Biodiesel production from candlenut oil using a non-catalytic supercritical methanol transesterification process: optimization,kinetics, and thermodynamic studies

The present study was conducted to determine the feasibility of biodiesel production from candlenut oil using supercritical methanol (scMeOH) as a non-catalytic transesterification process. The influence of the scMeOH transesterification process was determined with varying pressure (85–145 bar), temperature (260–300 °C), methanol to oil (M : O) ratio (15 : 1–35 : 1), and reaction time (15–25 min). The experimental conditions of the scMeOH transesterification process were designed using central composite design (CCD) of experiments, and the process was optimized using response surface methodology (RSM). It was found that scMeOH temperature, pressure, M : O ratio, and reaction time substantially influenced the transesterification process. The maximum biodiesel yield of 96.35% was obtained at an optimized scMeOH transesterification process at the pressure of 115 bar, the temperature of 285 °C, M : O ratio of 30 : 1, and reaction time of 22 min. A second-order kinetics model and Eyring equations were utilized to determine the kinetics and thermodynamics of biodiesel production from candlenut oil. The activation energy value was determined to be 28.35 KJ mol⁻¹. Analyses of the thermodynamic properties of biodiesel revealed that the transesterification process was non-spontaneous and endothermic. The physicochemical properties of produced candlenut biodiesel via scMeOH complied with most of the biodiesel properties as per ASTM D6751 and EN14214, thereby referring to good quality biodiesel production. The findings of the present study reveal that the scMeOH is an effective non-catalytic transesterification process for biodiesel production from candlenut oil.

The present study was conducted to determine the feasibility of biodiesel production from candlenut oil using supercritical methanol (scMeOH) as a non-catalytic transesterification process.     

Biofeedback training in patients with fecal incontinence

PURPOSE: This study was undertaken to assess the functional results of biofeedback training in patients with fecal incontinence in relation to clinical presentation and anorectal manometry results. METHODS: Twenty-six consecutive patients with fecal incontinence were treated with biofeedback training using anorectal manometry pressure for visual feedback. Ten patients had passive incontinence only, six patients had urge incontinence, and ten patients had combined passive and urge incontinence. RESULTS: Patients with urge incontinence had a lower maximum voluntary contraction pressure (92 ± 12 mmHg) and lower maximum tolerable volume (78 ± 13 ml) than patients with passive incontinence (140 ± 43 mmHg and 166 ± 73 ml). Twenty-two patients completed the treatment, five patients (23 percent) showed excellent improvement, nine patients (41 percent) had good results, and eight (36 percent) patients showed no improvement. At follow-up on average of 21 months after therapy, 41 percent of our patients reported continued improvement. The maximum tolerable volume was higher in those with excellent (140.4 ± 6.8 ml) or good (156.3 ± 6.64 ml) results of therapy than it was in those with poor results (88.5 ± 2.5 ml). Greater asymmetry of the anal sphincter also correlated to poor results. CONCLUSION: Biofeedback therapy improved continence immediately after training and at follow-up after 21 months, but the initial results were better. The urge fecal incontinence seems to be related to function of the external anal sphincter and to the maximum tolerable volume. Low maximum tolerable volume and anal sphincter asymmetry were associated with a poor outcome of therapy     

Airgun injuries of the brain

Brain injuries caused by airguns are serious. The optimal management is wound exploration, excision of contaminated tissues and removal of loose bone fragments. In addition, careful monitoring, prophylactic antibiotics and anticonvulsants are required. The outcome is dictated by the importance of the intracranial structures which the pellet transects and the development of complications. Removal of the pellet is desirable only if easily acccessible. We report five cases, of which four survived without deficits and one remained severely handicapped.     

Carotid artery thickness in children and young adults with end stage renal disease

Atherosclerosis is a major cause of morbidity and mortality for ESRD patients and we have little knowledge about the presence and risk factors of atherosclerosis in children with CRF. The measurement of carotid artery intima-media thickness (cIMT) using high-resolution ultrasonography is suggested as an excellent marker of subclinical atherosclerosis. In this study, we aimed to investigate the presence of atherosclerosis and to determine the relationship between atherosclerosis and some risk factors in children and young adults with ESRD. Thirty-four patients with ESRD and 20 controls were included in this study. The measurement of cIMT was performed by using a linear B-mode 7.5-MHz ultrasound transducer. We determined anemia, abnormal calcium/phosphate metabolism, hyperhomocysteinemia, hypertriglyceridemia and increased lipoprotein (a) levels in the ESRD group. The cIMT in the ESRD group was higher than in the control group (P<0.05). SBP, DBP, MAP, LVMI and LVH prevalence were statistically higher in the ESRD group (P<0.05). There were significant positive correlations between cIMT and LVMI, MBP, whereas a significant negative correlation was determined between cIMT and PTH in the ESRD group (P<0.05). When a multiple linear regression analysis was performed with cIMT as a dependent variable and LVMI, MBP, PTH, as independent variables, a significant positive correlation was determined between cIMT and LVMI (P<0.05). In conclusion, we think that arteriopathy occurs in children with ESRD. Left ventricular hypertrophy and hypertension may associate with vascular changes in children and young adults with ESRD. Further investigations are necessary to explain association of LVMI index with cIMT.     

Towards nationwide control of schistosomiasis in Yemen: a pilot project to expand treatment to the whole community

Both the urinary and intestinal forms of schistosomiasis are thought to be widespread in the Republic of Yemen, with estimates of 3 million people infected and 600 000 suffering clinical morbidity. Sub-national control has been ongoing since 2006 via the distribution of praziquantel (PZQ) against schistosomiasis and albendazole (ALB) against soil-transmitted helminths using school-based treatment. In preparation for a 6-year nationwide control programme with the aim of expanding treatment to the wider community, a new programmatic approach of complementing school-based distribution with community-based treatment was trialled in 10 highly endemic districts in three governorates in December 2009. The new approach achieved coverage of 90.1% of non-enrolled children: a 40% increase compared with the same districts in 2008, and coverage of 97.9% of enrolled children: a 2% increase compared to 2008. Coverage of females (children and adults) was 81.8%, and of adults in general was 73.9%. The total cost per person treated was US$0.66 (US$0.79 in 2008), which includes training, health education, social mobilization, distribution and drugs. These results provide hope that a combined school and community-based approach can be successfully implemented on a wider scale during the main control programme in 2010-2015, with approximately 10 million people targeted in the first year alone.     

Timing of long bone fracture fixation in severe traumatic brain injury

We present a review of the published evidence on the optimal timing for long bone fracture fixation in severe traumatic brain injury (TBI); a matter that remains under debate. Fifteen retrospective articles (level II-3 evidence) were considered suitable for the review. We conclude that the published evidence does not provide a definitive answer to the optimal timing of long bone fracture surgery in severe TBI, and a randomized controlled trial is required. We recommend a safe strategy that combines damage control surgery with a period of monitoring of intracranial pressure, cerebral perfusion pressure, and if available brain tissue oxygen until the patient is considered fit for the fracture fixation.     

Intracranial extraskeletal mesenchymal chondrosarcoma

Intracranial extraskeletal mesenchymal chondrosarcoma is a rare malignant variant of chondrosarcomas. We present a 5-year-old Saudi male child who was brought to the Emergency Department with the complaints of headache, irritability, vomiting, and unsteadiness of gait with right hemiparesis. Radiological studies confirmed the presence of a space-occupying lesion in the left cerebral hemisphere of the brain. Through a left temporoparietal craniotomy a total macroscopic excision of the tumor was carried out, and the tumor was found attached to the dura at the base of the temporal fossa. The tumor was well circumscribed, extra axial in location, and was easily dissected from the other part of the brain. The histopathological examination revealed the tumor to be a mesenchymal chondrosarcoma. This rare tumor of the pediatric age group should be included in the differential diagnosis of all intracranial tumors with aggressive characteristics.