Conference key distribution schemes for secure digital mobilecommunications

We propose a new service for digital mobile communication systems. The service enables two or more users to hold a secure conference. Two requirements must be considered: privacy and authentication. Privacy involves ensuring that an eavesdropper cannot intercept the conversations of the parties holding the conference. Authentication involves ensuring that service is not obtained fraudulently in order to avoid usage charges. We present two new conference key distribution schemes for digital mobile communication systems. In these schemes, a group of users can generate a common secret keg over a public channel so that they may hold a secure conference     

Proteinases in renal cell death

The role of proteinases in renal proximal tubule (RPT) cellular death was examined using specific inhibitors of proteinases. Rabbit RPT suspensions were incubated with antimycin A for 1 h or tetrafluoroethyl-L-cysteine (TFEC) for 4 h in the absence or presence of the specific cysteine proteinase inhibitor L-trans-epoxysuccinyl-leucylamido (4-guanidino)butane (E-64), the serine proteinase inhibitors N-p-tosyl-L-lysine chloromethyl ketone (TLCK) or 3,4-dichloroisocoumarin (DCS), the serine and cysteine proteinase inhibitors leupeptin or antipain, or the aspartic proteinase inhibitor pepstatin. E-64 and pepstatin decreased lactate dehydrogenase (LDH) release, a marker of cell death, from RPT exposed either to antimycin A or TFEC. TLCK, DCS, leupeptin, or antipain did not decrease antimycin A- or TFEC-induced cell death. Bromohydroquinone- or t-butylhydroperoxide-induced cell death was not decreased by any of the proteinase inhibitors. Loss of lysosomal membrane potential, indicated by neutral red release, occurred prior to the onset of antimycin A-induced cell death. Extensive inhibition of lysosomal cathepsins B and L by E-64 was correlated with cytoprotection. However, E-64 was only protective after some cell death had occurred. These results suggest that lysosomal cysteine and aspartic proteinases, but not serine proteinases, play a role in RPT cell death induced by antimycin A or TFEC. The observation that E-64 was only protective after some cell death had occurred suggests that lysosomal cathepsins are released from dying cells and subsequently attack the remaining viable cells.     

用复合烷基锂引发丁二烯聚合

对以环己烷为溶剂、四氢呋喃为微观结构调节剂、复合烷基锂为引发剂的丁二烯聚合反应过程进行了研究，考察了不同引发温度、不同配比的复合烷基锂对聚合反应的影响，并与以正丁基锂为引发剂的丁二烯聚合反应过程进行了比较。     

Characterization of type I 5 alpha-reductase activity in DU145 human prostatic adenocarcinoma cells

Each amino acid is represented by a vector of numerical measurements for the attributes of volume, area, hydrophilicity, polarity, hydrogen bonding, shape, and charge. Inter-residue distances are then calculated according to common metrics, and we introduce a new clustering objective function derived from information-theoretic considerations. The arguments of the function are the inter-object distances of the things to be clustered: in this case the amino acids. By means of approximating the solution of an integer programming problem, then, the residues are partitioned into clusters. The clusters obtained are compared with groups obtained in substitution/mutation studies and found to be similar. Thus, probably the strongest and most objective evidence to date is supplied for believing that physico-chemical properties account for the viability of substitutions and that the important similarities/differences are explained by a relatively small and simple set of properties.     

生物降解塑料开发现状与发展趋势

本文简要介绍国内外生物降解塑料的现状与发展趋势。     

Estimating eye care workforce supply and requirements

PURPOSE: To estimate the workforce supply and requirements for eye care in the United States. METHODS: Three models were constructed for analysis: supply of providers, public health need for eye care, and demand (utilization) for eye care. Ophthalmologists, other physicians, and optometrists were included in the models. Public health need was determined by applying condition-specific prevalence and incidence rates from population-based and other epidemiologic studies. Demand was determined by use of national databases, such as the National Ambulatory Care Survey, National Hospital Discharge Survey, and Medicare Part B. Time requirements for care were obtained through a stratified sample survey of the membership of the American Academy of Ophthalmology. RESULTS: Under modeling assumptions that use a work-time ratio of one between optometrists and ophthalmologists and between specialist and generalist ophthalmologists, a significant excess of eye care providers exists relative to both public health need and demand. Changes in the work-time ratio, work-hours per year per provider, care patterns for the same condition, or other factors could significantly reduce or eliminate the surplus relative to need. CONCLUSION: If optometrists are the preferred primary eye care provider, ophthalmologists would be in excess under all demand scenarios and all need scenarios where the optometrist to ophthalmologist work-time ratio is greater than 0.6. No excess of ophthalmologists would exist if ophthalmologists are the preferred primary eye care provider. Data on the appropriate work time ratio will help refine estimates of the imbalance between supply and requirements.     

Glomerular and tubular function in glycogen storage disease

Urinary protein and calcium excretion were assessed in 77 patients with the hepatic glycogen storage diseases (GSD): 30 with GSD-I (median age 12.4 years, range 3.2-32.9 years), 25 with GSD-III (median age 10.5 years, range 4.2-31.3 years) and 22 with GSD-IX (median age 11.8 years, range 1.2-35.4 years). Inulin (Cinulin) and para-aminohippuric acid (CPAH) clearances were also measured in 33 of these patients. Those with GSD-I had significantly greater albumin (F = 15.07, P < 0.001), retinol-binding protein (RBP) (F = 14.66, P < 0.001), N-acetyl-beta-D-glucosaminidase (NAG) (F = 9.41, P < 0.001) and calcium (F = 7.41, P = 0.001) excretion than those with GSD-III and GSD-IX. GSD-I patients (n = 18) also had significantly higher Cinulin (F = 5.57, P = 0.009), but CPAH did not differ (F = 0.77, NS). Renal function was normal in GSD-III and GSD-IX patients. In GSD-I, Cinulin (r = -0.51, P = 0.03) and NAG excretion (r = -0.40, P = 0.03) were inversely correlated with age, whereas albumin excretion was positively correlated with age (r = +0.41, P = 0.03). RBP and calcium excretion were generally high throughout all age groups. Hyperfiltration in GSD-I is associated with renal tubular proteinuria that occurs before the onset of significant albuminuria. Deficiency of glucose-6-phosphatase within the proximal renal tubule may primarily cause tubular dysfunction, glomerular hyperfiltration being a secondary phenomenon.     

自适应有源噪声控制的滤波-LMAD算法

本文研究了稳定非高斯环境下的自适应有源噪声控制问题，提出了滤波－ＬＭＡＤ（ｌｅａｓｔｍｅａｎａｂｓｏｌｕｔｅｄｅｖｉａｔｉｏｎ）算法及归一化滤波－ＬＭＡＤ算法，仿真结果表明，与常用的滤波－ＬＭＳ算法和归－化滤波－ＬＭＳ算法相比，本文提出了算法收敛速度更快。     

Psychiatric medication: what the occupational health nurse should know

1. Occupational health nurses need a general knowledge of psychiatric medications to work effectively with clients and their off site health providers. 2. Acquiring an understanding of the major classes of medications--anti-psychotic, anti-anxiety, anti-depressant, and antimanic--is important. 3. It is helpful to understand under what conditions and with which conditions psychotropic medications are helpful.