Enhanced production of butyric acid by solid-state fermentation of rice polishings by a mutant strain of Clostridium tyrobutyricum

Purpose: To enhance butyric acid production by solid-state fermentation with a hyper-producing mutant of Clostridium tyrobutyricum generated by random mutagenesis.Methods: Wild type C. tyrobutyricum was mutagenized with UV irradiation, nitrous acid, and ethidium bromide to obtain a hyper-producing strain. Various physiochemical parameters were optimized to increase the butyric acid yield.Results: The UV-induced mutant (C.TUV) produced significantly higher concentrations of butyric acid than the wild type parent, nitrous acid-induced, and ethidium bromide-induced strains. C.TUV increased butyric acid production 1.4-fold more than the parent strain. Fermentation with C.TUV with 2.5 g of rice polishings (w/w), a 2 % inoculum volume (v/v), and a 48-h incubation period at 37°C under anaerobic conditions produced 11.63 mg/100 g of butyric acid. The addition of 0.6 % corn steep liquor as a nitrogen source increased the butyric acid concentration to 26.09 mg/100 g.Conclusion: These optimized fermentation parameters on a small scale can be used on a commercial scale to mass-produce butyric acid.Keywords: Butyric acid, Mutant, Clostridium tyrobutyricum, Mutagen, Solid-state fermentatio

Factors Affecting the Service Quality and Customer Satisfaction in Telecom Industry of Pakistan

The current study focuses on the service quality factors which influence customer satisfaction in telecom industry of Pakistan. Customer satisfaction can be built up when brand satisfies the requirements and cravings of clients. Therefore, we took five service quality dimensions (empathy, reliability, assurance, responsiveness & tangibility) as predicting variables towards criterion variable customer satisfaction. This research was carried out on customers of telecom sector. An aggregate of 320 questionnaires were distributed among the customers of telecom industry of Pakistan through electronic forms as well as simple forms out of which 255 forms were returned i.e. response rate was79.7%. The outcomes of statistical tests demonstrate that three out of five predictor variables i.e. assurance, responsiveness and reliability have positive impact on customer satisfaction while empathy and tangibility have no significant influence on customer satisfaction. Research limitations and future plans also discussed in this research

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Multi-Objective Welding-Parameter Optimization Using Overlaid Contour Plots and the Butterfly Optimization Algorithm

Distortion and residual stress are two unwelcome byproducts of welding. The former diminishes the dimensional accuracy while the latter unfavorably affects the fatigue resistance of the components being joined. The present study is a multi-objective optimization aimed at minimizing both the welding-induced residual stress as well as distortion. Current, voltage, and welding speed were the welding parameters selected. It was observed that the parameters that minimize distortion were substantially different from those that minimized the residual stress. That is, enhancing dimensional accuracy by minimizing distortion results in an intensification of residual stresses. A compromise between the two objectives was therefore necessary. The contour plots produced from the response surfaces of the two objectives were overlaid to find a region with feasible parameters for both. This feasible region was used as the domain wherein to apply the novel butterfly optimization algorithm (BOA). This is the first instance of the application of the BOA to a multi-objective welding problem. Weld simulation and a confirmatory experiment based on the optimum weld parameters thus obtained corroborate the efficacy of the framework

Development and Characterization of Silver-Doped Multi-Walled Carbon Nanotube Membranes for Water Purification Applications

A unique approach was utilized to develop multi-walled carbon nanotube (MWCNT) silver (Ag) membranes. MWCNTs were impregnated with 1 wt% Ag loading, which resulted in a homogeneous dispersion of Ag in MWCNTs. MWCNTs impregnated with Ag were then uniaxially compacted at two different pressures of 80 MPa and 120 MPa to form a compact membrane. Compacted membranes were then sintered at two different temperatures of 800 °C and 900 °C to bind Ag particles with MWCNTs as Ag particles also act as a welding agent for CNTs. The powder mixture was characterized by FESEM, thermogravimetric analysis, and XRD, while the developed samples were characterized by calculating the porosity of membrane samples, contact angle, water flux and a diametral compression test. The developed membranes showed overall large water flux, while maximum porosity was found to decrease as the compaction load and sintering temperature increased. The mechanical strength of the membranes was found to increase as the compaction load increased. The hydrophilicity of the membranes remained unchanged after the addition of Ag particles. The developed membranes would be useful for removing a variety of contaminants from water

Survival and behavior of free and encapsulated probiotic bacteria under simulated human gastrointestinal and technological conditions

The present study was designed with the objective to compare the viability and stability of free and encapsulated probiotics under simulated technological and human gastrointestinal conditions. L. acidophilus was encapsulated using two wall materials (sodium alginate, soy protein isolate, and SA-SPI) by extrusion method for enhanced viability under stressed conditions. Free and encapsulated probiotics were subjected to some simulated technological and gastrointestinal conditions. Furthermore, free and encapsulated probiotics were also incorporated in dairy dessert to evaluate the viability and stability during storage. Encapsulation using sodium alginate and SPI as a coating materials significantly (p < .05) improved the survival of probiotics under simulated gastrointestinal and thermal conditions. The buffering effect of microbeads prolonged their survival and stability of under simulated conditions. The number of surviving probiotic cells encapsulated with sodium alginate, SPI, and SA-SPI over 120 days of product storage was 7.85 ± 0.39, 7.45 ± 0.37, and 8.50 ± 0.43 cfu/ml, respectively. In case of free cells, the surviving cells were just 3.5 ± 0.18 cfu/ml over the period of storage. In short, the study depicted that encapsulation provides protection during exposure to various hostile conditions

Investigation of the Impact Resistance Behavior of Customized Hair Clipper Comb Fabricated by Fused Deposition Modeling

This study consists of the development of a hair clipper comb finite element (FE) model, impact test analysis on the FE model, fabrication of the product using commercially available materials, followed by physical impact testing of the comb. Moreover, microscopic examination of the combs was performed to analyze the quality of the product and correlate the defects with the failure mechanism. The 3D model of comb for a Philips hair clipper was developed using ONSHAPE software, followed by a design study to understand the impact resistance of the product. The design study was performed using finite element analysis (FEA) explicit dynamic module, where two hair clipper comb designs, one with a solid body and the other with a shell were subjected to drop test simulation in two orientations: leg and head drop. Two readily available 3D printable plastic materials, Acrylonitrile Butadiene Styrene (ABS) and Polylactic acid (PLA) were selected for the FEA simulation while the comb was subjected to free fall from a height of 5 ft (1.67 m). The comb was dropped in two orientations: the head drop configuration and the leg drop configuration. For all combinations, the maximum stresses generated as a result of impact were noted and experiments performed to validate the simulation results. The four models were fabricated using fused deposition modeling (FDM) technique and were manually dropped from the same height. In line with the simulated results, models prepared from PLA material failed upon the impact while ABS samples having a comparatively better impact resistance sustained the impact without failure. Finally, fracture surface morphologies of the failed PLA component and the surface of ABS in as-printed condition were analyzed using Scanning Electron Microscopy (SEM). Based on the obtained results, the shell model made of ABS material turns out to be the most suitable choice out of all the designs considered

Association of exogenous factors with molecular epidemiology of Staphylococcus aureus in human oral cavity

The frequency of Staphylococcus aureus strains associated with oral cavity microbiota has prodigious consideration. Although S. aureus has been reflected as an ephemeral member of the human oral cavity microbiota, the isolation, identification, and characterization of S. aureus is important. The present study aimed to characterize S. aureus strains from the oral cavity microflora, isolation of S. aureus from the human oral cavity microbiota, and demographic information of the participants to evaluate exogenous factors associated with the presence of S. aureus and their genetic analysis linkage with different factors. The method used in this study is the isolation of oral cavity microbiomes using sheep blood agar and Mannitol salt agar. We performed antibiotic profiling with various antibiotics and genetic analysis utilizing gene-specific primers for specific genes, including nuc, mecA, pvl, agr, and coa. A significant number of S. aureus isolates were found in the oral cavity of humans 18/84 (21.42%), and all 18 strains tested positive for the confirmatory nuc gene. Antibiotic resistance-conferring gene mecA was positive in 10 (55.6%) isolates. It was found that the occurrence of pvl, agr, and coagulase (coa) genes was 9 (50%), 6 (33.33%), and 10 (55.6%), respectively. The genetic analysis reported that significant associations were present between male and mecA gene (P = 0.03) and coa (P = 0.03), smokers with the occurrence of mecA (P = 0.02), agr (P = 0.048) and coa (P = 0.02) genes. Likewise, the association of antibiotic usage was significantly found with mecA (P = 0.02), coa (P = 0.02); however, the individuals who have taken orthodontic treatment recently have a significant association with agr (P = 0.017). The use of mouth rinse was significantly associated with the prevalence of the pvl gene (P = 0.01), and tooth brushing frequency and inflammation of the buccal cavity were also statistically significant in relation to pvl gene prevalence (P = 0.02, 0.00, respectively). Moreover, calories and weight-controlled diet were significantly associated with mecA, agr, and highly significant with coa (P = 0.02, 0.048, 0.000), so all P < 0.05, and no significant association was found between the socioeconomic status of individuals with aforementioned analyzed genes