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31.
Droplet-based microfluidics has gained extensive research interest as it overcomes several challenges confronted by conventional single-phase microfluidics. The mixing performance inside droplets/slugs is critical in many applications such as advanced material syntheses and in situ kinetic measurements. In order to understand the effects of operating conditions on the mixing performance inside liquid slugs generated by a microfluidic T-junction, we have adopted the volume of fluid method coupled with the species transport model to study and quantify the mixing efficiencies inside slugs. Our simulation results demonstrate that an efficient mixing process is achieved by the intimate collaboration of the twirling effect and the recirculating flow. Only if the reagents are distributed transversely by the twirling effect, the recirculating flow can bring in convection mechanism thus facilitating mixing. By comparing the mixing performance inside slugs at various operating conditions, we find that slug size plays the key role in influencing the mixing performance as it determines the amount of fluid to be distributed by the twirling effect. For the cases where short slugs are generated, the mixing process is governed by the fast convection mechanism because the twirling effect can distribute the fluid to the flow path of the recirculating flow effectively. For cases with long slugs, the mixing process is dominated by the slow diffusion mechanism since the twirling effect is insufficient to distribute the large amount of fluid. In addition, our results show that increasing the operating velocity has limited effects on improving the mixing performance. This study provides the insight of the mixing process and may benefit the design and operations of droplet-based microfluidics. 相似文献
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Ajay Kumar D. H. Shah M. G. R. Rajan U. R. Thakare S. M. Sharma 《Indian journal of clinical biochemistry : IJCB》1992,7(2):159-164
An external quality assessment was conducted to assess the performance of various laboratories for RIA of thhyroid related
hormones in two phases. In the first phase thirty five laboratories participated. At the end of first phase a meeting cum
workshop was organised to discuss the results of first phase, difficultires faced by the participants and pinpoint the short
oming. A second phase was then initiated with an objective of improvement in the performance, if any, where twelve samples
from four pools were distributed to twenty four laboratories who participated for the second phase. The overall return of
the results increased significantly from 71.8% (1586/2208) for the first phase to 92.4% (732/792) for the second phase. The
inter laboratory %CV for T3, T4 and TSH were lower during the second phase (30.6%, 19.0% and 31.6% respectively) as compared to those observed during first
phase (36.3%, 22.7% and 52.8% respectively). Similarly, there was an improvement in reproducibility of ALTM as %CV for T3, T4 and TSH decreased from 6.0%, 9.8% and 13.4% respectively to 4.5%, 4.6% and 8.5% respectively. The individual performances
of the participating laboratories viz. bias, variability of bias and imprecision also showed a trend towards improvement as
percent laboratories having desirable or acceptable results for T3, T4 and TSH increased from 10.7%, 60.7% and 0.0% respectively to 20.8%, 66.7% and 22.2% respectively. External quality assessment
thus appears to be beneficial in assessing the performane of a laboratory in comfparison with other laboratories and indeed
helps in improving the performance. 相似文献
36.
R. K. Singh A. Bansal S. K. Bansal A. K. Upadhyay V. K. Singh 《Indian journal of clinical biochemistry : IJCB》1992,7(1):61-65
Nychthemeral rhythmicity of urinary copper (Cu) was studied in 40 clinically healthy volunteers and 35 renal stone formers.
A marked diurnal rhythm was noticed in urinary Cu levels in healthy subjects with maximum excretion at 0000 to 0600 hr followed
by a progressive fall during the rest of the period reaching minimum between 1200 to 1800 hr in males and 0600 to 1200 hr
in female volunteers. Similarly, all stone patients exhibited a definite rhythm in urinary Cu with significant amplitude and
acrophases at 2145 hr for males and 2141 hr for female stone formers. However, there was no difference in mean 24-hr Cu excretion
in male and female stone formers, whereas a significant change was observed in case of healthy subjects. Urinary Cu was found
to be significantly increased in renal stone formers in comparison to healthy controls of either sex attributing a significant
role of this overlooked trace mineral in the crystallization and/or activation of either of the process of stone formation
in the renal tubules. 相似文献
37.
R. Kumar R. Kapoor B. Mittal A. Kumar R. D. Mittal 《Indian journal of clinical biochemistry : IJCB》2003,18(2):209-215
Metabolic abnormalities were investigated in 44 stone patients with first time (group 1) and 56 with 2 times stone formation
(group 2), and in 25 normal individuals. 24hr urine was analysed spectrophotometrically for oxalate, calcium, magnesium, citrate,
uric acid, phosphate and creatinine. Hypocitraturia and hyperoxaluria were the common abnormalities in the stone formers.
Stone patients had significantly higher urinary oxalate, calcium and uric acid and lower phosphate than normal individuals.
Citrate/calcium and magnesium/calcium ratio were significantly high in normal individuals than stone formers. Patients in
group 2 excreted significantly higher urinary calcium and lower citrate that patients in group 1. Citrate/calcium ratio was
higher in group 1 than group 2. Hypocitraturia, hyperoxaluria, hypercalciuria and increased citrate/calcium and magnesium/calcium
ratio seem to be an essential risk factor for stone formation. Patients with recurrent stone formation could be distinguished
from patients with first time stone formation on the basis of urinary calcium and citrate. 相似文献
38.
Amitabha Ray Anil Kumar Bahadur S. L. Dayalu Naik Bhuvnesh Kumar Sharma 《Indian journal of clinical biochemistry : IJCB》2001,16(2):199-202
Endogenous oestrogens are thought to be involved in breast cancer, but few studies could show the direct relationship between
hormones and pathological process of the disease. In the present study, oestradiol was estimated in the serum of pre-and postmenopausal
breast cancer patients along with normal healthy controls and patients with carcinoma of the uterine cervix which is not dependent
on oestrogens. Premenopausal patients with breast cancer showed higher levels of oestradiol as compared to premenopausal control
women as well as cervical cancer patients. Whereas, no statistically significant differences were observed in serum oestradiol
levels amongst postmenopausal groups of breast cancer, cervical cancer and normal women. The result of the study reflects
the association of oestradiol as well as its difference in the pathological events of pre and postmenopausal breast cancer. 相似文献
39.
The level of serum cholesterol (Ch), serum-high density lipoprotein cholesterol (HDLc), serum-low density lipoprotein cholesterol
(LDLc), serum very low density lipoprotein cholesterol (VLDLc), Triglyceride (Tg), Apolipoprotein A-1, B and ratio of Apolipoprotein
A1/B were observed in 151 survivors of myocardial infarction in different age groups. A significant increase was found in
the level of triglyceride, LDLc, apolipoprotein-B and a significant decrease in apolipoprotein-A1 and the ratio of apolipoprotein
A1/B. No significant alteration was found in serum cholesterol, HDLc except in the age group of 31–40 years and 41–50 years
and VLDLc. Thus, serum Apo A-1 and Apo-B may be considerably better markers for coronary artery disease than traditional lipid
parameters. 相似文献
40.
Bhupendra Pal Singh Shailendra Dwivedi Urmila Dhakad Ramesh Chandra Murthy Vimal Kumar Choubey Apul Goel Satya Narayan Sankhwar 《Indian journal of clinical biochemistry : IJCB》2016,31(1):50-56
Deficiency or excess of certain trace elements has been considered as risk factor for prostate cancer. This study was aimed to detect differential changes and mutual correlations of selected trace elements in prostate cancer tissue versus benign prostatic hyperplasia tissue. Zinc, copper, iron, calcium and selenium were analysed in histologically proven 15 prostate cancer tissues and 15 benign prostatic hyperplasia tissues using atomic absorption spectrophotometer. Unpaired two tailed t test/Mann–Whitney U test and Pearson correlation coefficient were used to compare the level of trace elements, elemental ratios and their interrelations. As compared to benign prostatic tissue, malignant prostatic tissue had significantly lower selenium (p = 0.038) and zinc (p = 0.043) concentrations, a lower zinc/iron ratio (p = 0.04) and positive correlation of selenium with zinc (r = 0.71, p = 0.02) and iron (r = 0.76, p = 0.009). Considerably divergent interrelationship of elements and elemental ratios in prostate cancer versus benign prostatic hyperplasia was noted. Understanding of differential elemental changes and their interdependence may be useful in defining the complex metabolic alterations in prostate carcinogenesis with potential for development of element based newer diagnostic, preventive and therapeutic strategies. Further studies may be needed to elucidate this complex relationship between trace elements and prostate carcinogenesis. 相似文献