Direct solution to an optimal control problem of econometric systems

A direct solution is proposed to an optimal control problem of linear econometric systems with a quadratic welfare loss function when there are linear equality constraints on the control variables. The direct solution proposed here eliminates the problem of non-uniqueness of the optimal solution, which is present when this optimal control problem is solved using the recursive algorithm proposed by Chow,¹ Pindyck² and Tan.³ If a unique solution to the optimal control problem exists, then the direct solution and the recursive solution coincide.     

Zur Acylierung von Hydroxy- und Mercapto-carbonsäureestern nach dem Carbodiimid/Acylierungskatalysator-Verfahren

On the Acylation of Hydroxy- and Mercaptocarboxylic Acid Esters Using the Carbodiimide/Acylation Catalyst Method Acylation of esters of hydroxycarboxylic acids can be carried out easily and in good yields by using the carbodiimide/acylation catalyst method. The reaction has also been applied to dihydroxy- and mercaptocarboxylic acid esters. The compounds formed from certain esters of hydroxycarboxylic acids are unstable to heat and decompose easily to the free carboxylic acid. No racemization is observed when using enantiomeric hydroxycarboxylic acids. Use of racemic carboxylic acids leads to diastereomers, whose ¹H-NMR shifts for characteristic protons are different as expected. Five drugs are among the carboxylic acids investigated in this context.     

Release of 2-thiobarbituric acid reactive products from glutamate or deoxyribonucleic acid by 1,2,4-benzenetriol or hydroquinone in the presence of copper ions

Cytotoxic effects of various quinone compounds are thought to be due to the formation of semiquinone free radicals. Hydroquinone and 1,2,4-benzenetriol in the presence of copper ions release from glutamate or DNA aldehydic products capable of reacting with 2-thiobarbituric acid (TBA). The formation of TBA reactive products (TBAR) was greater in the presence of 1,2,4-benzenetriol in comparison with hydroquinone. Complete inhibition of formation of TBAR from glutamate by 1,2,4-benzenetriol and copper was observed in the presence of catalase, thiourea and mannitol. Albumin and superoxide dismutase offered substantial protection. Complete protection of formation of TBAR from DNA was observed in the presence of catalase and thiourea. Presence of albumin, mannitol and superoxide dismutase caused only partial inhibition. The formation of TBAR from glutamate or DNA is dependent on copper ion concentration. The present data indicate that hydroquinone and 1,2,4-benzenetriol in the presence of copper ions can lead to the formation of reactive hydroxyl radicals which can release TBAR from glutamate or DNA.     

Prosthetic joint infectionsin the elderly

Total joint arthroplasty is among the most remarkable advances in orthopaedic surgery for the elderly, enabling themto regain physical function and be free of pain. Although uncommon, infection of the prosthetic joint causes serious morbidity leading to poor functional outcome with a mortality approaching 8% in the elderly. Most infections occur through inoculation of the prosthesis at the time of implantation and are due to Gram-positive cocci, although a third of the episodes are due to Gram-negative bacilli from a secondary focus. The management presents a major clinical and therapeutic challenge due to systemic and local comorbid conditions in the elderly. Medical and surgical treatment decisions for infected joint prosthesis are complex and should be individualized in each case. Optimal nutrition is essential for a successful outcome. Adverse reactions to medications are more common in the elderly due to end organ dysfunction and drug-drug interactions.     

Influence of a calcium dependent protease inhibitor on platelet activation and secretion

Continuous proteolysis resulting in consumption of major cytoskeletal proteins may be essential for platelet activation and aggregation. In this study we evaluated the effect of a known protease inhibitor, Leupeptin, on agonist induced platelet aggregation and secretion. Platelets exposed to 10 ugs/ml of Leupeptin did not aggregate in response to the action of thrombin (0.2u/ml). However, a concentration of Leupeptin as high as 250 ugs/ml did not prevent arachidonate induced aggregation and secretion. Leupeptin (100 ugs/ml) effectively blocked thrombin (0.2 u/ml) induced elevation of cytosolic calcium, but did not affect arachidonate induced elevation of platelet intracellular calcium levels. At a concentration of 100 ug/ml, Leupeptin effectively blocked thrombin (0.5u/ml) induced clot formation of platelet poor plasma, suggesting that it can exert its effect on thrombin by preventing fibrinogen degradation. Effective K_i for the competitive inhibition of thrombin induced hydrolysis of a chromogenic substrate, S2238, by Leupeptin was 2.4 uM. Leupeptin inhibition of platelet function was reversible by washing platelets free of the polypeptide. Results of our study demonstrate that Leupeptin inhibits thrombin induced platelet activation, probably by interfering with its proteolytic activity on the platelet surface membrane. However, inhibition of platelet surface membrane associated proteases did not prevent activation of platelets by other agonists.     

Changes in selected biochemical parameters in the kidney and blood of the fish,Tilapia mossambica (Peters), exposed to heptachlor

Bulletin of Environmental Contamination and Toxicology -     

Atypical mycobacterial infection following blepharoplasty and full-face skin resurfacing with CO2 laser.

BACKGROUND: With the popularity of laser skin resurfacing for the correction of photoaging and the improvement of acne scarring, it is important to note complications that may result from this procedure. Infections must be recognized and treated early, as some can result in permanent local destruction and systemic spread to other body sites. OBJECTIVE: To increase the awareness of an unusual infection that may result from laser resurfacing. METHODS: We report the case of a 52-year-old woman who presented with two symmetrical nodules 1 month after full-face skin resurfacing with CO2 laser. These were found to be abscesses caused by Mycobacterium fortuitum infection. RESULTS: The diagnosis was established following surgical debridement and subsequent culture grown from the exudate. Oral antibiotic treatment guided by organism sensitivity resulted in complete clearance of the infection with no recurrence or sequelae after 3 years of follow-up. CONCLUSION: This case demonstrates that atypical mycobacterial infections may arise after laser resurfacing procedures, despite proper technique, sterile instrumentation, and appropriate perioperative medications and postoperative wound care. If diagnosed and treated early, this potentially disastrous complication can be cured with no permanent sequelae.     

Modulatory influence of injectable contraceptive steroid medroxyprogesterone acetate on methylcholanthrene-induced carcinogenesis in the uterine cervix of mouse.

Methylcholanthrene (approximately 300 micrograms) plus beeswax-impregnated thread, when placed inside the canal of the uterine cervix of virgin female adult mice for 30, 60 and 90 days produced cervical tumors in 0.0, 10 and 30% of mice, respectively. Employing this experimental cervical carcinogenesis model system, the present study evaluated the modulatory influence of medroxyprogesterone acetate (MPA) on the incidences of precancerous and cancerous lesions in the cervical epithelium as well as on phase I and phase II drug metabolizing enzymes and acid soluble sulfhydryl level in the liver. Intramuscular administration of MPA (50 micrograms every 5th day) to the carcinogen-thread inserted mice for 30, 60 and 90 days produced cervical tumors respectively in 0.0, 13.3 and 60.5% (P less than 0.05) of mice. A significant increase (P less than 0.05) in hyperplasia was also observed in the present study. A significant decrease in cytochrome b5 was found after 30 days.     

Nutrition, health and psychosocial profile of institutionalized children.

A study was undertaken to assess the health, nutrition and psychosocial profile of Institutionalized children in four States--Uttar Pradesh, Andhra Pradesh, Karnataka and West Bengal. A sample of 3,822 children from 70 institutions in 6-18 years age group formed the subjects of the study. It was observed that the destitute children were mainly taken care of in three types of institutions, viz, Voluntary, Government Aided and Government run institutions. Calorie deficiency and deficiency of Vitamins and minerals characterized the diets of these children. In general, there was no deficit of protein in their diets. Growth wise, these children were retarded both in height and weight compared to standards. However, they fared better in comparison to their age and sex counterparts in the rural and urban poor. Psychosocial profile of these children indicated that the prevailing environment in the institutions is less conducive for intellectual stimulation but not so for the development of skills of self-help, locomotion, socialization and imagery.