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Conformational distortion in solution processable PVK:TcTa blends and the effect on extra warm white organic phosphorescent light emitting diodes
No full textOrganic semiconductors generally display significant conformational flexibility which results in significant energetic disorder. In this research, ultraviolet photoelectron spectra are compared with the Gaussian density of states obtained from the density functional theory on assembly of molecules optimized using molecular dynamic simulations. It was found out that spin-coated organic semiconductor, tris(4-carbazoyl-9-ylphenyl)amine (TcTa), displays significant conformational distortion from its minimum geometry with significant Gaussian broadening. Adding poly(vinylcarbazole) (PVK) into TcTa results in increased face to face stacking of carbazole moieties from PVK as evident from increased red-shifted of absorption of PVK. Despite reduction of energy barrier upon addition of TcTa into PVK, the current efficiency of the extra warm white organic light emitting diodes showed limited improvement probably from the increased triplet quenchers from the carbazole dimers. © 201
A Nationwide Study Comparing Knowledge and Beliefs about HPV among Female Students before and after HPV Vaccination
No full textStudy Objective: To assess the knowledge and beliefs regarding human papillomavirus (HPV) and the HPV vaccine among girls before and after vaccination in the Malaysian HPV Immunisation Programme. Design: A nationwide longitudinal survey. Setting: Thirty-two randomly selected schools from 13 states and 3 federal territories in Malaysia from February to March 2013, and October to November 2013. Participants: Form One female students (13 years old). Interventions: None. Main Outcome Measures: Mean knowledge score of HPV infection. Results: A total of 2644 students responded to the prevaccination survey, of whom 2005 (70%) completed the postvaccination survey. The mean knowledge score was 2.72 (SD ± 2.20) of a maximum score of 10 in the prevaccination survey, which increased significantly to 3.33 (SD ± 1.73) after the 3 doses of HPV vaccine (P = .001). Many answered incorrectly that, “Only girls can get HPV infection” (91.5%, n = 1841 prevaccination vs 96.1%, n = 1927 postvaccination), and only a few were aware that, “Vaccinating boys helps to protect girls against HPV infection” (11.4%, n = 229 for prevaccination vs 10.2%, n = 206 for postvaccination). The mean knowledge score was significantly higher postvaccination among higher-income families and those with parents of a higher occupational status. Regarding beliefs about the HPV vaccine, 89.4% in the prevaccination survey held the view that they would not get a HPV infection, and the percentage remained similar in the postvaccination survey. Perceived severity of HPV infection also remained low in the pre- and postintervention groups. Only 21.5% reported receiving health information about HPV along with the provision of the HPV vaccine; those who received health information showed higher levels of knowledge. Conclusion: Findings revealed a general lack of knowledge and erroneous beliefs about HPV and the HPV vaccine even after receiving vaccination. This suggests that imparting accurate knowledge about HPV along with vaccine administration is essential. Specifically, girls from lower socioeconomic groups should be a target of educational intervention. © 2018 North American Society for Pediatric and Adolescent Gynecolog
Electrodeposited Co-Mn oxide composite electrodes for rechargeable Zn-air battery
No full textPorous manganese cobalt oxide (MCO) films were prepared directly on a conductive stainless steel (SS) mesh substrate via electrodeposition and an annealing treatment as composite air electrodes. The electrodeposition time ratio markedly influenced the surface morphological and electrochemical catalytic activities of MCO/SS electrodes. The sample 04 (− 0.8 V for 480 s followed by − 0.9 V for 240 s and annealed at 400 °C for 2 h) exhibited the highest reduction current among all electrodes. The electrochemical catalytic activity of the sample 04 as the air electrode for rechargeable zinc–air batteries was evaluated using galvanostatic charge and discharge cycling measurements in a solution of 6 M KOH. After 1000 cycles, sample 04 exhibited excellent cycling stability, with an overall potential gap of 0.75 V. The excellent performance of MCO/SS electrode in terms of stability and overall potential gap might be due to the ratio of Co oxide and Mn oxide, and its porous structure. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature
Maximum acceptable frequency of lift for combined manual material handling task in Malaysia
No full textBackground Extensive studies have been carried out over the years to determine the maximum acceptable weight that a worker is capable of lifting in a given situation among Occidental populations across Europe and US. Nonetheless, studies that place emphasis on using lifting frequency as the quantifying task parameter, especially in developing countries such as Malaysia, appear to be in scarcity. Hence, this study determined the maximum acceptable frequency of lift (MAFL) for combined manual material handling (MMH) tasks amongst Malaysian males. Method Two lifting loads were considered in this study: 1 kg and 5 kg. Each subject adjusted his frequency of lifting using a psychophysical approach. The subjects were instructed to perform combined MMH task as fast as they could over a period of 45 minutes without exhausting themselves or becoming overheated. The physiological response energy expenditure was recorded during the experimental sessions. The ratings of perceived exertion (RPE) for four body parts (forearms, upper arm, lower back and entire body) were recorded after the subjects had completed the instructed task. Results The mean frequencies of the MMH task had been 6.8 and 5.5 cycles/minute for lifting load of 1 and 5 kg, respectively, while the mean energy expenditure values were 4.16 and 5.62 kcal/min for 1 and 5 kg load, respectively. These displayed a significant difference in the Maximum Acceptable Frequency of Lift (MAFL) between the two loads, energy expenditure and RPE (p < 0.05) whereby the subjects appeared to work harder physiologically for heavier load. Conclusion It can be concluded that it is significant to assess physiological response and RPE in determining the maximum acceptable lifting frequency at varied levels of load weight. The findings retrieved in this study can aid in designing tasks that do not exceed the capacity of workers in order to minimise the risk of WRMSDs. © 2019 Widia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Thermoelectric power battery using al2o3 nanochannels of 10 nm diameter for energy harvesting of low-grade waste heat
No full textThis work reports the effective of thermal-to-electric energy conversion based on a fluidic transport of nanochannels electrochemical devices induced by a temperature gradient. Using highly order periodic and high aspect ratio anodized aluminum oxide (AAO) nanochannels with 10 nm-diameter and 3 µm-length, the Slip effect and Soret diffusion inside the nanochannels drive large ion separation of monovalent KCl electrolyte between hot reservoir and cold reservoir respectively to generate power density of 255 µW cm−2 at temperature difference of 30 °C. This device has distinct advantages for conventional thermoelectrochemical energy harvester. They do not require the presence of constant temperature gradient in order to operate, they do not require an external voltage to charge and are solely charged by the presence of heat. The need for expensive redox couple are eliminated. High voltage generated by 3 order magnitude higher than TEC than contain no nanochannel device using same KCl electrolyte. They retain charge for extended period of time, up to 60% after 48 h, hence demonstrating their strong viability as a thermally driven integrated generator-storage device. The fundamental explanation for high performance device is due to the ability for the nanochannels to drive and retain charge polarization under a temperature gradient due to slip of nanochannels wall and Soret effect of the electrolyte. © 2019 Elsevier Lt
Heavy/light chain assay in the monitoring of multiple myeloma
No full textSerum protein (SPE) and immunofixation electrophoresis (IFE) have been extensively validated for the routine use of identifying, characterising and quantifying monoclonal proteins. However, accurate quantitation of IgA monoclonal proteins can be difficult when they migrate in to the β fraction, due to co-migration with transferrin and complement components. The heavy/light chain (HLC) immunoassay is an additional tool for measuring intact immunoglobulin monoclonal proteins. Therefore, we aimed to examine the clinical utility of the HLC assay for the disease monitoring of IgG and IgA multiple myeloma (MM) patients. A total of 177 samples from 30 MM patients (21 IgG and 9 IgA) were analysed retrospectively with median number of six follow up samples per patient (range 3–13). Serum free light chains (sFLC) and HLC were quantified using Freelite and Hevylite immunoassays. Details of M-protein concentration, β-globulin levels, total immunoglobulin levels and disease treatment response were obtained from the laboratory and patient information system. Passing–Bablok regression analysis was performed to compare (i) M-protein quantification with involved HLC (iHLC) and (ii) total immunoglobulin with summated HLC pairs for each immunoglobulin type (e.g., IgGκ+IgGλ). For 127 IgG MM samples, IgG iHLC levels showed a good correlation with SPE quantification (iHLC y=0.96x+4.9; r=0.917) and summated HLC showed a good correlation with total IgG concentration (summated HLC y=0.94x+5.74; r=0.91). In total, 95/127 (75%) IgG MM follow-up samples had an abnormal HLC ratio and 122/127 (96%) had a positive SPE, probably due to the lower sensitivity of HLC assay in detecting clonality in patients with IgG MM. Consistent with this, one patient assigned a very good partial response by International Myeloma Working Group criteria would be assigned a complete response based on HLC measurements. For 50 IgA MM samples, 42/50 (84%) had an abnormal HLC ratio. Conversely, 50/50 (100%) of M-proteins showed β fraction migration and were difficult to accurately quantify by SPE. Therefore, M-protein concentration and iHLC did not correlate as well in IgA MM (y=1.9x–8.4; r=0.8) compared to IgG MM. However, there was good correlation between total IgA and summated IgA HLC (IgAκ+IgAλ y=1.35x–0.33; r=0.95). Of the 8/50 (16%) IgA samples with a normal HLC ratio, 6/8 (75%) were consistent with the disease status being in complete remission. Interestingly, in one IgA MM patient, SPE and IFE were negative, but the serum FLC ratio and involved FLC were highly abnormal, consistent with the presence of light chain escape. Our data suggest HLC measurements could add value to the current disease monitoring of MM patients. In IgG MM patients, the M-protein level correlated well with HLC values. The HLC assay complements the serum FLC assay and is especially useful for monitoring of IgA MM patients who display M-proteins migrating in the β region on SPE. © 2019 Royal College of Pathologists of Australasi
High performance graphene-like thinly layered graphite based visible light photodetector
No full textIn this work, the drop casting method is utilized to obtain a thin graphene-like graphite layer as a photodetection layer on a SiO2/Si substrate, and its performance is characterized to determine its potential use in commercial applications. The thin layer is formed by first synthesizing graphite soot from a butane flame before being turned into a liquid solution and drop-casted onto the substrate to form a thin graphene-like graphite film. Field emission scanning electron microscope and Raman vibrational mode analyses indicate that the fabricated graphene-like graphite layer has characteristics similar to the graphene. The graphene-like graphite photodetector demonstrates a narrow photoresponse from 530 to 680 nm, covering visible sources from green to red. The responsivity and external quantum efficiency of the device under the illumination of red laser 660 nm is found to be around 148 mA W−1 and 27.8% respectively and is faster than that reported for similar systems using graphene and reduced graphene oxide previously. A fast response time of 83.7 and 28 µs at a modulation frequency of 1.0 and 10000 Hz respectively from the graphene-like thinly layered graphite photodetector shows potential application for the development of low-cost carbon-based photodetectors in near future. © 2019, Springer Science+Business Media, LLC, part of Springer Nature
A Novel Supraretinacular Endoscopic Carpal Tunnel Release: Instrumentation and Technique (Cadaveric Study)
No full textPurpose: Endoscopic carpal tunnel release has been shown to be associated with a shorter return to work compared with open carpal tunnel release in the treatment of carpal tunnel syndrome. Unfortunately, it may be associated with a higher risk for median nerve injury when the carpal tunnel is used as a portal for instrumentation. The purpose of this study was to assess safety in using a newly designed retractor through a supraretinacular approach. Methods: We used 8 wrists (4 left and 4 right wrists) from 4 fresh-frozen cadavers for this study. Supraretinacular endoscopic carpal tunnel release using the supraretinacular retractor was performed by a single investigator, followed by exploration of the carpal tunnel and the structures surrounding it. Surgeries were performed using a new surgical instrument consisting of an arch-shaped blade and handle. It includes a retainer adapted to receive a 2.4- or 2.7-mm endoscope and to retain it at the apex of the arch, which can be moved in and out to visualize the entire transverse carpal ligament. The space below the blade is also used as a portal to insert scissors and instrumentation to cut the transverse carpal ligament. Results: All 8 carpal tunnels were completely released with no injury to the median nerve, superficial palmar arch, flexor tendon, or violation into Guyon canal. Mean distance of the flexor retinaculum division to the recurrent motor branch, palmar cutaneous branch, and superficial palmar arch was 6.87 ± 2.80, 7.13 ± 5.33, and 9.13 ± 4.42 mm, respectively. All specimens had an extraligamentous recurrent motor branch. Conclusions: The retractor and described technique were safe and effective in this cadaveric study. Further clinical trials are necessary before it can be adopted as a safe and reliable technique. Type of study/level of evidence: Therapeutic IV. © 2019 The Author
Comparing dental caries status using Modified International Caries Detection and Assessment System (ICDAS) and World Health Organization (WHO) indices among school children of Bhakkar, Pakistan
No full textObjective: To assess and compare the dental caries status among children using two methods. Methods: The cross-sectional study was conducted in October-November 2017 at five government and two private schools in Bhakkar, Punjab, Pakistan. It comprised children aged 11-12 years. World Health Organisation standards and the modified International Caries Detection and Assessment Systems methods were used were used to determine the dental caries status of each subject. Results of the two methods were compared at all cut- offs where appropriate, using SPSS 17. Results: Of the 183 subjects, 101(55.2%) were boys. Those aged 12 years were 112(61.2%) while 71(38.8%) were aged 11 years. There was no statistically significant difference in values of the Decayed Missing and Filled Surface/Decayed Missing and Filled Teeth index as well as the prevalence of dental caries between two methods (p>0.05 each). Intra-examiner reproducibility was higher with the World Health Organisation method compared to the other index used (p<0.05). Conclusion: Modified International Caries Detection and Assessment Systems method can be used in epidemiological surveys as it was found to provide results similar to the World Health Organisation criteria at cut-off point 2. © 2019 Journal of the Pakistan Medical Association. All rights reserved
A review on the advanced leachate treatment technologies and their performance comparison: an opportunity to keep the environment safe
No full textLandfill application is the most common approach for biowaste treatment via leachate treatment system. When municipal solid waste deposited in the landfills, microbial decomposition breaks down the wastes generating the end products, such as carbon dioxide, methane, volatile organic compounds, and liquid leachate. However, due to the landfill age, the fluctuation in the characteristics of landfill leachate is foreseen in the leachate treatment plant. The focuses of the researchers are keeping leachate from contaminating groundwater besides keeping potent methane emissions from reaching the atmosphere. To address the above issues, scientists are required to adopt green biological methods to keep the environment safe. This review focuses on the assorting of research papers on organic content and nitrogen removal from the leachate via recent effective biological technologies instead of conventional nitrification and denitrification process. The published researches on the characteristics of various Malaysian landfill sites were also discussed. The understanding of the mechanism behind the nitrification and denitrification process will help to select an optimized and effective biological treatment option in treating the leachate waste. Recently, widely studied technologies for the biological treatment process are aerobic methane oxidation coupled to denitrification (AME-D) and partial nitritation–anammox (PN/A) process, and both were discussed in this review article. This paper gives the idea of the modification of the conventional treatment technologies, such as combining the present processes to make the treatment process more effective. With the integration of biological process in the leachate treatment, the effluent discharge could be treated in shortcut and novel pathways, and it can lead to achieving “3Rs” of reduce, reuse, and recycle approach. © 2019, Springer Nature Switzerland AG