Effect of simultaneous infrared dry-blanching and dehydration on quality characteristics of carrot slices

This study investigated the effects of various processing parameters on carrot slices exposed to infrared (IR) radiation heating for achieving simultaneous infrared dry-blanching and dehydration (SIRDBD). The investigated parameters were product surface temperature, slice thickness and processing time. A three-factor factorial design was conducted to determine the influence of processing parameters on moisture reduction, drying rate, residual peroxidase (POD) activities, surface color change and vitamin C retention. High surface temperature and/or thin slices had faster inactivation of enzymes and quicker moisture removal compared to the low surface temperature and/or thick slices. A Middili model performed well for describing drying behavior during the treatment, while a biphasic model and a quantic model fit well for describing the POD inactivation and the surface color change during the process, respectively. The process which produced 1 log reduction in POD activity has resulted in moisture reduction from 40.2 to 88.8 g/100 g, overall color change (ΔE) from 3.17 to 5.13 and retention of vitamin C from 56.92 to 77.34 g/100 g compared to control. It was concluded that SIRDBD could be used as an alternative to produce high quality blanched and partially dehydrated fruits and vegetables.     

The interaction between the iron-responsive element binding protein and its cognate RNA is highly dependent upon both RNA sequence and structure

To assess the influence of RNA sequence/structure on the interaction RNAs with the iron-responsive element binding protein (IRE-BP), twenty eight altered RNAs were tested as competitors for an RNA corresponding to the ferritin H chain IRE. All changes in the loop of the predicted IRE hairpin and in the unpaired cytosine residue characteristically found in IRE stems significantly decreased the apparent affinity of the RNA for the IRE-BP. Similarly, alteration in the spacing and/or orientation of the loop and the unpaired cytosine of the stem by either increasing or decreasing the number of base pairs separating them significantly reduced efficacy as a competitor. It is inferred that the IRE-BP forms multiple contacts with its cognate RNA, and that these contacts, acting in concert, provide the basis for the high affinity of this interaction.     

Fiberoptic Applications in Pipes and Pipelines

The advent of fiberoptic technologies has provided the communication and instrumentation worlds with a new tool. Fiberoptics offer high noise immunity, large bandwidth, and interesting sensor properties. The uses of fibers span from the telecommunications area, to the futuristic medical and ``Star Wars' applications, to monitoring heat tracing on pipelines. A number of interesting and potentially useful applications of fiberoptics have been made to the area of pipes and pipelines. A summary of the basics of fiberoptics needed to understand applications in pipes and pipelines is provided. Communications, sensors, and unique applications are examined. Available literature related to the specific applications where fiberoptics are used in pipes and pipelines is referenced. Each example provides a new application of what promises to be a major technology of the 21st century. The understanding of fiberoptics today gives tomorrow's engineer a glimpse at tomorrow's monitoring, metering, and communication systems. A broad overview of these applications and an extensive referencing for further investigation is provided to give the interested engineer a good source document to start the study of fiberoptics for pipeline applications.     

Synthesis and biological activity of folic acid and methotrexate analogues containing L-threo-(2S,4S)-4-fluoroglutamic acid and DL-3,3-difluoroglutamic acid

Clinical and pathological features of 52 infants and children with atypical teratoid/rhabdoid tumor (ATT/RhT) of the central nervous system are defined. This tumor is typically misdiagnosed as a primitive neuroectodermal tumor (PNET) primarily because 70% of ATT/RhTs contain fields indistinguishable from classic PNETs. Separation of these two tumor types is crucial because the prognosis for ATT/RhT is given even when treatment includes surgery with or without radio and/or chemotherapy. These tumors are most common in infants less than 2 years of age. The cases described in this study arose in intracranially in all but one instance, although one-third had already spread throughout the subarachnoid space at presentation. Clinical signs and symptoms and radiological features do not distinguish ATT/RhTs from PNETs. The tumors are composed entirely (13%) or partly (77%) or rhabdoid cells. Seventy percent contains fields of typical PNET alone or in combinations with mesenchymal and/r epithelial elements. The immunohistochemical profile is unique: epithelial membrane antigen, vimentin, and smooth-muscle actin are positive in the majority of tumors and markers for germ-cell tumors are consistently negative. Abnormalities of chromosome 22 distinguish ATT/RhTs from PNETs, which typically display an i(17q) abnormality.     

Aqueous Precipitation of Spherical Zinc Oxide Powders for Varistor Applications

Aqueous precipitation has been used to prepare spherical ZnO particles. These powders have been shown to be suitable for use in the preparation of varistors. The uniform size distribution and uniform coating of these powders with the appropriate dopants allowed fabrication of varistors with improved properties over those fabricated from conventionally ball-milled and calcined powders. The improved properties were a high coefficient of nonlinearity (∼44) in the nonohmic region, a sharp change in electrical behavior from ohmic to nonohmic, and a high resistivity (5×10¹² SOM°m) at low voltages.     

Development and Evolution of Nanostructure in Bulk Thermoelectric Pb-Te-Sb Alloys

Motivated by reports of exceptionally high zT > 2 in thin film superlattices or “quantum well” materials with nanometer sized features, we have undertaken a study of composite materials with nanoscale features that promise to provide similar structures in bulk material. Nanometer scale layers of PbTe and Sb₂Te₃ with periodicities of 180 nm to 950 nm form when quenched eutectic PbTe-Sb₂Te₃ melt, crystallizing as Pb₂Sb₆Te₁₁, subsequently annealed. The lamellar spacing depends on the temperature and time of the anneal. The mechanism for the development of the nanostructures is probed by examining the fraction of material transformed as a function of anneal time. Preliminary analysis of the shape factor exponent reveals that the transformation to the nanostructured lamellae bears similarities to the thickening of very large plates. The coarsening of the lamellar spacing is also examined as a function of time and temperature.     

He-Ne激光与紫外线复合诱变桑黄菌原生质体的研究

对桑黄菌原生质体进行He-Ne激光与紫外复合诱变处理,经过3代筛选,筛选出了5株变异株S1~S5。5株变异株菌丝发酵产量比出发菌株均有所提高,S1比出发菌株增产64.06%;其中3株变异株多糖含量增加,多糖含量最高的菌株S4比出发菌株提高13.84%。酯酶同工酶分析表明变异株酯酶酶谱发生了变化,传代培养表明变异株具有较稳定的遗传性,正变异率估算表明He-Ne激光与紫外线复合诱变桑黄菌原生质体优于紫外线诱变。     

基于超声预处理的大米降血压多肽的制备及其功能评价

采用酶法制备大米降血压肽。本文研究大米降血压肽制备中底物蛋白的超声预处理、酶解产物的超滤提取纯化、大米降血压肽的抗消化道酶降解及原发性高血压大鼠(SHR)一次性灌胃试验等。试验结果表明,最优超声预处理的参数为每升处理液施加超声功率250 W、超声时间10 min、工作间歇比1:2、循环转速30 r/s。经过超声预处理,酶解产物对ACE的抑制率由未经超声预处理的69.8%提高到92.8%。5 kDa为最佳的超滤提取纯化截流分子质量。经过超滤,滤液的IC50值随大米多肽分子质量的降低而降至1.71 mg/mL。大米降血压多肽具有良好的抗消化道酶降解能力,对SHR大鼠具有明显的降血压效果。     

Atomic‐Precision Gold Clusters for NIR‐II Imaging

Near‐infrared II (NIR‐II) imaging at 1100–1700 nm shows great promise for medical diagnosis related to blood vessels because it possesses deep penetration and high resolution in biological tissue. Unfortunately, currently available NIR‐II fluorophores exhibit slow excretion and low brightness, which prevents their potential medical applications. An atomic‐precision gold (Au) cluster with 25 gold atoms and 18 peptide ligands is presented. The Au₂₅ clusters show emission at 1100–1350 nm and the fluorescence quantum yield is significantly increased by metal‐atom doping. Bright gold clusters can penetrate deep tissue and can be applied in in vivo brain vessel imaging and tumor metastasis. Time‐resolved brain blood‐flow imaging shows significant differences between healthy and injured mice with different brain diseases in vivo. High‐resolution imaging of cancer metastasis allows for the identification of the primary tumor, blood vessel, and lymphatic metastasis. In addition, gold clusters with NIR‐II fluorescence are used to monitor high‐resolution imaging of kidney at a depth of 0.61 cm, and the quantitative measurement shows 86% of the gold clusters are cleared from body without any acute or long‐term toxicity at a dose of 100 mg kg^?1.