rs8087522, rs17700633) were analyzed by a validated TaqMan® SNP genotyping assays. Univariate and multivariate analyses were performed. A P < 0.0125 (Bonferroni's correction) was considered significant ( Clinicaltrial.gov identifier NCT02458508). The median progression-free survival (PFS) and median overall survival (OS) of these patients were 9.54 (95% CI 5.4-14.3) months and 24.9 (95% CI 17.8-34.6) months, respectively. The MC4R rs489693 AA genotype was significantly associated with a shorter PFS and OS. Indeed, with regard to PFS, patients harboring the rs489693 AA genotype had a median PFS of 2.99 months whereas patients with AC/CC genotypes had a median PFS of 10.82 months (P = 0.009). Interestingly, the rs489693 AA patients also had a lower median OS as compared with the median OS of the AC/CC genotypes (10.75 vs. 29.5 months, respectively, P = 0.0001). This study suggests that the MC4R rs489693 AA genotype is significantly associated with a shorter PFS and OS in patients treated with radiotherapy and temozolomide. These findings represent a relevant effort to identify novel clinical markers for RT-CT therapy in GBM to be validated in future pharmacogenetic clinical trials
Knowledge and attitudes about health research amongst a group of Pakistani medical students
Background
Health research training is an important part of medical education. This study was conducted to assess the level of knowledge and attitudes regarding health research in a group of Pakistani medical students at Aga Khan University, Karachi. Methods
It was a cross-sectional pilot study conducted among a group of Pakistani medical students. Through stratified random sampling, a pre-tested, structured and validated questionnaire was administered to 220 medical students. Knowledge and attitudes were recorded on a scale (graduated in percentages). Results
Mean scores of students were 49.0% on knowledge scale and 53.7% on attitude scale. Both knowledge and attitudes improved significantly with increasing years of study in medical college [Regression coefficient 4.10 (p-value; 0.019) and 6.67 (p-value; \u3c 0.001) for knowledge and attitudes, respectively]. Conclusion
Medical students demonstrate moderate level of knowledge and attitude towards health research. Intensive training in this regard is associated with significant improvement in knowledge and attitudes of students towards health research
Futibatinib, an irreversible FGFR1-4 inhibitor, in patients with advanced solid tumors harboring FGF/FGFR aberrations: a phase I dose-expansion study
Futibatinib, a highly selective, irreversible FGFR1-4 inhibitor, was evaluated in a large multihistology phase I dose-expansion trial that enrolled 197 patients with advanced solid tumors. Futibatinib demonstrated an objective response rate (ORR) of 13.7%, with responses in a broad spectrum of tumors (cholangiocarcinoma and gastric, urothelial, central nervous system, head and neck, and breast cancer) bearing both known and previously uncharacterized FGFR1-3 aberrations. The greatest activity was observed in FGFR2 fusion/rearrangement-positive intrahepatic cholangiocarcinoma (ORR, 25.4%). Some patients with acquired resistance to a prior FGFR inhibitor also experienced responses with futibatinib. Futibatinib demonstrated a manageable safety profile. The most common treatment-emergent adverse events were hyperphosphatemia (81.2%), diarrhea (33.5%), and nausea (30.4%). These results formed the basis for ongoing futibatinib phase II/III trials and demonstrate the potential of genomically selected early-phase trials to help identify molecular subsets likely to benefit from targeted therapy
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