Age-related changes in blood lymphocyte subsets of Saudi Arabian healthy children

The age-related changes in absolute and percentage values of lymphocyte subsets in the peripheral blood of healthy children of different ages (1 month to 13 years) were studied by flow cytometry. The absolute and percentage values for most lymphocyte subpopulations differed substantially with age. Comparisons among age groups from infants through adults revealed progressive declines in the absolute numbers of leukocytes, total lymphocytes, and T, B, and natural killer (NK) cells. The percentages of T cells increased with age. Within the T-lymphocyte population, the CD8(+) subset increased but the CD4(+) subset decreased, resulting in a declining CD4(+)/CD8(+) ratio. The percentage of B cells declined, but that of NK cells remained unchanged. The percentage of HLA-DR+ T cells increased over time, but their number changed inconsistently. Our findings confirm and extend earlier reports on age-related changes in lymphocyte subpopulations. These data should be useful in the interpretation of disease-related changes, as well as therapy-dependent alterations, in lymphocyte subsets in children of different age groups.     

The effect of workload on the performance and availability of voting algorithms

Voting algorithms are a popular way to provide data consistency in replicated data systems. By maintaining multiple copies of data on distinct servers, they can increase the data's availability, as perceived by a user. Many models have been made to study the degree to which replication increases the availability of data, and some have been made to study the cost incurred in maintaining consistency. However, little work has been done to evaluate the time it takes to serve a request, accounting for server and network failures, or to determine the effect of workload on these measures. The effect of workload can be significant, since failures of system components are not important unless they are needed to deliver a service, and requests can force updates on data that would otherwise be outdated. In this paper, we use stochastic activity networks (SANs), a variant of stochastic Petri nets, to construct two variant models of a replicated file system, one using a static voting algorithm while the other using a dynamic voting algorithm to maintain data consistency. A Markov process representation is automatically constructed from each SAN model and is solved numerically. Specifically, we determine the availability and mean time to respond to write requests as a function of the number of replicated copies and workload offered to the system. The results illustrate that it is indeed possible to determine such measures analytically and that workload, as well as the number of copies, is an important determinant of availability and response time.     

Olefinations with a polymer-supported phosphinate

Ethyl 4-polystyryl(ethylphosphino)acetate has been prepared with a 2% crosslinked polystyrene. Its reactions with sodium exthoxide and an aldehyde or ketone give modified Wittig olefinations.     

Glyceride studies. V. The distribution of unsaturated acyl groups in vegetable triglycerides

The distribution of oleic, linoleic, linolenic, petroselinic, hexadec-9 and 11-enoic, sterculic, four conjugated octadecatrienoic acids, isolinolenic, and octadeca-6,9,12,15-tetraenoic acid in vegetable triglycerides has been studied by hydrolysis with pancreatic lipase. The results, discussed in terms of a selectivity factor, indicate that these unsaturated acids do not compete equally for the secondary hydroxyl group.     

Adjustment of the Position of the Reference Tap of an Adaptive Equalizer

The present structure of adaptive least mean-square error (LMSE) equalizers for data transmission has an unnecessary constraint of a fixed position for the reference tap. This constraint limits their performance. In this paper a gradient-directed method of adjusting the position of the reference tap is developed to minimize the mean-square distortion (MSD). A scheme for implementing this modified equalizer is proposed. Results of computer simulation are shown that indicate that for channels with delay distortion some improvement in performance can be achieved.     

Gamma-emitting radionuclides in the shallow marine sediments off the Sindh coast, Arabian Sea

Determination of gamma emitting radionuclides in shallow marine sediments off the Sindh coast has been carried out using a gamma spectrometry technique. The activity concentration measured in various sediment samples off the Sindh coast has been found to vary from 15.93 +/- 5.22 to 30.53 +/- 4.70 Bq kg(-1) for 226Ra, from 11.72 +/- 1.22 to 33.94 +/- 1.86 Bq kg(-1) for 228Ra and from 295.22 +/- 32.83 to 748.47 +/- 28.75 Bq kg(-1) for 40K. The calculated mean values of radium equivalent activity, absorbed dose rate and effective dose are 98 Bq kg(-1), 49 nGy h(-1) and 0.06 mSv y(-1), respectively. No artificial radionuclide was detected in the samples measured from the study area. As no data on radioactivity of the coastal environment of Pakistan are available, the data presented here will serve as baseline information on radionuclide concentration in shallow sea sediments off the Sindh coast. The data will also be useful for tracking pollution inventories from unusual radiological events (if any) in the territorial waters of the study area. Further, the information presented will contribute to modelling of a regional radioactivity database from the perspectives of the International Atomic Energy Agency's Asia-Pacific Marine Radioactivity Database and Global Marine Radioactivity Database.     

Morpho‐palynological investigations of natural resources: A case study of Surghar mountain district Mianwali Punjab,Pakistan

Surghar mountain belt has comparatively less natural resources of floral diversity because it is composed of minerals of different kinds making it less favorable for the growth of different vegetation. The pollen morphology of some selected plants from Surghar belt Mainwali has been evaluated. The pollen grains were measured and demonstrated using scanning electron microscopy (SEM). The examined plant specimens have a difference in size, shape, polarity, and their exine ornamentation. The pollen taxa show a huge variation in size and sculpture. Pollen fertility has also been estimated, shows that the selected plants are well‐known in the Surghar belt. The need of the hour is to conserve these plants having a higher fertility rate to cope with the deforestation in an area. The conclusion does not favor theories in which deforestation results in fast growth in population. It shows that the irrational management and unlawful cutting down of woods neglected by the forest department are the main causes of deforestation in the mountain belt of Mianwali. The findings show the importance of morphological characteristics in the identification of natural resource species in the area.     

Efficient conversion of light paraffinic naphtha to aromatics over metal-modified Mo/MFI catalysts

Journal of Porous Materials - The transformation of light naphtha to value-added aromatic compounds is gaining momentum in the petrochemical industry. In this work, a series of metal modified...     

Influence of Chemical Reaction on Mass Transport in Yield Stress Exhibiting Flow Regime

Theoretical Foundations of Chemical Engineering - In this study, the simulations for first-order chemical reactions (constructive and destructive) in the flow of the Casson fluid with...