Characterization of defect induced multilayer graphene

A study of oxygen plasma on multilayer graphene is done with different flow rates. This is to allow a controlled amount of defect fabricated on the graphene. Results from the study showed that the intensity ratio of defect between D peak and G peak was strongly depended on the amount of oxygen flow rate thus affected the 2D band of the spectra. The inter-defect distance LD ≥ 15 nm of each sample indicated that low-defect density was fabricated. The surface roughness of the multilayer graphene also increased and reduced the conductivity of the multilayer graphene

From shear exfoliation of graphite in Coca-Cola® to few-layer graphene for smart ink

Liquid-phase exfoliation of few-layer graphene in Coca-Cola ® was performed by a kitchen blender for rapid preparation of strain/light/humidity sensitive ink. The advantages of Coca-Cola as an exfoliating medium have been identified from the low structural defect (ID/IG = 0.39) and, moderate carbon to oxygen ratio (C/O = 2.6) obtained by the resulting graphene. It is discovered that a deposition of graphene on photo paper allowed a facile fabrication of smart paper that is able to detect minor strain (0 – 2.0%) with GF of 18.7. Meanwhile, the multi-responsiveness of ink towards light/humidity had been validated from the 10 s response time after the exposure to stimulants with the maximum resulting curvature degree of 16° and 14° under light and humidity changes, respectively. Finally, it is shown that our actuator is able to vertically lift a load (545 mg) from its initial flat position upon irradiation of light (200 mW/cm2)

A dual-responsive humidity sensitive-based cellulose paper: A fabrication of smart strip from sustainable nanoclay and graphite-beeswax composite

A highly humidity-responsive paper can detect moisture or OH-attached molecules at the sub-micron or nano level range. Applying hydrophilic nanoclay as an active material for water sensing would reduce the fabrication cost while remaining environmentally friendly. In this communication, we report the preparation of a nanoclay-inspired dual-responsive smart film that can signal humidity levels from mechanical and electrical responses. The paper will bend as the nanoclay layer swells whereas the resulting bending strain will trigger the electrical resistance changes in the hydrophobic electrically conductive graphite-beeswax layer

A Novel Hybrid Full Adder using 13 Transistors

Full adder is a basic and vital building block for various arithmetic circuits such as multipliers. In this paper, a hybrid 1-bit full adder using complementary metal-oxide semiconductor (CMOS) logic style had been designed. This hybrid adder divided into three modules. Module I is a three transistors XOR gate. Module II is a novel sum circuit which successfully modified with the usage of lesser number of transistors used. Module III is a carry circuit which uses the carry output of module I and several other input to generate carry output. Performance parameters such as power and delay were compared to some of the existing designs. With a 1.8V voltage supply, the average power consumption of proposed hybrid adder was found extremely low which is 2.09 μW and a very low delay of 350 ps. Design in both speed and energy consumption becomes even more significant as the wordlength of the adder increases. The full adder design is simulated using Tanner EDA version 16 using General Process Design Kit (GPDK) 250nm technology CMOS processes

Combination of cellulose tissue paper and bleach-treated graphene in stiffness reinforcement of polyvinyl alcohol film

A pre-treatment of graphene with bleach is considered one of the possible purification methods after liquid-phase exfoliation. However, the effect of this treatment on the mechanical reinforcement strategy for polymer film is yet to be investigated to date. In this full work, the influence of the C/O ratio, ID/IG, and volume of graphene after combination with cellulose tissue on the resulting stiffness of polyvinyl alcohol (PVA) composite film has been extensively studied. It is noticed that the incorporation of 30 ml graphene that had been pre-treated for 3 h into PVA had produced the best increment in elastic modulus (1.6 GPa against 0.4 GPa) while a shorter pre-treatment duration of graphene (1 h) would require more graphene volume (40 ml) to match the previous stiffness improvement level. By using the collected experimental data (90 samples), we further modeled the effect of tissue and PVA mass, C/O ratio, ID/IG, and graphene volume on modulus using machine learning (ML) algorithms

Combination of cellulose tissue paper and bleach-treated graphene in stiffness reinforcement of polyvinyl alcohol film

A pre-treatment of graphene with bleach is considered one of the possible purification methods after liquid-phase exfoliation. However, the effect of this treatment on the mechanical reinforcement strategy for polymer film is yet to be investigated to date. In this full work, the influence of the C/O ratio, ID/IG, and volume of graphene after combination with cellulose tissue on the resulting stiffness of polyvinyl alcohol (PVA) composite film has been extensively studied. It is noticed that the incorporation of 30 ml graphene that had been pre-treated for 3 h into PVA had produced the best increment in elastic modulus (1.6 GPa against 0.4 GPa) while a shorter pre-treatment duration of graphene (1 h) would require more graphene volume (40 ml) to match the previous stiffness improvement level. By using the collected experimental data (90 samples), we further modeled the effect of tissue and PVA mass, C/O ratio, ID/IG, and graphene volume on modulus using machine learning (ML) algorithms

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

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

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

Smart “Sticky Note” for strain and temperature sensing using few-layer graphene from exfoliation in red spinach solution

The synthesis of few-layer graphene from graphite typically uses N, N methyl pyrrolidone (NMP) or dimethylformamide (DMF) due to the strong affinity of both solvents for graphite. However, NMP and DMF are known as carcinogens and a long-time exposure to these substances may subject users to potential risk of major health issue later. Therefore, a replacement with dispersing solvent that is not only harmless but also able to exfoliate graphite at an excellent concentration yield must be outlined for a sustainable mass-production of graphene. In this work, we have successfully exfoliated graphite to few-layer graphene with a recorded yield concentration of up to 0.75 mg/ml (2.5 h) just by using extracted red spinach/water mixture as an exfoliating medium. The prepared graphene was found to possess less structural defect (ID/IG: 0.5) and high C/O ratio (6.8) and can be used further as an electrical conductive ink for smart “Sticky Note” sensor. The fabricated device was able to detect strain and temperature with gauge factor and temperature coefficient resistance of 23.5 and -32.14 × 10-4 Ω/ºC, respectively. We believe that this study would be useful for the preparation of environmental-friendly graphene that is not only strain and thermally sensitive but also producible at low -cost

Combination of cellulose tissue paper and bleach-treated graphene in stiffness reinforcement of polyvinyl alcohol film

A pre-treatment of graphene with bleach is considered one of the possible purification methods after liquid-phase exfoliation. However, the effect of this treatment on the mechanical reinforcement strategy for polymer film is yet to be investigated to date. In this full work, the influence of the C/O ratio, ID/IG, and volume of graphene after combination with cellulose tissue on the resulting stiffness of polyvinyl alcohol (PVA) composite film has been extensively studied. It is noticed that the incorporation of 30 ml graphene that had been pre-treated for 3 h into PVA had produced the best increment in elastic modulus (1.6 GPa against 0.4 GPa) while a shorter pre-treatment duration of graphene (1 h) would require more graphene volume (40 ml) to match the previous stiffness improvement level. By using the collected experimental data (90 samples), we further modeled the effect of tissue and PVA mass, C/O ratio, ID/IG, and graphene volume on modulus using machine learning (ML) algorithms