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The overuse and reliance on pesticides has caused insects to develop resistance with global concerns. To address this problem extensive research is directed to find new and sustainable alternatives using chemical-free and resistance-free solutions for pest control. This paper presents a comprehensive investigation of the insecticidal properties of several types of industrially produced graphene powder materials such as graphene and graphene oxide (GO) with micro- and nano size and different structural and chemical properties as new contact nanopesticides against three major stored grain insects: the rice weevil Sitophilus oryzae (L.)˙, the lesser grain borer, Rhyzopertha dominica (F.)˙ and the larger grain borer, Prostephanus truncatus Horn. Bioassays were performed using different concentrations, i.e., 0, 100, 500 and 1000 ppm of graphene powders on the mortality of selected adult insects recorded after 3, 7, 14, and 21 days of exposure and progeny production after 65 days. Results showed that graphene oxide (GO) has no insecticidal efficacy while graphene powders with nano-size particles showed significantly enhanced insecticidal performance compared to micron-size graphene powders. The observed insecticidal effects are explained by the higher probability that nano-sized graphene particles adhere on the insect body compared to large particles. The mortality is proposed as the result of physical mode of action of attached graphene nanoparticles causing stronger interruption of the protective cuticle layer, gas respiratory functions and faster mortality. The findings of this study revealed that it is important to select graphene materials with optimal structural and interfacial properties to achieve the highest insecticidal performance in potential development of a new generation of sustainable insecticides., Competing Interests: Declaration of Competing Interest ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. ☐The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Graphene powders as new contact nanopesticides: revealing key parameters on their insecticidal activity for stored product insects., (Copyright © 2024. Published by Elsevier Ltd.)

Global population ageing underscores the imperative of ageism and dementia-ism in the heath care setting as there is both anecdotal and published evidence that older persons are liable to receive less than optimum evidence-based treatments on account of their age and apparent frailty. This article explores the reasons for this phenomenon and limitations of current approaches of clinical decision making. We propose a framework to guide decision making to optimize care, with a paradigm shift in redefining a default toward clinical practice guideline-recommended treatments, guided by evidence-based medicine within an ethical means-end proportionality framework, and regularly reviewed advance care plans and goals of care conversations to secure the best interests of older persons., Competing Interests: Disclosure The authors declare no conflict of interest., (Copyright © 2024 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

Curcumin (Cur) is an acidic polyphenol with some effects on α-glucosidase (α-Glu), but Cur has disadvantages such as being a weak target, lacking passing the blood-brain barrier and having low bioavailability. To enhance the curative effect of Cur, the hybrid composed of ZnO nanoparticles decorated on rGO was used to load Cur (ZnO@rGO-Cur). The use of the multispectral method and enzyme inhibition kinetics analysis certify the inhibitory effect and interaction mechanism of ZnO@rGO-Cur with α-Glu. The static quenching of α-Glu with both Cur and ZnO@rGO-Cur is primarily driven by hydrogen bond and van der Waals interactions. The conformation-changing ability by binding to the neighbouring phenolic hydroxyl group of Cur increased their ability to alter the secondary structure of α-Glu, resulting in the inhibition of enzyme activity. The inhibition constant (K i, Cur  > K is,ZnO@rGO-Cur ) showed that the inhibition effect of ZnO@rGO-Cur on α-Glu was larger than that of Cur. The CCK-8 experiments proved that ZnO@rGO nanocomposites have good biocompatibility. These results suggest that the therapeutic potential of ZnO@rGO-Cur composite is an emerging nanocarrier platform for drug delivery systems for the potential treatment of diabetes mellitus., (© 2024 John Wiley & Sons Ltd.)

Research on graphene-related two-dimensional (2D) materials (GR2Ms) in recent years is strongly moving from academia to industrial sectors with many new developed products and devices on the market. Characterization and quality control of the GR2Ms and their properties are critical for growing industrial translation, which requires the development of appropriate and reliable analytical methods. These challenges are recognized by International Organization for Standardization (ISO 229) and International Electrotechnical Commission (IEC 113) committees to facilitate the development of these methods and standards which are currently in progress. Toward these efforts, the aim of this study was to perform an international interlaboratory comparison (ILC), conducted under Versailles Project on Advanced Materials and Standards (VAMAS) Technical Working Area (TWA) 41 "Graphene and Related 2D Materials" to evaluate the performance (reproducibility and confidence) of the thermogravimetric analysis (TGA) method as a potential new method for chemical characterization of GR2Ms. Three different types of representative and industrially manufactured GR2Ms samples, namely, pristine few-layer graphene (FLG), graphene oxide (GO), and reduced graphene oxide (rGO), were used and supplied to ILC participants to complete the study. The TGA method performance was evaluated by a series of measurements of selected parameters of the chemical and physical properties of these GR2Ms including the number of mass loss steps, thermal stability, temperature of maximum mass change rate ( T p ) for each decomposition step, and the mass contents (%) of moisture, oxygen groups, carbon, and impurities (organic and non-combustible residue). TGA measurements determining these parameters were performed using the provided optimized TGA protocol on the same GR2Ms by 12 participants across academia, industry stakeholders, and national metrology institutes. This paper presents these results with corresponding statistical analysis showing low standard deviation and statistical conformity across all participants that confirm that the TGA method can be satisfactorily used for characterization of these parameters and the chemical characterization and quality control of GR2Ms. The common measurement uncertainty for each parameter, key contribution factors were identified with explanations and recommendations for their elimination and improvements toward their implementation for the development of the ISO/IEC standard for chemical characterization of GR2Ms.

Graphene oxide (GO) has been recognized as a thermally unstable and energetic material, but surprisingly its environmental and safety risks were not fully explored, defined, and regulated. In this study, systematic explosivity and flammability characterizations of commercial GO materials were conducted to evaluate the influence of key parameters such as physical forms (paste, powders, films, and aerogels), temperature, heating rate, mass, and heating environment, as well as their potential safety and environmental impacts. Results based on thermogravimetric analysis (TGA) showed that GO in paste and powder forms have lower temperature thresholds (>180-192 °C) to initiate micro-explosions compared to GO film and aerogels (> 205 °C and 213 °C) regardless of the environment (inert, air, or oxygen). The observed explosive behavior can be explained by thermal runaway reactions as a result of thermal deoxygenation and decomposition of oxygen functional groups. Flammability rating and limiting oxygen index (LOI) results confirmed that GO films are flammable materials that can spontaneously propagate flame in a low oxygen environment (~11 %). These results provided new insights about potential safety and environmental risks of GO materials, which somehow were not considered, suggesting urgent actions to improve current safety protocols for labeling, handling, transporting, and storage practices from manufacturers to the end-users., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The development of next-generation of bioinks aims to fabricate anatomical size 3D scaffold with high printability and biocompatibility. Along with the progress in 3D bioprinting, 2D nanomaterials (2D NMs) prove to be emerging frontiers in the development of advanced materials owing to their extraordinary properties. Harnessing the properties of 2D NMs in 3D bioprinting technologies can revolutionize the development of bioinks by endowing new functionalities to the current bioinks. First the main contributions of 2D NMS in 3D bioprinting technologies are categorized here into six main classes: 1) reinforcement effect, 2) delivery of bioactive molecules, 3) improved electrical conductivity, 4) enhanced tissue formation, 5) photothermal effect, 6) and stronger antibacterial properties. Next, the recent advances in the use of each certain 2D NMs (1) graphene, 2) nanosilicate, 3) black phosphorus, 4) MXene, 5) transition metal dichalcogenides, 6) hexagonal boron nitride, and 7) metal-organic frameworks) in 3D bioprinting technology are critically summarized and evaluated thoroughly. Third, the role of physicochemical properties of 2D NMSs on their cytotoxicity is uncovered, with several representative examples of each studied 2D NMs. Finally, current challenges, opportunities, and outlook for the development of nanocomposite bioinks are discussed thoroughly., (© 2021 Wiley-VCH GmbH.)

The rapid advancement of internet of things (IoT)-enabled applications along with connected automation in sensing technologies is the heart of future intelligent systems. The probable applications have significant implications, from chemical process monitoring to agriculture, mining, space, wearable electronics, industrial manufacturing, smart cities, and point-of-care (PoC) diagnostics. Advancing sensor performance such as sensitivity to detect trace amounts (ppb-ppm) of analytes (gas/VOCs), selectivity, portability, and low cost is critical for many of these applications. These advancements are mainly achieved by selecting and optimizing sensing materials by their surface functionalization and/or structural optimization to achieve favorable transport characteristics or chemical binding/reaction sites. Surprisingly, the sensor geometry, shapes, and patterns were not considered as critical parameters, and most of these sensors were designed by following simple planar and interdigitated electrode geometry. In this study, we introduce a new bioinspired fractal approach to design chemoresistive sensors with fractal geometry, which grasp the architecture of fern leaves represented by the geometric group of space-filling curves of fractal patterns. These fractal sensors were printed by an extrusion process on a flexible substrate (PET) using specially formulated graphene ink as a sensing material, which provided significant enhancement of the active surface area to volume ratio and allowed high-resolution fractal patterning along with a reduced current transportation path. To demonstrate the advantages and influence of fractal geometry on sensor performance, here, three different kinds of sensors were fabricated based on different fractal geometrics (Sierpinski, Peano, and Hilbert), and the sensing performance was explored toward different VOC analytes (e.g., ethanol, methanol, and acetone). Among all these fractal-designed sensors including interdigitate sensors, the Hilbert-designed printed sensor shows enhanced sensing properties in terms of fast response time (6 s for 30 ppm), response value (14%), enhanced detection range (5-100 ppm), high selectivity, and low interference to humidity (up to RH 80%) for ethanol at room temperature (20 °C). Moreover, a significant improvement of this sensor performance was observed by applying the mechanical deformation (positive bending) technique. The practical application of this sensor was successfully demonstrated by monitoring food spoilage using a commercial box of strawberries as a model. Based on these presented results, this biofractal biomimetic VOC sensor is demonstrated for a prospective application in food monitoring.

Counterfeits in the supply chain of high-value advanced materials such as graphene and their derivatives have become a concerning problem with a potential negative impact on this growing and emerging industry. Recent studies have revealed alarming facts that a large percentage of manufactured graphene materials on market are not graphene, raising considerable concerns for the end users. The common and recommended methods for the characterization of graphene materials, such as transmission electron microscopy (TEM), atomic force microscopy (AFM), and Raman spectroscopy based on spot analysis and probing properties of individual graphene particles, are limited to provide the determination of the properties of "bulk" graphene powders at a large scale and the identification of non-graphene components or purposely included additives. These limitations are creating counterfeit opportunities by adding low-cost black carbonaceous materials into manufactured graphene powders. To address this problem, it is critical to have reliable characterization methods, which can probe the specific properties of graphene powders at bulk scale, confirm their typical graphene signature, and detect the presence of unwanted additional compounds, where the thermogravimetric analysis (TGA) method is one of the most promising methods to perform this challenging task. This paper presents the evaluation of the TGA method and its ability to detect low-cost carbon additives such as graphite, carbon black, biochar, and activated carbon as potential counterfeiting materials to graphene materials and their derivatives such as graphene oxide (GO) and reduced GO. The superior performance of the TGA method is demonstrated here, showing its excellent capability to successfully detect these additives when mixed with graphene materials, which is not possible by two other comparative methods (Raman spectroscopy and powder X-ray diffraction (XRD)), which are used as the common characterization methods for graphene materials.

Owing to many fascinating properties including high thermal and chemical stability, excellent electrical insulation, fire-retardant and antibacterial properties, hexagonal boron nitride (hBN) has emerged as a prominent 2D material for broad applications. However, the production of high quality of hBN by chemical exfoliation from its precursor is still challenging. This paper presents a high-yield (+83%), low-cost and energy-efficient wet chemical exfoliation strategy, which produces few-layers (FL, 3-6 layers) of edge-functionalized (OH) hBN nanosheets with uniform size (486 ± 51 nm). This optimized preparation is established based on a comprehensive investigation on the key exfoliation parameters such as exfoliation temperature, time and amount of the oxidant (potassium permanganate). High quality of FL-hBN was confirmed by various characterization techniques including scanning electron microscopy coupled with energy dispersive X-ray, transmission electron microscopy, Raman, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy analyses. The outcome of this study paves a promising pathway to effectively produce hBN through a cost-efficient exfoliation approach, which has a significant impact on industrial applications., (© 2021 IOP Publishing Ltd.)

Printed electronic sensors offer a breakthrough in the availability of low-cost sensor devices for improving the quality of human life. Conductive ink is the core of printing technology and also one of the fastest growing sector among all ink industries. Among many developed conductive inks, graphene-based inks are especially recognized as very promising for future fabrication of devices due to their low cost, unique properties, and compatibility with various platforms such as plastics, textiles, and paper. The development of graphene ink formulations for achieving high conductivity and high resolution printing is highly realized in 2D inkjet printing. Unfortunately, the ongoing development of graphene inks is possibly hampered by the non-uniform particle size and structures (e.g., different shapes and number of layers), which adversely affect printing resolution, conductivity, adhesion, and structural integrity. This study presents an environmentally sustainable route to produce graphene inks specifically designed for 3D extrusion-printing. The application of the prepared ink is demonstrated by mask-free automatic patterning of sensing devices for the detection of volatile organic compounds (VOCs). The sensing devices fabricated with this new ink display high-resolution patterning (average height/thickness of ∼12 μm) and a 10-fold improvement in the surface area/volume (SA/V) ratio compared to a conventional drop casting method. The extrusion printed sensors show enhanced sensing characteristics in terms of sensitivity and selectivity towards trace amount of VOC (e.g. 5 ppm ethanol) at room temperature (20 °C), which highlights that our method has highly promising potential in graphene printing technology for sensing applications.

The development of low-cost and high performing hydrogen gas sensors is important across many sectors, including mining, energy and defense using hydrogen (H 2 ) gas. Herein, we demonstrate a new concept of H 2 sensors based on Pd/Cr nanogaps created by using a simple mechanical bending deformation technique. These nanogap sensors can selectively detect the H 2 gas based on transduction of the volume expansion after H 2 uptake into an electrical signal by palladium-based metal-hydrides that allows closure of nanogaps for electrons flowing or tunneling. While this break-junction architecture, according to literature, can provide several advantages with research gaps in terms of fabricating nanogap sensors with ultra-fast response (≤4 s), the size of nanogap (≤20 nm) and their relationship with time response and recovery as addressed in this paper. Based on the computational modelling outcome, the size of the nanogaps can be investigated in order to optimize the fabrication conditions. Indeed, a single nanogap with optimum width (15 nm) acts as an on-off switch for best performing hydrogen detection. Moreover, with the unique design of Pd/Cr nanogap, the developed sensing device meets major requirement of advanced H 2 gas sensor including room temperature (25 °C) operation, detection of trace amounts (10-40,000 ppm), good linearity, ultra-fast response-recovery time (3/4.5 s) and high selectivity. The presented economical lithography-free fabrication method has simple circuitry, low power consumption, recyclability, and favorable aging properties that promises great potential to be used for many practical applications of H 2 detection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Graphene and related 2D materials offer an ideal platform for next generation disruptive technologies and in particular the potential to produce printed electronic devices with low cost and high throughput. Interest in the use of 2D materials to create functional inks has exponentially increased in recent years with the development of new ink formulations linked with effective printing techniques, including screen, gravure, inkjet and extrusion-based printing towards low-cost device manufacturing. Exfoliated, solution-processed 2D materials formulated into inks permits additive patterning onto both rigid and conformable substrates for printed device design with high-speed, large-scale and cost-effective manufacturing. Each printing technique has some sort of clear advantages over others that requires characteristic ink formulations according to their individual operational principles. Among them, the extrusion-based 3D printing technique has attracted heightened interest due to its ability to create three-dimensional (3D) architectures with increased surface area facilitating the design of a new generation of 3D devices suitable for a wide variety of applications. There still remain several challenges in the development of 2D material ink technologies for extrusion printing which must be resolved prior to their translation into large-scale device production. This comprehensive review presents the current progress on ink formulations with 2D materials and their broad practical applications for printed energy storage devices and sensors. Finally, an outline of the challenges and outlook for extrusion-based 3D printing inks and their place in the future printed devices ecosystem is presented.

The synthesis of graphene materials with multiple surface chemistries and functionalities is critical for further improving their properties and broadening their emerging applications. We present a simple chemical approach to obtain bulk quantities of multifunctionalized reduced graphene oxide (rGO) that combines chemical doping and functionalization using the thiol-ene click reaction. Controllable modulation of chemical multifunctionality was achieved by simultaneous nitrogen doping and gradual chemical reduction of graphene oxide (GO) using ammonia and hydrazine, followed by covalent attachment of amino-terminated thiol molecules using the thiol-ene click reaction. A series of N-doped rGO (N-rGO) precursors with different levels of oxygen groups were synthesized by adjusting the amount of reducing agent (hydrazine), followed by subsequent covalent attachment of cysteamine via the thermal thiol-ene click reaction to yield different ratios of mixed functional groups including N (pyrrolic N, graphitic N, and aminic N), S (thioether S, thiophene S, and S oxides), and O (hydroxyl O, carbonyl O, and carboxyl O) on the reduced GO surface. Detailed XPS analysis confirmed the disappearance of unstable pyridinic N in cys-N-rGO and the reduction degree threshold of N-rGO for effective cysteamine modification to take place. Our study establishes a strong correlation between different reduction degrees of N-rGO with several existing oxygen functional groups and addition of new tunable functionalities including covalently attached nitrogen (amino) and sulfur (C-S-C, C=S, and S-O). This simple and versatile approach provides a valuable contribution for practical designing and synthesis of a broad range of functionalized graphene materials with tailorable functionalities, doping levels, and interfacial properties for potential applications such as polymer composites, supercapacitors, electrocatalysis, adsorption, and sensors., Competing Interests: The authors declare no competing financial interest., (Copyright © 2019 American Chemical Society.)

Engineering of multifunctional binding chemistry on graphene composites using thiol-ene click reaction for selective and highly efficient adsorption of mercury(II) is demonstrated. Graphene oxide (GO) is used as an initial material for covalent attachment of cysteamine molecules by thiol-ene click reaction on C═C groups to achieve a partially reduced graphene surface with multiple binding chemistry such as O, S, and N. Batch adsorption studies showed remarkable adsorption rate with only 1 mg L -1 dosage of adsorbent used to remove 95% Hg (II) (∼1.5 mg L -1 ) within 90 min. The high adsorption capacity of 169 ± 19 mg g -1 , high selectivity toward Hg in the presence of 30 times higher concentration of competing ions (Cd, Cu, Pb) and high regeneration ability (>97%) for five consecutive adsorption-desorption cycles were achieved. Comparative study with commercial activated carbon using spiked Hg (II) river water confirmed the high performance and potential of this adsorbent for real mercury remediation of environmental and drinking waters.

Aims: Older adults who live alone are vulnerable physically, emotionally and socially. However, there is a trend towards children not living with their parents. We studied the willingness of teenagers today to live with and care for their aged parents tomorrow, and the reasons for their decision., Methods: A convenient sample of 1405 teenage students (M age  = 14.9 ± 1.30) in the north region of Singapore completed a purpose-designed questionnaire. Structural equation modeling was used to explore the relationships between teenagers' closeness to grandparents, challenges faced living with grandparents, positive and negative perceptions towards aging, and willingness to stay with aged parents in the future, stratified by sex. Thematic analysis was used to understand the reasons for their choice., Results: The majority (85.6%) chose to live with their parents, and the significant predictors were "closeness to grandparents" (P = 0.034) and "positive perceptions towards aging" (P < 0.01), but not "challenges in living with grandparents" (P = 0.391) or "negative perceptions" (P = 0.302). Among teenagers with positive perceptions, boys were more likely to live with their parents (P < 0.01). Conversely, among teenagers with negative perceptions, girls were more likely to do so (P = 0.026). Primary reasons for willingness included: "desire to care," "expression of love," "sense of responsibility" and "prompted by moral values.", Conclusions: Efforts should be undertaken to strengthen teenagers' relationships with grandparents, and promote positive perceptions towards aging to better sustain the family as a social safety net for aging and frail older adults. Geriatr Gerontol Int 2018; 18: 957-964., (© 2018 Japan Geriatrics Society.)

Background: Patients with early cognitive impairment (ECI) face the prospect of progressive cognitive decline that impairs their ability to make decisions on financial and personal matters. Advance care planning (ACP) is a process that facilitates decision making on future care and often includes identifying a proxy decision maker. This prospective study explores factors related to completion or non-completion of ACP in patients with ECI., Methods: Patients with ECI (n = 158, M age = 76.2 ± 7.25 years) at a memory clinic received psycho-education and counseling on the importance of ACP and followed-up longitudinally for up to 12 months to ascertain if ACP had been completed. Univariate and logistic regression were used to analyze factors related to completion and non-completion of ACP., Results: Seventy-seven patients (48.7%) were initially willing to consider ACP after the counseling and psycho-educational session but only 17 (11.0%) eventually completed ACP. On logistic regression, patients who were single were 8.9 times more likely to complete ACP than those who were married (p = 0.007). Among those initially willing to consider ACP, factors impeding completion of ACP included patient (48.0%), process (31.0%), and family factors (21.0%)., Conclusions: As unmarried patients may not have immediate family members to depend on to make decisions, they may perceive ACP to be more important and relevant. Understanding the barriers to ACP completion can facilitate targeted interventions to improve the uptake of ACP.

Background: Advance care planning (ACP) is an important component to holistic care for people with early cognitive impairment (ECI) who are generally still mentally capable of making rational decisions. This study explores the willingness of people with ECI to engage in ACP and how clinical and behavioral variables shape their decisions., Methods: Ninety-eight persons with ECI (mild cognitive impairment or early dementia, Clinical Dementia Rating = 0.5/1.0) and assessed to have adequate insight (Clinical Insight Rating Scale) underwent an ACP information session. They were assessed on their knowledge of dementia (Knowledge of Alzheimer Disease) and willingness to engage in ACP, and were interviewed on their beliefs and attitudes toward ACP (Perceived Barriers and Benefits Scale to ACP). Univariate analysis and logistic regression identified factors that predicted persons willing or unwilling to engage in ACP based on their responses to the perceived barriers and benefits of ACP as well as sociodemographic and clinical variables., Results: Fifty-two persons (54%) were keen on ACP. On univariate analysis, persons with better executive function [Frontal Assessment Battery (FAB)] (t = -3.63, P < .0001), were more educated (t = -2.11, P = .038) and had lower barriers to ACP (t = 2.47, P = .015), particularly less "passive coping" (t = 2.83, P = .006), were more keen on ACP. Logistic regression revealed that the combined predictive model comprising FAB, education, and passive coping as a whole reliably differentiated those unwilling to engage in ACP from those who were willing (χ(2) = 18.995, P = .001 with df = 4). Wald criterion showed that FAB (P = .016) and passive coping (P = .023) contributed most to prediction., Conclusions: Better education and executive function predict willingness to engage in ACP, and these factors are instrumental in a person's ability to acquire knowledge and process information. Initiating ACP discussions early, increasing efforts at education, and providing tailored information are important interventions that facilitate completion of ACP., (Copyright © 2015 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

We present a solution for detecting dementia-related travel patterns using only inertial sensors. The results and lessons learnt from the experiments on dementia and non-dementia subjects are reported.

The ageing population is posing new challenges to Singapore's healthcare system. The rise of dual income and the decline of extended families, as well as an increase in age-related degenerative disorders due to increased longevity render it difficult for the family to remain the primary social safety net to care for our elderly in their own homes. Consequently, nursing homes may become increasingly relevant for resource and expertise-challenged families to cope with the burden of caring for a frail and dependent elderly. However, as the recent Nightingale Nursing Home elderly mistreatment incident attests, the standards of some have been found wanting. This paper will trace the history of nursing homes in Singapore and the evolution of government policies towards them, discuss the challenges and trade-offs of nursing home regulation, and provide suggestions for better care and governance.

Background: For decades, copper sulphide has been renowned as the superior optical and semiconductor materials. Its potential applications can be ranged from solar cells, lithium-ion batteries, sensors, and catalyst systems. The synthesis methodologies of copper sulphide with different controlled morphology have been widely explored in the literature. Nevertheless, the understanding on the formation chemistry of CuS is still limited. The ultimate approach undertaking in this article is to investigate the formation of CuS hexagonal plates via the optimization of reaction parameters in hydrothermal reaction between copper (II) nitrate and sodium thiosulphate without appending any assistant agent., Results: COVELLITE (CUS) HEXAGONAL PLATES WERE FORMED AT COPPER ION: thiosulphate ion ([Formula: see text]) mole ratio of 1:2 under hydrothermal treatment of 155°C for 12 hours. For synthesis conducted at reaction temperature lower than 155°C, copper sulphate (CuSO4), krohnite (NaCu2(SO4)(H2O)2] and cyclooctasulphur (S8) were present as main impurities with covellite (CuS). When [Formula: see text] mole ratio was varied to 1: 1 and 1: 1.5, phase pure plate-like natrochalcite [NaCu2(SO4)(H2O)] and digenite (Cu9S5) were produced respectively. Meanwhile, mixed phases of covellite (CuS) and cyclooctasulphur (S8) were both identified when [Formula: see text] mole ratio was varied to 1: 2.5, 1: 3 and 1: 5 as well as when reaction time was shortened to 1 hour., Conclusions: CuS hexagonal plates with a mean edge length of 1 μm, thickness of 100 nm and average crystallite size of approximately (45 ± 2) nm (Scherrer estimation) were successfully synthesized via assisting agent- free hydrothermal method. Under a suitable [Formula: see text] mole ratio, we evidenced that the formation of covellite (CuS) is feasible regardless of the reaction temperature applied. However, a series of impurities were attested with CuS if reaction temperature was not elevated high enough for the additional crystallite phase decomposition. It was also identified that [Formula: see text] mole ratio plays a vital role in controlling the amount of cyclooctasulphur (S8) in the final powder obtained. Finally, reaction time was recognized as an important parameter in impurity decomposition as well as increasing the crystallite size and crystallinity of the CuS hexagonal plates formed.

A diversity of strategies is evolved by RNA viruses to manipulate the host translation machinery in order to create an optimal environment for viral replication and progeny production. One of the common viral targets is the alpha subunit of eukaryotic initiation factor 2 (eIF-2alpha). In this report, we show that phosphorylation of eIF-2alpha was severely suppressed in human and animal cells infected with the coronavirus infectious bronchitis virus (IBV). To understand whether this suppression is through inhibition of protein kinase R (PKR), the double-stranded-RNA-dependent kinase that is one of the main kinases responsible for phosphorylation of eIF-2alpha, cells infected with IBV were analyzed by Western blotting. The results showed that the level of phosphorylated PKR was greatly reduced in IBV-infected cells. Overexpression of IBV structural and nonstructural proteins (nsp) demonstrated that nsp2 is a weak PKR antagonist. Furthermore, GADD34, a component of the protein phosphatase 1 (PP1) complex, which dephosphorylates eIF-2alpha, was significantly induced in IBV-infected cells. Inhibition of the PP1 activity by okadaic acid and overexpression of GADD34, eIF-2alpha, and PKR, as well as their mutant constructs in virus-infected cells, showed that these viral regulatory strategies played a synergistic role in facilitating coronavirus replication. Taken together, these results confirm that IBV has developed a combination of two mechanisms, i.e., blocking PKR activation and inducing GADD34 expression, to maintain de novo protein synthesis in IBV-infected cells and, meanwhile, to enhance viral replication.

Objective: Few studies have explored the relationship between orthostatic hypotension (OH) and cognition. The aim of this study was to examine the association of OH with cognitive impairment and decline in a cohort of Chinese elderly, and its effect modification by blood pressure (BP) status at baseline., Method: Among 2,321 community-living older adults, free of cardiovascular disease and stroke, baseline BP measurements were used to determine the presence of OH and categorize participants as hypotensives, normotensives or hypertensives. The Mini-Mental State Examination (MMSE) was used to assess cognitive impairment (MMSE score <24). Cognitive decline (decrease in MMSE score by > or =1) was assessed from 1 to 2 years of follow-up for 1,347 participants without baseline cognitive impairment., Results: Mean age of the subjects was 65.5 years and 381 (16.6%) showed OH. OH was not associated with cognitive impairment overall. However, among hypotensives, OH increased the odds of cognitive impairment (OR = 4.1, 95% CI = 1.11-15.1), while hypertensives with OH showed reduced odds of cognitive impairment (OR = 0.48, 95% CI = 0.26-0.90). Among cognitively intact participants, OH was not associated with cognitive decline overall or in BP subgroups., Conclusion: The increased risk of cognitive impairment in hypotensives with OH suggests that hypotension with OH may be an early comorbid marker of a primary incipient dementia., (Copyright 2008 S. Karger AG, Basel.)

Background/aims: Clock Drawing Tests are commonly used for cognitive screening, but their clinical utility has not yet been studied in Chinese Singaporeans. We examined the usefulness of a Clock Drawing Test, CLOX, in detecting dementia in our population and explored its performance in the dementia subtypes, Alzheimer's disease (AD), and the vascular composite group (VCG) of AD with cerebrovascular disease and vascular dementia., Method: CLOX was administered to 73 subjects (49.3%) with dementia and 75 healthy controls (50.7%). Receiver operating characteristic analysis determined the diagnostic accuracy and optimal cut-off scores, stratified by education. Analysis of Variance was used to compare CLOX scores between AD and VCG., Results: The diagnostic accuracy (area under the curve) was 84 and 85% for CLOX1 and CLOX2, respectively. Cut-offs at 10 for CLOX1 and 12 for CLOX2 yielded sensitivities of 75.3 and 75%, and specificities of 76 and 80%, respectively. The mean CLOX1 but not CLOX2 scores for AD (8.1) and VCG (5.5) remained significantly different (p = 0.002) after adjustment for the covariates age, gender, education, MMSE and dementia stage., Conclusion: Our results support CLOX as a valid cognitive screen in Singaporean Chinese with adequate psychometric properties. In addition, CLOX may aid as an adjunct in differentiating AD from dementia with a vascular element, e.g. AD with cerebrovascular disease and vascular dementia., (2007 S. Karger AG, Basel)

Objectives: Major thoracic surgery is associated with trauma-related immunological changes. These may impair anti-tumour immunity. We hypothesize that the reduced operative trauma associated with a video-assisted thoracic surgery (VATS) approach may decrease acute phase responses and, consequently, lead to better preservation of immune function. This prospective randomized study compared the effects of conventional open thoracic surgery and VATS on acute phase responses in patients undergoing pulmonary lobectomy., Methods: Acute phase indicators were analyzed in patients undergoing lobectomy for suspected bronchogenic carcinoma. Surgery was prospectively randomized to pulmonary lobectomy by VATS or limited postero-lateral thoracotomy. Blood was taken pre-operatively and at 4, 24, 48, 72, 120 and 168 h post-operatively for analysis of C-reactive protein (CRP; 41 patients: open, n=22; VATS, n=19) interleukin (IL)-6, tumour necrosis factor (TNF) receptors (TNF-sR55, TNF-sR75) and P-selectin (24 patients: open, n=12; VATS, n=12). Samples taken at 48 and 168 h were also analyzed for phagocyte reactive oxygen species (ROS) production (25 patients: open, n=16; VATS, n=19)., Results: Surgery increased acute phase responses. VATS was associated with lower CRP and IL-6 levels. In the open surgery group, significant increases in ROS in neutrophils (up to 36% greater than before surgery, n=12, P<0.02-0.05) were detected at 2 days after surgery, but in the VATS group, the increase after surgery (of up to 17%, n=18) did not reach significance. Similarly, monocyte ROS increases of up to 25% in the mean ROS in the open surgery group and of up to 17% in the VATS group were detected on days 2 and 7 after surgery., Conclusions: VATS pulmonary lobectomy is associated with reduced peri-operative changes in acute phase responses. This finding may have implications for peri-operative tumour immuno-surveillance in lung cancer patients.

Genetic variation at the human leukocyte antigen (HLA) loci has been shown to be an important risk factor for progression to HIV disease, but its significance in infection is less well understood. We have investigated its role in HIV transmission in a cohort of individuals at risk for heterosexual infection. Analysis of over 80 individuals revealed that that the degree of concordance at HLA A, B, and DR loci differs significantly between transmitting and nontransmitting couples at risk for heterosexual HIV transmission (p <.02), suggesting that allogeneic immune responses may confer a degree of protection against HIV infection. Analysis of the frequencies of specific alleles at the A, B, and DR loci revealed a significantly higher frequency of HLA DR5 among exposed uninfected individuals, relative to population controls.

Background: Immunosuppression associated with surgery may predispose to increased tumour growth or recurrence. Lymphocytes are central components of the immune network, signalling specific and non-specific responses in tumour immunosurveillance. This study was therefore designed to compare the effects of minimally invasive and conventional approaches to major thoracic surgery on lymphocyte populations and oxidative activity., Patients and Methods: The effects of conventional and minimally invasive video-assisted thoracic surgery (VATS) on the numbers and types of circulating lymphocytes and on lymphocyte oxidation were compared in a prospective randomized study of 41 patients undergoing lobectomy for peripheral bronchogenic carcinoma. Blood taken pre-operatively and on days 2 and 7 post-operatively was analysed for T (CD4, CD8), B (CD19) and natural killer (NK) (CD56, CD16) cell counts and for lymphocyte oxidative activity. Leucocyte numbers were compared with pre-surgical values and oxidative rate with healthy donor controls., Results: Lymphocyte counts fell after surgery; VATS was associated with less effect on circulating T (CD4) cells at 2 days and on NK lymphocytes at 7 days post-surgery. Lymphocyte oxidation was less suppressed in the VATS group 2 days after surgery. In general, post-surgical changes in key cells of cellular immunity were smaller in the VATS group, and recovery to normal levels was more rapid., Conclusion: The degree of invasiveness of thoracic surgery may influence the extent of immunosuppression in patients undergoing pulmonary lobectomy for pulmonary neoplasm.

We have studied the evolution of hepatitis C virus (HCV) from a common source following serial transmission from contaminated batches of anti-D immunoglobulin. Six secondary recipients were each infected with virus from identifiable primary recipients of HCV-contaminated anti-D immunoglobulin. Phylogenetic analysis of virus E1/E2 gene sequences [including the hypervariable region (HVR)] and part of NS5B confirmed their common origin, but failed to reproduce the known epidemiological relationships between pairs of viruses, probably because of the frequent occurrence of convergent substitutions at both synonymous and nonsynonymous sites. There was no evidence that the rate at which the HCV genome evolves is affected by transmission events. Three different mechanisms appear to have been involved in generating variation of the hypervariable region; nucleotide substitution, insertion/deletion of nucleotide triplets at the E1/E2 boundary and insertion of a duplicated segment replacing almost the entire HVR. These observations have important implications for the phylogenetic analysis of HCV sequences from epidemiologically linked isolates.

Objective: To investigate the infectivity for hepatitis C virus (HCV) of intravenous anti-D immunoglobulin batches manufactured in Ireland between 1991 and 1994., Methods: Women who had received anti-D manufactured between 1991 and 1994 were screened for serological markers of HCV infection and for the presence of HCV RNA by RT-PCR amplification and virus genotyping., Results: 44 women exposed to anti-D manufactured between 1991 and 1994 were polymerase chain reaction positive for HCV RNA, 19 of whom were infected with genotype 3a virus shown by phylogenetic analysis of the NS5B gene to be closely related to that from the single implicated donor., Conclusions: Anti-D manufactured in 1991-1994 transmitted infection of HCV genotype 3a. The prevalence of HCV-specific antibody in anti-D recipients was relatively low (0.59%), consistent with the low level of virus RNA in these anti-D batches.

The prevalence, incidence, clinical features, and natural history of hepatitis G virus (HGV) or GB virus C (GBV-C) were investigated in a non-remunerated blood donor population to determine its clinical significance and its impact on blood safety. Of 1020 regular blood donors, 23 (2.25%) were positive for plasma HGV/GBV-C RNA. Alanine aminotransferase levels were lower than in uninfected donors (median, 20 IU/mL; 32 IU/mL in controls; P=.015). Clinical examination produced no other evidence for hepatitis or for shared nonhepatic diseases. Fifteen of 17 donors excreted HGV/GBV-C in saliva (mean level, 8x103 copies of RNA/mL). Testing of previous donations indicated an incidence of 170-200 new infections with HGV/GBV-C per 100,000 donor-years. The absence of further clinicopathologic data and the limitations of current polymerase chain reaction-based methods for screening suggests that it is neither necessary nor practical to commence screening.

This look-back study was undertaken to identify newborn infants who had been infected with the hepatitis C virus (HCV) as a result of transfusions received before the introduction of routine screening in 1991 and to determine the transmission rates and persistence of transfusion-transmitted HCV infection acquired in the neonatal period. A total of 24 infants, transfused between 1980 and 1991, were identified as having received potentially infected blood from 11 blood donors. Ten of the donors had been administered batches of anti-D in 1977 known to have transmitted HCV genotype 1b infection. HCV RNA was detected in five of these donors when tested in 1994-95; the past donations of five of the donors, who had received anti-D immunoglobulin and had serological evidence of previous HCV infection but who were PCR negative when tested in 1994-95, were considered of lower risk. The source and time of acquisition of HCV infection for the one remaining donor in the study was not determined. Twenty-one (88%) of the 24 children were living at time of lookback. The median age at transfusion was 12 days. The median age at time of testing was 6.3 years. One child, who tested negative, was excluded from further analysis of HCV transmission, due to incomplete transfusion records. Overall, 12 of 20 (60%) children tested were positive for anti-HCV and seven (35%) were HCV RNA positive. Twelve (71%) of the 17 recipients of viraemic blood were ELISA positive and seven (41%) were PCR positive. Resolved HCV infection, as determined by ELISA pos, RIBA pos or indeterminate and PCR negativity, occurred in five of 12 (42%). In many instances there was more than one recipient per HCV infected donation. All of the reported children are clinically asymptomatic. However, the duration of HCV infection is relatively short and there is evidence of a degree of hepatitis in five of the seven children who are HCV RNA positive as judged by mildly elevated transaminase levels. The three who have undergone liver biopsy show mild hepatitis. The lower rates of persistence of HCV infection in this study may be due to the young age at exposure or to the source of infection which for all but one of the children was linked to one HCV genotype from female donors. Sharing of units of blood among multiple infants should be discouraged.

Background: There is growing evidence that blood transfusion is associated with clinical factors that can lead to transfusion-induced immunosuppression. This effect can be beneficial or deleterious., Methods: The effect of perioperative allogeneic blood transfusion on survival was studied retrospectively in 524 patients who were discharged from the hospital after esophagogastrectomy for carcinoma performed in a single unit over a 10-year period., Results: The median operative blood loss for the series was 500 mL (range, 50 to 3,750 mL). Three hundred thirty-five patients (64%) received a perioperative allogeneic blood transfusion related to esophagogastrectomy, and 189 (36%) did not. The median perioperative blood transfusion administered was 900 mL (range, 300 to 12,950 mL). Perioperative allogeneic blood transfusion was associated with reduced survival for patients in stage III (p < 0.05) at 1 year, but no significant difference was found in this stage at 3 or 5 years after resection. Stage III disease accounted for 250 (48%) of the 524 patients discharged., Conclusions: Although perioperative allogeneic blood transfusion does not affect long-term survival after esophagogastrectomy for carcinoma, it does have a significant association with short-term survival in a group whose overall survival is often limited after resection. Attention should be directed toward minimizing operative blood loss and transfusing only for factors known to be clinically important, such as oxygen delivery and hemodynamics, not arbitrary hemoglobin levels.

The long-term evolution of the hepatitis C virus hypervariable region (HVR) and flanking regions of the E1 and E2 envelope proteins have been studied in a cohort of women infected from a common source of anti-D immunoglobulin. Whereas virus sequences in the infectious source were relatively homogeneous, distinct HVR variants were observed in each anti-D recipient, indicating that this region can evolve in multiple directions from the same point. Where HVR variants with dissimilar sequences were present in a single individual, the frequency of synonymous substitution in the flanking regions suggested that the lineages diverged more than a decade previously. Even where a single major HVR variant was present in an infected individual, this lineage was usually several years old. Multiple lineages can therefore coexist during long periods of chronic infection without replacement. The characteristics of amino acid substitution in the HVR were not consistent with the random accumulation of mutations and imply that amino acid replacement in the HVR was strongly constrained. Another variable region of E2 centered on codon 60 shows similar constraints, while HVR2 was relatively unconstrained. Several of these features are difficult to explain if a neutralizing immune response against the HVR is the only selective force operating on E2. The impact of PCR artifacts such as nucleotide misincorporation and the shuffling of dissimilar templates is discussed.

For many RNA viruses, relatively recent times of origin of extant viruses are implied by the high rate of substitution observed in longitudinal studies. However, extrapolation of short-term rates of substitution can give misleading estimates of times of divergence. We show here that the common ancestor of different types of hepatitis C virus (HCV) is older than previously thought. The rate of HCV sequence change was measured amongst a cohort of individuals infected following administration of anti-D immunoglobulin. Virus sequences were obtained in the E1 and NS5B genes and compared with each other and with sequences from an infective batch. Taking account of the bias towards synonymous transition substitutions, the time of divergence of variants of subtype 1b is estimated to have occurred 70-80 years ago. The numerous subtypes of HCV are proposed to derive from more than 300 years of endemic infection in certain geographical regions, with recent spread of some subtypes to other parts of the world. Estimation of the time of origin of the major HCV genotypes (types 1-6) is problematic, but our data and analogy with other viruses suggest that divergence occurred at least 500-2000 years ago.

Intravenous immunoglobulin (IVIG) concentrates were originally developed as replacement therapy for individuals with primary deficiencies of the immune system. However, in various well-designed, controlled clinical trials, the ability of IVIG to prevent and possibly treat infections in patients with secondary immune deficiencies has also been considered. In this review, we briefly consider these different applications and suggest whether the data are sufficient to employ IVIG in these clinical settings.

Background and Objectives: Human B19 parvovirus (B19), identified in 1975, was only recognised as the causative agent of fifth disease in 1983. The incidence of viraemia is low, around 1 in 1,000, but is sufficient to ensure that most plasma pools for fractionation contain some virus. While infection usually occurs in childhood and is benign, chronic infection sometimes occurs and may be of concern in certain patient groups., Materials and Methods: This review is based on a meeting held in March 1995, and addresses recent concerns regarding the potential transmission of B19 infection by pooled plasma products., Results: Recent data on the pathophysiology and assay of this virus are summarised along with possible approaches to donor screening, product screening, and virus removal. Only five cases of symptomatic infection have been reported in persons with haemophilia, but no technology for virus removal is established, and infection may be of concern in pregnant women, and in patients with enhanced red cell turnover or who are immunosuppressed, including those infected with human immunodeficiency virus, but only rarely in immunocompetent patients., Conclusions: For the future, well-validated assays relevant to virus infectivity are required if blood donations, plasma pools, or plasma products are to be screened, and an in-process virus inactivation step for B19 would be highly desirable. In the interim, non-plasma or recombinant products or a selective transfusion policy might be used in patient groups in which B19 infection is of particular concern. Further clinical data on the prognosis and impact of B19 infection are needed to justify both such policies and the future adoption of new technologies designed to reduce any excess B19 infectivity arising from transfused products.

Reactive oxygen intermediate (roi) generation was investigated in phagocytes of 39 patients undergoing pulmonary resection for lung cancer and 39 paired healthy controls. Generation of roi in monocytes and neutrophils was monitored using 2',7'-dichlorofluorescin diacetate. Activation associated with hydrophobic interactions was probed by analysis of phagocyte roi activation by arachidonic acid and gamma-linolenic acid. Patient roi was measured pre-operatively and 2 and 7 days post-operatively. Elevated (P < 0.01) roi production was detected in neutrophils of lung cancer patients. Surgery was associated with an increase (P < 0.05-P < 0.01) in phagocyte roi at 2 and 7 days post-op. Phagocyte roi was stimulated by arachidonic acid and gamma-linolenic acid (1-40 microM) both pre- and post-operatively. Differences in arachidonic acid and gamma-linolenic acid stimulation between patient and control and pre- and post-op patient phagocytes suggest arachidonic acid involvement in phagocyte activation during reactive responses to lung carcinoma and surgery.