硝酸银电位滴定法测定铁矿石中水溶氯

以2g/L硫酸钾为溶解试剂,硝酸银为滴定剂,电位滴定法测定铁矿石中的水溶氯,通过电极电位-浓度二次微商滴定曲线,计算二次微商等于零时对应的V为滴定终点,可省去绘制E-V曲线或ΔE/ΔV-V一次微商曲线作图带来的麻烦。试验比较了温度、酸度、搅拌方式等对测定结果的影响,对干扰元素及活度与浓度的关系进行了分析。方法的相对标准偏差小于2.12%,用于实际样品分析加标回收率在90.0%~108.0%之间。     

一种新型水溶性金属注射成形用粘结剂的研制

论文在抽提MI M粘结剂中水溶性组分及高分子组元功能的基础上,通过参数计算、溶解试验确定了水溶性组分的品种、PEG的分子量分布,进而结合混合试验以及扫描电镜测试确定了水溶性MI M粘结剂中的高分子组元和整个粘结剂配方。结果表明,PEG是一种合适的水溶性组分,恰当的分子量分布,即10%PEG600+30%PEG1000+60%PEG1500的混合配方可以满足MI M工艺对其热收缩率的要求;PEG-POM具有热力学相容性,其混合物流动性、冷却强度好但水溶性差;PMMA分子量对PMMA-PEG的混合性具有决定性的作用,在PMMA分子量适中(M=(40·7~98·4)×104)时,PEG-PMMA混合物相容性、冷却强度和水溶性都较好,但流动性稍差;当PEG-POM-PMMA三者以75∶23∶2配比组成三元系时,它兼备了PEG-POM和PEG-PMMA二元体系的优点,总体效果最好。为了增加粘结剂水溶性组分PEG的热稳定性、改善组分间的相容性、降低黏度和增加粘结剂对粉末的润湿性,粘结剂需要配以适量抗氧剂BHT、增塑剂DOP和表面活性剂。最终确定粘结剂适宜配方为:PEG72%,POM23%,PMMA2%,SA2%,DOP1%,BHT0·01%。     

从硝酸银废液中回收成品银的方法研究

提出了一种从硝酸银废液中回收银新方法。可直接得到成品银。新方法操作简单，劳动强度低。银回收率高。产品纯度高。     

A new class of soluble guanylate cyclase activators, generating nitric oxide

Derivatives of diazetidine-di-N-oxides have been found capable nonenzymatic generation of nitric oxide by a principally new mechanism of nitric oxide splitting at physiological values of pH. The effects of the synthesized compounds on human platelet soluble guanylate cyclase activity have been studied. Four of seven derivatives exhibited a distinct correlation between the ability of being decomposed with nitric oxide formation and soluble guanylate cyclase activation. Among those, 3-bromo-4-methyl-3.4-tetramethylene-diazetidine-di-N-oxide proved to be the most effective activator, its spasmolytic effect being commensurate with the glyceryl trinitrate activity. The data obtained open up new opportunities for a search into new vasodilatory agents among compound whose chemical structure provides nitric oxide generation and guanylate cyclase activation in human tissues. Besides, they provide evidence that 1.2-diazetidine-1.2-di-N-oxide derivatives are perspective objects for creating new vasodilatory drugs.     

A structural rationale for the design of water soluble peptide-derived neurokinin-1 antagonists

Molecular models of a pharmacophore for NK1 neurokinin antagonists and of ligand-receptor complexes for the human NK1 G protein-coupled receptor are presented. The models develop a structural rationale for the discovery of the recently described highly potent peptidomimetic NK1 antagonists S18523 and S19752 which were designed to be water soluble. Water solubility was conferred on these compounds by introduction of an anionic butyl-tetrazole substituent on the scaffold of dipeptide-derived NK1 antagonist analogues. The models provide convincing evidence that the anionic butyl-tetrazole moieties of S18523 and S19752 protrude outside the membrane-spanning domain of the receptor and do not interfere significantly with the core of the antagonist binding site. It is emphasized that this result could only be obtained through the combination of the two modelling approaches. The result suggest a general way to modify the transport properties of the peptidomimetic antagonists without altering the receptor-binding interaction, and it outlines the potential of including the combination of pharmacophore models and crude models of receptor-ligand complexes early in the drug design process.     

Water debinding behaviour of water soluble Ti-MIM feedstock

Abstract

A water soluble polyethylene glycol (PEG) based binder system was used to formulate three feedstocks containing prealloyed Ti–6Al–4V, NiTi and blended elemental Ni/Ti powders respectively. The selection of these metal powders was to investigate the effect of powder characteristics such as particle size and particle shape. Various solid loadings were investigated in these feedstocks. The water debinding behaviours were systematically studied in terms of debinding temperature, time, sample thickness, powder characteristics and solid loading. Corresponding debinding rate was calculated from the measurements using a shrinking core reaction kinetic model.     

A new view of water dynamics in immobilized proteins

The inflection frequency of the deuteron magnetic relaxation dispersion from water in rotationally immobilized protein samples has recently been found to be essentially independent of temperature and protein structure. This remarkable invariance has been interpreted in terms of a universal residence time of 1 microseconds for protein-associated water molecules. We demonstrate here that this interpretation is an artifact of the conventional perturbation theory of spin relaxation, which is not valid for rotationally immobile proteins. Using a newly developed non-perturbative, stochastic theory of spin relaxation, we identify the apparent correlation time of 1 microseconds with the inverse of the nuclear quadrupole frequency, thus explaining its invariance. The observed dispersion profiles are consistent with a broad distribution of residence times, spanning the microseconds range. Furthermore, we argue that the deuteron dispersion is due to buried water molecules rather than to the traditional surface hydration previously invoked, and that the contribution from rapidly exchanging protein hydrogens cannot be neglected. The conclusions of the present work are also relevant to proton relaxation in immobilized protein samples and to magnetic resonance imaging of soft tissue.     

新型高效节能高压水除鳞系统

高压水除鳞效果的好坏直接影响钢板产品的表面质量及轧辊寿命.本文介绍了一种新型高效节能高压水除鳞系统,该系统应用高压变频调速技术、宽窄除鳞独立或联用控制技术、低压预充水技术、隔膜式蓄势罐缓冲减振技术、高压大流量离心泵、自动反洗过滤装置、2级计算机系统自动控制等多项前沿技术,取得了较好的经济与社会效益.     

HpSS: a new silver staining method for Helicobacter pylori

Fifty-seven patients with clinically localized prostate cancer were treated by radical prostatectomy or external radiation therapy following pelvic lymphadenectomy. Comparing the outcome of radiotherapy with that of prostatectomy in 42 T2 patients without lymph node metastasis, the 5-year cause-specific survival did not differ between the radical prostatectomy group (n = 31) and radiotherapy group (n = 11). The 5-year disease-free survival of the prostatectomy group, however, was superior to that of radiotherapy group (p = 0.01). To cure patients with T2 prostate cancer, therefore, it is supposed that radical prostatectomy should be performed. To improve the treatment outcome after radiotherapy, stereotactic radiosurgery for prostate cancer has been attempted in our institution. Phantom experiments using a linear accelerator demonstrated a round dose distribution, and high reproducibility of prostate positioning was confirmed by CT when a thermoplastic immobilization device was used to fix the pelvis. In one patient with localized prostate cancer treated by radiosurgery, acute complication has not been recognized during the 5 week follow-up. Radiosurgery may be available to treat clinically localized prostate cancer.     

锰银矿同步浸出锰、银新工艺试验研究

介绍了在H2O2体系中处理锰银矿新方法。针对矿石中锰和银的赋存形式,采用在硫酸溶液中加入H2O2可以实现二氧化锰还原和银氧化同时进行。为了进一步提高银的浸出率,在溶液中加入高锰酸钾,以浸出未被二氧化锰包裹的银。研究结果表明,在最佳浸出条件下,锰浸出率可达到96．71％,银浸出率达85．1％。     

新型含银配合物的合成与表征

合成了一种由银直接连接Anderson型钼氧酸盐阴离子形成的新型二维配合物,并用单晶X射线衍射仪测定了其晶体结构,用元素分析仪及红外光谱等进一步表征了化合物的结构。含银配合物为三斜晶系,P-1空间群,晶胞参数为a=1.1676(3)nm,b=1.2205(4)nm,c=1.2566(6)nm;α=95.313(5)°,β=113.974(5)°,γ=117.079(3)°;V=1.3695(9)nm3,Z=1。配合物中,相邻的4个{Fe(OH)6Mo6O18}3-之间存在两种连接方式,一种是被孤立的{AgO6}八面体通过端氧沿b轴连接起来;另一种则是被2个共边相连的{AgO6}八面体通过端氧沿b轴桥连起来。这两种连接方式沿c轴方向交替排列形成了二维网状结构。     

Antarelix (EP 24332) a novel water soluble LHRH antagonist

A novel water soluble LHRH antagonist (EP 24332-Antarelix) is described. Its activity in vitro and in vivo in several animal models is given. Antarelix (Ac-D-Nal, D-Cpa, D-Pal, Ser, Tyr, D-Hci, Leu, Lys-(iPr), Pro, D-Ala-NH2) in view of its potency, modest histamine-liberating activity and high water solubility has been selected for further development.     

Release kinetics of coated, donut-shaped tablets for water soluble drugs

Coated, donut-shaped tablets (CDST) were designed to achieve parabolic and linear drug release profiles. When rapidly erodible polymers (HPMC E3, HPC, PEG8000, PEOs (Mw=100000 and 200000)) were used, the release profiles of diltiazem HCl from the tablets becomes parabolic whereas zero-order release was achieved by using slowly erodible polymers (HPMC E5, HPMC E15, PEO (Mw=300000)). Drug release from the rapidly erodible polymers was governed by the pure erosion of the polymer while both polymer erosion and drug diffusion controlled drug release from the slowly erodible polymers. As drug loading was increased from 10% to 39% w/w, the drug release rate from CDST based on HPMC E3 became faster and parabolic whereas that from CDST based on HPMC E5 was linear. The slowly erodible polymer (HPMC E5) provided parabolic release profiles when drug loading was greater than 49% w/w. In this case, drug release mechanisms likely shifted from a combination of polymer erosion and drug diffusion to pure polymer erosion due to the enhancement of polymer erosion by faster influx of water. As drug solubility decreased from 61.6% w/v (diltiazem HCl), 1.0% w/v (theophylline), to 0.5% w/v (nicardipine HCl), the drug release rate from CDST based on HPMC E3 decreased due to polymer erosion mechanism but there was little difference in release rate from CDST based on HPMC E5 due to the greater contribution of drug diffusion to drug release kinetics along with polymer erosion. As expected, the drug release rate of diltiazem HCl from HPMC E3 and E5 was significantly influenced by stirring rate and hole size.