Date palm biochar-polymer composites: An investigation of electrical, mechanical, thermal and rheological characteristics.

The application of biochar (BC) as a filler in polymers can be viewed as a sustainable approach that incorporates pyrolysed waste based value-added material and simultaneously mitigate bio-waste in a smart way. The overarching aim of this work was to investigate the electrical, mechanical, thermal and rheological properties of biocomposite developed by utilizing date palm waste-derived BC for the reinforcing of polypropylene (PP) matrix. Date palm waste derived BC prepared at (700 and 900°C) were blended at different proportions with polypropylene and the resultant composites (BC/PP) were characterized using an array of techniques (scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier transform infra-red spectroscopy). Additionally the thermal, mechanical, electrical and rheological properties of the BC/PP composites were evaluated at different loading of BC content (from 0 to15% w/w). The mechanical properties of BC/PP composites showed an improvement in the tensile modulus while that of electrical characterization revealed an enhanced electrical conductivity with increased BC loading. Although the BC incorporation into the PP matrix has significantly reduced the total crystallinity of the resulted composites, however; a positive effect on the crystallization temperature (Tc) was observed. The rheological characterization of BC/PP composites revealed that the addition of BC had minimal effect on the storage modulus (G') compared to the neat (PP).

Effect of Span 60 on the Microstructure, Crystallization Kinetics, and Mechanical Properties of Stearic Acid Oleogels: An In-Depth Analysis.

Modulation of crystallization of stearic acid and its derivatives is important for tuning the properties of stearate oleogels. The present study delineates the crystallization of stearic acid in stearate oleogels in the presence of Span 60. Microarchitecture analysis revealed that stearic acid crystals in the oleogels changed its shape from plate-like structure to a branched architecture in the presence of Span 60. Consequently, a significant variation in the mobility of the solute molecules inside the oleogel (Fluorescence recovery after photobleaching studies, FRAP analysis) was observed. Thermal analysis (gelation kinetics and DSC) revealed shortening of nucleation induction time and secondary crystallization with an increase in the Span 60 concentration. Furthermore, isosolid diagram suggested better physical stability of the formulations at higher proportions of Span 60. XRD analysis indicated that there was a decrease in the crystal size and the crystallinity of the stearic acid crystals with an increase in Span 60 concentration in the Span 60 containing oleogels. However, crystal growth orientation was unidirectional and found unaltered with Span 60 concentration (Avarmi analysis using DSC data). The mechanical study indicated a composition-dependent variation in the viscoelastic properties (instantaneous [τ1 ], intermediate [τ2 ], and delayed [τ3 ] relaxation times) of the formulations. In conclusion, Span 60 can be used to alter the kinetics of the crystallization, crystal habit and crystal structure of stearic acid. This study provides a number of clues that could be used further for developing oleogel based formulation.

Physicians' knowledge and practice towards medical error reporting: a cross-sectional hospital-based study in Saudi Arabia.

Identifying reasons for under-reporting is crucial in reducing the incidence of medical errors. We studied physicians' knowledge of the occurrence, frequency and causes of medical errors and their actual practice toward reporting them. A cross-sectional, self-administered questionnaire was answered by 107 physicians at a tertiary-care hospital in Saudi Arabia. The questionnaire had 6 sections covering demographic data, knowledge, attitudes and practice towards reporting medical errors, perceived causes of and frequency of medical errors in their hospital and personal experiences of medical error reporting. Physicians tended not to report medical errors when no harm had occurred to patients. One-third of respondents feared punitive actions if they reported errors and only 56.4% felt that error reporting had led to positive changes in overall care. A majority of errors were related to late interventions and misdiagnosis. Under-reporting of medical errors was common in this hospital. Physicians did not appreciate attempts to improve the system of error reporting and a culture of blame still prevailed.

Physicians' knowledge and practice towards medical error reporting: a cross-sectional hospital-based study in Saudi Arabia

Identifying reasons for under-reporting is crucial in reducing the incidence of medical errors. We studied physicians' knowledge of the occurrence,frequency and causes of medical errors and their actual practice toward reporting them. A cross-sectional, self-administered questionnaire was answered by 107 physicians at a tertiary-care hospital in Saudi Arabia. The questionnaire had 6 sections covering demographic data,knowledge, attitudes and practice towards reporting medical errors, perceived causes of and frequency of medical errors in their hospital and personal experiences of medical error reporting. Physicians tended not to report medical errors when no harm had occurred to patients. One-third of respondents feared punitive actions if they reported errors and only 56.4% felt that error reporting had led to positive changes in overall care. A majority of errors were related to late interventions and misdiagnosis. Under-reporting of medical errors was common in this hospital. Physicians did not appreciate attempts to improve the system of error reporting and a culture of blame still prevailed

L'identification des raisons de la sous-notification est cruciale pour reduire l'incidence des erreurs medicales. Nous avons etudie les connaissances des medecins sur la survenue, la frequence et les causes des erreurs medicales ainsi que leur pratique reelle en termes de notification. Un autoquestionnaire transversal a ete rempli par 107 medecins dans un hopital de soins tertiaires en Arabie saoudite. Le questionnaire presentait six sections couvrant les donnees demographiques, les connaissances, les attitudes et les pratiques vis-a-vis de la notification des erreurs medicales, les causes percues et la frequence des erreurs medicales dans leur hopital ainsi que les experiences personnelles en matiere de notification. Les medecins avaient tendance a ne pas notifier les erreurs medicales lorsque les patients n'avaient souffert d'aucun dommage. Un tiers des repondants craignaient les actions punitives s'ils notifiaient des erreurs et seuls 56,4 % pensaient que la notification des erreurs entrainait des modifications positives pour l'ensemble des soins. Une majorite d'erreurs etait liee a des interventions tardives et des erreurs de diagnostic. La sous-notification des erreurs medicales etait frequente dans cet hopital. Les medecins ne percevaient pas positivement les tentatives d'amelioration du systeme de notification des erreurs et la culture du blame restait prevalente

Thermal, creep-recovery and viscoelastic behavior of high density polyethylene/hydroxyapatite nano particles for bone substitutes: effects of gamma radiation.

BACKGROUND: High Density Polyethylene (HDPE) is one of the most often used polymers in biomedical applications. The limitations of HDPE are its visco-elastic behavior, low modulus and poor bioactivity. To improve HDPE properties, HA nanoparticles can be added to form polymer composite that can be used as alternatives to metals for bone substitutes and orthopaedic implant applications. METHOD: In our previous work (BioMedical Engineering OnLine 2013), different ratios of HDPE/HA nanocomposites were prepared using melt blending in a co-rotating intermeshing twin screw extruder. The accelerated aging effects on the tensile properties and torsional viscoelastic behavior (storage modulus (G') and Loss modulus (G")) at 80°C of irradiated and non-irradiated HDPE/HA was investigated. Also the thermal behavior of HDPE/HA were studied. In this study, the effects of gamma irradiation on the tensile viscoelastic behavior (storage modulus (E') and Loss modulus (E")) at 25°C examined for HDPE/HA nanocomposites at different frequencies using Dynamic Mechanical Analysis (DMA). The DMA was also used to analyze creep-recovery and relaxation properties of the nanocomposites. To analyze the thermal behavior of the HDPE/HA nanocomposite, Differential Scanning Calorimetry (DSC) was used. RESULTS: The microscopic examination of the cryogenically fractured surface revealed a reasonable distribution of HA nanoparticles in the HDPE matrix. The DMA showed that the tensile storage and loss modulus increases with increasing the HA nanoparticles ratio and the test frequency. The creep-recovery behavior improves with increasing the HA nanoparticle content. Finally, the results indicated that the crystallinity, viscoelastic, creep recovery and relaxation behavior of HDPE nanocomposite improved due to gamma irradiation. CONCLUSION: Based on the experimental results, it is found that prepared HDPE nanocomposite properties improved due to the addition of HA nanoparticles and irradiation. So, the prepared HDPE/HA nanocomposite appears to have fairly good comprehensive properties that make it a good candidate as bone substitute.

Production of fructose from highly concentrated date extracts using Saccharomyces cerevisiae.

Large amounts of low-quality dates produced worldwide are wasted. Here, highly concentrated fructose syrups were produced via selective fermentation of date extracts with Saccharomyces cerevisiae. Syrups with 95.4-99.9 % (w/w) fructose yields were obtained from date extracts having an initial sugar range of 49-374 g/l without media supplementation; the corresponding ethanol yields were between 69 and 52 % (w/w). At 470 g initial sugars/l, fructose and ethanol yields were 84 and 47 % (w/w), respectively, and the product contained 62 % (w/w) fructose, which is higher than the widely available commercial 42 and 55 % (w/w) high fructose corn syrups. The commercial potential for conversion of waste dates to high-value products is thus demonstrated.

Stretch Polytetrafluoroethylene Grafts for Hemodialysis Angioaccess: Three-year Experience.

We report the results of 90 stretch polytetrafluoroethylene (PTFE) grafts in 78 chronic renal failure patients over a 3-year period from 1995-1998. The grafts were used as primary access in 15% of the patients. The cumulative patency was 63.3% and there were no complications in 48.8% of the cases. Infection was encountered in 15.5% and thrombosis in 31.1% of the grafts. Intimal hyperplasia, venous anastomotic stenosis, improper puncture technique and subclavian vein stenosis were the major causes of failure of grafts. We conclude that stretch PTFE grafts as angioaccesses may provide good patency and durability.

"Outbreak" of hand injuries during Hajj festivities in Saudi Arabia.

Pediatric hand surgeons in Europe and North America are aware of the yearly "outbreak" of pediatric hand injuries on Halloween from carving pumpkins. This study reports another yearly "outbreak" of hand injuries--in Saudi Arabia from slaughtering sheep. During the 3 days of festivities following the Hajj ceremony, hundreds of thousands of sheep are slaughtered. Over 4 consecutive years, 298 patients attended the emergency room of Riyadh Central Hospital with injuries related to the slaughtering of animals sustained during the 3 days of festivity. Almost three quarters of patients (73%) were injured on the first day of festivity. The majority (92%) were nonprofessionals. Children accounted for 6.7% of patients. In adults, the female-to-male ratio was 1:7. The most common mechanism of injury was a knife cut (80.9%). Almost three quarters of injuries (73.5%) affected the hands, with more involvement of the left than the right hand. Only 7.7% of patients with hand injuries were admitted to the hospital for treatment. It was concluded that implementing safety measures while slaughtering, and educating the general population would be important in the prevention of these hand injuries in Saudi Arabia.

Effect of central 5-hydroxytryptamine depletion on tolerance of delay of reinforcement: evidence from performance in a discrete-trials "time-left" procedure.

This experiment examined the effect of destruction of the ascending 5-hydroxytryptaminergic (5HTergic) pathways on performance on a new discrete-trials version of the "time-left" procedure. Rats received either injections of 5,7-dihydroxytryptamine into the dorsal and median raphe nuclei or sham lesions. They were trained in a discrete trials schedule in which reinforcers were provided for responding on either of two levers, A and B. At a random time point, t s after the start of each trial, the two levers were inserted into the operant chamber: a response on A resulted in the delivery of one food pellet after dA s, whereas a response on B resulted in the delivery of two pellets after 84-t s. The value of dA was varied between 1 and 12 s in different phases of the experiment. Both groups showed an increasing tendency to respond on lever B as a function of time within the trial. Logistic functions were fitted to the data from each group, and a value of the "indifference point" (T50: the time within the trial at which proportional choice of B attained a value of 50%) was derived for each rat. For each value of dA, the values of T50 were significantly greater in the lesioned rats than in the control rats, reflecting a rightward shift of the logistic function in the lesioned group. The levels of 5HT and 5-hydroxyindoleacetic acid were reduced in the brains of the lesioned rats, but the levels of noradrenaline and dopamine were not significantly altered. The results provide further evidence for the involvement of the ascending 5HTergic pathways in the control of operant behaviour by delayed positive reinforcers.

Comparative clinical pharmacology of rocuronium, cisatracurium, and their combination.

BACKGROUND: The comparative clinical pharmacology of cisatracurium and rocuronium and their combinations has not been reported. In this study, the authors compared the relative potency and the clinical profile and characterized the interaction of both drugs. METHODS: Two hundred twenty adults classified as American Society of Anesthesiologists physical status I and anesthetized with propofol-fentanyl-nitrous oxide were studied. In part 1, the neuromuscular-blocking effects of cisatracurium and rocuronium were assessed after administration of bolus doses of 20-50 microg/kg and 100-300 microg/kg, respectively. In part 2, we compared the time course of 1xED50, 1, 1.5, and 2xED95 doses of both drugs (where ED50 and ED95 are, respectively, the doses producing 50% and 95% depression of the first twitch height [T1]). In part 3, equieffective combinations of both drugs were studied to characterize their interaction. RESULTS: The calculated ED50 values and their 95% confidence intervals were 111 (107-115) and 26.2 (25.8-26.5) microg/kg [corrected] for rocuronium and cisatracurium, respectively. Compared with equipotent doses of cisatracurium, rocuronium had a faster onset, and a faster spontaneous T1 and train-of-four recovery times that were significant except at maximum recovery with the 2xED95 dose. The interaction between rocuronium and cisatracurium was synergistic, and the time profile of the combination group was different from that of the single-dose groups. CONCLUSIONS: Cisatracurium is four to five times more potent than rocuronium. Rocuronium had a faster onset of action, a shorter clinical duration, and a faster spontaneous recovery rate compared with equipotent doses of cisatracurium.

Modified Salter's innominate osteotomy.

Twenty paediatric patients with congenital dislocation of the hip were treated with a modification of the classic technique of Salter's osteotomy. Along with open reduction and femoral shortening osteotomy, the resected femoral segment, which measured 10-40 mm in width (mean 16 mm), was used to stabilize the Salter's osteotomy. The patients were aged between 2 and 9 years (mean 3.8 years). After a mean follow-up of 16 months (range 6-60 months) all patients had full bone healing and complete incorporation of femoral bone graft with the acetabulum. No patient had re-dislocation, subluxation or displacement of the graft.

Effect of destruction of noradrenergic neurones with DSP4 on performance on a free-operant timing schedule.

This experiment examined the effect of destroying central noradrenergic neurones, using the selective neurotoxin DSP4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine], on performance in a free-operant timing schedule. Rats received either systemic treatment with DSP4 or vehicle-alone injections. They were trained to press levers for a sucrose reinforcer. Training sessions consisted of 40, 50-s trials in which reinforcers were available on a variable-interval 25-s schedule; in the first 25 s of each trial, reinforcers were only available for responses on lever A, whereas in the last 25 s reinforcers were available only for responses on lever B. Data were collected from probe trials (four per session), in which no reinforcers were delivered, during the last ten of 60 training sessions. Both groups showed decreasing response rates on lever A, and increasing response rates on lever B, as a function of time from the onset of the trial. Quantitative indices of timing behaviour were derived from a two-parameter logistic function fitted to the relative response rates on lever B (response rate on lever B, expressed as a percentage of overall response rate); this function accounted for > 90% of the data variance in each group. The DSP4-treated group showed a significantly lower value of the indifference point (i.e. the time corresponding to 50% responding on lever B) than the control group. The slope of the function and the rate of switching between response alternatives did not differ significantly between the two groups. The concentrations of noradrenaline were markedly reduced in the neocortex and hippocampus of the DSP4-treated group, but the concentrations of dopamine, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid were not significantly altered. It is suggested that results may be consistent with a role of the dorsal ascending noradrenergic pathway in behavioural "arousal".

5-hydroxytryptamine and impulse control: prospects for a behavioural analysis.

Impulsiveness is a significant clinical problem associated with a variety of psychiatric and neuropsychiatric disorders. Clinical and experimental studies have provided evidence that individuals displaying impulsive behaviour tend to show signs of deficient functioning of the ascending 5-hydroxytryptaminergic (5-HTergic) pathways of the brain. A persistent problem in investigations of the biological basis of impulsive behaviour has been the lack of a satisfactory definition of 'impulsiveness', as distinct from other behavioural features, such as aggression, which are often apparent in 'impulsive' individuals. Research in the experimental analysis of behaviour suggests that two important characteristics of 'impulsiveness' are (i) deficient tolerance of delay of gratification and (ii) inability to inhibit or delay voluntary behaviour; both of these characteristics are amenable to study in laboratory animals. We describe some delayed reinforcement and delayed response paradigms which purport to capture these behavioural characteristics, and review recent evidence that manipulation of 5-HTergic function alters behaviour in these paradigms. It is argued that the two characteristics of 'impulsiveness' are themselves the product of disturbance of more fundamental behavioural processes; the nature of these processes is considered.

Effect of central 5-hydroxytryptamine depletion on performance in the "time-left" procedure: further evidence for a role of the 5-hydroxytryptaminergic pathways in behavioural "switching".

This experiment examined the effect of destruction of the ascending 5-hydroxytryptaminergic (5HTergic) pathways on performance in a free-operant timing schedule: the "time-left" procedure. Rats received either injections of 5,7-dihydroxytryptamine into the dorsal and median raphe nuclei or sham lesions. They were trained in a discrete trials schedule in which reinforcers were provided for responding on either of two levers, A and B. At a random time point, t s after the start of each trial, a response on A resulted in the delivery of one food pellet after dA s, whereas a response on B resulted in the delivery of two pellets after 60-t s. The value of dA was varied between 1 and 8 s in different phases of the experiment. Both groups showed decreasing response rates on lever A and increasing response rates on lever B as a function of time within the trial. An index of timing (T75: the time within the trial at which relative response rate on B attained a value of 75%) was systematically related to the value of dA, but did not differ significantly between lesioned and control rats. However, the lesioned group showed significantly higher rates of switching between response alternatives than the sham-lesioned group at all values of dA. The levels of 5HT and 5-hydroxyindoleacetic acid were reduced in the brains of the lesioned rats, but the levels of noradrenaline and dopamine were not significantly altered. The results provide further evidence that the ascending 5HTergic pathways may contribute to the inhibitory regulation of switching between behavioural states.

Cervical spinal injuries caused by collision of cars with camels.

We report 16 patients who sustained spinal injuries by collision of their cars with camels. Out of the 16 patients, 10 had severe spinal injuries with neurological deficits. The pattern of injury, possible mechanism of injury and recommendations for avoiding these severe injuries are suggested.

Destruction of central noradrenergic neurones with DSP4 impairs the acquisition of temporal discrimination but does not affect memory for duration in a delayed conditional discrimination task.

This experiment examined the effect of destroying central noradrenergic neurones using the selective neurotoxin N-(2-chloroethyl)-n-ethyl-2-bromobenzylamine (DSP4) on the acquisition of a temporal discrimination and on memory for duration, using a delayed conditional discrimination task. In phase I, rats that had received systemic treatment with DSP4 and vehicle-treated control rats were trained in a series of discrete trials to press lever A following a 2-s presentation of a light stimulus, and lever B following an 8-s presentation of the same stimulus. Following stimulus offset, a response on a panel placed midway between the two levers was required to initiate lever presentation; a single response on either lever resulted in withdrawal of both levers and, in the case of a "correct" response, reinforcer delivery. Both groups acquired accurate discrimination, achieving 90% correct choices within 50 sessions; the DSP4-treated group acquired accurate performance more slowly than the control group. In phase II, delays were interposed between stimulus offset and lever presentation in 50% of the trials. In the absence of a delay, discriminative accuracy was lower in the DSP4-treated group than in the control group. Accuracy declined as a function of post-stimulus delay in both groups; both groups showed a delay-dependent bias towards responding on lever A ("choose-short" bias). Neither of these effects differed significantly between the two groups. The concentrations of noradrenaline in the parietal cortex and hippocampus were reduced by 90% and 89% in the DSP4-treated group, compared to the levels in the control group, but the levels of dopamine, 5-hydroxytryptamine and 5-hydroxyindoleacetic acid did not differ significantly between the groups. The results confirm the deleterious effect of DSP4 on the acquisition of temporal discrimination, but do not provide evidence for a role of the noradrenergic innervation of the hippocampus and neocortex in temporal working memory.

Predisposing factors to industrial hand injuries in Saudi Arabia.

A prospective study was performed on 108 consecutive cases of industrial hand injuries in Saudi Arabia to highlight predisposing factors to injury. Traumatic amputations and fractures of the radial three digits were the commonest injuries. Eighty patients (74%) worked for more than 8 hours per day, which is against Saudi labour law. Only 5% of the injured workers had similar jobs previously or formal training prior to employment. The majority (81%) admitted that safety measures were not being followed at the time of injury. Ten workers (9%) had a previous history of industrial hand injury. It was concluded that strict implementation of safety measures and Saudi labour law, proper training of employees, and the development of agencies for the prevention of occupational accidents would be important in the prevention of industrial hand injuries in Saudi Arabia.