2,224 research outputs found
Complete larval development of the hermit crabs Clibanarius aequabilis and Clibanarius erythropus (Decapoda : Anomura : Diogenidae), under laboratory conditions, with a revision of the larval features of genus Clibanarius
The complete larval development (four zoeae and one megalopa) of Clibanarius aequabilis and C. erythropus, reared under laboratory conditions, is described and illustrated. The larval stages of the two northeastern Atlantic Clibanarius species cannot be easily differentiated. Their morphological characters are compared with those of other known Clibanarius larvae. The genus Clibanarius is very homogeneous with respect to larval characters. All Clibanarius zoeae display a broad and blunt rostrum, smooth abdominal segments and an antennal scale without a terminal spine. Beyond the second zoeal stage, the fourth telson process is present as a fused spine, and the uropods are biramous. In the fourth larval stage all species display a mandibular palp. The Clibanarius megalopa presents weakly developed or no ocular scales, symmetrical chelipeds, apically curved corneous dactylus in the second and third pereiopods, and 5-11 setae on the posterior margin of the telson. Apart from the number of zoeal stages, Clibanarius species may be separated, beyond the second zoeal stage, by the telson formula and the morphology of the fourth telson process.info:eu-repo/semantics/publishedVersio
Categorical Dimensions of Human Odor Descriptor Space Revealed by Non-Negative Matrix Factorization
In contrast to most other sensory modalities, the basic perceptual dimensions of olfaction remain unclear. Here, we use non-negative matrix factorization (NMF) – a dimensionality reduction technique – to uncover structure in a panel of odor profiles, with each odor defined as a point in multi-dimensional descriptor space. The properties of NMF are favorable for the analysis of such lexical and perceptual data, and lead to a high-dimensional account of odor space. We further provide evidence that odor dimensions apply categorically. That is, odor space is not occupied homogenously, but rather in a discrete and intrinsically clustered manner. We discuss the potential implications of these results for the neural coding of odors, as well as for developing classifiers on larger datasets that may be useful for predicting perceptual qualities from chemical structures
Herpes encephalitis presenting as mild aphasia: Case report
BACKGROUND: Encephalitis presenting as a change in mental status can be challenging to recognize in the primary care setting. However, early detection via a low threshold of suspicion can be useful, leading in turn to early treatment and improved survival. CASE PRESENTATION: We present a case which we consider relevant to primary care practitioners. The patient in question presented with relatively mild mental status changes, progressing to confusion, dysnomia and delirium over a period of three days. While infection did not appear to be the leading cause on her differential diagnosis, she was found on extensive workup to have encephalitis caused by Herpes Simplex Virus type 1. CONCLUSION: The case is instructive for general practitioners and other clinicians to maintain vigilance for central nervous system (CNS) infections which may present atypically
Drivers for the implementation of circular economy in the Nigerian AECO industry: a structural equation modelling approach
Purpose
This study aims to investigate the drivers influencing the implementation of circular economy principles in the Nigerian architecture, engineering, construction and operation (AECO) industry across diverse regions of Nigeria.
Design/methodology/approach
A quantitative research approach was adopted, using a structured questionnaire distributed to AECO professionals across four selected regions (North Central, North West, South-South and South West) in Nigeria. The data were analysed using Kruskal–Wallis test and structural equation modelling (SEM).
Findings
The study findings show a robust consensus of opinions among the respondents across regions and professions. The SEM analysis establishes the significant influence of the hypothesized drivers, regulatory and institutional, supply chain collaboration, technological advancements, organizational support and business strategies on the successful implementation of circular economy principles in the Nigerian AECO industry.
Research limitations/implications
The study is limited to specific regions and professions within Nigeria. Further limitation is the quantitative orientation of this study, which collects data using only a questionnaire.
Practical implications
The findings imply that stakeholders can adopt a unified approach to promote circular economy principles in the AECO industry. By recognizing the common understanding of circular economy drivers, collaborative efforts can be streamlined to advance sustainability, resource efficiency and circularity in the industry.
Originality/value
This study contributes to the nascent field of circular economy implementation in the Nigerian AECO industry. It offers a unique perspective by exploring variations in stakeholder opinions, providing insights into the nuanced understanding of circular economy drivers
Peroxisome Proliferator-Activated Receptor alpha (PPAR alpha) down-regulation in cystic fibrosis lymphocytes
Background: PPARs exhibit anti-inflammatory capacities and are potential modulators of the inflammatory response. We hypothesized that their expression and/or function may be altered in cystic fibrosis (CF), a disorder characterized by an excessive host inflammatory response.
Methods: PPARα, β and γ mRNA levels were measured in peripheral blood cells of CF patients and healthy subjects via RT-PCR. PPARα protein expression and subcellular localization was determined via western blot and immunofluorescence, respectively. The activity of PPARα was analyzed by gel shift assay.
Results: In lymphocytes, the expression of PPARα mRNA, but not of PPARβ, was reduced (-37%; p < 0.002) in CF patients compared with healthy persons and was therefore further analyzed. A similar reduction of PPARα was observed at protein level (-26%; p < 0.05). The transcription factor was mainly expressed in the cytosol of lymphocytes, with low expression in the nucleus. Moreover, DNA binding activity of the transcription factor was 36% less in lymphocytes of patients (p < 0.01). For PPARα and PPARβ mRNA expression in monocytes and neutrophils, no significant differences were observed between CF patients and healthy persons. In all cells, PPARγ mRNA levels were below the detection limit.
Conclusion: Lymphocytes are important regulators of the inflammatory response by releasing cytokines and antibodies. The diminished lymphocytic expression and activity of PPARα may therefore contribute to the inflammatory processes that are observed in CF
Ventricular Stimulus Site Influences Dynamic Dispersion of Repolarization In The Intact Human Heart
The spatial variation in restitution properties in relation to varying stimulus site is poorly defined. This study aimed to investigate the effect of varying stimulus site on apico-basal and transmural activation time (AT), action potential duration (APD) and repolarization time (RT) during restitution studies in the intact human heart. Ten patients with structurally normal hearts, undergoing clinical electrophysiology studies were enrolled. Decapolar catheters were placed apex to base in the endocardial right ventricle (RVendo) and left ventricle (LVendo), and an LV branch of the coronary sinus (LVepi) for transmural recording. S1-S2 restitution protocols were performed pacing RVendo apex, LVendo base and LVepi base. Overall 725 restitution curves were analyzed, 74% of slopes had an Smax>1 (p < 0.001), mean Smax=1.76. APD was shorter in the LVepi compared to LVendo regardless of pacing site (30ms difference during RVendo pacing, 25ms during LVendo and 48ms during LVepi; 50(th) quantile, p<0.01). Basal LVepi pacing resulted in a significant transmural gradient of RT (77ms, 50(th) quantile: p<0.01), due to loss of negative transmural AT-APD coupling (mean slope 0.63±0.3). No significant transmural gradient in RT was demonstrated during endocardial RV or LV pacing, with preserved negative transmural AT-APD coupling (mean slope -1.36 ±1.9 and -0.71 ±0.4, respectively). Steep ARI restitution slopes predominate in the normal ventricle and dynamic ARI, RT gradients exist which are modulated by the site of activation. Epicardial stimulation to initiate ventricular activation promotes significant transmural gradients of repolarization that could be pro-arrhythmic
Three-dimensional visualization software assists learning in students with diverse spatial intelligence in medical education
This study evaluated effect of mental rotation (MR) training on learning outcomes and explored effectiveness of teaching via three-dimensional (3D) software among medical students with diverse spatial intelligence. Data from n = 67 student volunteers were included. A preliminary test was conducted to obtain baseline level of MR competency and was utilized to assign participants to two experimental conditions, i.e., trained group (n = 25) and untrained group (n = 42). Data on the effectiveness of training were collected to measure participants\u27 speed and accuracy in performing various MR activities. Six weeks later, a large class format (LCF) session was conducted for all students using 3D software. The usefulness of technology-assisted learning at the LCF was evaluated via a pre- and post-test. Students\u27 feedback regarding MR training and use of 3D software was acquired through questionnaires. MR scores of the trainees improved from 25.9±4.6 points to 28.1±4.4 (P = 0.011) while time taken to complete the tasks reduced from 20.9±3.9 to 12.2±4.4 minutes. Males scored higher than females in all components (P = 0.016). Further, higher pre- and post-test scores were observed in trained (9.0±1.9 and 12.3±1.6) versus untrained group (7.8±1.8; 10.8±1.8). Although mixed-design analysis of variance suggested significant difference in their test scores (P \u3c 0.001), both groups reported similar trend in improvement by means of 3D software (P = 0.54). Ninety-seven percent of students reported technology-assisted learning as an effective means of instruction and found use of 3D software superior to plastic models. Software based on 3D technologies could be adopted as an effective teaching pedagogy to support learning across students with diverse levels of mental rotation abilities
Adherence to Tuberculosis Therapy among Patients Receiving Home-Based Directly Observed Treatment: Evidence from the United Republic of Tanzania.
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Non-adherence to tuberculosis (TB) treatment is the leading contributor to the selection of drug-resistant strains of Mycobacterium tuberculosis and subsequent treatment failure. Tanzania introduced a TB Patient Centred Treatment (PCT) approach which gives new TB patients the choice between home-based treatment supervised by a treatment supporter of their own choice, and health facility-based treatment observed by a medical professional. The aim of this study was to assess the extent and determinants of adherence to anti-TB therapy in patients opting for home-based treatment under the novel PCT approach. In this cross-sectional study, the primary outcome was the percentage of patients adherent to TB therapy as detected by the presence of isoniazid in urine (IsoScreen assay). The primary analysis followed a non-inferiority approach in which adherence could not be lower than 75%. Logistic regression was used to examine the influence of potentially predictive factors. A total of 651 new TB patients were included. Of these, 645 (99.1%) provided urine for testing and 617 patients (95.7%; 90%CI 94.3-96.9) showed a positive result. This result was statistically non-inferior to the postulated adherence level of 75% (p<0.001). Adherence to TB therapy under home-based Directly Observed Treatment can be ensured in programmatic settings. A reliable supply of medication and the careful selection of treatment supporters, who preferably live very close to the patient, are crucial success factors. Finally, we recommend a cohort study to assess the rate of adherence throughout the full course of TB treatment
Estrogen and progesterone receptor levels in nonneoplastic breast epithelium of breast cancer cases versus benign breast biopsy controls
<p>Abstract</p> <p>Background</p> <p>Previous studies and biological mechanisms of carcinogenesis suggest that the steroid receptor content of benign breast epithelium may be related to breast cancer risk. The objective in this study was to compare the levels of estrogen receptor-α (ER) and progesterone receptor (PR) in nonneoplastic breast epithelium between breast cancer cases and biopsy controls.</p> <p>Methods</p> <p>Between 1995 and 1997 at two sites (Women's College Hospital in Toronto and Kingston General Hospital), 667 women who were scheduled for diagnostic excisional breast biopsies completed a questionnaire providing personal information and agreed to allow analysis of routinely resected tissue. Histological slides with nonneoplastic epithelium were available for 101 cancer cases and 200 biopsy controls in Toronto and for 105 cancer cases and 119 controls in Kingston. Nonneoplastic epithelium was examined with immunohistochemical assays to determine the percent of epithelial cells staining for ER and PR. Unconditional logistic regression was used to calculate odds ratios (OR) stratified by study site.</p> <p>Results</p> <p>The ER content of nonneoplastic tissue was higher in cases than biopsy controls in unadjusted analyses; after adjustment for age, however, a weak association remained in only one of the study sites. After adjustment for age, the PR content of nonneoplastic tissue was slightly lower in breast cancer cases than controls in one study site. Furthermore, this inverse association was confined to women with PR negative breast cancer in comparison to the controls. No interaction between ER and PR content of nonneoplastic tissue was observed in relation to the odds of having breast cancer.</p> <p>Conclusion</p> <p>The results of this study are consistent with only a slight indication of increased ER levels in nonneoplastic tissue in breast cancer cases relative to controls. This study contributes to the understanding of breast cancer by examining both ER and PR in nonneoplastic tissue. Limitations remain, however, such as the necessity of using as controls women with benign breast changes, difficulties in selecting the appropriate tissue for analysis, and tissue sampling concurrent to diagnosis.</p
Experiences, attitudes and barriers towards research amongst junior faculty of Pakistani medical universities
<p>Abstract</p> <p>Background</p> <p>The developing world has had limited quality research and in Pakistan, research is still in its infancy. We conducted a study to assess the proportion of junior faculty involved in research to highlight their attitude towards research, and identify the factors associated with their research involvement.</p> <p>Methods</p> <p>A cross-sectional study was conducted in four medical universities/teaching hospitals in Pakistan, representing private and public sectors. A pre-tested, self-administered questionnaire was used to collect information from 176 junior faculty members of studied universities/hospitals. Logistic regression analysis was used to identify factors related to attitudes and barriers in research among those currently involved in research with those who were not.</p> <p>Results</p> <p>Overall, 41.5% of study subjects were currently involved in research. A highly significant factor associated with current research involvement was research training during the post-graduate period (p < 0.001). Other factors associated with current involvement in research were male gender, working in the public sector and previous involvement in research. Overall, a large majority (85.2%) of doctors considered research helpful in their profession and had a positive attitude towards research; nevertheless this positive attitude was more frequently reported by doctors who were currently involved in research compared to those who were not (OR = 4.69; 95% CI = 1.54-14.26). Similarly, a large proportion (83.5%) of doctors considered research difficult to conduct; higher by doctors who were not presently involved in research (OR = 2.74; 95% CI = 1.20-6.22)</p> <p>Conclusion</p> <p>Less than half of the study participants were currently involved in research. Research output may improve if identified barriers are rectified. Further studies are recommended in this area.</p
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