Enhancement of 2,3-butanediol production by Klebsiella pneumoniae PTCC 1290: Application of Taguchi methodology for process optimization

2,3-Butanediol production parameter optimization using Klebsiella pneumoniae PTCC 1290 was performed using the design of experiments available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi protocol. Optimal levels of physical parameters and key media components namely temperature, pH, inoculum size, agitation, acetic acid and succinic acid were determined. 2,3-Butanediol production obtained from the 18 sets offermentation experiments performed with the selected factors and levels were further processed with Qualitek-4 software at bigger is better as quality character. The optimized conditions showed an enhanced 2,3-butanediol production of 35.8% (from 11.856 to 18.459 g l-1). The optimal combinations of factors obtained from the proposed design of experiments methodology was further validated by conducting fermentation experiments and the obtained results revealed an enhanced 2,3-butanediol production of 25.8%. Taguchi approach of design of experiments resulted in evaluating the main and interaction effects of the factors individually and in combinatio

The histological study of osseous regeneration following implantation of various bone graft biomaterials

Background: While various biomaterials are used for bone regeneration, the relative comparative efficiency of them has not been thoroughly investigated.Purpose: This study evaluated histopathological events during osseous healing after implantation of following bone grafts: Demineralized freeze‑dried cortical bone powder (DFDB), natural coral implants, calcium sulfate‑based putty containing demineralized bone matrix (CaS‑DBM), and pure‑phase beta tricalcium phosphate ceramic granules (β‑TCP).Materials and Methods: Fifty‑six Wistar Albino rats were used for this study. The postimplantation osseous healing was evaluated at 3rd, 6th weeks after the operation.Results: DFDB did not induce bone formation in 3 weeks period, but it showed a highly osteoinductive effect at the end of 6th week period. The effects of coral implants on bone formation both at 3 and 6 weeks period were much higher than the DFDB. CaS‑DBM showed higher bone formation than β‑TCP at 3rd, 6th weeks. It was found that coral and CaS‑DBM had a more beneficial impact on early bone healing compared to β‑TCP and DFDB. All these graft biomaterials are useable in human bone defects. The main difference in the ossous healing properties of these materials is observed early postimplantation with the delayed healing outcome being similar.Keywords: Graft materials, histological observation, osseous healin

Effectiveness of Problem-Focused Coping Strategies on the Burden on Caregivers of Hemodialysis Patients

Background: Studies have shown that family caregivers of hemodialysis patients experience high levels of burden. However, these caregivers are often neglected, and no studies are available on the effectiveness of coping strategies on the burden of care among these caregivers. Objectives: This study aimed to examine the effectiveness of problem-focused coping strategies (communication skills, anger management, and deep breathing) on the burden on caregivers of hemodialysis patients. Patients and Methods: A randomized controlled clinical trial was conducted on 76 family caregivers of hemodialysis patients referred to Shahid Hasheminejad hemodialysis center in Tehran, Iran. The subjects were equally allocated into two groups of 38. Through a coin-tossing method, caregivers of patients who referred on even or odd days of the week were randomly assigned into the intervention group or the control group, respectively. The intervention group received four training sessions on problem-focused coping strategies, but the control group did not receive any intervention. Both groups answered the caregiver’s burnout inventory at the start and six weeks after the last educational session. Descriptive statistics, chi-square, Fisher’s exact test, independent-samples t-test, and Mann-Whitney U test were used to analyze the data. Results: The majority of caregivers (54%) were in the age range of 35 - 55 years, female (68.4%), and married (70%). No significant difference was found between the baseline mean caregivers’ burden scores of the intervention and control groups (88.56 ± 11.74 vs. 84.97 ± 15.13, P = 0.308). However, the mean caregivers’ burden in the intervention group decreased, and the two groups were significantly different at the end of the study (58.77 ± 6.64 vs. 87.84 ± 11.74, P < 0.001). Conclusions: The current study showed the effectiveness of problem-focused coping strategies on reducing the burden on caregivers of hemodialysis patients. Authorities and policymakers in the healthcare system are responsible for developing strategies to integrate educational programs, such as the program implemented in the current study, into the country’s healthcare system

Surface coupling effects on the capacitance of thin insulating films

A general form for the surface roughness effects on the capacitance of a capacitor is proposed. We state that a capacitor with two uncoupled rough surfaces could be treated as two capacitors in series which have been divided from the mother capacitor by a slit. This is in contrast to the case where the two rough surfaces are coupled. When the rough surfaces are coupled, the type of coupling decides the modification of the capacitance in comparison to the uncoupled case. It is shown that if the coupling between the two surfaces of the capacitor is positive (negative), the capacitance is less (higher) than the case of two uncoupled rough plates. Also, we state that when the correlation length and the roughness exponent are small, the coupling effect is not negligible

A rare variation of the inferior alveolar artery with potential clinical consequences

Variations of the inferior alveolar artery are seemingly quite rare, especially with regard to its origin from the maxillary artery. We present an unusual case of an inferior alveolar artery that originated from the external carotid artery. To the best of our knowledge, our case is one of only two reports of the inferior alveolar artery arising from the external carotid artery. The clinician who deals with the mandibular region should be aware of such a variation in the arterial architecture