Effect of antimicrobial compounds tylosin and chlortetracycline during batch anaerobic swine manure digestion

Tylosin and chlortetracycline (CTC) are antimicrobial chemicals that are fed to >45% of the US swine herds at therapeutic and sub-therapeutic dosages to enhance growth rates and treat swine health problems. These compounds are poorly absorbed during digestion so that the bioactive compound or metabolites are excreted. This study investigated the degradation and stabilization of swine manure that contained no additives and compared the observed processes with those of manure containing either tylosin or CTC. The batch anaerobic incubation lasted 216 days. The breakdown of insoluble organic matter through anaerobic hydrolysis reactions was faster for manure containing CTC compared with tylosin or no-antimicrobial treatments. Volatile fatty acid (VFA) accumulation, including acetate, butyrate, and propionate, was greater for CTC-containing manure compared to tylosin and no-antimicrobial treatments. The relative abundance of two aceticlastic methanogens, Methanosaetaceae and Methanosarcinaceae spp., were less for CTC manure than manure with no-antimicrobial treatment. In addition, generation of methane and carbon dioxide was inhibited by 27.8% and 28.4%, respectively, due to the presence of CTC. Tylosin effects on manure degradation were limited, however the relative abundance of Methanosarcinaceae spp. was greater than found in the CTC or no-antimicrobial manures. These data suggest that acetate and other C-1 VFA compounds would be effectively utilized during methanogenesis in the presence of tylosin.     

Mathematical modelling of protein diffusion in microcapsules: A comparison with experimental results

The objective of this study was to develop a general diffusion model for describing mass transport phenomena and membrane diffusivities in alginate—polylysine (PLL) microcapsules. Good agreement between calculated and experimental protein concentration profiles was obtained based on a microcapsule model, consisting of a capsule membrane containing a partially impermeable alginate gel core with a decreasing gel pore size towards the centre of the capsule. The apparent size of the impermeable gel core and the capsule membrane permeability were directly dependent on the size of the diffusing protein and the alginate-PLL reaction time. The presence of this impermeable core may hinder the commercial and clinical use of these microcapsules in cell culture engineering and cell transplantation by affecting cell viability.     

Variation of the specific surface area and porosity of zinc oxide prepared in various atmospheres

Specific surface area and pore structure studies were carried out on zinc oxide samples prepared from zinc oxalate dihydrate by heating at 330 and 370°C and in various atmospheres of water vapour, oxygen and hydrogen. The variation of S_BET with water vapour pressure for the samples heated at 330°C was found to show a behaviour which can be compared with the Smith-Topley effect. For the samples prepared at 370°C, rapid sintering occurred, and the Smith-Topley effect was not followed in this case. Zinc oxide prepared in an oxygen atmosphere gave higher surface area values than that prepared in a hydrogen atmosphere, which is thought to be due to the oxidation of the carbon impurities on the surface. Analysis of nitrogen adsorption isotherms by the t-method revealed the existence of micropores in the sample prepared at 330°C in vacuo. The rest of the samples have wide pores.     

Residualisation and resilience: public housing in Hong Kong

Public housing has been an important element in the welfare state and a substantial literature has analysed its origins and growth in different places. However, as it has matured and been redefined by privatisation and regeneration, debates have changed and increasingly been concerned with residualisation and decline. This paper outlines considerations affecting comparative analysis of public housing and presents new material related to explanations for the resilience of public housing in Hong Kong.     

灌排系统水转化模拟模型研究

受自然与人为因素综合影响,灌区水转化过程复杂多变。以湖北漳河水库灌区为例,分别从水平和垂直方向描述典型灌排系统的水转化过程,以水量平衡原理为基础,研发灌排系统边界处置、稻作区田间多层土壤、塘坝及排水沟道之间多个水转化模拟子模块,由此构建一种客观描述灌排系统边界半封闭结构及其水平输送、垂直运动与渠-田-沟-塘水转化过程的耦合模拟模型,解决了应用流域分布式水文模型求解灌区水转化过程中面临的灌区边界不确定、分层土壤简化处理等问题。利用漳河灌区谭店灌排系统2014-2015年水平衡测试观测数据对该模型进行检验,采用拉丁超立方抽样法对模型参数进行分层抽样,并利用偏相关法分析参数敏感性。通过模型计算可得,支沟率定期和验证期模拟结果的复相关系数分别为0.83、0.70,Ens系数分别为0.81、0.68,斗沟率定期和验证期模拟结果的复相关系数分别为0.79、0.68,Ens系数分别为0.73、0.62,结果表明该模型适用于灌排系统水转化过程模拟。与SWAT模型对比,对于同一研究区域,复相关系数由0.11提高到0.73,Ens系数由-0.71提高到0.70,进一步验证了该模型的先进性,为灌排系统尺度水转化模拟和机制研究提供了新方法。     

Gray-scale ultrasound: utility preoperatively and postoperatively in a patient with obstructive jaundice

We present a case of obstructing calculi of the common bile duct diagnosed by ultrasonography. Postoperatively, a sterile abscess due to bile leakage at the distal common bile duct developed, and was also diagnosed by ultrasound Ultrasonography was useful in following the course of clearing of the bile collection. Preoperative ultrasound evaluation of the jaundiced patient should be followed by postoperative sonography, especially if complications occur.     

Modification and abolition of re-entry within the His-Purkinje system in man by diphenylhydantoin

The phenomenon of macrore-entry (Re) within the His-Purkinje system (HPS) was consistently observed in 10 of 19 patients during retrograde refractory period studies. Effects of intravenous infusion of diphenylhydantoin (DPH) on Re were studied in these 10 patients 10 minutes after completion of infusion (mean plasma level equal to 17.0 microgram/ml). Diphenylhydantoin modified determinants of Re in seven patients (group I) and abolished Re in the remaining three patients (group II). In group I, DPH shortened the critical V1 V2 from 310.0 +/- 30.5 to 292.9 +/- 25.6 msec (P less than 0.025) and critical V2 H2 intervals for Re from 201.4 +/- 18.4 to 185.0 +/- 13.8 msec (P greater than 0.05). In group II, DPH abolished Re in two of three patients by precluding attainment of critical V2 H2 intervals whereas Re was abolished in the remaining one patient despite attainment of critical V2 H2 intervals (vs control). For both groups, DPH significantly shortened functional and effective refractory periods of the HPS (P less than 0.001 and less than 0.01, respectively) without significantly affecting the effective refractory period of the ventricular muscle. Diphenylhydantoin either completely abolished or significantly shortened the retrograde gap zones in the HPS. It is concluded that diphenylhydantoin significantly shortens His-Purkinje system refractoriness, abolishing Re in the patients with higher degree of improvement in refractoriness.     

Passively addressed FLC display possessing an inherent gray scale and memory

Abstract— A passively addressed 64 × 64 ferroelectric liquid‐crystal display (FLCD) has been developed. The display matrix has a 33 × 33 mm² aperture, and the FLC layer thickness is 5.2 ± 0.2 μm. The display device operates with a frame frequency of 30 Hz (at V_row = ±18 V, V_col = ±9 V, T = 23°C), generating a continuous gray scale which can be memorized for more than 10 days after the driving voltage is switched off. A new approach for multiplex electronic addressing of the FLCD gray scale is proposed. The conditions of the hysteresis‐free gray‐scale generation for multiplex addressing and the gray‐scale memorization after the voltage is switched off, as well as the time steadiness of memorized images, are considered.     

Participation of AT1 and AT2 receptor subtypes in the tonic inhibitory modulation of baroreceptor reflex response by endogenous angiotensins at the nucleus tractus solitarii in the rat

Although myelin basic protein (MBP)-recognizing T cells are not readily obtained after immunization of BALB/c mice with MBP (reflecting the BALB/c resistance to actively induced experimental autoimmune encephalomyelitis (EAE)), they can be expanded and cloned after several rounds of in vitro culture. The majority of BALB/c-derived clones recognize an epitope defined by MBP peptide 59-76. When transferred to naive BALB/c recipients, these clones cause classical EAE, with characteristic inflammation and demyelination of the central nervous system (CNS). We previously showed that two related clones recognizing a minor epitope, defined by MBP peptide 151-168, cause inflammation and demyelination preferentially of the peripheral nervous system (PNS). Because MBP has alternatively spliced isoforms, residues 151-168 are not present contiguously in all MBP isoforms. In order to determine whether induction of PNS disease is idiosyncratic to these sister clones, or related to their properties of epitope recognition, an independent T-cell line with similar recognition properties was studied. Clone 116F, derived from a BALB/c shiverer mouse, expresses a different T-cell receptor (TCR), with distinct TCR contact residues, but like the previously described T cells, this clone requires residues from both exons 6 and 7 for optimal stimulation. When adoptively transferred to BALB/c recipients, this clone preferentially induces disease of the PNS. A control BALB/c shiverer-derived MBP 59-76-recognizing clone, in contrast, induces CNS disease. These data strongly suggest that the site of disease initiation may correlate with epitope recognition, particularly when alternative isoforms are involved.