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81.
Assessing potential dietary toxicity of heavy metals in selected vegetables and food crops 总被引：3，自引：0，他引：3
Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely： inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil （total or bioavailable concentration） that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include： soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity. 相似文献
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83.
On dendritic cell-based therapy for cancers 总被引：3，自引：0，他引：3
Dendritic cells (DCs), the most prevalent antigen-presenting cell in vivo, had been widely characterized in the last three decades. DCs are present in almost all tissues of the body and play cardinal roles in recognition of microbial agents,autoantigens, allergens and alloantigen. DCs process the microbial agents or their antigens and migrate to lymphoid tissues to present the antigenic peptide to lymphocytes. This leads to activation of antigen-specific lymphocytes. Initially, it was assumed that DCs are principally involved in the induction and maintenance of adaptive immune responses, but now it is evident that DCs also have important roles in innate immunity. These features make DCs very good candidates for therapy against various pathological conditions including malignancies. Initially, DC-based therapy was used in animal models of cancers. Data from these studies inspired considerable optimism and DC-based therapies was started in human cancers 8 years ago. In general,DC-based therapy has been found to be safe in patients with cancers, although few controlled trials have been conducted in this regard. Because the fundamentals principles of human cancers and animal models of cancers are different, the therapeutic efficacy of the ongoing regime of DC-based therapy in cancer patients is not satisfactory. In this review, we covered the various aspects that should be considered for developing better regime of DC-based therapy for human cancers. 相似文献
84.
This study surveys 200 Malay students enrolled in three Chinese primary schools in relation to three issues, i.e., parental choice of schooling, learning processes and inter-ethnic friendship patterns. The three issues are explored through a combination of quantitative and qualitative research methodologies. Parental expectations for their children's learning and academic outcomes emerge as the dominant factor influencing Malay enrollment in Chinese primary schools. Unfortunately, the Malay students are unable to meet these high expectations due to learning difficulties that stem from the lack of proficiency in the Chinese-medium of instruction, despite intervening measures by the school authorities. Their learning difficulties are also compounded by the lack of parental inputs as well as the limited use of code-switching by teachers. Meanwhile, the fostering of inter-ethnic friendships is impeded by ethnic differences, the rise of Islamic awareness and the increased numerical size of Malay students. However, there is a willingness among the Malay students to interact with the Chinese students through task-related activities, indicating that the fostering of inter-ethnic friendships needs to be guided by a convergence of interests. 相似文献
85.
This study explored the usage and applications of barcode technologies through a survey carried out in eight libraries in Dhaka City of Bangladesh. The survey included the following: Inception year, software used to barcode, areas in which barcodes are being used in libraries, training of library staff, and satisfaction of users and information professionals. The merits and demerits of barcode technologies are presented. 相似文献
86.
Nasreen Noor Najmul Islam Shagufta Moin Abbas Ali Mahdi Sapna Jaiswal Farzana Bano 《Indian journal of clinical biochemistry : IJCB》2008,23(3):227-232
To probe the glutathione peroxidase (GPx) activity coupled to ROS and TNF-α levels in younger versus elderly primigravidas.
Monocytes were isolated from blood of young and elderly primigravidas after 12 hrs, 24 hrs and 14 days postpartum. Age-matched
healthy female donors served as controls. Thereafter, the above monocytes were subjected to evaluation of GPx activity, levels
of pro-inflammatory cytokine TNF-α and reactivity/specificity towards anti-TNF-α antibody. Suppression in GPx activity with
simultaneous enhancement of TNF-α levels in monocytes was observed after 12 hrs and 24 hrs of spontaneous labor pain-induced
maternal delivery through normal vaginal route. Conversely, an enhancement of GPx activity and decrease in TNF-α levels were
observed on day 14 of postpartum, thereby indicating reversal of the impaired neutralizing mechanisms. The antioxidant network
combating ROS was stronger in younger primigravidas. Capability of TNF-α and ROS suppression was somewhat lesser in elderly
primigravidas even 14 days of postpartum via normal vaginal route. The capability of GPx activity enhancement with simultaneous
suppression in ROS and TNF-α, decreases in elderly primigravidas. This may act as one of the important parameters leading
to a variety of complications encountered by elderly primigravidas. 相似文献
87.
Mst. Marium Begum Zakia Sultana Md. Ershad Ali Md. Safkath Ibne Jami Proma Khondkar Md. Masuduzzaman Khan Md. Mominul Haque 《Indian journal of clinical biochemistry : IJCB》2014,29(4):452-461
High blood glucose level, elevated level of liver enzyme, necrosis and shrinkage of islets of Langerhans has been implicated in the pathogenesis of type 2 diabetes. High blood glucose cause oxidative stress, production of free radical as well as elevated SGPT and SGOT level. Both glibenclamide and simvastatin in fixed dose used as antihyperglycemic antidyslipidemic and antioxidative agents for type 2 diabetes treatment. This study therefore aimed to evaluate the antihyperglycemic, antidyslipidemic and antioxidative effect of fixed dose combination of glibenclamide (0.6 mg/70 kg body weight) and simvastatin (5 mg/70 kg body weight) on long term alloxan induced diabetic rats with cardiovascular disease using various diagnostic kits as a parameter of phamacotherapeutic and pharmacological effect. The study was carried out using 96 Swiss Albino male rats weighing about 200–220 g. Combination therapy induced a significant decrease in blood glucose level in alloxan induced diabetic rats, from 33.75 ± 1.65 to 5.80 ± 0.07 mmol/l 2 h after last dose administration, after 4 weeks treatment. In case of dyslipidemic effect, combination therapy reduced total cholesterol (45 %), triglyceride (36 %) and low density lipoprotein-cholesterol (32 %) levels significantly and increased high density lipoprotein-cholesterol level (57 %) in comparison with their respective diabetic control groups. Results of this study showed that combination therapy effectively decreased SGPT (ALAT) (55 %) and SGOT (ASAT) (51 %) in comparison with diabetic control group. It was also observed that catalase and superoxide dismutase enzyme activity was increased by 58 and 91 % respectively in comparison with diabetic control group after 4 weeks treatment with combination of both drugs. In conclusion, these findings of combination therapy (glibenclamide and simvastatin) on alloxan induced diabetes in rats are significantly better than monotherapy using single drug. The results of the present study suggest that, combination of the fixed dose of glibenclamide and simvastatin might be efficacious in patients with diabetic dyslipidemia and increased oxidative stress. Furthermore, this combination therapy offer dosage convenience to the patients and by virtue of its dual mode of action might be a useful addition to the therapeutic armamentarium for patients with diabetic dyslipidemia and oxidative stress. 相似文献
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89.
Kotaro Hashikura Jad Musaddiq Bin Jaafar Akira Kojima Md Abdus Samad Kamal Kou Yamada 《Journal of The Franklin Institute》2021,358(1):474-493
This paper addresses the output regulation problem for a class of preview control systems, and derives a state feedback law which suppresses the steady-state error caused by the excitation from polynomial or sinusoidal exogenous inputs. Recently, the output regulation condition for the broader class of distributed parameter systems is characterized via the operator regulator equation. We show that a solution of the operator regulator equation specialized to the preview control system is obtained by solving the matrix regulator equation, and provide the state feedback law which attenuates the transient error optimally with respect to an LQ (Linear Quadratic) performance index. 相似文献
90.
Claudia Mitchell David Dillon Teresa Strong‐Wilson Kathleen Pithouse Faisal Islam Kevin O’Connor 《Changing English: An International Journal of English Teaching》2010,17(1):45-55
In this article, we focus on the use of the visual for reflection in ‘alternative’ pre‐service teacher education and, in particular, we address the question: How and what can we learn about teacher education using the visual? By way of illustration, we focus on the use of pre‐service teachers’ photographs in a public exhibition, participatory video documentary production and pre‐service teachers’ use of photographs in their professional teaching portfolios. The article draws from research done in relation to three alternative pre‐service teacher education projects based at McGill University in Canada and the University of KwaZulu‐Natal in South Africa. 相似文献