The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis

Background  

In observational studies anaemia and iron deficiency are associated with cognitive deficits, suggesting that iron supplementation may improve cognitive function. However, due to the potential for confounding by socio-economic status in observational studies, this needs to be verified in data from randomised controlled trials (RCTs).     

Effects of a fibre-enriched milk drink on insulin and glucose levels in healthy subjects

Background  

The glycaemic response to foods is dependent on the quality and content of carbohydrates. Carbohydrates in the form of dietary fibre have favourable effects on insulin and glucose metabolism and may help to control energy intake. Dairy products have a relatively low carbohydrate content, and most of the carbohydrate is in the form of lactose which causes gastrointestinal symptoms in part of the population. In order to avoid these symptoms, dairy products can be replaced with lactose-free dairy products which are on the market in many parts of the world. However, the effects of lactose-free products on insulin and glucose metabolism have not been studied.     

Indices of insulin sensitivity and secretion from a standard liquid meal test in subjects with type 2 diabetes, impaired or normal fasting glucose

Background  

To provide an initial evaluation of insulin sensitivity and secretion indices derived from a standard liquid meal tolerance test protocol in subjects with normal (NFG), impaired fasting glucose (IFG) or type 2 diabetes mellitus.     

Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality

Background

Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria.

Methods

Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined.

Results

Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis.

Conclusions

A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health.     

Effect of adhesive air-drying time on bond strength to dentin: A systematic review and meta-analysis

ObjectiveThe objective of this review was to evaluate the effect of air-drying time on the adhesion (bond) strength of adhesives to dentin in previously published studies and to conduct a meta-analysis to quantify the differences in the bond strength obtained after the different air-drying times.MethodsAn electronic search was performed using the Medline, Cochrane library, and Scopus databases. The included studies were laboratory studies that investigated the effect of adhesive air-drying time on adhesion (bond) strength of resin-based adhesives to coronal dentin. Studies which evaluated the effect of adhesives air-drying time on physical and mechanical properties of adhesives, interfacial properties, bond strength to root dentin, enamel, or bond strength of indirect composite restoration or orthodontic bracket, were excluded. The methodological quality of included studies was assessed. Meta-analysis was performed using Comprehensive Meta-Analysis software, version 2.0 (Biostat, Englewood, NJ, USA). The results of the meta-analysis were subjected to a further one-way analysis of variance, followed by the Tukey post hoc multiple comparison using R-software, version 3.4.3 (R Foundation for Statistical Computing, Vienna, Austria).ResultsThirteen studies fulfilled the inclusion criteria of this review, while only five studies were included in meta-analysis. The effect of adhesive air-drying time on the bond strength was significant in eight studies (61.5%), material-dependent in four studies (30.8%), and not significant in one study (7.7%). Eight studies (61.54%) presented a medium-risk of bias, three studies (23.08%) presented a low-risk of bias, and two studies (15.38%) presented a high-risk of bias. The analysis of micro-tensile bond strength (μTBS) of adhesives showed statistically significant difference between different air-drying times (p<0.05). The highest mean μTBS values were: 52.9 ± 11.38 MPa (obtained after air-drying of adhesives for 30 s), followed by 48.26 ± 9.77 MPa (15 s), and 37.76 ± 1.45 (25 s), while the lowest mean μTBS was 33.98 ± 2.30 MPa and 35.79 ± 6.63 MPa (5 s) obtained after 10 s and 5 s respectively.ConclusionThe air-drying time of adhesives is crucial to the adhesion strength to coronal dentin. Adhesive air-drying for shorter durations (5–10 s) may be insufficient to obtain adequately durable bonding to dentin, instead, Air-drying should be performed for longer durations (15–30 s), considering the pressure and distance of air-drying source.     

The Biomarker-Surrogacy Evaluation Schema: a review of the biomarker-surrogate literature and a proposal for a criterion-based, quantitative, multidimensional hierarchical levels of evidence schema for evaluating the status of biomarkers as surrogate endpoints

There are clear advantages to using biomarkers and surrogate endpoints, but concerns about clinical and statistical validity and systematic methods to evaluate these aspects hinder their efficient application. Section 2 is a systematic, historical review of the biomarker-surrogate endpoint literature with special reference to the nomenclature, the systems of classification and statistical methods developed for their evaluation. In Section 3 an explicit, criterion-based, quantitative, multidimensional hierarchical levels of evidence schema - Biomarker-Surrogacy Evaluation Schema - is proposed to evaluate and co-ordinate the multiple dimensions (biological, epidemiological, statistical, clinical trial and risk-benefit evidence) of the biomarker clinical endpoint relationships. The schema systematically evaluates and ranks the surrogacy status of biomarkers and surrogate endpoints using defined levels of evidence. The schema incorporates the three independent domains: Study Design, Target Outcome and Statistical Evaluation. Each domain has items ranked from zero to five. An additional category called Penalties incorporates additional considerations of biological plausibility, risk-benefit and generalizability. The total score (0-15) determines the level of evidence, with Level 1 the strongest and Level 5 the weakest. The term ;surrogate' is restricted to markers attaining Levels 1 or 2 only. Surrogacy status of markers can then be directly compared within and across different areas of medicine to guide individual, trial-based or drug-development decisions. This schema would facilitate communication between clinical, researcher, regulatory, industry and consumer participants necessary for evaluation of the biomarker-surrogate-clinical endpoint relationship in their different settings.     

Extraction of polyphenolic dyes from henna,pomegranate rind,and Pterocarya fraxinifolia for nylon 6 dyeing

Acid and disperse dyes are two well‐known synthetic materials that are primarily used for dyeing of nylon 6 fibres. Despite their good performance, several negative impacts on the environment, including air and water pollution, are major concerns to researchers. An alternative ecofriendly approach to the dyeing of nylon 6 is the use of natural dyes, given their abundant natural sources, biocompatibility, biodegradability, non‐toxicity, non‐allergic responses, and non‐carcinogenic effects on human life. Based on these advantages, we extracted polyphenolic dyes from henna leaves, pomegranate rind, and Pterocarya fraxinifolia leaves and studied the dyeability on nylon 6 fabric using three compounds of aluminium sulfate, tannic acid, and tin chloride as toxic and non‐toxic mordants before dyeing. Fourier transform infrared spectra of the nylon 6 fabric confirmed the coordination complexes and π–π bonding between the mordants and the dyes. Colorimetric and fastness results showed that the mordants increased the colour strength and improved the fastness properties of the fibres. Our results suggest that tin chloride and aluminium sulfate as metal mordants can be successfully replaced with tannic acid as a biomordant in the natural dyeing of nylon 6. Also, cost assay showed that dyeing of nylon 6 with extracted natural dyes from waste leaves could be a sustainable and economical substitute for synthetic dyeing.     

Does green tea affect postprandial glucose,insulin and satiety in healthy subjects: a randomized controlled trial

Background  

Results of epidemiological studies have suggested that consumption of green tea could lower the risk of type 2 diabetes. Intervention studies show that green tea may decrease blood glucose levels, and also increase satiety. This study was conducted to examine the postprandial effects of green tea on glucose levels, glycemic index, insulin levels and satiety in healthy individuals after the consumption of a meal including green tea.     

Emerging technologies for selenium separation and recovery from aqueous systems: A review for sustainable management strategy

Selenium (Se) is known both as an essential micronutrient for human health as well as a toxic element when consumed in excess. This work endeavours to critically review the existing selenium literature over the period 1980–2021, following a systematic sub-classification into the domains of occurrence, speciation, and existing conventional and advanced technologies, while directing further research towards emerging integrated sustainable recovery strategies. The review reveals that the majority of the conventional and advanced separation techniques eventually lead to secondary pollution rather than offering a complete solution, whereas resource recovery studies from water are very scant. Some of the techniques, being miserably slow, cannot be applied in the situations of the occurrence of excess selenium in drinking water, posing a serious threat to human health. Research efforts have so far been directed mainly at the removal of selenium rather than recovery through processes that have the potential of turning selenium abatement technology into a sustainable one with value addition. Emerging integrated technologies involving resource recovery from waste streams or generated sludge such as physicochemical technologies, biochemical reduction, electro-biological reduction, and membrane-based hybrid technologies are presently at a very early development stage. Moreover, the application of studies where Se nanoparticles (SeNPs) ormetal selenides are obtained is very limited, which may be attributed to the particle size, purity, morphology, and challenges involved in their separation. This review evaluates the challenges in separation and resource recovery from contaminated streams and points future research in a new direction.     

Simple maximum likelihood estimates of efficacy in randomized trials and before-and-after studies, with implications for meta-analysis

Efficacy, which we define as the effect of receiving intervention on health outcomes among a group of subjects, is the quantity of interest for many investigators. In contrast, intent-to-treat analyses in randomized trials and their analogue for observational before-and-after studies compare outcomes between randomization groups or before-and-after time periods. When there is switching of interventions, estimates based on intent-to-treat are biased for estimating efficacy. By constructing a model based on potential outcomes, one can make reasonable assumptions to estimate efficacy under 'all-or-none' switching of interventions in which switching occurs immediately after randomization or at the start of the time period. This paper reviews the basic methodology, with emphasis on simple maximum likelihood estimates that arise with completely observed outcomes, partially missing binary outcomes, and discrete-time survival outcomes. Particular attention is paid to estimating efficacy in meta-analysis, where the interpretation is much more straightforward than with intent-to-treat analyses.     

RF-magnetron sputter deposited hydroxyapatite-based composite & multilayer coatings: A systematic review from mechanical,corrosion, and biological points of view

Till date, a variety of efforts have been made to develop the essential properties of hydroxyapatite as the most promising bioactive ceramic used in a broad spectrum of clinical applications from bone-tissue engineering to the bio-coatings applied on the implants. Radio frequency magnetron sputtering provides multiple advantages including high efficiency, favorable bonding strength, and controllable properties, therefore an increasing tendency has been emerged for exploiting its benefits in fabrication of HAp bio-coatings. The present review strives to systematically address all of the reported results in the field of RFMS'ed HAp-based composite and multilayer bio-coatings with putting the stress on drawing a clear correlation between the assessed variables, e.g. chemical composition and content of reinforcing phase(s) and interlayer(s), operating conditions, pre/post treatments, and the final characteristics of the bio-coatings. The facing challenges and future horizons of these systems are also treated in detail.     

Nutrition and cancer: A review of the evidence for an anti-cancer diet

It has been estimated that 30–40 percent of all cancers can be prevented by lifestyle and dietary measures alone. Obesity, nutrient sparse foods such as concentrated sugars and refined flour products that contribute to impaired glucose metabolism (which leads to diabetes), low fiber intake, consumption of red meat, and imbalance of omega 3 and omega 6 fats all contribute to excess cancer risk. Intake of flax seed, especially its lignan fraction, and abundant portions of fruits and vegetables will lower cancer risk. Allium and cruciferous vegetables are especially beneficial, with broccoli sprouts being the densest source of sulforophane. Protective elements in a cancer prevention diet include selenium, folic acid, vitamin B-12, vitamin D, chlorophyll, and antioxidants such as the carotenoids (α-carotene, β-carotene, lycopene, lutein, cryptoxanthin). Ascorbic acid has limited benefits orally, but could be very beneficial intravenously. Supplementary use of oral digestive enzymes and probiotics also has merit as anticancer dietary measures. When a diet is compiled according to the guidelines here it is likely that there would be at least a 60–70 percent decrease in breast, colorectal, and prostate cancers, and even a 40–50 percent decrease in lung cancer, along with similar reductions in cancers at other sites. Such a diet would be conducive to preventing cancer and would favor recovery from cancer as well.     

The long-term role of organic amendments in building soil nutrient fertility: a meta-analysis and review

An exhaustive meta-analysis of 132 long-term (≥ 10 years) studies worldwide was carried out to determine the effects of the use of organic amendments (OA) and OA + inorganic fertiliser (IF) on soil nutrient fertility. The responses of (1) crop yield [over the whole duration of the period (yield_m) and at the end of the experiment (yield_f)], (2) soil organic carbon (OC), (3) size of microbial biomass, and (4) Olsen phosphorus (P) to OA and OA + IF compared with IF only (standard control) and no fertilisation (nil control) were investigated. The overall effect of OA alone on yield was significant when compared with the nil control, but not when compared with the standard control. Only when OA and IF were added to soils that met specific conditions (low initial fertility, sandy texture, near-neutral pH values, under tropical climate) they rendered a significantly greater yield_f than the corresponding standard controls. The continuous application of manure caused greater relative and absolute gains in soil OC than straw + IF but did not produce significant greater yields while causing a considerable increase in Olsen P over time. The use of OA and OA + IF increased the resilience of agronomic systems over that of IF alone, as inferred from the smaller coefficient of variation of crop yield over time. We conclude that while the use of OA along with IF provides some additional benefits on yields as compared with IF application alone (especially under the above-mentioned conditions), the selection of the OA type and application rate should be carefully considered in order to maximise the nutrient use efficiency and minimise any undesirable effects to the environment.     

Bioinspired fibrillar adhesives: a review of analytical models and experimental evidence for adhesion enhancement by surface patterns

Fibrillar structures are found on the attachment pads of insects and small reptiles. These structures enable exquisite conformation to rough surfaces, increase the number of van der Waals interactions between the structure and the target surface, and thus enhance adhesion. Biomimetic adhesives replicate this effect by patterning polymer films with micron- or sub-micron-sized protrusions. Numerical contact-mechanics models as well as experimental adhesion measurements have been reported for a variety of protrusion shapes including flat, rounded, mushroom and spatula geometries. Although superior adhesion has been reported for the mushroom and spatula tip geometries, straight, flat-tipped pillars offer the potential for much simpler mass production such as by injection moulding and are thus the focus of this review. Existing models for straight, flat-tipped pillar arrays do not fully agree with reported experimental results. Analytical models are generally limited to elastic materials, and inherently assume that neighbouring pillars behave independently. For elastic pillars in close proximity, however, pillars do in fact interact mechanically, affecting adhesion. Moreover, visco- and hyper-elastic materials are often used in practice, yet dissipative effects receive little attention in analytical models. We find that no study has conclusively investigated the limit of adhesive strength achievable by fibrillar adhesives. It also remains unclear what happens to the adhesive strength as the areal density of contacting regions approaches 100%.     

Carbon,nitrogen and phosphorus recovery from liquid swine wastes: a review

Due to the pollution characteristics of the wastewater generated in piggeries, these waste streams have to be treated before discharging into the environment. These wastes have a high content of organic matter, nitrogen and phosphorus that can be converted or recovered into valuable products. The valuation of swine waste by anaerobic digestion has already been assessed, but no systematic review on the technologies used for recovering nutrients from this waste has been reported to date. Therefore, the present work has the goal of presenting the most studied technologies to different scales of recovery of carbon (i.e. organic matter), nitrogen and phosphorus from swine waste. The main characteristics and parameters of the processes involved in these technologies (mainly air stripping, membrane, enhance biological phosphorus removal and struvite formation) are also highlighted, pointing out its advantages and disadvantages and posing some final feasibility considerations on the subject addressed. Experiments reported in the literature proved that technologies used for nutrient recovery from swine waste are mostly applied to the effluents previously treated by anaerobic digestion as a primary treatment, and greater effort is required for the future implementation of these technologies in large scale. © 2020 Society of Chemical Industry     

微藻水热液化生物油化学性质与表征方法综述

微藻水热液化生物油由于性质较差,不能直接作为车载燃料使用,与现代石油炼制工艺结合是一种新的应用途径。综述了微藻生物油的化学性质,包括化学组成、官能团组成与杂原子化合物组成等信息,比较分析了GC-MS、FTIR、NMR和FT-ICR MS等表征方法的异同,简要回顾了微藻水热液化反应机理和精制方法。重点指出微藻水热液化生物油中含氧、含氮化合物含量较高,并具有较高的芳香度和不饱和度,催化加氢精制能够有效脱除杂原子,并增加烷烃含量。微藻基生物燃料的发展,不仅需要精制工艺的提升,也有赖于表征方法的进步。