Aqueous nanofluids containing paraffin-filled MWCNTs for improving effective specific heat and extinction coefficient.

This paper presents measurements of the effective specific heat and the extinction coefficient for aqueous nanofluids dispersed with paraffin-filled Multi-Walled Carbon NanoTubes (MWCNTs). The MWCNTs were filled with paraffin wax by capillary action. Centrifugal decanting was used to modify the traditional two-step method so as to produce a nanofluid dispersion that was more stable than that produced by the traditional method. The stability of each suspension was quantitatively evaluated with a laser scattering method over 7 days. A differential scanning calorimetry (DSC) and the three-slap method were used to measure the effective specific heat and the extinction coefficient of the nanofluids, respectively. The measured effective specific heat of the water-based paraffin-filled MWCNTs nanofluid, with a volume fraction of 1%, was up to 5.1% larger than that for the water-based MWCNT nanofluids without paraffin wax. The nanofluid extinction coefficient was shown to increase linearly with the volume fraction for data within the independent scattering regime, which occurred when the nanoparticle-distance/wavelength ratio (c/λ) was less than 2.

Effect of IF-WS2 Nanolubricant on R134a Boiling on a Reentrant Cavity Surface.

This report quantifies the influence of inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles on the pool-boiling performance of R134a/polyolester mixtures on a commercial (Turbo-ESP) boiling surface. Tungsten disulfide nanoparticles, of roughly 150 nm, were used at a 15% mass fraction in a base polyolester lubricant to produce the test nanolubricant. The nanolubricant was mixed with R134a at a 1% mass fraction. The study showed that the nanolubricant caused an average 37% degradation in the boiling heat flux as compared to R134a/neat-lubricant boiling on a reentrant cavity surface at the same superheat. Similarly, boiling with R134a/neat-lubricant caused, on average, a 27% degradation in the boiling heat flux as compared to pure R134a boiling and the same superheat. An analysis was presented which showed that the nanoparticles were too large and too dense to promote a boiling enhancement. In addition, the fullerene-like structure and the large size encouraged nanoparticle settling, which presumably filled cavities of the boiling surface leading to additional boiling degradations.

Effect of mesh wick geometry on the maximum heat transfer rate of flat-micro heat pipes with multi-heat sources and sinks.

This paper presents a theoretical investigation of the thermal characteristics of flat-micro heat pipes (FMHPs) with multi-heat sources and sinks. Analytical solutions of the pressure and the temperature distributions of FMHPs with multi-heat sources and sinks were obtained based on the modified liquid pressure drop. The solutions were used to identify the key engineering parameters of a mesh wick with microscale length that affect the maximum heat transfer rate of the FMHPs with multi-heat sources and sinks. The effects of the key engineering parameters on the maximum heat transfer rate of the FMHPs were presented for two limits. The first limit is the capillary limit and the other is the allowable maximum temperature limit which is used to ensure that the maximum surface temperature of the FMHP with the maximum heat transfer rate calculated at the capillary limit does not exceed the allowable maximum temperature of the electronic components. Finally, the theoretically results for the optimized wick structure for the corresponding maximum heat transfer rate and the surface temperature distribution of the FMHP were compared for the capillary limit only and for the maximum temperature limit cases, respectively.

Pool boiling of HFO-1336mzz(Z) on a reentrant cavity surface.

This paper quantifies the pool boiling performance of R1336mzz(Z) on a flattened, horizontal Turbo-ESP surface for air-conditioning and industrial heat recovery applications for heat fluxes between roughly 10 kWm-2 and 120 kWm-2. The R1336mzz(Z) pool boiling curve was measured for three saturation temperatures and exhibited the best performance with respect to saturation temperature near the middle saturation temperature of 298.1 K. The study showed that the boiling performance of R1336mzz(Z) on the Turbo-ESP did not differ statistically from that of R123 for heat fluxes between 13 kWm-2 and 59 kWm-2. For heat fluxes larger than 59 kWm-2, the R123 boiling heat flux was up to 5% larger than the heat flux for R1336mzz(Z). A pool boiling model was modified to include a convective term and was used to predict boiling heat transfer for the test refrigerants on the Turbo-ESP surface, mostly, to within ±0.5 K.

Pool Boiling of Low-GWP Replacements for R134a on a Reentrant Cavity Surface.

This paper quantifies the pool boiling performance of R134a, R1234yf, R513A, and R450A on a flattened, horizontal reentrant cavity surface. The study showed that the boiling performance of R134a on the Turbo-ESP exceeded that of the replacement refrigerants for heat fluxes greater than 20 kWm-2. On average, the heat flux for R1234yf and R513A was 16 % and 19 % less than that for R134a, respectively, for R134a heat fluxes between 20 kWm-2 and 110 kWm-2. The heat flux for R450A was on average 57 % less than that of R134a for heat fluxes between 30 kWm-2 and 110 kWm-2. A model was developed to predict both single-component and multi-component pool boiling of the test refrigerants on the Turbo-ESP surface. The model accounts for viscosity effects on bubble population and uses the Fritz (1935) equation to account for increased vapor production with increasing superheat. Both loss of available superheat and mass transfer resistance effects were modeled for the refrigerant mixtures. For most heat fluxes, the model predicted the measured superheat to within ± 0.31 K.

Horizontal convective boiling of R1234yf, R134a, and R450A within a micro-fin tube.

This paper presents local convective boiling heat transfer and Fanning friction factor measurements in a micro-fin tube for R134a and two possible low global warming potential (GWP) refrigerant replacements for R134a, namely R1234yf and R450A. Test section heating was achieved with water in either counterflow or in parallel flow with the test refrigerant to provide for a range of heat fluxes for each thermodynamic quality. An existing correlation from the literature for single and multi-component mixtures was shown to not satisfactorily predict the convective boiling measurements for flow qualities greater than 40%. Accordingly, a new correlation was developed specifically for the test fluids of this study so that a fair comparison of the heat transfer performance of the low GWP refrigerants to that of R134a could be made. The new correlation was used to compare the heat transfer coefficient of the three test fluids at the same heat flux, saturated refrigerant temperature, and refrigerant mass flux. The resulting example comparison, for the same operating conditions, showed that the heat transfer coefficient of the multi-component R450A and the single-component R1234yf were, on average, 15% less and 5% less, respectively, than that of the single-component R134a. Friction factor measurements were also compared to predictions from an existing correlation. A new correlation for the friction factor was developed to provide a more accurate prediction. The measurements and the new models are important for the evaluation of potential low-GWP refrigerants replacements for R134a.

Assessment and monitoring of water quality of the gulf of Morbihan, a littoral ecosystem under high anthropic pressure.

This field study is intended to propose a global methodology to assess and monitor the water quality of the gulf of Morbihan, a littoral ecosystem under increasing anthropic pressure. To this end, the Locmariaquer site, where Crassostrea gigas is extensively cultivated, was selected to perform a one-year follow-up of tissular glutathione S-transferase and acetylcholinesterase specific activities in this filter feeder organism. Calculation of an integrated index, corresponding to the ratio of the two enzymes activities, allowed to discriminate from the environmental noise, several clusters which could be representative environmental stress, potentially latent pollution. Moreover, the estrogenic activity was assessed in water samples collected at Locmariaquer and other strategic sites of the gulf. The results evidenced a low estrogenic-disrupting compound contamination of waters. Overall, this methodology produced an accurate outlook of a basal state for the gulf and could be developed in the context of a chronic monitoring of this site.

Viscosity, density, and thermal conductivity of aluminum oxide and zinc oxide nanolubricants.

This paper presents liquid kinematic viscosity, density, and thermal conductivity measurements of eleven different synthetic polyolester-based nanoparticle nanolubricants (dispersions) at atmospheric pressure over the temperature range 288 K to 318 K. Aluminum oxide (Al2O3) and zinc oxide (ZnO) nanoparticles with nominal diameters of 127 nm and 135 nm, respectively, were investigated. A good dispersion of the spherical and non-spherical nanoparticles in the lubricant was maintained with a surfactant. Viscosity, density, and thermal conductivity measurements were made for the neat lubricant along with eleven nanolubricants with differing nanoparticle and surfactant mass fractions. Existing models were used to predict kinematic viscosity (±20%), thermal conductivity (±1%), and specific volume (±6%) of the nanolubricant as a function of temperature, nanoparticle mass fraction, surfactant mass fraction, and nanoparticle diameter. The liquid viscosity, density and thermal conductivity were shown to increase with respect to increasing nanoparticle mass fraction.

Fossilized bioelectric wire - the trace fossil Trichichnus.

The trace fossil Trichichnus is proposed as an indicator of fossil bioelectric bacterial activity at the oxic-anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. Trichichnus is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary. Trichichnus, formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner, Trichichnus forms dense filamentous fabric, which reflects that it is produced by modern large, mat-forming, sulfide-oxidizing bacteria, belonging mostly to Thioploca-related taxa, which are able to house a complex bacterial consortium. Several stages of Trichichnus formation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore, Trichichnus can be considered a fossilized "electric wire".

Accidental intoxication with hydrochloric acid and hydrofluoric acid mixture.

The paper describes a fatal case of accidental ingestion of a mixture of hydrochloric acid and hydrofluoric acid. The man was admitted to hospital, where appropriate treatment, adequate to his condition, was instituted. Numerous ventricular fibrillation episodes, for which the patient was defibrillated repeatedly, were observed during the period of hospitalization. The patient was in a critical condition, with progressive symptoms of hypovolemic shock and multiorgan failure. On the next day after admission, signs of electromechanical dissociation progressing to asystole were noted. The instituted resuscitation procedure proved ineffective and the patient died. Autopsy revealed brownish discoloration of the esophageal, gastric, and small intestinal mucous membranes. Numerous ulcerations without signs of perforation were found both in the esophagus and in the stomach. The mucous membrane of the small intestine demonstrated focal rubefactions, whereas no focal lesions of the large intestinal mucosa were seen. Microscopic investigation of the biopsy specimens collected from the stomach, duodenum and small intestine revealed mucous membrane necrosis foci, reaching the deeper layers of the wall of these organs. The mucous membrane of the large intestine was congested. Bioptates obtained from the lungs indicated the presence of hemorrhagic infarcts and focal extravasations. Poisoning with the aforementioned acids with consequent necrosis of the esophageal, gastric, duodenal and small intestinal walls with hemorrhages to the gastrointestinal tract, as well as extravasations and hemorrhagic infarcts in the lungs was considered to be the cause of death.

Partnering to enhance interprofessional service-learning innovations and addictions recovery.

CONTEXT: Service-learning programs are reported to benefit students, faculty, higher education institutions, community agencies and the relationships among these groups. An interprofessional service-learning paradigm may strengthen these benefits. Community settings can expose students to social and cultural determinants of health, in addition to those biomedical determinants more commonly addressed in health sciences curricula. These experiences can also enhance student understanding of the complexities underlying treatment and prevention of modern health problems, particularly chronic diseases. OBJECTIVE: The purpose of this initiative was to create and deliver interprofessional service-learning innovations that would enhance student learning and addictions recovery. To address this initiative, the University of Washington's Health Science Partnerships in Interdisciplinary Clinical Education (HSPICE) and the Salvation Army Adult Rehabilitation Center (ARC) began a community-campus partnership in 1997. Innovations took into account student educational objectives established by HSPICE which included: participation in interdisciplinary teams, in conjunction with community partners to identify and reduce population-based health issues, realization and articulation of biases regarding issues faced by the participating community, acquiring an understanding of the broader determinants of health and developing an understanding of why the complexity of population health requires interdisciplinary strategies for cost effectiveness. DISCUSSION: Findings are reported from evaluations, needs assessments and ongoing feedback of men recovering from addictions, as applied to health education materials and presentations developed for the ARC. Future directions are highlighted, including the need for further research and evaluation efforts aimed at rigorously assessing cost savings and student knowledge, skills and cultural sensitivity, among others.

Factors determining the contamination of bone tissue procured from cadaveric and multiorgan donors.

There is an increasing demand for bone allografts that are widely used in orthopedic reconstructive procedures. The bone tissue may be harvested from two sources: cadavers and multiorgan donors. Providing safe and valuable bone allografts is of paramount importance. Contamination of allografts during bone retrieval seems to be one of the most important problems since pathogenic microorganisms might be responsible for postoperative infections and complications in the healing process. The purpose of our study was to identify all factors contributing to bacteriological contamination of harvested bones. Therefore, we have considered factors such as harvesting environment, explantation techniques, storage and preparation of allografts, number of preceding procurements from the same donor, procurement duration, and time interval between death and tissue procurement. The microbiological evaluation of allografts has been performed by taking cultures from all collected bones. Our study revealed significantly greater contamination rates of bone allografts harvested from morgue than from multiorgan donors. According to this observation, we suggest that orthopedic surgeons should pay particular attention to obtain more bones of the highest quality, personally participating in multiorgan procurements.

Hydrogel dressings in the treatment of wounds with skin defect complications.

Background. The purpose of the present study was to compare the performance of the Hydrogel dressing with that of traditional dressings in the treatment of wounds with skin defects.
Material and methods. 32 patients with traumatic skin defects were included in the study. 16 were treated with Hydrogel dressings, and 16 with traditional dressings. We compared the time required for complete epithelialization and the level of pain experienced on removal.
Results. The trial dressing demonstrated faster healing time (ave. 5-6 days faster). The patients from the experimental group experienced less during dressing changes.
Conclusions. We found that dressings demonstrated significantly faster epithelialization time in comparison with traditional wound dressings. The application of Hydrogel dressings enhanced patient comfort.

An atypical surgical solution in a hangman's fracture: case report.

Anyone who is familiar with the pathomechanism of hangman's fractures will surely think twice before considering this type of injury to be relatively safe, on the grounds that a fracture of the C2 arches creates the conditions for decompressing the spinal cord, while the fact that the entire posterior complex is maintaining the ligament connection means that the fracture is relatively stable. Doe to the complexity of the pathomechanism involved in fractures, it is difficult to set the displacement non-surgically, and it may be dangerous to do so in the event of uncontrolled spine distraction. This article describes the surgical solution used to treat patient with a hangman's fracture using the anterior and posterior approaches simultaneously. The surgical procedure described here made it possible to decompress the spinal cord, perform a solid fixation, mobilize the patient quickly after surgery, and initiate effective rehabilitation.

CYP2D6 and GSTM1 genotypes in a Polish population.

OBJECTIVE: The aim of the present study was to investigate the distribution of the CYP2D6 and GSTM1 genotypes in a Polish population. METHODS: One hundred and forty-five unrelated healthy individuals from the western region of Poland were studied. The CYP2D6 genotype was analysed by means of polymerase chain reaction (PCR) amplification for the CYP2D6*3 and CYP2D6*4 alleles. The GSTM1 genotype was also analysed by means of a PCR assay to determine two genotypes: GSTM1-1 (positive) and GSTM1-0 (negative). RESULTS: Fourteen subjects (9.6%) were classified as poor metabolisers. The frequency of CYP2D6*4 and CYP2D6*3 was 23.1% and 2.1%, respectively. The frequency of GSTM1 nulled genotype in a Polish population came to 49%. CONCLUSION: The frequencies of poor metabolisers for CYP2D6 and GSTM1 nulled genotype among a Polish population were similar to those observed in other Caucasian populations.

Expression of CYP2M1, CYP2K1, and CYP3A27 in brain, blood, small intestine, and other tissues of rainbow trout.

Expression of five constitutive forms of cytochrome P450 [(LMC1 (CYP2M1), LMC2 (CYP2K1), LMC3, LMC4, and LMC5 (CYP3A27)] in selected tissues from sexually immature 2-year old female and male rainbow trout (Oncorhynchus mykiss) were examined at the translational level by Western blot using polyclonal antibodies raised in rabbits against those purified trout hepatic P450s. Tissues examined were from brain, liver, muscle, blood, head kidney, trunk kidney, upper intestine, stomach, heart, and gonad (ovary or testis). The results showed that the liver was the major organ for expression of all the trout P450s studied. Trunk kidney was the secondary expression site except for LMC5. Selective translational expression of these P450 isoforms or similar proteins was observed for LCM1 and LMC5 in brain; for LMC2 and LMC5 in female upper intestine; and for LMC2 in blood plasma of the fish studied under the experimental and sampling conditions.

Avoiding tropical infections and parasitic disease.

The incidence of tropical disease among people returning from long distance journeys is increasing and nurses need to improve their knowledge of these conditions. It is more important to know where to obtain accurate and up-to-date information on tropical diseases. Travellers need advice on prophylactic measures, and this may involve altering lifestyle patterns while abroad. Nurses should be alert to the possibility of tropical or infectious diseases when patients return from abroad, and should consider measures such as barrier nursing where appropriate.

Malaria--an old challenge in a modern age.

The incidence of malaria is increasing worldwide, and has reemerged in some areas where it was previously eradicated. The importance of full compliance with prophylactic medication must be stressed to travellers. Although aware of malarial symptoms, most travellers do not consult a doctor as soon as they appear. Health education about malaria represent a key area of occupational nurses' role.