Nanotechnology in fibrous materials–a new perspective

This issue reviews various areas where nanotechnology has come up predominately in fibrous materials, namely in electrospun polymeric nanofibers and polymer layered silicate nanocomposites. It includes synthesis, characterization, various methods of collecting nanofibers, factors affecting electrospinning, methods of increasing the productivity of the electrospinning process, and different electrospinning designs. It also covers synthesis and characterization of polymer nanocomposites. Various properties of nanocomposites are discussed. The rheological behavior and morphology of nanocomposites are covered. Different modeling and simulation methods applicable to electrospun nanofibers and polymer layered silicate nanocomposites are discussed. Some of the potential application areas of electrospun nanofibers, polymer layered silicate nanocomposites, and various products available in the market based on nanotechnology are also discussed. Some of the lacking areas and future prospects in nanofibrous structures (nanofibers and nanocomposites) are emphasized in this issue.     

Vitamin D Status in South Asian Populations – Risks and Opportunities

Human body acquires a significant amount of vitamin D by cutaneous synthesis under the action of sunlight and less is supplied through nutritional sources. Diversified sociocultural and economic determinants have been identified that limit the dietary intake of vitamin D and enough distribution of sunlight to maintain optimal levels of 25-hydroxyvitamin D (25(OH)D). Consequently, the world has witnessed a high prevalence of hypovitaminosis D in resource-limited South Asian countries. The purpose of this review is to provide a South Asian perspective of vitamin D status, critically examining India, Pakistan, Bangladesh, and Sri Lanka, and to shed light on potential determinants (latitude and season, sunshine exposure habits, age, gender, and genetic factors) leading to hypovitaminosis D among a variety of population groups. Literature search was carried out using bibliographic databases “PubMed,” “Google Scholar,” and “ScienceDirect.com.” Serum 25(OH)D level, 20–50 nmol/L, was mainly taken as vitamin D deficiency, and determinants of low serum 25(OH)D concentration of the population under study were also considered. The review concludes that vitamin D deficiency is highly prevalent among South Asian populations and global efforts are needed to overcome hypovitaminosis in the region. In addition, dietary diversification, supplementation and fortification of foods with vitamin D, adequate exposure to sunlight, and consumption of animal foods were suggested as viable approaches to maintain 25(OH)D levels for optimal health.     

Ochratoxin A in liquorice products – a review

Liquorice is a herbal medicine produced mainly in China and Iran. This plant is suspected to contain ochratoxin A (OTA), a secondary metabolite produced by fungi. Although liquorice is not included in the daily dietary of humans, the high levels of OTA reported in this product have concerned consumers. Registration of a standard method for measuring the amount of this mycotoxin in liquorice-derived products is an important challenge and requires the introduction of a reliable, simple, fast-performance and reproducible technique. This review examines studies carried out concerning the occurrence of OTA in liquorice products. Recent information regarding contaminated liquorice, the regulatory framework and methods to degrade OTA in liquorice are discussed.     

Fumonisins in plant-origin food and fodder – a review

Fumonisins are mycotoxins produced by the Fusarium group of fungi commonly found on crops, mainly on maize. Some data suggest that as much as 25% of world crops may be lost because of mycotoxin contamination. Therefore, researchers in many countries (particularly in those in which relatively large amounts of maize are directly consumed by humans) are concerned with fumonisin levels in plant-origin foodstuffs and feeds available in their local markets. There is no doubt the levels are strongly correlated with the climate conditions prevailing in the region in which the maize was cultivated: the hotter the climate, the more serious the problem. Negative consequences of consumption of fumonisin-contaminated food by humans include an increased risk of oesophagus cancer and decreased body mass growth. In recent years some trials have been undertaken to reduce fumonisin levels in food and feed by the application of isothiocyanates naturally occurring in plants or peptidoglycans isolated from lactic acid bacteria (LAB). The results of these studies suggested that some reduction in contamination levels might be achieved. Additionally, some recent studies indicate that Sphingopyxis sp. bacteria produce enzymes that are able to break down the fumonisin molecule. Some fumonisins present in food may be bound/coupled with other compounds, and therefore difficult to detect. Such complexes in which the toxins are masked or hidden may even be at higher levels than the not-bound (free) molecules. The problem of how to evaluate effectively and efficiently the concentration of fumonisins in various foodstuffs is therefore a real-life challenge for scientists.     

Nanotechnology – a new route to high-performance functional textiles

The use of nanomaterials- and nanotechnology-based processes is growing at a tremendous rate in all fields of science and technology. Textile industry is also experiencing the benefits of nanotechnology in its diverse field of applications. Textile-based nanoproducts starting from nanocomposite fibers, nanofibers to intelligent high-performance polymeric nanocoatings are getting their way not only in high performance advanced applications but nanoparticles are also successfully being used in conventional textiles to impart new functionality and improved performance. Greater repeatability, reliability and robustness are the main advantages of nanotechnological advancements in textiles. Nanoparticle application during conventional textile processing techniques, such as finishing, coating and dyeing, enhances the product performance manifold and imparts hitherto unachieved functionality. New coating techniques like sol-gel, layer-by-layer, plasma polymerization etc. can develop multi-functionality, intelligence, excellent durability and weather resistance to fabrics. The present paper focuses on the development and potential applications of nanotechnology in developing multifunctional and smart nanocomposite fibers, nanofibers and other new finished and nanocoated textiles. The four main areas of textile chemical processing, namely nanofinishing, nanocoating, nanocomposite coating and nanodyeing, are covered in the first section of this paper and the second section deals with developments in nanocomposite fibers and nanofibers. The influence of nanomaterials in textile finishing and processing to enhance product performance is discussed. Nanocoating is a relatively new technique in the textile field and is currently under research and development. Polymeric nanocomposite coatings, where nanoparticles are dispersed in polymeric media and used for coating applications, are the most promising route to develop multifunctional and intelligent high-performance textiles. Not much research has been done on applying the concept of nanotechnology in dyeing of textiles except a few reports on dye particle size reduction, structural change in fibers or the surface etching of textiles to create nanostructured surfaces. The reduction in water consumption during nanotechnology applications in textile processing has the potential to control the effluent problems of a textile process house. The most researched area to produce multifunctional, smart fibers is the preparation of nanocomposite fibers where the exceptional properties of nanoparticles have been utilized to enhance and impart several functionalities on conventional textile grade fibers. Nanofibers are gaining popularity in some specialized technical applications such as filter fabric, antibacterial patches and chemical protective suits. Nanotechnological advances in these two areas of nanocomposite fibers and nanofibrous forms have also been reviewed.     

Print clarity on digitally printed textiles – a quantitative evaluation

Abstract

Print clarity of a digitally printed product has great impact on the final esthetic appearance and performance of the printed products. Print clarity on various textile substrates is considered as image sharpness in this research. The current standard test method is a subjective test where a printed fabric is evaluated visually by one or more human subjects. To advance digital printing of textiles further, it is critical to create a quantitative evaluation method for testing print clarity (sharpness), as has been done with paper. In this paper, a quantitative evaluation of the print clarity (sharpness) of a digitally printed test pattern on textiles was created. Different colors, directions, and fabrics (substrates) were considered in the design of experiment. Eight similar weight and structure woven polyester samples along with a paper substrate were printed with MS JP7 printers using nano-pigments and printed in two directions. The resulting prints were scanned with an EPSON Expression 11000XL Photo Scanner. Several software packages, including Image-Pro and MatLab, were used to process data to analyze and compare image contrast of the test pattern under different conditions. Improved print clarity in digital printing on polyester woven fabric was explored. The newly developed test method is a quantitative test method that makes optimization of the print quality (sharpness) easier and more accurate.     

Suitability of auger drill sampling for the measurement of?moisture content gradient in kiln-dried South African grown Eucalyptus grandis poles

Moisture content (MC) gradient at the time of preservation plays a pivotal role in determining the success of the preservation process. The South African pole drying industry relies on auger drill sampling to determine whether the MC of dried poles is acceptable for preservative treatment. The objectives of this study were to determine: (i)?the reliability and (ii)?potential sources of errors of the auger drill MC sampling method on kiln dried E.?grandis poles. Destructive oven-dry MC determination on sample blocks of 12.5?mm thickness and 25?mm width as the benchmark method and auger drill samples in increments of 25?mm were used to determine the MC gradient at the theoretical ground line (TGL) of poles. Results showed that the MC of 25?mm deep increment auger drill samples did not differ from those measured using the block method. However, there were differences between MC values measured using the auger drill and block methods when samples of 50?mm or 75?mm in length were considered. Differences in MC values measured after drying also occurred in parts of the poles where moisture was still high, i.e., above fibre saturation point. It was concluded that SANS 5983 (South African Bureau of Standards. Standard method for preparation of test specimens for moisture content determination in timber and timber products, 2008), which specifies taking single radial auger drill samples of depth 70±5?mm at mid length, is a reliable method for measuring MC in a kiln dried E.?grandis pole. It is recommended that MC is determined in auger increments of 25?mm at the most critical zone of a pole, such as the TGL rather than mid length.     

A green material from rock: basalt fiber – a review

The nature is continually providing varied resources for creating textile materials for various applications. Although many textile fibers in the nature are provided with the fibrous kind itself it additionally offers raw materials that may be changed and formed into a filament in a way similar to the melt and solution spinning of other textile fibers. Basalt is an igneous rock, which is solidified volcanic lava. In recent years, basalt received attention as a replacement for asbestos fibers. Basalt has emerged as a contender in the fiber reinforcement of composites. Basalt fiber (BF) is capable to withstand very high temperature and can be used in high performance applications. This paper is review of state of art of knowledge of BF, the production methods, properties and its applications.     

Breeding aflatoxin-resistant maize lines using recent advances in technologies – a review

Aflatoxin contamination caused by Aspergillus flavus infection of corn is a significant and chronic threat to corn being used as food or feed. Contamination of crops at levels of 20 ng g^?1 or higher (as regulated by the USFDA) by this toxin and potent carcinogen makes the crop unsalable, resulting in a significant economic burden on the producer. This review focuses on elimination of this contamination in corn which is a major US crop and the basis of many products. Corn is also “nature's example” of a crop containing heritable resistance to aflatoxin contamination, thereby serving as a model for achieving resistance to aflatoxin contamination in other crops as well. This crop is the largest production grain crop worldwide, providing food for billions of people and livestock and critical feedstock for production of biofuels. In 2011, the economic value of the US corn crop was US$76 billion, with US growers producing an estimated 12 billion bushels, more than one-third of the world's supply. Thus, the economics and significance of corn as a food crop and the threat to food safety due to aflatoxin contamination of this major food crop have prompted the many research efforts in many parts of the world to identify resistance in corn to aflatoxin contamination. Plant breeding and varietal selection has been used as a tool to develop varieties resistance to disease. This methodology has been employed in defining a few corn lines that show resistance to A. flavus invasion; however, no commercial lines have been marketed. With the new tools of proteomics and genomics, identification of resistance mechanisms, and rapid resistance marker selection methodologies, there is an increasing possibility of finding significant resistance in corn, and in understanding the mechanism of this resistance.     

Economic evaluation of participation in a voluntary Johne's disease prevention and control program from a farmer's perspective–The Alberta Johne's Disease Initiative

The Alberta Johne's Disease Initiative (AJDI) is a Johne's disease (JD) control program with the goal of reducing the spread of Mycobacterium avium ssp. paratuberculosis (MAP) through implementation of best management practices. The objective was to estimate the economic benefit of participation in the AJDI. A decision tree was constructed in which disease prevalence, test characteristics, and probabilities for implementation of best management practices suggested by herd veterinarians were implemented. Analysis was performed using a Markov analysis, and input data were assigned using estimates from the AJDI and published data. A cost-effectiveness analysis was performed and the net benefit of participation (from the perspective of a dairy farmer) in the AJDI compared with no participation was calculated. A series of 1-way sensitivity analyses were used to control for uncertainty. Farms participating in the AJDI were estimated to have a net benefit of Can$74 per cow over the course of 10 yr. If project costs were covered by the participating farm, the net benefit was Can$27. In addition to the effects on MAP infection, a reduction in calf diarrhea was modeled for farms that improved their calf management through the use of pasteurizers. In that case, the additional costs outweighed additional revenues compared with the baseline analysis, resulting in a reduced net benefit of Can$19. Participation would not be cost effective if cows in early stages of MAP infection did not have decreased production and if prevalence of MAP infection did not increase on farms with poor management. A limitation of the study, despite high uncertainty in some input parameters, was the lack of knowledge regarding changes in prevalence on farms with various management strategies. In conclusion, participation in the AJDI was cost effective for the average Alberta dairy farm.     

International investment in developing country agriculture—issues and challenges

The recent surge of international investment in developing country agriculture has generated considerable debate. Some of the largest transactions involve investors from the Gulf States purchasing or leasing land in poor, food-insecure African countries, to grow food that will be exported back to the investing country. Unlike the investments of the past, these are resource-seeking rather than market-seeking, and involve acquisition of land and actual production rather than looser forms of joint venture. Investing countries appear to be driven by food security concerns, including price volatility and market risks faced by large food importers. Host countries have been equally keen to attract such investment, for various potential benefits—but there are concerns about whether these benefits will be realized, and about lack of community involvement in the decision process. This paper discusses the nature and driving forces behind these investments, and the economic, political, institutional, legal and ethical issues they raise for host countries, investors and the international community. The paper suggests that alternative approaches might be as effective, and more acceptable, than long-term leases or outright purchases. Further, an international initiative (voluntary code of conduct, guidelines, statement of principles etc.) could highlight host country interests and also guide investors toward socially responsible investment.     

Is acculturation a risk factor for early smoking initiation among Chinese American minors? A comparative perspective

OBJECTIVE: To determine the extent to which Chinese American and white minors differ in age of smoking initiation, and to determine the effect of acculturation on smoking initiation. DESIGN: Cross-sectional telephone surveys. SETTING: Stratified random samples of the state of California, United States. SUBJECTS: 347 Chinese American and 10 129 white adolescents aged 12 through 17 years, from the California Tobacco Survey (1990-93) and the California Youth Tobacco Survey (1994-96). OUTCOME MEASURES: Hazards (risk) of smoking initiation by age, smoking initiation rate, cumulative smoking rate, mean age of smoking initiation, and acculturation status. STATISTICAL METHODS: Life table methods, proportional hazards models, and chi(2) tests. RESULTS: The risk of smoking initiation by age among Chinese American minors was about a third of that among white minors. The risk for Chinese Americans continued to rise even in later adolescence, in contrast to that for whites, which slowed after 15 years of age. Acculturation was associated significantly with smoking onset among Chinese Americans. Acculturation, smoking among social network members, attitudes toward smoking, and perceived benefits of smoking were associated with the difference in hazards of smoking onset between Chinese American minors and their white counterparts. CONCLUSIONS: Chinese American adolescents had a lower level and a different pattern of smoking onset than white adolescents. Levels of acculturation and other known risk factors were associated with the hazards of smoking initiation among Chinese American minors and with the difference in smoking initiation between the Chinese and white adolescents. Tobacco prevention policies, strategies, and programmes for ethnically diverse populations should take acculturation factors into account.     

Analysis of urban consumers’ willingness to pay a premium for African Leafy Vegetables (ALVs) in Kenya: a case of Eldoret Town

This study surveyed urban consumers in Eldoret Town, Kenya to determine the willingness to pay (WTP) a premium for African leafy vegetables (ALVs) and the underlying determinants using the semi-double bounded contingent valuation choice and logit models, respectively. Consumers generally preferred ALVs to exotic leafy vegetables and were willing to pay an average premium of 79 % for them: 88 % and 70 % in open air and supermarkets, respectively. The WTP premium was positively influenced by age, presence of children in the household, years of schooling of the household decision maker and the number of years the consumers had been consuming ALVs. Implications for policy are drawn.     

Advances in high-resolution mass spectrometry based on metabolomics studies for food – a review

Food authenticity becomes a necessity for global food policies, since food placed in the market without fail has to be authentic. It has always been a challenge, since in the past minor components, called also markers, have been mainly monitored by chromatographic methods in order to authenticate the food. Nevertheless, nowadays, advanced analytical methods have allowed food fingerprints to be achieved. At the same time they have been also combined with chemometrics, which uses statistical methods in order to verify food and to provide maximum information by analysing chemical data. These sophisticated methods based on different separation techniques or stand alone have been recently coupled to high-resolution mass spectrometry (HRMS) in order to verify the authenticity of food. The new generation of HRMS detectors have experienced significant advances in resolving power, sensitivity, robustness, extended dynamic range, easier mass calibration and tandem mass capabilities, making HRMS more attractive and useful to the food metabolomics community, therefore becoming a reliable tool for food authenticity. The purpose of this review is to summarise and describe the most recent metabolomics approaches in the area of food metabolomics, and to discuss the strengths and drawbacks of the HRMS analytical platforms combined with chemometrics.     

Efficiency scenarios of charcoal production and consumption – a village case study from Western Tanzania

Availability and access to energy is strongly linked to food security as cooking is needed to make foods ready for consumption. Without access to energy, there is no food security. In rural Tanzania, the population strongly depends on traditional biofuels such as firewood and charcoal. Under the pressure of population growth, energy demand will substantially increase in the next decades. The potential of improved efficiency in charcoal production and efficient cooking stoves were evaluated using scenario analysis. For quantitative data collection, a household survey was conducted in Laela village (2010). The sampling process was based on relative income classes (ICs) defined by local representatives and extending  from “rich” (IC 1) to “below self-sufficiency” (IC 4). Based on quantitative survey data, we calculated the quantity of pre-carbonised fuelwood associated with charcoal consumption for ICs in order to display specific consumption patterns. Further, we applied scenario analysis and projected charcoal consumption by 2030 including population growth (+3.41%/year), improved kiln efficiencies (11.1%–20%) and different dissemination rates of efficient stoves (0%–100%). Results of consumption patterns showed that fuelwood consumption in IC 1 was twice that of IC 4, when a conversion efficiency of 11.1% was applied. Calculations of the scenario analyses showed that overall energy consumption will almost double by 2030. The combined approach of a moderate improvement of conversion efficiency (15.6%) combined with a dissemination rate for energy efficient stoves of 50% would overcome the effect of population growth in projected energy consumption and offer a means of coping with future bioenergy demands.     

Developments of mathematical models for simulating vacuum cooling processes for food products – a review

Vacuum cooling is a rapid cooling method widely used in cooling some food products. Simulating the vacuum cooling process with mathematical models helps to acquire a more intuitive understanding and optimize the whole cooling process. However, there is no review summarizing the mathematical models of vacuum cooling. In this review, heat and mass transfer process during vacuum cooling, types of mathematical models for vacuum cooling, and numerical methods including finite difference method, finite element method and finite volume method used for process simulation are introduced in details. The food products used in numerical simulation study of vacuum cooling generally include liquid food, vegetables and cooked meat. The ranges of application of various numerical methods are also discussed. Moreover, heat and mass transfer coefficients have a great influence on the accuracy of the model, and are generally provided by the literature. The investigations presented in this review invariably demonstrate that mathematical modeling can provide good prediction of key information of vacuum cooling process, and has a great potential to improve vacuum cooling process in the food industry. However, more efforts are still needed to realize the industrial translation of laboratory results.     

Is agriculture connected with stunting in Indonesian children living in a rice surplus area? A case study in Demak regency,central Java

Central Java province plays the main role in the production of food for national stocks in Indonesia, in which Demak is one of the 35 Regencies. Demak Regency had the sixth highest rice productivity in 2013, but at the same time, the seventh highest percentage of child malnutrition. This paradox between high rice productivity and low nutritional status of children triggered an interest in analyzing the correlations between agricultural production of households in the Demak Regency and the prevalence of stunting of children under-five. In December 2014 to February 2015, a cross-sectional survey was carried out in three sub-districts in Demak (Karanganyar, Dempet and Gajah) having the highest rice production and at the same time poor nutritional status of under-five children. The oldest under-five children from farmer family backgrounds were selected. Data on general characteristics, anthropometry of the children, as well as household socio-economics, including agricultural characteristics were obtained. Of the 335 children, 31.9% of them were stunted. A higher proportion of households that grew rice solely or mainly for own consumption (62.4%) and had significantly smaller sized rice-fields (p = 0.041) had stunted rather than non-stunted children. In total, rice production, farm income and agriculture diversity of families with non-stunted children were not significantly different from those of stunted children. However, yearly expenditure for improving family health and environmental conditions were significantly higher among non-stunted than stunted children (p = 0.044). Family decisions about what to spend money on also seemed to influence the nutritional status of the children, rather than nutritional diversity or revenue from agriculture itself. Therefore, improvement of agricultural production and diversity should be accompanied by education on household expenditure.