Precision and Sensitivity in Detailed-Balance Reaction Networks

We study two specific measures of quality of chemical reaction networks, Precision and Sensitivity. The two measures arise in the study of sensory adaptation, in which the reaction network is viewed as an input-output system. Given a step change in input, Sensitivity is a measure of the magnitude of the response, while Precision is a measure of the degree to which the system returns to its original output for large time. High values of both are necessary for high-quality adaptation. We focus on reaction networks without dissipation, which we interpret as detailed-balance, mass-action networks. We give various upper and lower bounds on the optimal values of Sensitivity and Precision, characterized in terms of the stoichiometry, by using a combination of ideas from matroid theory and differential-equation theory. Among other results, we show that this class of non-dissipative systems contains networks with arbitrarily high values of both Sensitivity and Precision. This good performance does come at a cost, however, since certain ratios of concentrations need to be large, the network has to be extensive, or the network should show strongly different time scales

Hydatid disease of the breast

Cystic hydatid disease is caused by the parasite Echinococcus granulosus. Humans are the accidental intermediate hosts of this organism. Hydatid disease is endemic in countries in which raising sheep and cattle constitutes an important means of livelihood. The most commonly affected organs are the liver and lungs. Involvement of the kidney, bone, brain and other organs is rare. Breast involvement in this disease is also very rare. A case of isolated hydatid cyst of the breast is presented, along with a review of the literature and a discussion on the pertinent clinical and radiological aspects of the disease

Frequency and Outcome of Carotid Atheromatous Disease in Patients With Stroke in Pakistan

Background And Purpose: Limited data exist on the frequency and outcome of carotid artery disease in Pakistan. Such information would help guide the usefulness of screening for the condition in this low-middle income health care setting. Methods: A prospective, descriptive study was conducted among 3 large teaching hospitals in Karachi, Pakistan. Patients referred for carotid Doppler ultrasound examination were included if they had experienced a stroke or TIA within the previous month. The severity and morphology of carotid disease were characterized by trained technicians using standardized criteria. Demographic and risk factor data were collected at baseline, and the outcome of Patients was assessed at least 6 months later. Results: A total of 672 Patients underwent bilateral carotid Doppler ultrasound (1344 carotid examinations). The findings revealed 0% to 50% stenosis in 526 (78%), 51% to 69% stenosis in 57 (8%), 70% to 99% stenosis in 82 (12%), and total occlusion in 7 Patients (1%). Potentially surgically correctable disease, defined as 70% to 99% carotid artery stenosis, was present in only 79 (12%) Patients, of whom 47 (60%) were ipsilateral symptomatic, 15 (20%) asymptomatic, and 17 (20%) had status unknown. Outcome information at \u3e= 6 months follow-up was available for 36 of the 47 (76%) surgically correctable and only 4 of these Patients (12%) had undergone surgical or radiological intervention (carotid endarterectomy in 3 Patients and carotid stenting in 1 Patient). Conclusion: The frequency of carotid artery disease of at least moderate severity is very low in Patients with recent stroke or TIA and there is low utilization of high-cost, carotid intervention procedures in Pakistan. These data raise questions regarding the applicability and cost-effectiveness of routine carotid ultrasound screening in our country and similar population in Asia. The local socio-economic and clinical data do not support routine carotid Doppler ultrasound in every Patient with stroke and TIA in Pakistan. Studies are warranted to determine predictors of significant carotid artery stenosis in stroke/TIA Patients of our country to develop reliable stroke guidelines appropriate for local population

Gender Identity Disorder is Not Simply Two in One

A Case Report on Gender Identity Disorder with Recurrent Depressive Disorder is presented. Individuals having this disorder often exhibit discomfort about their actual anatomic gender, and they may have wished to alter their bodies. Sex role-stereotypes adopted during childhood are the beliefs, characteristics and behaviors of individual cultures that are considered normal and appropriate for boys and girls to possess. These "norms" are influenced by one's family and friends, the mass-media, and their community. Since some cultures disapprove of cross-gender behavior, it often results in significant problems for affected individuals and those in close relationships with them. The importance of treatment is not only because of the high rate of mental-health problems, including Depression but with higher suicide rate among untreated transsexual people than in the general population. These problems are not usually related to the gender identity issues themselves, but the social and cultural responses to gender-deviated individuals. An example which classically illustrates Gender Identity Disorder is the case of a young man from Brunei Darussalam, who was seen and treated. This contribution will highlight the cultural and religious perspective of this Disorder

The epidemic of HIV/AIDS in developing countries; the current scenario in Pakistan

HIV (Human Immunodeficiency virus) causes (acquired immunodeficiency syndrome) AIDS, in which the immune system of body totally fails to develop any defense against the foreign invaders. Infection with HIV occurs by transfer of blood, semen, and breast milk. HIV/AIDS is a global problem and it results nearly 25 million deaths worldwide. Developing countries like Pakistan have issues regarding Public Health. Currently, epidemic of HIV/AIDS is established in Pakistan and there is a threat of an expanded HIV/AIDS outbreak in the country. The major reason is that population is engaging in high-risk practices, low awareness about HIV/AIDS, and treacherous blood transfusion practices. A supplementary threat to Pakistan is India because both sharing a border and India is facing a rapidly growing HIV/AIDS epidemic. Local NGOs, National and International organizations are warning that in near future Pakistan may experiences bad situation regarding HIV/AIDS

Effects of Aluminium Exposures on Growth, Photosynthetic Efficiency, Lipid Peroxidation, Antioxidant Enzymes and Artemisinin Content of Artemisia annua L.

Acid soils are widely distributed at a global scale; under acidic conditions, the solubility of aluminium (Al) increases and the elevated concentration of toxic Al3+ in soil solution seriously limits crop production. There is no information on the effects of aluminium (Al) on Artemisia annua L., which is a most important antimalarial plant in the recent time being artemisinin; responsible for its antimalarial activity. In this report, we describe the effects of Al contamination on growth, photosynthetic efficiency, membrane damage, antioxidant enzyme activities and changes in artemisinin content in A. annua. Al addition to the soil medium significantly reduced the yield and growth of the plants. Lower values of net photosynthetic rate, stomatal conductance, internal CO2 and total chlorophyll content were observed as a result of different Al concentrations applied. The activities of nitrate reductase (NR) and carbonic anhydrase (CA) were also found to be hampered by Al exposure to the plants. Al enhanced lipid peroxidation rate (TBRAS content) and activated the activities of catalase (CAT), peroxidase (POX) and superoxide dismutase (SOD) enzymes in the treated plants. The elicitation in the endogenous ROS levels, due to the Al treatments, was also noticed in the present study. Furthermore, enhanced artemisinin content and yield was obtained at 0.10mM concentration of soil applied Al. Our study provides evidence that excess Al in soil hamper the growth and yield, slow down the activities of NR and CA, induce lipid peroxidation and antioxidant enzymes but a low level of Al-toxicity can induce artemisinin content in A. annua plants.Key words: Aluminium (Al); Artemisia annua L.; Artemisinin; Lipid peroxidation; Reactive oxygen species (ROS)Tariq Aftab et al. Effects of Aluminium Exposures on Growth, Photosynthetic Efficiency, Lipid Peroxidation, Antioxidant Enzymes and Artemisinin Content of Artemisia annua L. J Phytol 2/8(2010) 23-37