An efficient method for enhancing convective heat transfer

A new efficient method for enhancing convective heat transfer in tubular heat exchangers is developed, which can be called the deep profiling method. The potential of the method is illustrated experimentally on a laboratory tube-in-tube heat exchanger.Translated from Teoreticheskie Osnovy Khimicheskoi Tekhnologii, Vol. 38, No. 6, 2004, pp. 634–649.Original Russian Text Copyright © 2004 by Konoplev, Aleksanyan, Rytov, Berlin.     

Mortality and neurologic morbidity after repair of traumatic aortic disruption

BACKGROUND: Traumatic disruption of the thoracic aorta frequently results in death before operative repair. The determinants of mortality after repair, however, are uncertain. In addition, intraoperative strategies for reducing the incidence of spinal cord injury remain controversial. METHODS: The records of 45 consecutive patients undergoing repair of traumatic disruption of the thoracic aorta at a single institution during a 9-year period were reviewed in a retrospective fashion. Patient age ranged from 15 to 81 years (mean age, 33.9 years). Twenty-two patients (49%) had multiple associated injuries, and 8 (18%) had isolated aortic injuries. Nine patients (20%) experienced preoperative hypotension (systolic blood pressure of less than 90 mm Hg). Repair was performed with partial bypass in 22 patients, a heparinized shunt in 2, and no distal perfusion (clamp and sew technique) in 21. RESULTS: Nine patient (20%) died after operation. Multivariate logistic regression analysis of preoperative and intraoperative variables identified advancing age and preoperative hypotension as independent predictors of operative death. The presence of associated injuries was not an independent predictor of operative death. All 4 patients with injuries proximal to the aortic isthmus died. Ten patients were excluded from analysis of spinal cord injury either because of preoperative neurologic deficit or because of death before postoperative evaluation. Six (17%) of the remaining 35 patients had development of paraplegia: 5 of the 15 patients having the clamp and sew technique, 1 of the 2 with a shunt, and 0 of the 18 patients with bypass (p < 0.05, clamp and sew versus bypass). In the clamp and sew group, patients in whom paraplegia developed had significantly longer aortic clamp times than those without neurologic injury (40.6 +/- 4.4 minutes versus 28.7 +/- 2.9 minutes, respectively; p < 0.05). CONCLUSIONS: Advancing age, preoperative hypotension, and perhaps injury location are important determinants of death after repair of traumatic disruption of the thoracic aorta. Adjunctive perfusion with partial bypass should be used during repair to reduce the incidence of spinal cord injury.     

Analysis of neural crest cell migration in Splotch mice using a neural crest-specific LacZ reporter

In the last decades, several therapies for unipolar depression have been developed, for example cognitive therapy, behavior therapy and pharmacotherapy. A new kind of therapy is bibliotherapy. What is new in this treatment modality is not the content, because bibliotherapy usually uses a cognitive-behavioral approach. Only the form in which it is presented is new. In bibliotherapy the patient takes a standardized treatment home, in book form, and works it through more or less independently. Contacts with therapists are only supportive or facilitative. No traditional relationship between therapist and patient is developed. In this article the relevance of bibliotherapy for the clinical practice is presented and a meta-analysis of the research into bibliotherapy is described.     

The effect of the chronic internal administration of the new Russian n-3 polyunsaturated fatty acid concentrate--epaden--on blood coagulation system indices in rabbits

Daily oral 6-week administration of epaden in a dose containing 0.3 g eucosopentanoic acid and 0.05 g docosahexaenoic acid caused decrease in collagen-induced platelet aggregation in rabbits in vivo and in the activity of the tissue type plasminogen activator, as well as reduction in the level of antithrombin III cofactor activity. No changes were encountered in ADP-induced aggregation, in the platelet count, in platelet adhesion to collagen, and in activated partial thromboplastin time.     

Defibrillation efficacy with endocardial electrodes is influenced by reductions in cardiac preload

Several studies were undertaken to develop three-dimensional (3-D) cell culture models that allow conditions closer to the in vivo situation. To this end, alginate gels were tested as a 3-D cell culture model that might be useful in the study of the effects of UVA on human dermal fibroblasts. Cell culture in alginate gels and the irradiation conditions were optimized. Results showed that optimized cultures in alginate gels experienced considerable cell death on UVA irradiation compared to the classical monolayer cell culture. Viability tests (cell counting and neutral red assay) were performed to show that only UVA-irradiated alginate gels were responsible for this cytotoxicity. The implication of oxygen species in the phototoxicity induced by ultraviolet light has already been described; for this reason we investigated whether oxygen species were involved in the cytotoxicity induced by alginate upon UVA irradiation. It appeared that superoxide anion is not implicated.     

The quality of friendships between children with and without learning problems

The nature and quality of preadolescent friendships between children with and without learning problems due to mental retardation or mild cognitive difficulties were investigated. Based on an assessment of the reciprocal relationship status of 373 children, including 54 with learning problems, 33 friend and 32 acquaintance dyads were identified. Of these dyads, half included a child with learning problems and half consisted of 2 children without learning problems. The dyads were observed performing a play task. Unlike friendships between children without disabilities, friendships between children with and without learning problems were marked by limited collaboration and shared decision-making, a low level of cooperative play and shared laughter, and an asymmetrical, hierarchical division of roles. The importance of advancing beyond the study of the social acceptance of children with learning problems to study the qualitative aspects of their friendships was discussed.     

Radiolabeling of the rat P2X4 purinoceptor: evidence for allosteric interactions of purinoceptor antagonists and monovalent cations with P2X purinoceptors

The rat recombinant P2X4 purinoceptor was expressed in CHO-K1 cells, and binding studies were performed using the radioligand [35S]adenosine-5'-O-(3-thio)triphosphate ([35S]ATPgammaS). In 50 mM Tris/1 mM EDTA assay buffer, pH 7.4 at 4 degrees, [35S]ATPgammaS bound with high affinity to the P2X4 purinoceptor (KD = 0.13 nM, Bmax = 151 pmol/mg of protein). The purinoceptor agonists ATP and 2-methylthioadenosine triphosphate possessed nanomolar affinity for the P2X4 purinoceptor, whereas the antagonist suramin possessed much lower affinity (IC50 = 0.5 mM). Cibacron blue was more potent than suramin but produced a biphasic competition curve, whereas d-tubocurarine potentiated binding at concentrations in excess of 10 microM. The complex effects of cibacron blue and d-tubocurarine seemed to be due to an allosteric interaction with the P2X4 purinoceptor because these compounds affected radioligand dissociation, measured after isotopic dilution with unlabeled ATPgammaS. Cibacron blue (1-100 microM) and d-tubocurarine (0.1-1 mM) produced rapid (10 sec to 5 min) decreases or increases, respectively, in the level of [35S]ATPgammaS binding measured immediately after initiation of the dissociation reaction. However, the subsequent rates of radioligand dissociation were not markedly different from those measured in their absence. Monovalent cations produced similar affects on the P2X4 purinoceptor and, like d-tubocurarine, increased [35S]ATPgammaS binding. The actions of d-tubocurarine and sodium were not additive. The findings from this study indicate that [35S]ATPgammaS can be used to label the P2X4 purinoceptor and suggest that this binding can be enhanced by monovalent cations and d-tubocurarine and may be subject to negative allosteric modulation to varying degrees by different purinoceptor antagonists.     

The association between maternal cocaine use and placenta previa

We compared various diagnostic tests for their abilities to detect Mycobacterium ulcerans infection in specimens from patients with clinically active disease. Specimens from 10 patients from the area of Zangnanado (Department of Zou, Benin) with advanced, ulcerated active M. ulcerans infections were studied by direct smear, histopathology, culture, PCR, and oligonucleotide-specific capture plate hybridization (OSCPH). A total of 27 specimens, including 12 swabs of exudate collected before debridement and 15 fragments of tissue obtained during debridement, were submitted to bacteriologic and histopathologic analysis. The histopathologic evaluation of tissues from all six patients so tested revealed changes typical of those caused by M. ulcerans infection. Five specimens were contaminated, and M. ulcerans was cultivated on L?wenstein-Jensen medium from 12 of the remaining 22 (54.5%) specimens. Detection of mycobacteria was performed by PCR, and M. ulcerans was detected by OSCPH with a new probe (5'-CACGGGATTCATGTCCTGT-3') reacting with M. ulcerans and Mycobacterium marinum. In 10 of 22 (45.5%) specimens, M. ulcerans was identified by PCR-OSCPH. There was no statistically significant difference between the detection of M. ulcerans by culture and by PCR-OSCPH (P > 0.05). This is the first demonstration of an amplification system (PCR-OSCPH) with a sensitivity similar to that of culture for the direct and rapid recognition of M. ulcerans in clinical specimens. This system is capable of identifying M. ulcerans, even in paucibacillary lesions. Our findings suggest that PCR-OSCPH should be used in the quest for the elusive environmental reservoir(s) of M. ulcerans.