Effective in-field thermal conductivity of ferrofluids.

A structural model to predict in-field thermal conductivity of ferrofluids is proposed in this study and is validated by the experimental data from the literature. The model is able to capture the aggregation development of the magnetic particles with increasing magnetic field strength. Introducing a compression function that can be found empirically, the model can accurately predict the thermal conductivity, especially the plateauing at low and high magnetic fields.

Eggshell temperature manipulations during incubation and in ovo injection of thyroxine are associated with a decreased incidence of cold-induced ascites in broiler chickens.

A hypothesis was tested that eggshell temperature manipulations during incubation and in ovo injection of thyroxine (T4) would help their progeny chicks to better survive the ascites-inducing condition during the growing period. In experiment 1, a total of 4,800 hatching eggs was randomly arranged in a 2 × 4 factorial design (8 replicates of 75 eggs per treatment), in which the eggs were incubated at a constant eggshell temperature (EST) of 37.8°C throughout the incubation period (CON) or were exposed to 15°C for one h on d 11, 13, 15, and 17 of incubation (EST manipulations; ESTM), and 4 treatment groups of 3 control groups (no injection; INJN, needle pricked; INJP, and sterilized distilled water injection; INJW) and one T4 treatment group (injected with sterilized distilled water containing 65 ng of T4; INJT4). In experiment 2, 240 one-day-old male broiler chicks from 2 temperature conditions and injection (INJN and INJT4) treatment groups were reared for 42 d in a completely randomized design with a 2 × 2 factorial arrangement. To induce ascites, all chicks were exposed to a 15°C room temperature from 14 d onwards. Results from experiment 1 showed that second-grade chicks and yolk sac weight were decreased, and body weight at hatch was increased in the ESTM and INJT4 groups. Also, final body weight was increased in the ESTM group. Ascites mortality rate was decreased in the ESTM and INJT4 groups. In the ESTM and INJT4 groups, the red blood cell (RBC) and the packed cell volume (PCV) count were decreased. In conclusion, the results showed that the ESTM and INJT4 treatments during incubation were associated with improved chick quality, productive performance of broilers, and a decreased incidence of cold-induced ascites in broiler chickens.

Direct observations of field-induced assemblies in magnetite ferrofluids.

Evolution of microstructures in magnetite-based ferrofluids with weak dipolar moments (particle size ≤ 10 nm) is studied with an emphasis on examining the effects of particle concentration (ϕ) and magnetic field strength (H) on the structures. Nanoparticles are dispersed in water at three different concentrations, ϕ = 0.15%, 0.48%, and 0.59% (w/v) [g/ml%] and exposed to uniform magnetic fields in the range of H = 0.05-0.42 T. Cryogenic transmission electron microscopy is employed to provide in-situ observations of the field-induced assemblies in such systems. As the magnetic field increases, the Brownian colloids are observed to form randomly distributed chains aligned in the field direction, followed by head-to-tail chain aggregation and then lateral aggregation of chains termed as zippering. By increasing the field in low concentration samples, the number of chains increases, though their length does not change dramatically. Increasing concentration increases the length of the linear particle assemblies in the presence of a fixed external magnetic field. Thickening of the chains due to zippering is observed at relatively high fields. Through a systematic variation of concentration and magnetic field strength, this study shows that both magnetic field strength and change in concentration can strongly influence formation of microstructures even in weak dipolar systems. Additionally, the results of two commonly used support films on electron microscopy grids, continuous carbon and holey carbon films, are compared. Holey carbon film allows us to create local regions of high concentrations that further assist the development of field-induced assemblies. The experimental observations provide a validation of the zippering effect and can be utilized in the development of models for thermophysical properties such as thermal conductivity.

The effect of radiology services outsourcing on patients' satisfaction in Tehran city hospitals.

Background: To have a developed society we should have healthy, active, and happy individuals and present that extended healthcare services perform an essential function in increasing the society's health level. Health in a society includes the society's, and people comfort with the condition and an assuring the situation that they can live healthily. Also, considering the self-governing plan of hospitals from 1995, the hospital authorities should choose a method of presenting services, and, the hospital is ready to present those activities during its own activities from an economic viewpoint. The current study was done while trying to discover the effect of the Outsourcing of the Radiology Unit on the patients' satisfaction in hospitals of Tehran. Method: The present research was done in a case-evidence and sectional study. Considering the weight of a month's references to the Radiology Unit, which included around 1200 individuals, the volume of samples for measuring the frequency of the patients' satisfaction with the means of Morgan table was similar to 291 individuals. To decrease the error percentage in each hospital we questioned 300 individuals. (n+10) were questioned and the gathered information were examined by what means SPSS application variant 21 and were then studied by climagraph - Smirnoph, Du Whitman - Vitney K tests. Findings: the mean of the patients' satisfaction of turned over and non-turned over Radiology Unit services were 41.46 and 45, respectively (from the maximum score of 60). A meaningful variation was seen among the patients' Satisfaction in the two hospitals from the analytical viewpoint (p-value<0.001) and there was also a significant difference between the patients' waiting time (p-value<0.001). The research's findings showed that the outsourcing has a negative influence on the patients' satisfaction and the duration of their waiting time. Conclusion: Many times, managers do the outsourcing without considering individual and organizational dimensions and characteristics by just justifying it based on decreasing the expenses. Therefore, it is essential for authorities to consider not only the economic characters but also the individual and human aspects while setting the outsourcing contracts and arrangements.

A Comparison between Shear Bond Strength of VMK Master Porcelain with Three Base-metal Alloys (Ni-cr-T3, VeraBond, Super Cast) and One Noble Alloy (X-33) in Metal-ceramic Restorations.

STATEMENT OF PROBLEM: The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain. MATERIALS AND METHOD: Three different groups of base-metal alloys (Ni-cr-T3, Super Cast, and VeraBond) and one group of noble alloy (X-33) were selected. Each group consisted of 15 alloy samples. All groups went through the casting process and change from wax pattern into metal disks. The VMK Master Porcelain was then fired on each group. All the specimens were put in the UTM; a shear force was loaded until a fracture occurred and the fracture force was consequently recorded. The data were analyzed by SPSS Version 16 and One-Way ANOVA was run to compare the shear strength between the groups. Furthermore, the groups were compared two-by-two by adopting Tukey test. RESULTS: The findings of this study revealed shear bond strength of Ni-Cr-T3 alloy was higher than the three other alloys (94 MPa or 330 N). Super Cast alloy had the second greatest shear bond strength (80. 87Mpa or 283.87 N). Both VeraBond (69.66 MPa or 245 N) and x-33 alloys (66.53 MPa or 234 N) took the third place. CONCLUSION: Ni-Cr-T3 with VMK Master Porcelain has the greatest shear bond strength. Therefore, employment of this low-cost alloy is recommended in metal-ceramic restorations.

Centralization of ovarian cancer surgery: do patients benefit?

BACKGROUND: The aim of the study was to compare the effect of surgery in patients with ovarian cancer by gynecologist-oncologists and general gynecologists on overall survival. MATERIAL AND METHODS: In a retrospective study all patients diagnosed with primary ovarian cancer at Vali-e-Asr Hospital (Tehran, Iran) between April 1999 and January 2005 were eligible for enrollment. A total 157 consecutive patients with ovarian cancer were available for analysis. There were no significant differences between the two groups with respect the stage, age and histological type of tumor. Of 157 patients, 60 were treated by gynecologist-oncologists and 95 by general gynecologists, and two patients were treated by general surgeons. RESULTS: The number of patients who had optimal cytoreductive surgery performed was higher in the gynecologist-oncologist group than the number in the general gynecologist group (p < 0.001). The majority of patients in the general gynecologist group needed a second operation while only a few in the gynecologist-oncologist group needed one (p < 0.001).The interval between initial surgery and beginning of chemotherapy was significantly longer in the gynecologist-oncologist group as compared to the general oncologist group (p = 0.001). Overall survival and disease-free survival were considerably better in the gynecologist-oncologist group but the difference was not significant. CONCLUSION: Patients with ovarian cancer should be referred to Gynecology-Oncology Departments for optimal treatment.

Irritant effect, prevention of blood feeding and toxicity of nets impregnated with different pyrethroids on An. stephensi.

A resistant strain of An. stephensi was confirmed to have high resistance to knock down and kill by four different pyrethroids in bioassays in comparison with a susceptible strain. Permethrin, lambda-cyhalothrin and deltamethrin were more irritant to the susceptible strain than the resistant as judged by time for first take-off, but nets treated with alphacypermethrin appeared to be more irritant to the resistant An. stephensi than the susceptible. With all the pyrethroids tested, the resistant strain spent a longer time in contact with a treated net, which was in contact with a human arm, than did the susceptible strain. With permethrin the resistant strain fed significantly more successfully through the treated netting than did the susceptible strain. With deltamethrin there was a non-significant tendency in the same direction in comparing the two strains. However, with alphacypermethrin there was a non-significant tendency in the reverse direction. After 15 min in the cage which tested for the ability to feed through a pyrethroid treated net, observed mortality was higher with the susceptible than the resistant strain. Thus there was no sign that the longer resting of the resistant strain on treated netting would compensate for the fact that a higher dose was needed to kill this strain. Such compensation has been suggested with West African An. gambiae where treated nets continue to work well against a highly resistant wild population. However, this does not seem to apply to our resistant An. stephensi.

Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in swab specimens by the Hybrid Capture II and PACE 2 nucleic acid probe tests.

BACKGROUND AND OBJECTIVES: The Digene Hybrid Capture II (HC II) CT/GC Test (Digene Corp., Beltsville, MD) is a new nucleic acid signal amplification-based test for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in specimens from the genital tract. For optimal results, the HC II CT/GC Test employs a special conical shaped brush for cervical specimen collection from nonpregnant women and swabs from pregnant women. GOALS: To validate a protocol for HC II C. trachomatis and N. gonorrhoeae testing of specimens collected for the GenProbe PACE 2 System. STUDY DESIGN: Specimens were collected from 1,746 patients with a swab and placed in GenProbe transport media according to the manufacturer's recommended procedure. The specimens were first tested at two clinical laboratories by the PACE 2 system, and then blindly tested by HC II CT/GC using an adjusted cutoff value. Discrepant specimens were adjudicated by polymerase chain reaction (PCR), and the result common to two of the three testing methods (HC II, PACE 2, and PCR) was defined as the consensus result. RESULTS: Combining the data from both sites, the relative sensitivity of the HC II Test compared with the consensus result for the detection of 1,761 specimens for C. trachomatis and 1,750 specimens for N. gonorrhoeae was 100% for both organisms. The relative specificities for C. trachomatis and N. gonorrhoeae detection were 99.8% and 99.7%, respectively. The relative sensitivities of the PACE 2 CT and GC Systems were 86.5% and 87.1%, respectively, with relative specificities of 99.9% and 100%. The difference in sensitivity between HC II and PACE 2 for C. trachomatis detection was significant (P < 0.016). CONCLUSION: The HC II CT/GC Test can be performed using specimens collected in GenProbe transport media and has a significantly greater sensitivity for C. trachomatis detection than the PACE 2 System.

Effect of particle shape of acetyl salicylic acid powders on gastric damages in rats.

In this study the correlation between particle shape of acetyl salicylic acid (ASA) powders and gastric damage was studied. It is highly possible that different pharmaceutical particulate systems having different shape factors, cause different damages in contact with stomach walls. In this study five types of ASA powders in the same size range with different shape factors were chosen. From different shape factors, two important known as "elongation" and "sphericity" were selected and by means of "image analyser" were quantitatively calculated. The highest measured shape factor for elongation was 5.9 and for sphericity was 3.7, and the smallest shape factor for elongation was 1.4 and for sphericity was 1.4. For animal study, a suspension of each powder was orally administered by feeding needle, and drug was entered into the stomaches of fasting rats. After four hours, rats were killed and their stomaches were observed. Maximum number of ulcers were produced by particles with corrugated flat surfaces and the least damage was produced by particles with elongated bodies. Therefore, the most important factor resulting highly intensive ulcers in rat stomach, is flaky particles with corrugated shapes.