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1.
N. Maithili Karpaga Selvi M. G. Sridhar R. P. Swaminathan R. Sripradha 《Indian journal of clinical biochemistry : IJCB》2015,30(2):180-186
It is known that there is a significant interplay of insulin resistance, oxidative stress, dyslipidemia, and inflammation in type 2 diabetes mellitus (T2DM). The study was undertaken to investigate the effect of turmeric as an adjuvant to anti-diabetic therapy. Sixty diabetic subjects on metformin therapy were recruited and randomized into two groups (30 each). Group I received standard metformin treatment while group II was on standard metformin therapy with turmeric (2 g) supplements for 4 weeks. The biochemical parameters were assessed at the time of recruitment for study and after 4 weeks of treatment. Turmeric supplementation in metformin treated type 2 diabetic patient significantly decreased fasting glucose (95 ± 11.4 mg/dl, P < 0.001) and HbA1c levels (7.4 ± 0.9 %, P < 0.05). Turmeric administered group showed reduction in lipid peroxidation, MDA (0.51 ± 0.11 µmol/l, P < 0.05) and enhanced total antioxidant status (511 ± 70 µmol/l, P < 0.05). Turmeric also exhibited beneficial effects on dyslipidemia LDL cholesterol (113.2 ± 15.3 mg/dl, P < 0.01), non HDL cholesterol (138.3 ± 12.1 mg/dl, P < 0.05) and LDL/HDL ratio (3.01 ± 0.61, P < 0.01) and reduced inflammatory marker, hsCRP (3.4 ± 2.0 mg/dl, P < 0.05). Turmeric supplementation as an adjuvant to T2DM on metformin treatment had a beneficial effect on blood glucose, oxidative stress and inflammation. 相似文献
2.
Applying metal organic frameworks (MOFs) in electrochemical systems is a currently emerging field owing to the rich metal nodes and highly specific surface area of MOFs. However, the problems for MOFs that need to be solved urgently are poor electrical conductivity and low ion transport. Here we present a facile in situ growth method for the rational synthesis of MOFs@hollow mesoporous carbon spheres (HMCS) yolk–shell-structured hybrid material for the first time. The size of the encapsulated Zeolitic Imidazolate Framework-67 (ZIF-67) is well controlled to 100 nm due to the spatial confinement effect of HMCS, and the electrical conductivity of ZIF-67 is also increased significantly. The ZIF@HMCS-25% hybrid material obtained exhibits a highly efficient oxygen reduction reaction activity with 0.823 V (vs. reversible hydrogen electrode) half-wave potential and an even higher kinetic current density (JK = 13.8 mA cm−2) than commercial Pt/C. ZIF@HMCS-25% also displays excellent oxygen evolution reaction performance and the overpotential of ZIF@HMCS-25% at 10 mA cm−2 is 407 mV. In addition, ZIF@HMCS-25% is further employed as an air electrode for a rechargeable Zn–air battery, exhibiting a high power density (120.2 mW cm−2 at 171.4 mA cm−2) and long-term charge/discharge stability (80 h at 5 mA cm−2). This MOFs@HMCS yolk–shell design provides a versatile method for the application of MOFs as electrocatalysts directly. 相似文献
3.
Most metal–organic frameworks (MOFs) hardly maintain their physical and chemical properties after exposure to alkaline aqueous solutions, thus precluding their use as potential electrode materials for electrochemical energy storage devices. Here, we present the design and synthesis of a highly alkaline-stable metal oxide@MOF composite, Co3O4 nanocube@Co-MOF (Co3O4@Co-MOF), via a controllable and facile one-pot hydrothermal method under highly alkaline conditions. The obtained composite possesses exceptional alkaline stability, retaining its original structure in 3.0 M KOH for at least 15 days. Benefitting from the exceptional alkaline stability, unique structure, and larger surface area, the Co3O4@Co-MOF composite shows a specific capacitance as high as 1020 F g−1 at 0.5 A g−1 and a high cycling stability with only 3.3% decay after 5000 cycles at 5 A g−1. The as-constructed solid-state flexible device exhibits a maximum energy density of 21.6 mWh cm−3. 相似文献
4.
Jyotsna A. Patil Arun J. Patil Ajit V. Sontakke Sanjay P. Govindwar 《Indian journal of clinical biochemistry : IJCB》2012,27(2):134-140
The aim of this study was to see the biochemical effects of pesticides on sprayers of grape gardens before and after 15 days of vitamin E supplementations in Western Maharashtra (India), who were occupationally exposed to various pesticides over a long period of time (about 5 to 15 years). Blood samples were collected from all study group subjects for biochemical parameters assays before and after 15 days of vitamin E supplementation. Sprayers of grape gardens were given 400 mg of vitamin E tablet/day for 15 days. After 15 days of vitamin E supplementation to sprayers of grape gardens, we observed significantly decreased aspartate transaminase (10.88 %, P < 0.05, r = 0.88), alanine transaminase (25.92 %, P < 0.01, r = 0.46) and total proteins (3.32 %, P < 0.01, r = 0.33), whereas, no statistically significant change was found in serum acetyl cholinesterase, C-reactive proteins, albumin (ALB), globulins and ALB/globulin ratio as compared to before vitamin E supplementation. Sprayers of grape gardens, who received vitamin E supplementation, showed significantly decreased serum lipid peroxide (LP) (18.75 %, P < 0.001, r = 0.63) and significantly increased RBC-superoxide dismutase (SOD) (12.88 %, P < 0.001, r = 0.85), RBC-Catalase (CAT) (24.49 %, P < 0.001, r = 0.70), plasma ceruloplasmin (CP) (4.6 %, P < 0.01, r = 0.80), serum zinc (4.57 %, P < 0.01, r = 0.83) and serum copper (4.37 %, P < 0.01, r = 0.79) as compared to values before vitamin E supplementation. These results showed that vitamin E supplementation has ameliorating effects on these transaminase enzymes, suggesting that it may have a protective effect on liver, from pesticides induced damage. In this study vitamin E supplementation might have decreased LP levels by breaking chain reaction of lipid peroxidation. Present results indicate that vitamin E plays a crucial role in restoring the antioxidant enzymes such as SOD, CAT and CP, in population exposed to pesticides. This helps to enhance its antioxidant ability. Therefore, it is suggested that farmers, pesticide applicators, workers in the pesticide industry and other pesticide users, who come in regular contact with pesticides, may be benefited by supplementation with vitamin E. 相似文献
5.
Temperature probes onboard the Chang’E-4 (CE-4) spacecraft provide the first in situ regolith temperature measurements from the far side of the Moon. We present these temperature measurements with a customized thermal model and reveal the particle size of the lunar regolith at the CE-4 landing site to be ∼15 μm on average over depth, which indicates an immature regolith below the surface. In addition, the conductive component of thermal conductivity is measured as ∼1.53 × 10–3 W m–1 K–1 on the surface and ∼8.48 × 10–3 W m–1 K–1 at a depth of 1 m. The average bulk density is ∼471 kg m–3 on the surface and ∼824 kg m–3 in the upper 30 cm of the lunar regolith. These thermophysical properties provide important additional ‘ground truth’ at the lunar far side, which is critical for the future analysis and interpretation of global temperature observations. 相似文献
6.
Shuangshuang Tan Yalong Jiang Shuyan Ni Hao Wang Fangyu Xiong Lianmeng Cui Xuelei Pan Chen Tang Yaoguang Rong Qinyou An Liqiang Mai 《国家科学评论(英文版)》2022,9(11)
The uncontrollable formation of Li dendrites has become the biggest obstacle to the practical application of Li-metal anodes in high-energy rechargeable Li batteries. Herein, a unique LiF interlayer woven by millimeter-level, single-crystal and serrated LiF nanofibers (NFs) was designed to enable dendrite-free and highly efficient Li-metal deposition. This high-conductivity LiF interlayer can increase the Li+ transference number and induce the formation of ‘LiF–NFs-rich’ solid–electrolyte interface (SEI). In the ‘LiF–NFs-rich’ SEI, the ultra-long LiF nanofibers provide a continuously interfacial Li+ transport path. Moreover, the formed Li–LiF interface between Li-metal and SEI film renders low Li nucleation and high Li+ migration energy barriers, leading to uniform Li plating and stripping processes. As a result, steady charge–discharge in a Li//Li symmetrical cell for 1600 h under 4 mAh cm−2 and 400 stable cycles under a high area capacity of 5.65 mAh cm−2 in a high-loading Li//rGO–S cell at 17.9 mA cm−2 could be achieved. The free-standing LiF–NFs interlayer exhibits superior advantages for commercial Li batteries and displays significant potential for expanding the applications in solid Li batteries. 相似文献
7.
Yuxiang Zhang Haixu Bo Zhe Jiang Yu Wang Yunfei Fu Bingwei Cao Xuewen Wang Jiaqi Chen Rui Li 《国家科学评论(英文版)》2021,8(11)
In early 2020, unprecedented lockdowns and travel bans were implemented in Chinese mainland to fight COVID-19, which led to a large reduction in anthropogenic emissions. This provided a unique opportunity to isolate the effects from emission and meteorology on tropospheric nitrogen dioxide (NO2). Comparing the atmospheric NO2 in 2020 with that in 2017, we found the changes of emission have led to a 49.3 ± 23.5% reduction, which was ∼12% more than satellite-observed reduction of 37.8 ± 16.3%. The discrepancy was mainly a result of changes of meteorology, which have contributed to an 8.1 ± 14.2% increase of NO2. We also revealed that the emission-induced reduction of NO2 has significantly negative correlations to human mobility, particularly that inside the city. The intra-city migration index derived from Baidu Location-Based-Service can explain 40.4% ± 17.7% variance of the emission-induced reduction of NO2 in 29 megacities, each of which has a population of over 8 million in Chinese mainland. 相似文献
8.
K. Rohini Surekha Bhat P. S. Srikumar A. Mahesh Kumar 《Indian journal of clinical biochemistry : IJCB》2015,30(3):329-333
The present study was aimed at assessing alterations in serum PCT in terms of its relation to body weight gain in pulmonary tuberculosis (PTB) patients undergoing treatment. Among patients (25–75 years) diagnosed with pulmonary tuberculosis, those that were new smear positive, showed sputum conversion at the end of 2 months and were declared clinically cured at the end of 6 months, were included in the study (n = 40). Serum procalcitonin was determined by BRAHMS PCT-Q kit. Patients were divided into two study groups—Group 1 (n = 21; serum PCT > 2 ng/ml at diagnosis), Group 2 (n = 19; serum PCT > 10 ng/ml at diagnosis). Body weights of all patients were obtained at three different time points, PTB-0 (at diagnosis), PTB-2 (after 2 months of intensive treatment) and PTB-6 (after 6 months of treatment). In both groups, mean body weights at PTB-2 and PTB-6 were significantly higher than those at PTB-0 and at PTB-6 were significantly higher than those at PTB-2. However, percentage body weight gain following 2 months of intensive treatment was higher in group 1 (4.05 % gain, p < 0.01) than in group 2 (2.75 % body weight gain, p < 0.05). Thus, the percentage gain in group 1 was tending more towards the desirable minimum gain of 5 % during intensive phase. Increase in serum PCT levels in pulmonary tuberculosis is inversely associated with body weight gain during treatment. Thus, PCT could play a role in regulation of body weight gain in anorectic conditions like tuberculosis. 相似文献
9.
Pannuru Padmavathi Vaddi Damodara Reddy Kodidela Swarnalatha Reddyvari Hymavathi N. Ch. Varadacharyulu 《Indian journal of clinical biochemistry : IJCB》2015,30(2):204-209
The present study was designed to understand the cigarette smoking-induced alterations in hormones and the resulting changes in platelet serotonin (5-hydroxytryptamine, 5-HT) and monoamine oxidase (MAO-B) activity in chronic smokers. Human male volunteers aged 35 ± 8 years, were divided into two groups, namely controls and smokers (12 ± 2 cigarettes per day for 7–10 years). Results showed that cigarette smoking significantly (p < 0.05) elevated plasma triiodothyronine (T3), cortisol and testosterone levels with significant (p < 0.05) reduction in plasma tryptophan and thyroxin (T4). Moreover, smokers showed reduced platelet 5-HT levels and MAO-B activity. In smokers, plasma cortisol was negatively correlated with tryptophan (r = −0.386), platelet MAO-B (r = −0.264), and 5-HT (r = −0.671), and positively correlated with testosterone (r = 0.428). However, testosterone was negatively correlated with platelet MAO-B (r = −0.315), and 5-HT (r = −.419) in smokers. Further, smokers plasma T3 levels were negatively correlated with platelet MAO-B (r = −0.398), and 5-HT (r = −0.541), whereas T4 levels were positively correlated with platelet MAO-B (r = 0.369), and 5-HT (r = 0.454). In conclusion, our study showed that altered testosterone and cortisol levels may aggravate behavior, mood disturbances and symptoms of depression by decreasing platelet 5-HT and MAO-B activity in smokers. 相似文献
10.
Anthony J. Usoro Aniebietabasi S. Obot Itemobong S. Ekaidem Okon E. Akaiso Alphonsus E. Udoh O. Akinloye 《Indian journal of clinical biochemistry : IJCB》2015,30(1):59-65
Prostate carcinoma is the most frequently diagnosed malignancy and the second leading cause of death as a result of cancer in men in the US and other parts of the world. There are conflicting reports on the serum levels of testosterone and 17β-estradiol (E2) in benign prostatic hyperplasia (BPH) and prostate cancer. This study was designed to evaluate the serum concentrations of these hormones in patients with these disorders. Serum levels of prostate specific antigen (PSA), total testosterone and estradiol were determined in 228 subjects comprising of 116 subjects with BPH, 62 subjects with prostate cancer (CaP) and 50 age-matched apparently healthy controls, using ELISA methods. PSA levels were significantly elevated (p < 0.05) in BPH subjects than controls, while there was no significant difference (p > 0.05) in testosterone and estradiol levels of these subjects. PSA and estradiol levels were significantly higher (p < 0.05) in CaP subjects than in controls, while there was no observed significant difference (p > 0.05) in testosterone levels. CaP subjects had significantly raised PSA, testosterone, and estradiol levels than BPH subjects. The mean molar ratio of testosterone: E2 was lowest among CaP patients (134:1) and highest among controls (166:1). Significant positive correlation between PSA and 17β-estradiol was observed in prostate disorders (BPH and CaP patients: r = 0.347; p = 0.000). Significant negative correlations between testosterone and PSA were also observed among BPH patients (r = −0.221, p = 0.049) and control subjects (r = −0.490, p = 0.000). No significant correlation existed between testosterone and PSA in CaP patients (r = 0.051, p = 0.693). Correlations between age and estradiol in both BPH and CaP were not significant (p > 0.05). This study has shown that, there was a significant increase in serum estradiol in CaP subjects, while the testosterone levels in both BPH and CaP subjects were not different from those of controls. 相似文献
11.
The goal of the study presented in this article is to investigate to what extent the classification of a web page by a single genre matches the users’ perspective. The extent of agreement on a single genre label for a web page can help understand whether there is a need for a different classification scheme that overrides the single-genre labelling. My hypothesis is that a single genre label does not account for the users’ perspective. In order to test this hypothesis, I submitted a restricted number of web pages (25 web pages) to a large number of web users (135 subjects) asking them to assign only a single genre label to each of the web pages. Users could choose from a list of 21 genre labels, or select one of the two ‘escape’ options, i.e. ‘Add a label’ and ‘I don’t know’. The rationale was to observe the level of agreement on a single genre label per web page, and draw some conclusions about the appropriateness of limiting the assignment to only a single label when doing genre classification of web pages. Results show that users largely disagree on the label to be assigned to a web page. 相似文献
12.
Montgomery multiplication over rings 总被引:1,自引:0,他引:1
Montgomery multiplication of two elements a and b of a finite field Fq is defined as abr-1 where r is a fixed field element in . In this paper we define Montgomery multiplication of elements a(x) and b(x) in a polynomial ring modulo the ideal generated by a reducible polynomial f(x). We then show that Montgomery multiplication over a field represented by a polynomial ring modulo an irreducible pentanomial can be performed more efficiently in terms of time delay by embedding the field in a quotient of a polynomial ring modulo a reducible trinomial. The trinomial has a degree that is slightly higher than that of the pentanomial, thereby increasing the number of gates in the multiplier by a small amount. 相似文献
13.
Simple and sensitive Liquid Chromatography-Tandem Mass Spectrometry (LCMS/MS)
method was developed and validated, then was implicated on hypertensive human
subjects to study drug interaction of atorvastatin (ATVS) and Olmesartan (OLM) on
status of Angiotensin-II (ANG-II). The ANG-II in plasma was extracted with 5 mL
methanol containing 5 % formic acid through C18 (cartridges)
liquid–liquid extraction, dried and reconstituted with 1 mL of 16 % acetonitrile in
0.1 % formic acid in water. The chromatographic separation of ANG-II with a Agilent
technology 6410 Triple quadrupole was carried multiple reaction monitoring scan mode
with a Agilent 1290 Infinity LC system for UHPLC. The sample were separated on a
(Thermo Scientific) Hy-Purity advance (50 × 4.6 mm, 5 μm) using Mobile Phase A: 16 %
acetonitrile in 0.1 % formic acid in water and Mobile Phase B: 0.1 % formic acid in
methanol at a flow rate of 0.3 mL/min, performed at ambient temperature. The mobile
phase gradient of 16 % acetonitrile in water was linearly increased to 38 %
acetonitrile over 10 min and subsequently the mobile-phase was increased to 100 %
acetonitrile over 15 min. The developed method was validated for specificity,
accuracy, precision, stability, linearity, sensitivity and recovery. The method was
linear between peak area ratio of standard and internal standard over the range of
50–800 ng/mL. The method was successfully applied for the drug interaction study
revealed levels of ANG-II were significantly higher in ATVS + OLM treatment
condition as compared to individual treatment of OLM. This reflects the reason of
low effectiveness of ATVS + OLM in combination instead of synergistic
activity.
Electronic supplementary material
The online version of this article (doi:10.1007/s12291-014-0457-x) contains supplementary material, which is available to authorized users. 相似文献14.
Arun Kumar Singh Sunita Tiwari Abhishek Gupta Kamla Kant Shukla Kumar Gaurav Chhabra Achileshwar Pandey Aditya Bhushan Pant 《Indian journal of clinical biochemistry : IJCB》2015,30(3):255-262
Metabolic syndrome (MetS) is a cluster of interrelated common clinical disorders. The role of resistin in insulin sensitivity and MetS is controversial till date. So, the aim of the present study was to investigate the relationship of plasma resistin levels with markers of the MetS in Indian subjects. In a case control study, total 528 subjects were selected for the study. 265 (194 male and 71 female) were cases (with MetS) and 263 (164 male and 99 female) were controls (without MetS). Required anthropometric measurements and calculations were carried out accordingly. All the Biochemical estimations were carried out according to standard protocol. Resistin level was measured by the standard protocol (By ELISA i.e. enzyme linked immunosorbent assay) as illustrated in the kit. Insulin level was also measured by the standard protocol as illustrated in the kit and insulin resistance was calculated by the standard procedures. Plasma resistin levels were significantly higher in cases compared with controls (male = 13.05 ± 4.31 vs. 7.04 ± 2.09 ng/ml; p ≤ 0.001 and female = 13.53 ± 4.14 vs. 7.42 ± 2.30 ng/ml; p ≤ 0.001). Plasma resistin levels were well correlated with waist circumference, glucose, triglycerides, waist/hip ratio, systolic and diastolic blood pressure, high density lipoprotein, total cholesterol, serum low density lipoprotein, serum very low density lipoprotein, insulin and insulin resistance. Plasma resistin levels were elevated in presence of the MetS and were associated with increased metabolic risk factors. 相似文献
15.
Nitrogen oxides (NOx, the sum of nitric oxide (NO) and N dioxide (NO2)) emissions and deposition have increased markedly over the past several decades, resulting in many adverse outcomes in both terrestrial and oceanic environments. However, because the microbial NOx emissions have been substantially underestimated on the land and unconstrained in the ocean, the global microbial NOx emissions and their importance relative to the known fossil-fuel NOx emissions remain unclear. Here we complied data on stable N isotopes of nitrate in atmospheric particulates over the land and ocean to ground-truth estimates of NOx emissions worldwide. By considering the N isotope effect of NOx transformations to particulate nitrate combined with dominant NOx emissions in the land (coal combustion, oil combustion, biomass burning and microbial N cycle) and ocean (oil combustion, microbial N cycle), we demonstrated that microbial NOx emissions account for 24 ± 4%, 58 ± 3% and 31 ± 12% in the land, ocean and global environment, respectively. Corresponding amounts of microbial NOx emissions in the land (13.6 ± 4.7 Tg N yr−1), ocean (8.8 ± 1.5 Tg N yr−1) and globe (22.5 ± 4.7 Tg N yr−1) are about 0.5, 1.4 and 0.6 times on average those of fossil-fuel NOx emissions in these sectors. Our findings provide empirical constraints on model predictions, revealing significant contributions of the microbial N cycle to regional NOx emissions into the atmospheric system, which is critical information for mitigating strategies, budgeting N deposition and evaluating the effects of atmospheric NOx loading on the world. 相似文献
16.
J.E. Rubio 《Journal of The Franklin Institute》1980,309(5):301-308
Control problems in Hilbert spaces are treated in a measure-theoretical framework; instead of dealing with a set of admissible trajectory-control pairs, a set of measures defined by the boundary conditions and the differential equations of the problem are considered. The concept of weak controllability is introduced; a system has this property if every pair of initial and final points, (ta,xa) and (tb,xb) can be weakly joined; this is possible if a set of linear equalities involving measures has a solution. In turn, this is shown to be equivalent to the possibility of extending a linear functional in a positive manner. Necessary and sufficient conditions for controllability are derived, and applied to the study of a finite-dimensional system with the control appearing linearly. 相似文献
17.
N. Unni C. Sumithra R. Lakshman Lakshmi N. Leela Menon K. N. Subhakumari V. S. Sheejamol 《Indian journal of clinical biochemistry : IJCB》2015,30(2):161-166
PCOS is a heterogeneous endocrine disorder with diverse clinical presentation. Oxidative stress plays a key role in the pathophysiology of this disease. Serumhigh sensitive C-reactive protein (hsCRP), a marker of chronic low grade inflammation, is indicative of future development of cardiovascular disease. Our aim is to evaluate the oxidant status and hsCRP levels in PCOS. The study involved 61 cases and 61 controls in the age group of 18–40 years diagnosed with PCOS. Erythrocyte malondialdehyde (MDA), superoxide dismutase (SOD), serum hsCRP, gonadotrophins, thyroid stimulating hormone, prolactin, glycemic status and lipid profile were estimated. Erythrocyte MDA (p < 0.001), SOD (p = 0.007) and serum hsCRP (p < 0.001) were significantly elevated in PCOS patients than controls. Oxidative stress is present in women with PCOS along with elevated hsCRP. 相似文献
18.
Surupa Basu Ruchi Gupta Monjori Mitra Apurba Ghosh 《Indian journal of clinical biochemistry : IJCB》2015,30(2):167-173
Vitamin D deficiency is highly prevalent in Indian children of northern, western and southern states. Serum 25 hydroxy cholecalferol (ng/ml) was analyzed in 310 children and adolescents of pediatric hospital of Kolkata, India. Serum calcium (mg/dl), phosphorous (mg/dl) and alkaline phosphatase (IU/L) data was obtained. Median 25(OH)D was 19 ng/ml. 19.2 % of population had serum 25(OH)D < 10 ng/ml (severe deficiency), 52.9 % had <20 ng/ml (deficiency), 24.5 % had 20–29 ng/ml (insufficiency) and 22.6 % had >30 ng/ml (optimum). Deficiency was highest in adolescents (86.1 %), followed by school children (61.0 %), lowest in pre-school children (41.6 %). 25(OH)D concentrations was lowest in winters (P = 0.002) and spring (P = 0.03) compared to summer. There was no correlation with calcium (P = 0.99), phosphorous (P = 0.23) and ALP (P = 0.63). There is high prevalence of vitamin D deficiency in children and adolescents of eastern India. Prevalence was lower in younger subjects. 25(OH)D did not correlate with bone mineral markers. 相似文献
19.
Arun Kumar B. S. Dhillon D. N. Rao Geetha Menon Hari Shankar L. K. Dhaliwal Maiti Leema Nomita Chandhiok Neeta Kumar Rohini Sehgal Suneeta Mittal Sumitu Sahdev Kandpal Shobha V. L. Jindal 《Indian journal of clinical biochemistry : IJCB》2012,27(4):405-409
Malondialdehyde (MDA) is widely used as oxidative stress biomarker in biomedical research. Plasma is stored in deep freezers generally till analysis. Effect of such storage on MDA values, which may be variable and prolong, was incidentally observed in the ongoing study which is to estimate oxidative stress with oral iron. Plasma from blood samples of pregnant women (20–30 years age) in third trimester of singleton pregnancy (n = 139), consuming oral iron tablets was stored at −20 °C with intention of MDA estimation, as soon as possible. However logistic problems led this storage for prolonged and variable period (1–708 days). When values of MDA estimated using “Ohkawa” 79 method and readings were plotted against time to check the temporal effect, it showed a hyperbolic curve. Standard deviation (SD) was lowest when samples were tested within 3 weeks time. The samples analyzed within 3 weeks had mean ± SD value of 31.59 ± 26.11 μmol/L, while 123.7 ± 93.97 and 366.5 ± 189.8 μmol/L for samples stored for 1–3 and 4 months to 1 year respectively. Mean ± SD were 539.9 ± 196.8 in the samples store for more than a year. Rate of change in values was also lowest (0.0433 μmol/L/day) in the samples tested within first 3 weeks, which rose to 1.2 μmol/L/day during 3 month’s storage. This rate peaked at storage of 120 days (1.87 μmol/L/day) and fell to 0.502 μmol/L/day in the second year of storage. It is concluded that at −20 °C, only 3 weeks of storage time should be considered valid for fairly acceptable stability in MDA values. 相似文献
20.
The non-rivalness of scientific knowledge has traditionally underpinned its status as a public good. In contrast we model science as a contribution game in which spillovers differentially benefit contributors over non-contributors. This turns the game of science from a prisoner's dilemma into a game of ‘pure coordination’, and from a ‘public good’ into a ‘contribution good’. It redirects attention from the ‘free riding’ problem to the ‘critical mass’ problem. The ‘contribution good’ specification suggests several areas for further research in the new economics of science and provides a modified analytical framework for approaching public policy. 相似文献