Hasil untuk "Chemical technology"

Neelima Mahato, A. Banerjee, Alka Gupta et al.

C. Rose, A. Parker, B. Jefferson et al.

The safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On-site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh feces and urine was collected from the medical literature as well as the treatability sector. The data were summarized and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators, and chemical processes was then assessed. Results showed that the median fecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Fecal output in healthy individuals was 1.20 defecations per 24 hr period and the main factor affecting fecal mass was the fiber intake of the population. Fecal wet mass values were increased by a factor of 2 in low income countries (high fiber intakes) in comparison to values found in high income countries (low fiber intakes). Feces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25–54% of dry solids) of the organic fraction of the feces. Undigested carbohydrate, fiber, protein, and fat comprise the remainder and the amounts depend on diet and diarrhea prevalence in the population. The inorganic component of the feces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 L/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions, as well as water, salt, and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus, and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the fecal and urine composition and these variables should always be considered if the generation rate, physical, and chemical composition of feces and urine is to be accurately predicted.

Meihong Wang, A. Lawal, P. Stephenson et al.

Mukul Kumar, Y. Ando

G. Los, L. Encell, M. Mcdougall et al.

L. Banszerus, M. Schmitz, S. Engels et al.

A novel dry transfer technique opens the door to large-scale CVD graphene with carrier mobilities of up to several 100,000 cm2 V−1 s−1. Graphene research has prospered impressively in the past few years, and promising applications such as high-frequency transistors, magnetic field sensors, and flexible optoelectronics are just waiting for a scalable and cost-efficient fabrication technology to produce high-mobility graphene. Although significant progress has been made in chemical vapor deposition (CVD) and epitaxial growth of graphene, the carrier mobility obtained with these techniques is still significantly lower than what is achieved using exfoliated graphene. We show that the quality of CVD-grown graphene depends critically on the used transfer process, and we report on an advanced transfer technique that allows both reusing the copper substrate of the CVD growth and making devices with mobilities as high as 350,000 cm2 V–1 s–1, thus rivaling exfoliated graphene.

P. Duxson, J. Provis, G. C. Lukey et al.

J. Peña-Bahamonde, Hang N. Nguyen, S. Fanourakis et al.

Graphene’s unique physical structure, as well as its chemical and electrical properties, make it ideal for use in sensor technologies. In the past years, novel sensing platforms have been proposed with pristine and modified graphene with nanoparticles and polymers. Several of these platforms were used to immobilize biomolecules, such as antibodies, DNA, and enzymes to create highly sensitive and selective biosensors. Strategies to attach these biomolecules onto the surface of graphene have been employed based on its chemical composition. These methods include covalent bonding, such as the coupling of the biomolecules via the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide reactions, and physisorption. In the literature, several detection methods are employed; however, the most common is electrochemical. The main reason for researchers to use this detection approach is because this method is simple, rapid and presents good sensitivity. These biosensors can be particularly useful in life sciences and medicine since in clinical practice, biosensors with high sensitivity and specificity can significantly enhance patient care, early diagnosis of diseases and pathogen detection. In this review, we will present the research conducted with antibodies, DNA molecules and, enzymes to develop biosensors that use graphene and its derivatives as scaffolds to produce effective biosensors able to detect and identify a variety of diseases, pathogens, and biomolecules linked to diseases.

K. Jensen

A. Mustafa, Bachirou Guene Lougou, Y. Shuai et al.

Abstract The continuous consumption of fossil fuels causes two important impediments including emission of large concentrations of CO2 resulting in global warming and alarming utilization of energy assets. The conversion of greenhouse gas CO2 into solar fuels can be an expedient accomplishment for the solution of both problems, all together. CO2 reutilization into valuable fuels and chemicals is a great challenge of the current century. Owing to limitations in traditional approaches, there have been developed many novel technologies such as photochemical, biochemical, electrochemical, plasma-chemical and solar thermochemical. They are currently being used for CO2 capture, sequestration, and utilization to transform CO2 into valuable products such as syngas, methane, methanol, formic acid, as well as fossil fuel consumption reduction. This review summarizes different traditional and novel thermal technologies used in CO2 conversion with detailed information about their working principle, types, currently adopted methods, developments, conversion rates, products formed, catalysts and operating conditions. Moreover, a comparison of these novel technologies in terms of distinctive key features such as conversion rate, yield, use of earth metals, renewable energy, investment, and operating cost has been provided in order to have a useful review for future research direction.

Luiz F. T. Novaes, Jinjian Liu, Yifan Shen et al.

Electrochemistry has recently gained increased attention as a versatile strategy for achieving challenging transformations at the forefront of synthetic organic chemistry. Electrochemistry's unique ability to generate highly reactive radical and radical ion intermediates in a controlled fashion under mild conditions has inspired the development of a number of new electrochemical methodologies for the preparation of valuable chemical motifs. Particularly, recent developments in electrosynthesis have featured an increased use of redox-active electrocatalysts to further enhance control over the selective formation and downstream reactivity of these reactive intermediates. Furthermore, electrocatalytic mediators enable synthetic transformations to proceed in a manner that is mechanistically distinct from purely chemical methods, allowing for the subversion of kinetic and thermodynamic obstacles encountered in conventional organic synthesis. This review highlights key innovations within the past decade in the area of synthetic electrocatalysis, with emphasis on the mechanisms and catalyst design principles underpinning these advancements. A host of oxidative and reductive electrocatalytic methodologies are discussed and are grouped according to the classification of the synthetic transformation and the nature of the electrocatalyst.

LIN Yongfeng, CHENG Zhen, LIU Wenmei, ZOU Zehua, LIU Hong, LIU Guangming, LIU Qingmei

In this study, the physicochemical properties of polysaccharides from Houttuynia cordata Thunb. fermented with Lactiplantibacillus plantarum HM6008 (FHCTP) were determined, and the antiallergic activity was evaluated using rat basophilic leukemia (RBL)-2H3 cells. The results showed that fermentation increased the ratio of mannose to sulfate in FHCTP. Compared with H. cordata Thunb. polysaccharides (HCTP), the particle size of FHCTP decreased by 26.67%, and its stability in aqueous solution increased. The inhibition rate of FHCTP on the degranulation of RBL-2H3 cells was significantly higher than that of HCTP, (82.79 ± 5.19)% versus (53.75 ± 1.95)%. After FHCTP intervention, the expression of fragment crystallizable epsilon receptor I (FcεRI) was significantly down-regulated, and the average fluorescence intensity decreased from 2 458.00 ± 7.50 to 1 495.00 ± 28.50. Both FHCTP and HCTP effectively inhibited the isomerization of cytoskeletal proteins and the increase of intracellular calcium ion concentration. In addition, in the mouse passive cutaneous anaphylaxis assay, FHCTP showed a more significant inhibitory effect on dye extravasation in mouse ears, indicating stronger antiallergic activity. In conclusion, FHCTP has better stabilizing effect on mast cells and effectively alleviates mast cell-mediated passive cutaneous anaphylaxis in mice. The results of this research are expected to promote the development and application of antiallergic products from edible and medicinal materials.

A. Capel, R. Rimington, M. Lewis et al.

M. Panza, Salvatore G. Pistorio, K. Stine et al.

Advances in carbohydrate chemistry have certainly made common oligosaccharides much more accessible. However, many current methods still rely heavily upon specialized knowledge of carbohydrate chemistry. The application of automated technologies to chemical and life science applications such as genomics and proteomics represents a vibrant field. These automated technologies also present opportunities for their application to organic synthesis, including that of the synthesis of oligosaccharides. However, application of automated methods to the synthesis of carbohydrates is an underdeveloped area as compared to other classes of biomolecules. The overarching goal of this review article is to present the advances that have been made at the interface of carbohydrate chemistry and automated technology.

Javier Urieta‐Mora, Inés García‐Benito, Agustín Molina‐Ontoria et al.

K. Dionisio, Katherine A. Phillips, P. Price et al.

Quantitative data on product chemical composition is a necessary parameter for characterizing near-field exposure. This data set comprises reported and predicted information on more than 75,000 chemicals and more than 15,000 consumer products. The data’s primary intended use is for exposure, risk, and safety assessments. The data set includes specific products with quantitative or qualitative ingredient information, which has been publicly disclosed through material safety data sheets (MSDS) and ingredient lists. A single product category from a refined and harmonized set of categories has been assigned to each product. The data set also contains information on the functional role of chemicals in products, which can inform predictions of the concentrations in which they occur. These data will be useful to exposure and risk assessors evaluating chemical and product safety. Design Type(s) data integration objective Measurement Type(s) physicochemical characterization Technology Type(s) digital curation Factor Type(s) chemical product Design Type(s) data integration objective Measurement Type(s) physicochemical characterization Technology Type(s) digital curation Factor Type(s) chemical product Machine-accessible metadata file describing the reported data (ISA-Tab format)

Dongrui Wang, Yaokang Zhang, Xi Lu et al.

T. Mattisson, M. Keller, Carl Linderholm et al.

J. Devkota, P. Ohodnicki, D. Greve

Surface acoustic wave (SAW) technology provides a sensitive platform for sensing chemicals in gaseous and fluidic states with the inherent advantages of passive and wireless operation. In this review, we provide a general overview on the fundamental aspects and some major advances of Rayleigh wave-based SAW sensors in sensing chemicals in a gaseous phase. In particular, we review the progress in general understanding of the SAW chemical sensing mechanism, optimization of the sensor characteristics, and the development of the sensors operational at different conditions. Based on previous publications, we suggest some appropriate sensing approaches for particular applications and identify new opportunities and needs for additional research in this area moving into the future.