378 research outputs found

    Optimization of Crude Oil Biodegradation of Fungi Isolated from Refinery Effluent Site using Response Surface Methodology

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    The activities involved in the production and exploration of crude oil has constantly polluted the environment. This study investigated the ability of an indigenous fungus to utilize petroleum hydrocarbon. Response Surface Methodology was used to optimize the effects of pH, microbial concentration (spores/ml), and contact time (days) on the crude oil removal efficiency in refinery effluent. Monocillium sp. was isolated and used for the treatment of refinery effluent due to its predominance in the contaminated soil. Twenty experimental runs were analyzed to determine the effect of pH, microbial concentration and contact time on the oil removal efficiency. From theexperimental results obtained, a maximum oil removal efficiency of 98.42 % was achieved at a pH of 6.5, contact time of 14 days, and a microbial concentration of 3 spores/ml. The results obtained showed the percentage of crude oil removal in the effluent sample  increased with an increase in time. Optimization of the experimental result was achieved at a removal efficiency of 98.59 %, a contact time of 13.96 days, a pH of 6.85, and a microbial concentration of 3.01 spores/ml. The findings of this study revealed that Monocillium sp. is a viable hydrocarbon degrader, and can be used in the bioremediation of petroleum contaminated environments. Keywords: Response surface, optimization, bioremediation, hydrocarbon, removal efficiency, Monocillium sp

    The Effect of Strain Rate on Electrical and Mechanical Characteristics of Pure Aluminum Using Equal Channel Angular Pressing (ECAP)

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    -During equal-channel angular pressing (ECAP), the effect of severe plastic deformation (SPD) rate on both the electrical (electrical resistance, denoted as (R),Ω and The electrical resistivity denoted as (ρ), Ω.m) and mechanical characteristics (Ultimate Tensile Strength abbreviated as (UTS), MPa and Micro-Hardness measured in Vickers Hardness Number, abbreviated as VHN) of pure aluminum alloy are experimentally investigated.ECAP was used to improve the pure aluminum alloy\u27s microstructure at room temperature, which had samples with square cross sections. The findings indicate that as the rate of strain decreases from 0.3 to 0.1 s^-1, there is a gradual increase in both Ultimate Tensile Strength (UTS) and hardness, with the highest values observed at a strain rate of 0.025 s^-1.This study empirically explored the influence of ECAP on the macrostructure, microstructure, mechanical properties, and electrical properties of pure aluminum alloy at different strain rates (s^-1) – 0, 0.025, 0.1, and 0.3. In summary, it was observed that under the optimized ECAP conditions, specifically at a strain rate of 0.025 s^-1, the ultimate tensile strength increased by approximately 266%, micro-hardness by about 210%, and electrical resistivity by roughly 250% compared to the base material. The maximum value of the ultimate tensile strength was equal to 93 MPa, while the maximum value of hardness was equal to 41 VNN, and the maximum value of electrical resistivity was equal to 1.8 Ω.m, which is equivalent to the ratios mentioned above. Additionally, there was notable fragmentation of course second-phase particles and microstructure refinement

    Comparative Assessment of Crude Oil Degradation by Monocillium sp. and Aspergillus niger

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    Fungi dwelling in soils contaminated by petroleum products can survive on these hydrocarbons due to the highly effective extracellular enzymes. Species belonging to the genus, Aspergillus are known to be efficient degraders of various classes of hydrocarbons as well as other organic contaminants. In this study, the biodegradation of crude oil by Aspergillus niger and Monocillium sp. were compared using laboratory microcosms.The moulds were isolated from a site receiving effluent from a petroleum refinery. They were identified using their macroscopic and microscopic characteristics and subsequently screened for their ability to utilize hydrocarbons for their metabolic requirements. Following the biodegradation studies, Aspergillus niger and Monocillium sp. recorded an increase in hydrocarbon utilizing fungal counts of 8.5 x 107 spores/ml and 6.1 x 107 spores/ml and crude oil weight loss of 80 % and 70 %. Both fungi were tested singly and in a consortium for their ability to degrade crude oil, itwas observed that Monocillium sp. and A.niger performed better when tested individually (94.2 %; 92.8 %) than in consortium (76.3 %). This may suggest that their combined metabolism may have created some antagonistic effect on the degradation process as opposed to their enzymatic capabilities which appeared to be more favourable to the process. The biodegradation experiment analysis showed that contact time plays a  significant role in biodegradation of crude oil (p<0.05), and Monocillium sp. and Aspergillus niger are excellent crude oil degraders and can be usedin the bioremediation of petroleum-contaminated soil and water. Keywords: Biodegradation, Aspergillus niger, Monocillium sp., soil, Crude oi

    The Effect of Strain Rate on Electrical and Mechanical Characteristics of Pure Aluminum Using Equal Channel Angular Pressing (ECAP)

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    -During equal-channel angular pressing (ECAP), the effect of severe plastic deformation (SPD) rate on both the electrical (electrical resistance, denoted as (R),Ω and The electrical resistivity denoted as (ρ), Ω.m) and mechanical characteristics (Ultimate Tensile Strength abbreviated as (UTS), MPa and Micro-Hardness measured in Vickers Hardness Number, abbreviated as VHN) of pure aluminum alloy are experimentally investigated.ECAP was used to improve the pure aluminum alloy\u27s microstructure at room temperature, which had samples with square cross sections. The findings indicate that as the rate of strain decreases from 0.3 to 0.1 s^-1, there is a gradual increase in both Ultimate Tensile Strength (UTS) and hardness, with the highest values observed at a strain rate of 0.025 s^-1.This study empirically explored the influence of ECAP on the macrostructure, microstructure, mechanical properties, and electrical properties of pure aluminum alloy at different strain rates (s^-1) – 0, 0.025, 0.1, and 0.3. In summary, it was observed that under the optimized ECAP conditions, specifically at a strain rate of 0.025 s^-1, the ultimate tensile strength increased by approximately 266%, micro-hardness by about 210%, and electrical resistivity by roughly 250% compared to the base material. The maximum value of the ultimate tensile strength was equal to 93 MPa, while the maximum value of hardness was equal to 41 VNN, and the maximum value of electrical resistivity was equal to 1.8 Ω.m, which is equivalent to the ratios mentioned above. Additionally, there was notable fragmentation of course second-phase particles and microstructure refinement

    Development of IgY antibodies for control of tetanus

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    Tetanus is a cut and often highly fatal infectious disease that affects both human and animals; the disease caused by exotoxin which produced by C. tetani. In the current study, we try to get hyperimmune IgY in chicken egg against tetanus toxin and use it as prophylaxis and therapeutic treatment for tetanus. The obtained IgY titer after inoculation of tetanus toxin in chicken eggs was 1320 limit of flocculation (Lf-eq) after 72 hr. IgY in adose of 4500 Lf-eq can be protect donkey after artificial infection by 1 minimum lethal dose (MLD) of C. tetani. While a dose of 30000 Lf-eq IgY intramuscularly two times daily for 2 injections, with 9500 Limit of flocculation Lf-eq IgY intrathecally in subarachnoid space was 100% curative for a donkey which was challenged with 1 MLD of C. tetani. Furthermore, IgY was evaluated experimentally in comparison with IgG in mice. IgY has equally efficacy to IgG in prophylaxis and treatment of tetanus

    Myoclonus and other jerky movement disorders

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    Myoclonus and other jerky movements form a large heterogeneous group of disorders. Clinical neurophysiology studies can have an important contribution to support diagnosis but also to gain insight in the pathophysiology of different kind of jerks. This review focuses on myoclonus, tics, startle disorders, restless legs syndrome, and periodic leg movements during sleep. Myoclonus is defined as brief, shock-like movements, and subtypes can be classified based the anatomical origin. Both the clinical phenotype and the neurophysiological tests support this classification: cortical, cortical-subcortical, subcortical/non-segmental, segmental, peripheral, and functional jerks. The most important techniques used are polymyography and the combination of electromyography-electroencephalography focused on jerk-locked back-averaging, cortico-muscular coherence, and the Bereitschaftspotential. Clinically, the differential diagnosis of myoclonus includes tics, and this diagnosis is mainly based on the history with premonitory urges and the ability to suppress the tic. Electrophysiological tests are mainly applied in a research setting and include the Bereitschaftspotential, local field potentials, transcranial magnetic stimulation, and pre-pulse inhibition. Jerks due to a startling stimulus form the group of startle syndromes. This group includes disorders with an exaggerated startle reflex, such as hyperekplexia and stiff person syndrome, but also neuropsychiatric and stimulus-induced disorders. For these disorders polymyography combined with a startling stimulus can be useful to determine the pattern of muscle activation and thus the diagnosis. Assessment of symptoms in restless legs syndrome and periodic leg movements during sleep can be performed with different validated scoring criteria with the help of electromyography

    MRI-Based Radiomics Analysis for the Pretreatment Prediction of Pathologic Complete Tumor Response to Neoadjuvant Systemic Therapy in Breast Cancer Patients: A Multicenter Study

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    Simple SummaryThe prediction of pathologic complete response (pCR) to neo-adjuvant systemic therapy (NST) based on radiological assessment of pretreatment MRI exams in breast cancer patients is not possible to date. In this study, we investigated the value of pretreatment MRI-based radiomics analysis for the prediction of pCR to NST. Radiomics, clinical, and combined models were developed and validated based on MRI exams containing 320 tumors collected from two hospitals. The clinical models significantly outperformed the radiomics models for the prediction of pCR to NST and were of similar or better performance than the combined models. This indicates poor performance of the radiomics features and that in these scenarios the radiomic features did not have an added value for the clinical models developed. Due to previous and current work, we tentatively attribute the lack of significant improvement in clinical models following the addition of radiomics features to the effects of variations in acquisition and reconstruction parameters. The lack of reproducibility data meant this effect could not be analyzed. These results indicate the need for reproducibility studies to preselect reproducible features in order to properly assess the potential of radiomics.This retrospective study investigated the value of pretreatment contrast-enhanced Magnetic Resonance Imaging (MRI)-based radiomics for the prediction of pathologic complete tumor response to neoadjuvant systemic therapy in breast cancer patients. A total of 292 breast cancer patients, with 320 tumors, who were treated with neo-adjuvant systemic therapy and underwent a pretreatment MRI exam were enrolled. As the data were collected in two different hospitals with five different MRI scanners and varying acquisition protocols, three different strategies to split training and validation datasets were used. Radiomics, clinical, and combined models were developed using random forest classifiers in each strategy. The analysis of radiomics features had no added value in predicting pathologic complete tumor response to neoadjuvant systemic therapy in breast cancer patients compared with the clinical models, nor did the combined models perform significantly better than the clinical models. Further, the radiomics features selected for the models and their performance differed with and within the different strategies. Due to previous and current work, we tentatively attribute the lack of improvement in clinical models following the addition of radiomics to the effects of variations in acquisition and reconstruction parameters. The lack of reproducibility data (i.e., test-retest or similar) meant that this effect could not be analyzed. These results indicate the need for reproducibility studies to preselect reproducible features in order to properly assess the potential of radiomics

    Gravitational radiation from gamma-ray bursts as observational opportunities for LIGO and VIRGO

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    Gamma-ray bursts are believed to originate in core-collapse of massive stars. This produces an active nucleus containing a rapidly rotating Kerr black hole surrounded by a uniformly magnetized torus represented by two counter-oriented current rings. We quantify black hole spin-interactions with the torus and charged particles along open magnetic flux-tubes subtended by the event horizon. A major output of Egw=4e53 erg is radiated in gravitational waves of frequency fgw=500 Hz by a quadrupole mass-moment in the torus. Consistent with GRB-SNe, we find (i) Ts=90s (tens of s, Kouveliotou et al. 1993), (ii) aspherical SNe of kinetic energy Esn=2e51 erg (2e51 erg in SN1998bw, Hoeflich et al. 1999) and (iii) GRB-energies Egamma=2e50 erg (3e50erg in Frail et al. 2001). GRB-SNe occur perhaps about once a year within D=100Mpc. Correlating LIGO/Virgo detectors enables searches for nearby events and their spectral closure density 6e-9 around 250Hz in the stochastic background radiation in gravitational waves. At current sensitivity, LIGO-Hanford may place an upper bound around 150MSolar in GRB030329. Detection of Egw thus provides a method for identifying Kerr black holes by calorimetry.Comment: to appear in PRD, 49
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