不同脱毒方法对玉米秸秆水解液酒精发酵的影响

利用湿热预处理(195℃,15 min)后的玉米秸秆水解液,考察了3种不同脱毒方法(中和法、饱和生石灰法和Na2SO3法)对水解液中的抑制剂的去除效果,研究了树干毕赤酵母(Pichia stipitis 58376)对脱毒后的水解液酒精发酵情况.结果表明:玉米秸秆水解液经过3种方法脱毒处理后,醛类抑制荆(糠醛和5-羟甲...     

Preparation of Spherical, Submicrometer Oxide Particles by Hydrolysis of Emulsified Alkoxide Droplets

A new method for forming spherical, submicrometer ceramic oxide particles by the hydrolysis of emulsified alkoxide droplets is reported. Emulsions are formed of alkoxide droplets dispersed in an inert, polar solvent. The alkoxide droplets are hydrolyzed to form oxide particles by adding water to the emulsion. It was shown that individual droplets acted as "microreactors" and controlled the powder size, shape, and composition. Both single-oxide and mixed-oxide powders were formed by this technique.     

Electrospun microporous gelatin–polycaprolactone blend tubular scaffold as a potential vascular biomaterial

The work reported involved the fabrication of an electrospun tubular conduit of a gelatin and polycaprolactone (PCL) blend as an adventitia‐equivalent construct. Gelatin was included as the matrix for increased biocompatibility with the addition of PCL for durability. This is contrary to most of the literature available for biomaterials based on blends of gelatin and PCL where PCL is the major matrix. The work includes the assiduous selection of key electrospinning parameters to obtain smooth bead‐free fibres with a narrow distribution of pore size and fibre diameter. Few reports elucidate the optimization of all electrospinning parameters to fabricate tubular conduits with a focus on obtaining homogeneous pores and fibres. This stepwise investigation would be unique for the fabrication of gelatin–PCL electrospun tubular constructs. The fabricated microfibrous gelatin–PCL constructs had pores of size ca 50–100 μm reportedly conducive for cell infiltration. The measured value of surface roughness of 57.99 ± 17.4 nm is reported to be favourable for protein adhesion and cell adhesion. The elastic modulus was observed to be similar to that of the tunica adventitia of the native artery. Preliminary in vitro and in vivo biocompatibility tests suggest safe applicability as a biomaterial. Minimal cytotoxicity was observed using MTT assay. Subcutaneous implantation of the scaffold demonstrated acute inflammation which decreased by day 15. The findings of this study could enable the fabrication of smooth bead‐free microfibrous gelatin–PCL tubular construct as viable biomaterial which can be included in a bilayer or a trilayer scaffold for vascular tissue engineering. © 2019 Society of Chemical Industry     

Quantitation of vitamin K in human milk

A quantitative method was developed for the assay of vitamin K in human colostrum and milk. The procedure combines preparative and analytical chromatography on silica gel in a nitrogen atmosphere followed by reversed phase high performance liquid chromatography (HPLC). Two HPLC steps were used: gradient separation with ultraviolet (UV) detection followed by isocratic separation detected electrochemically. Due to co-migrating impurities, UV detection alone is insufficient for identification of vitamin K. Exogenous vitamin K was shown to equilibrate with endogenous vitamin K in the samples. A statistical method was incorporated to control for experimental variability. Vitamin K₁ was analyzed in 16 pooled milk samples from 7 donors and in individual samples from 15 donors at 1 month post-partrum. Vitamin K₁ was present at 2.94±1.94 and 3.15±2.87 ng/mL in pools and in individuals, respectively. Menaquinones, the bacterial form of the vitamin, were not detected. The significance of experimental variation to studies of vitamin K in individuals is discussed.     

Dietary intakes of six intense sweeteners by Irish adults

This research investigated the intakes of six intense sweeteners: acesulfame-K (E950), aspartame (E951), cyclamate (E952), saccharin (E954), sucralose (E955), and steviol glycosides (E960) in the diets of Irish adults, using data from the National Adult Nutrition Survey. A food label survey that included products currently available on the Irish market supplemented the analysis. Sweetener intakes were investigated using three different exposure scenarios; beginning with a crude assessment which assumed that all foods permitted to contain the additives of interest always did contain them, and at their maximum permitted level (Tier 1). Refined assessments estimated intakes of the six sweeteners using food consumption data up to brand level with additive occurrence data from a survey of products currently available on the Irish market (Tier 2) and sweetener concentration data (Tier 3). Results of all exposure assessment scenarios demonstrate that intakes of each of the sweeteners of interest by the total population were below the relevant ADI level (mg kg^?1 bodyweight^?1), even by high consumers (P99). The three sweeteners consumed in highest amounts were acesulfame-k, aspartame, and sucralose. The main sources of these sweeteners in the diet were ‘cider and perry’, ‘energy reduced and no added sugar (ER and NAS) carbonated flavoured drinks’, ‘table-top sweeteners’, ‘dairy products’, ‘solid food supplements’, and ‘sauces’. Intakes of the six intense sweeteners are currently not a concern among Irish adults. However, exposure to these chemicals should be monitored on a regular basis due to evolving market and consumption patterns.     

Application of multimedia models for screening assessment of long-range transport potential and overall persistence

We propose a multimedia model-based methodology to evaluate whether a chemical substance qualifies as POP-like based on overall persistence (Pov) and potential for long-range transport (LRTP). It relies upon screening chemicals against the Pov and LRTP characteristics of selected reference chemicals with well-established environmental fates. Results indicate that chemicals of high and low concern in terms of persistence and long-range transport can be consistently identified by eight contemporary multimedia models using the proposed methodology. Model results for three hypothetical chemicals illustrate that the model-based classification of chemicals according to Pov and LRTP is not always consistent with the single-media half-life approach proposed by the UNEP Stockholm Convention and thatthe models provide additional insight into the likely long-term hazards associated with chemicals in the environment. We suggest this model-based classification method be adopted as a complement to screening against defined half-life criteria at the initial stages of tiered assessments designed to identify POP-like chemicals and to prioritize further environmental fate studies for new and existing chemicals.     

Extreme catalysts from low-temperature environments

Cold-loving or psychrophilic organisms are widely distributed in nature as a large part of the earth's surface is at temperatures around 0 degrees C. To maintain metabolic rates and to prosper in cold environments, these extremophilic organisms have developed a vast array of adaptations. One main adaptive strategy developed in order to cope with the reduction of chemical reaction rates induced by low temperatures is the synthesis of cold-adapted or psychrophilic enzymes. These enzymes are characterized by a high catalytic activity at low temperatures associated with a low thermal stability. A study of protein adaptation strategies suggests that the high activity of psychrophilic enzymes could be achieved by the destabilization of the active site, allowing the catalytic center to be more flexible at low temperatures, whereas other protein regions may be destabilized or as rigid as their mesophilic counterparts. Due to these particular properties, psychrophilic enzymes offer a high potential not only for fundamental research but also for biotechnological applications.     

Antioxidant capacity and related parameters of different fruit formulations

Fruits and vegetables are known as good sources of phytochemicals, essential to prevent degenerative diseases like cancer and cardiovascular diseases (CVD). They contain a variety of antioxidants, which are useful to scavenge radical oxygen species (ROS). Besides smoothies, fruit purees, concentrates and juices - used by the food industry for these new beverages - were analysed. Total phenolics by Folin-Ciocalteu method, vitamin C content and antioxidant capacity (AOC) by FRAP, TEAC and ORAC assay were analysed by using high-throughput methods on a microplate reader. Vitamin C content ranged from 31 ± 3 mg/100 g in drinkable pomegranate concentrate to 1373 ± 125 mg/100 g in acerola puree; total phenolics content was quantified between 51 ± 1 mg gallic acid equivalents (GAE)/100 g in the mango-peach smoothie and 1152 ± 62 mg/100 g in the ascorbic acid rich acerola puree. The AOC differed depending on kind of fruit and antioxidant assay used. In most fruit products the major portion of AOC was generated by polyphenolic compounds, except acerola puree and orange juice. Very good correlations between total phenolics content and antioxidant capacity were found in the single fruit products, however not in the fruit and vegetable smoothies. Most of the analysed smoothies were able to supply with one package nearly the recommended dietary intake (RDI) of vitamin C for adults of 100 mg per day.     

Fire safe,sustainable loose furnishing

The aim of this exploratory study has been to investigate the fire properties and environmental aspects of different upholstery material combinations, mainly for domestic applications. An analysis of the sustainability and circularity of selected textiles, along with lifecycle assessment, is used to qualitatively evaluate materials from an environmental perspective. The cone calorimeter was the primary tool used to screen 20 different material combinations from a fire performance perspective. It was found that textile covers of conventional fibres such as wool, cotton and polyester, can be improved by blending them with fire resistant speciality fibres. A new three‐dimensional web structure has been examined as an alternative padding material, showing preliminary promising fire properties with regard to ignition time, heat release rates and smoke production.