159 research outputs found

    Effects of protein deficiency on testosterone levels, semen quality and testicular histology in the developing male rat

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    The aim of the study was to evaluate the effects of protein deficiency on plasma testosterone levels, epididymal sperm characteristics and testicular histology in the developing male rat. Twenty four Wistar albino rats were used in the study and were fed with a diet variously containing 3 %, 10 % and 20 % protein. Plasma testosterone levels were significantly lower in rats fed 3 % protein when compared to rats fed 10 % and 20 % protein (P<0.05). Testicular weight in protein deficient rats (rats fed 3 % and 10 % protein) was significantly lower than that of a control group (20 % protein) (P<0.05). No sperm was present in the epididymal duct lumen, but germ cells were observed in some duct lumens in rats fed 3 % protein. Epididymal weight decreased significantly in rats fed 3 % protein compared to rats fed 10 % and 20 % protein (P<0.05). The results of this study clearly show that protein deficiency in developing male rats adversely affects gonadal endocrine function, testicular histology and spermatogenesis

    Utjecaj oligosaharida hitozana na određene hematološke pokazatelje u štakora izloženih kadmiju

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    The aim of the study was to investigate the effects of chitosan oligosaccharide (COS) on some hematological parameters, and define the percentage of alpha-naphthyl acetate esterase (ANAE) positive lymphocytes in rats that had been exposed to cadmium (Cd). Thirty-two (n = 32) male Wistar albino rats were randomly divided into four groups as the control (C), chitosan oligosaccharide (COS), cadmium (Cd), and Cd + COS (CdCOS) groups. Blood samples were collected to assess erythrocytes (RBC), leukocytes (WBC), hemoglobin levels (HGB), hematocrit values (HCT), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV), platelets (PLT), and alpha-naphthyl acetate esterase (ANAE) positive lymphocytes. The number of WBCs significantly increased in the Cd group compared to the C, CdCOS, and COS groups (P<0.05). Although the lymphocyte count decreased significantly in the Cd group (P<0.05), it was ameliorated by COS treatment in the CdCOS group compared to the Cd group (P<0.05). Also, the percentage of peripheral blood ANAE positive lymphocytes decreased significantly in the CdCOS and Cd groups (P<0.05). COS exhibits a partially protective effect on some hematological characteristics, apart from the percentage of ANAE positive lymphocyte in cases of chronic Cd exposure.Cilj ovog rada bio je istražiti učinak oligosaharida hitozana (COS) na određene hematološke pokazatelje odnosno postotak limfocita pozitivnih na alfa-naftil-acetat-esterazu (ANAE) u štakora izloženih kadmiju (Cd). Mužjaci (n = 32) pasmine Wistar albino, slučajnim odabirom podijeljeni su u četiri skupine: kontrolnu (C), skupinu s oligosaharidom hitozanom (COS), skupinu s kadmijem (Cd) i skupinu s kadmijem i oligosaharidom hitozanom (CdCOS). Prikupljeni su uzorci krvi kako bi se odredili eritrociti (RBC), leukociti (WBC), hemoglobin (HGB), hematokrit (HCT), prosječni hemoglobin u eritrocitima (MCH) i njegova koncentracija (MCHC), prosječan obujam eritrocita (MCV), trombociti (PLT), te limfociti pozitivni na alfa-naftil-acetat-esterazu (ANAE). Broj leukocita znakovito je porastao u skupini Cd u usporedbi s kontrolnom skupinom te skupinama C, CdCOS, i COS (P < 0,05). Iako je broj limfocita znakovito smanjen u skupini Cd (P < 0,05), to je ublaženo primjenom COS-a u skupini CdCOS u usporedbi sa skupinom Cd (P < 0,05). Također, postotak limfocita iz periferne krvi pozitivnih na ANAE znakovito je smanjen u skupinama CdCOS i Cd (P < 0,05). COS je, u slučaju kronične izloženosti štakora kadmiju, pokazao djelomice zaštitni učinak na određene hematološke značajke, osim na postotak limfocita pozitivnih na ANAE

    Comparison of the maternal and neonatal effects of bupivacaine plus fentanyl and ropivacaine plus fentanyl during cesarean delivery

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    Purpose: The aim of the present study was to compare the anesthetic efficacy, and fetal and maternal effects of 7.5 mg (1 ml) intrathecal 0.75% hyperbaric ropivacaine + 25 ìg (0.5 ml) fentanyl versus 5 mg (l ml) intrathecal 0.5% hyperbaric bupivacaine + 25 ìg (0.5 ml) fentanyl in elective cesarean delivery.Materials and Methods: The study included 40 ASA I–II cases scheduled for cesarean delivery that were randomized into two groups of 20 cases each. Cases in the RF group were administered 0.75% hyperbaric ropivacaine + 25 ìg (0.5 ml) fentanyl and those in the BF group were administered 5 mg (l ml) hyperbaric bupivacaine + 25 ìg (0.5 ml)fentanyl into the spinal space. The time until spinal anesthesia in the T4 dermatome, overall duration of analgesia, hemodynamic parameters, Apgar score of newborns at 1–5 min, fetal blood gas values (pH, PO2, PCO2, HCO3., and BE), maternal side effects, the degree of motor block, maternal need for ephedrine, objective pain scale score, and patient satisfaction were recorded in each group.Results: There were no significant differences between the groups in terms of the parameters evaluated (P &gt; 0.05).Conclusion: In elective cesarean delivery, the combinations of bupivacaine + fentanyl or ropivacaine + fentanyl exhibited similar anesthetic efficacy, and fetal and maternal effects.Key words: Bupivacaine, cesarean, opioid, ropivacain

    Numerical simulation of small perturbation on an accretion disk due to the collision of a star with the disk near the black hole

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    In this paper, perturbations of an accretion disk by a star orbiting around a black hole are studied. We report on a numerical experiment, which has been carried out by using a parallel-machine code originally developed by D\"{o}nmez (2004). An initially steady state accretion disk near a non-rotating (Schwarzschild) black hole interacts with a "star", modeled as an initially circular region of increased density. Part of the disk is affected by the interaction. In some cases, a gap develops and shock wave propagates through the disk. We follow the evolution for order of one dynamical period and we show how the non-axisymetric density perturbation further evolves and moves downwards where the material of the disk and the star become eventually accreted onto the central body. When the star perturbs the steady state accretion disk, the disk around the black hole is destroyed by the effect of perturbation. The perturbed accretion disk creates a shock wave during the evolution and it loses angular momentum when the gas hits on the shock waves. Colliding gas with the shock wave is the one of the basic mechanism of emitting the XX-rays in the accretion disk. The series of supernovae occurring in the inner disk could entirely destroy the disk in that region which leaves a more massive black hole behind, at the center of galaxies.Comment: 20pages, 8 figures, accepted for publication in Astrophysics and Space Scienc

    Quality improvement in ammonium nitrate production using Six Sigma methodology

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    Six sigma has been used in different industries to reach operational excellence. However, in the chemical industry, the application of this methodology is limited. This research presents an implementation of the six sigma method for ammonium nitrate (AN) content optimization in condensate production for a fertilizer company in Colombia. The paper aims to determine the levels for input variables in the process, to meet desirable standards for condensate quality in terms of ammonium nitrate content. Based on the DMAIC steps implementation, it was possible to establish the main variables affecting the condensate quality and their optimal levels to reach an ammonium nitrate content below 15,000 ppm. These results demonstrate the impact that a six sigma project may have on operational effectiveness and quality improvement for meeting the customer requirements

    Lessons for Remote Post-earthquake Reconnaissance from the 14 August 2021 Haiti Earthquake

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    On 14th August 2021, a magnitude 7.2 earthquake struck the Tiburon Peninsula in the Caribbean nation of Haiti, approximately 150 km west of the capital Port-au-Prince. Aftershocks up to moment magnitude 5.7 followed and over 1,000 landslides were triggered. These events led to over 2,000 fatalities, 15,000 injuries and more than 137,000 structural failures. The economic impact is of the order of US$1.6 billion. The on-going Covid pandemic and a complex political and security situation in Haiti meant that deploying earthquake engineers from the UK to assess structural damage and identify lessons for future building construction was impractical. Instead, the Earthquake Engineering Field Investigation Team (EEFIT) carried out a hybrid mission, modelled on the previous EEFIT Aegean Mission of 2020. The objectives were: to use open-source information, particularly remote sensing data such as InSAR and Optical/Multispectral imagery, to characterise the earthquake and associated hazards; to understand the observed strong ground motions and compare these to existing seismic codes; to undertake remote structural damage assessments, and to evaluate the applicability of the techniques used for future post-disaster assessments. Remote structural damage assessments were conducted in collaboration with the Structural Extreme Events Reconnaissance (StEER) team, who mobilised a group of local non-experts to rapidly record building damage. The EEFIT team undertook damage assessment for over 2,000 buildings comprising schools, hospitals, churches and housing to investigate the impact of the earthquake on building typologies in Haiti. This paper summarises the mission setup and findings, and discusses the benefits, and difficulties, encountered during this hybrid reconnaissance mission

    Analyzing collaborative learning processes automatically

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    In this article we describe the emerging area of text classification research focused on the problem of collaborative learning process analysis both from a broad perspective and more specifically in terms of a publicly available tool set called TagHelper tools. Analyzing the variety of pedagogically valuable facets of learners’ interactions is a time consuming and effortful process. Improving automated analyses of such highly valued processes of collaborative learning by adapting and applying recent text classification technologies would make it a less arduous task to obtain insights from corpus data. This endeavor also holds the potential for enabling substantially improved on-line instruction both by providing teachers and facilitators with reports about the groups they are moderating and by triggering context sensitive collaborative learning support on an as-needed basis. In this article, we report on an interdisciplinary research project, which has been investigating the effectiveness of applying text classification technology to a large CSCL corpus that has been analyzed by human coders using a theory-based multidimensional coding scheme. We report promising results and include an in-depth discussion of important issues such as reliability, validity, and efficiency that should be considered when deciding on the appropriateness of adopting a new technology such as TagHelper tools. One major technical contribution of this work is a demonstration that an important piece of the work towards making text classification technology effective for this purpose is designing and building linguistic pattern detectors, otherwise known as features, that can be extracted reliably from texts and that have high predictive power for the categories of discourse actions that the CSCL community is interested in

    Analytic frameworks for assessing dialogic argumentation in online learning environments

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    Over the last decade, researchers have developed sophisticated online learning environments to support students engaging in argumentation. This review first considers the range of functionalities incorporated within these online environments. The review then presents five categories of analytic frameworks focusing on (1) formal argumentation structure, (2) normative quality, (3) nature and function of contributions within the dialog, (4) epistemic nature of reasoning, and (5) patterns and trajectories of participant interaction. Example analytic frameworks from each category are presented in detail rich enough to illustrate their nature and structure. This rich detail is intended to facilitate researchers’ identification of possible frameworks to draw upon in developing or adopting analytic methods for their own work. Each framework is applied to a shared segment of student dialog to facilitate this illustration and comparison process. Synthetic discussions of each category consider the frameworks in light of the underlying theoretical perspectives on argumentation, pedagogical goals, and online environmental structures. Ultimately the review underscores the diversity of perspectives represented in this research, the importance of clearly specifying theoretical and environmental commitments throughout the process of developing or adopting an analytic framework, and the role of analytic frameworks in the future development of online learning environments for argumentation

    Establishment of a human cell-based in vitro battery to assess developmental neurotoxicity hazard of chemicals

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    Developmental neurotoxicity (DNT) is a major safety concern for all chemicals of the human exposome. However, DNT data from animal studies are available for only a small percentage of manufactured compounds. Test methods with a higher throughput than current regulatory guideline methods, and with improved human relevance are urgently needed. We therefore explored the feasibility of DNT hazard assessment based on new approach methods (NAMs). An in vitro battery (IVB) was assembled from ten individual NAMs that had been developed during the past years to probe effects of chemicals on various fundamental neurodevelopmental processes. All assays used human neural cells at different developmental stages. This allowed us to assess disturbances of: (i) proliferation of neural progenitor cells (NPC); (ii) migration of neural crest cells, radial glia cells, neurons and oligodendrocytes; (iii) differentiation of NPC into neurons and oligodendrocytes; and (iv) neurite outgrowth of peripheral and central neurons. In parallel, cytotoxicity measures were obtained. The feasibility of concentration-dependent screening and of a reliable biostatistical processing of the complex multi-dimensional data was explored with a set of 120 test compounds, containing subsets of pre-defined positive and negative DNT compounds. The battery provided alerts (hit or borderline) for 24 of 28 known toxicants (82% sensitivity), and for none of the 17 negative controls. Based on the results from this screen project, strategies were developed on how IVB data may be used in the context of risk assessment scenarios employing integrated approaches for testing and assessment (IATA).European Food Safety Authority (EFSA-Q-2018-00308), the Danish Environmental Protection Agency (EPA), Denmark, under the grant number MST-667-00205, the State Ministry of Baden-Wuerttemberg, Germany, for Economic Affairs, Labour and Tourism (NAM-Accept), the project CERST (Center for Alternatives to Animal Testing) of the Ministry for culture and science of the State of North-Rhine Westphalia, Germany (file number 233–1.08.03.03- 121972/131–1.08.03.03–121972), the European Chemical Industry Council Long-Range Research Initiative (Cefic LRI) under the project name AIMT11 and the BMBF (NeuroTool). It has also received funding from the European Union's Horizon 2020 research and innovation program under grant agreements No. 964537 (RISK-HUNT3R), No. 964518 (ToxFree), No. 101057014 (PARC) and No. 825759 (ENDpoiNTs)
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