19 research outputs found

    Analysis of Dryness Effect on Skin by Adapting Hyperelastic Constitutive Model / Nor Fazli Adull Manan ...[et al.]

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    The El Nino phenomenon can damage the skin and cause sickness such as skin cancer, heat stroke and heat exhaustion. Due to this phenomenon, an analysis on mechanical properties on animal skin is carried out, where sheepskin is used for investigation through uniaxial tensile test. The aim of this study is to investigate the effect of varied temperature on mechanical properties of animal skin. The process consists of an integration between experimental and numerical approach. A uniaxial tensile test is performed first to measure the basic mechanical parameter of stress-stretch by following the ASTM D2209-00 International testing standard. Next, the hyperelastic constitutive model Arruda and Boyce (A&B) equation is simplified via numerical approach for finding the material parameter. Then, a graph of Stress – Stretch (σ-λ) is plotted for a curve fit with the experimental data to obtain the mechanical properties of the material parameter. As a result, the material parameter which are Arruda and Boyce coefficient, μ and Arruda and Boyce exponent, N are 4.967(MPa) and 3.116, respectively, for SL Temp 33. However, μ and N for SNL Temp 33 are 5.134 (MPa) and 2.357. In contrast, the value of the value of μ and N for SL Temp 36 are 4.943(MPa) and 2.728 and for SNL Temp 36 are 5.199(MPa) and 2.209 .Therefore, this study could be useful for future studies in analysis of skin by adapting hyperelastic constitutive model

    Date-leaf carbon particles for green enhanced oil recovery

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    Green enhanced oil recovery (GEOR) is an environmentally friendly enhanced oil recovery (EOR) process involving the injection of green fluids to improve macroscopic and microscopic sweep efficiencies while boosting tertiary oil production. Carbon nanomaterials such as graphene, carbon nanotube (CNT), and carbon dots have gained interest for their superior ability to increase oil recovery. These particles have been successfully tested in EOR, although they are expensive and do not extend to GEOR. In addition, the application of carbon particles in the GEOR method is not well understood yet, requiring thorough documentation. The goals of this work are to develop carbon nanoparticles from biomass and explore their role in GEOR. The carbon nanoparticles were prepared from date leaves, which are inexpensive biomass, through pyrolysis and ball-milling methods. The synthesized carbon nanomaterials were characterized using the standard process. Three formulations of functionalized and non-functionalized date-leaf carbon nanoparticle (DLCNP) solutions were chosen for core floods based on phase behavior and interfacial tension (IFT) properties to examine their potential for smart water and green chemical flooding. The carboxylated DLCNP was mixed with distilled water in the first formulation to be tested for smart water flood in the sandstone core. After water flooding, this formulation recovered 9% incremental oil of the oil initially in place. In contrast, non-functionalized DLCNP formulated with (the biodegradable) surfactant alkyl polyglycoside and NaCl produced 18% more tertiary oil than the CNT. This work thus provides new green chemical agents and formulations for EOR applications so that oil can be produced more economically and sustainably

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

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    Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P &lt; 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

    Frequency of isolated positive sputum cultures among pulmonary tuberculosis patients

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    Department of Obstetrics and Gynecology # 36, College of Medicine and Research Center, King Khalid University Hospital, PO Box 2925, Riyadh 11461, Kingdom of Saudi Arabia.OBJECTIVE: The occurrence of isolated positive sputum cultures among pulmonary tuberculosis (PTB) patients during treatment is not widely reported. This study describes the frequency of isolated positive sputum cultures among PTB patients after initiation of chemotherapy. METHODS: Fifty sputum culture positive PTB patients, consisting of 38 (76%) males and 12 (24%) females with a mean age of 34.31 +/- 19.54 (13-75) years, were studied prospectively over a period of 10 months (September 1999 to June 2000) at Sahary Chest Hospital, Riyadh, Kingdom of Saudi Arabia. The majority of patients received standard 4-drug short-course antimicrobial chemotherapy. Weekly sputum smears and cultures were carried out for each patient during the treatment. RESULTS: Isolated positive sputum cultures were encountered in 4 (8%) of the studied patients. Two of them had 2 consecutive positive smears and cultures in their third and fourth week during treatment and were attributed to poor compliance to the treatment. Of the remaining 2 patients, one had single isolated culture in his fourth week, while the fourth patient showed a slight growth in the fifth week of the treatment. Due to the undetermined status of the smear and very few colonies in the culture, these 2 isolated cultures were attributed to the carry-over contamination during the laboratory procedures. The same treatment was continued with strict monitoring of compliance to the treatment and laboratory protocols. All of the 4 patients converted to negative before leaving the hospital. CONCLUSION: Isolated positive sputum cultures might appear (infrequently) during treatment either due to the treatment noncompliance or carry over contamination. However, under either circumstance, the same treatment should be continued along with strict monitoring of treatment compliance and specimen decontamination and related laboratory protocols

    A Hybrid Joint Based Controller for an Upper Extremity Exoskeleton

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    This paper presents the modelling and control of a two degree of freedom upper extremity exoskeleton. The Euler-Lagrange formulation was used in deriving the dynamic modelling of both the human upper limb as well as the exoskeleton that consists of the upper arm and the forearm. The human model is based on anthropometrical measurements of the upper limb. The proportional-derivative (PD) computed torque control (CTC) architecture is employed in this study to investigate its efficacy performing joint-space control objectives specifically in rehabilitating the elbow and shoulder joints along the sagittal plane. An active force control (AFC) algorithm is also incorporated into the PD-CTC to investigate the effectiveness of this hybrid system in compensating disturbances. It was found that the AFC- PD-CTC performs well against the disturbances introduced into the system whilst achieving acceptable trajectory tracking as compared to the conventional PD-CTC control architecture

    Aerosol-assisted chemical vapor deposition of silver thin film electrodes for electrochemical detection of 2-nitrophenol

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    Present work reports a simple, cost-effective and facile approach for electrochemical sensing of 2-nitrophenol (2-NP) as the model analyte using silver thin film electrodes. Thickness controlled silver thin films are grown on ITO glass substrates at 400°C for varying deposition times of 10–45 minutes using methanol solution of silver triflouroacetate (Ag(CF3COO)), via aerosol assisted chemical vapor deposition (AACVD). XRD, XPS, SEM and EDX analysis of the films verified the presence of crystalline and phase pure elemental silver with micro/nanometer dimensions whereas a growth pattern from spherical nanoparticles to continuous thin films is observed over time. All Ag-electrodes were used to investigate the electrochemical behavior of 2-NP by cyclic voltammetry (CV) while the quantitative profiling was done by LSV. The results indicate that the Ag-electrode developed in 30 min manifested excellent electrocatalytic activity toward 2-NP reduction, thereby lowering the reduction overpotential and increasing the reduction current which is attributed to the percolated metallic network in its micro/nanostructure. This particular electrode exhibited a dynamic range = 50–450 μM, detection limit = 12 nM, and high selectivity from potential interfering agents, a performance much better than the available thin film sensors and Ag-disk electrode
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