The effects of temperature and frequency dispersion on sound speed in bulk poly (vinyl alcohol) poly (N-isopropylacrylamide) hydrogels caused by the phase transition.

Bulk Poly (Vinyl Alcohol) (PVA) Poly (N-isopropyl acrylamide) (PNIPAm) hydrogel, one of the thermally responsive phase transitive hydrogels, is a versatile material due to its sharp volumetric phase transition and anomalous behaviors with facile tunability by thermal stimulation. At the lower critical solution temperature (LCST) of 33 °C, the hydrogels undergo a volumetric phase transition that causes drastic, non-monotonic change in the elastic modulus, viscosity, stiffness, and speed of sound. Here, we report the temperature and frequency dependence of the speed of sound in bulk PVA-PNIPAm hydrogel as measured by means of a planar resonant cavity. The linear response theory is applied for calculation of frequency dependent speed of sound. Comparisons find standard time of flight techniques underestimate the speed of sound by up to 6%, with variation in the frequency dependent speed of sound reaching as high as 200 m/s in the ultrasonic range of 0.2-0.8 MHz. The first characterization of frequency dependent speed of sound in PVA-PNIPAm hydrogel is addressed and delineated into its phase transition behaviors as connected to temperature. The findings can lead to better characterization of mechanical properties using ultrasonic spectroscopy, and higher resolution in ultrasonic imaging applications with dispersive media.

A micro-pipette thermal sensing technique for measuring the thermal conductivity of non-volatile fluids.

This research work demonstrates an innovative technique to measure the thermal conductivity of a small volume of non-volatile liquids. The method utilizes a micro-pipette thermal sensor (MPTS) (tip diameter < 2 µm) and is based on laser point heating thermometry and transient heat transfer. A laser beam is irradiated at the sensor tip immersed in a few microliters of the test fluid and the transient temperature change is recorded with the sensor. This temperature change is dependent on the surrounding fluid's thermal properties, such as thermal conductivity and diffusivity. The numerical solution for transient temperature profile for a point source is obtained using the finite element method in the COMSOL software. To determine the optimizing parameters such as thermal conductivity and power absorbed at the sensor tip, the multi-parameter fitting technique is used in MATLAB, which will fit the COMSOL simulation result with the experimental data. Three liquids with known thermal conductivity were tested to verify that the technique can be used to determine the thermal conductivity with high accuracy, and in addition, the thermal conductivity of growth media and serum used for culturing cancer cells is estimated. With the sensor size of 1-2 µm, we demonstrate the possibility of using this described method as the MPTS technique for measuring the thermal properties of microfluidic samples and biological fluids.

Steady heat conduction-based thermal conductivity measurement of single walled carbon nanotubes thin film using a micropipette thermal sensor.

In this paper, we describe the thermal conductivity measurement of single-walled carbon nanotubes thin film using a laser point source-based steady state heat conduction method. A high precision micropipette thermal sensor fabricated with a sensing tip size varying from 2 µm to 5 µm and capable of measuring thermal fluctuation with resolution of ±0.01 K was used to measure the temperature gradient across the suspended carbon nanotubes (CNT) film with a thickness of 100 nm. We used a steady heat conduction model to correlate the temperature gradient to the thermal conductivity of the film. We measured the average thermal conductivity of CNT film as 74.3 ± 7.9 W m(-1) K(-1) at room temperature.

Prevalence of complementary and alternative medicine (CAM) use by menopausal women: a systematic review of surveys.

Large proportions of women have turned to complementary and alternative medicine (CAM) for relief from their menopausal symptoms. This highlights the need for more rigorous research into CAM. This article is aimed at critically reviewing surveys that examine the prevalence of CAM use by menopausal women worldwide. Eleven databases were searched for peer-reviewed surveys published in any language between 01 January 2000 and 27 October 2012. The bibliographies of the retrieved articles and relevant book chapters were also hand searched. Twenty-six surveys were identified, and they included a total of 32,465 menopausal women. The majority of these surveys were of poor methodological quality. Based on 6 surveys, 32.9% of women stated they were current/regular CAM users. Based on 9 surveys, 50.5% of women reported that they used CAM specifically for their menopausal symptoms. The average 12-month prevalence of CAM use was 47.7% (range: 33.1-56.2). Fifty-five percent of women did not disclose their use of CAM to their healthcare professional. The majority of women sought information about CAM from the media. The most popular CAM modality was herbal medicine, followed by soy/phytoestrogens, evening primrose oil, relaxation and yoga. There are a large number of predominantly low-quality surveys monitoring the prevalence of CAM use among menopausal women worldwide. The available evidence suggests that the prevalence of CAM use is high.

Epidemiology of Clostridium difficile infections in a tertiary-care hospital in Korea.

To survey healthcare-associated Clostridium difficile infection (HA-CDI) in a 900-bed tertiary-care hospital, we prospectively investigated the epidemiology of CDI and distribution of PCR-ribotypes. From February 2009 through January 2010, all patients with HA-CDI were enrolled. Epidemiological information and prescription records for antibiotics were collected. The C. difficile isolates were characterized using reference strains and were tested for antibiotic susceptibility. During the survey, incidence of HA-CDI was 71.6 per 100 000 patient-days. In total, 140 C. difficile isolates were obtained from 166 patients with HA-CDI. The PCR-ribotyping yielded 38 distinct ribotypes. The three most frequently found ribotypes made up 56.4% of all isolates; they comprised 37 isolates (26.4%) of PCR-ribotype 018, 22 (15.7%) of toxin A-negative PCR-ribotype 017, and 20 (14.3%) of PCR-ribotype 001. Clostridium difficile PCR-ribotype 018 was present in all departments throughout the hospital during the 11 months, whereas ribotype 017 and ribotype 001 appeared mostly in the pulmonary department. Hypervirulent C. difficile PCR-ribotype 027 was detected in 1 month on two wards. The incidence of CDI in each department showed a seven-fold difference, which correlated significantly with the amount of prescribed clindamycin (R = 0.783, p 0.013) or moxifloxacin (R = 0.733, p 0.025) in the departments. The rates of resistance of the three commonest ribotypes to clindamycin and moxifloxacin were significantly higher than those of other strains (92.1% versus 38.2% and 89.5% versus 27.3%, respectively). CDI is an important nosocomially acquired infection and this study emphasizes the importance of implementing country-wide surveillance to detect and control CDI in Korea.

Insular cortex is a trait marker for pain processing in fibromyalgia syndrome--blood oxygenation level-dependent functional magnetic resonance imaging study in Korea.

OBJECTIVES: To investigate the variability in cerebral activation according to pain intensity and the association between variability in cerebral activation and clinical features in patients with fibromyalgia syndrome (FMS) using functional magnetic resonance imaging (fMRI). METHODS: Nineteen FMS female patients and 22 age-matched healthy female controls were enrolled in this study. Changes in cerebral activation area were measured using blood oxygenation level-dependent (BOLD) contrast fMRI after application of both medium and high pressure stimuli to the left thumbnail bed. RESULTS: We identified the insular cortex (IC) and superior temporal gyrus (STG) as regions of interest (ROIs) in this analysis. Cerebral activation at the bilateral IC in response to high pressure stimuli was significantly greater in FMS patients than it was in the controls, whereas there were no differences in BOLD signal changes in the STG regions between FMS patients and controls, irrespective of pain level. Prominent signal changes at both ROIs in FMS patients were noted between high and medium pressure (p<0.001 contralateral IC, p=0.001 for ipsilateral IC, p=0.008 for contralateral STG, and p=0.049 for ipsilateral STG). BOLD signal changes on the contralateral STG after medium stimuli were correlated with tender point count (r=0.586, p=0.013). CONCLUSIONS: This study revealed more distinct signal variability in the ICs in FMS patients than in those of controls in response to high pressure stimuli. The IC can therefore be considered to be a region susceptible to pain perception in FMS patients.

Focused-ion-beam-assisted selective control of graphene layers: acquisition of clean-cut ultra thin graphitic film.

A focused-ion beam (FIB) and a nanomanipulator provide a novel way to selectively control and obtain a few layers of graphene. Because of its weak van der Waals force in the interlayer of graphite, the nanomanipulator could easily exfoliate a graphitic thin layer with no wrinkles on the surface from a highly oriented pyrolitic graphite (HOPG) by applying a shear force which exceeds the static interlayer shear force. Subsequently, a few layers of graphene were successfully obtained by applying a uniform shear force from a detached graphitic thin layer that had been transferred to a pre-determined site on an oxide wafer. The required shear force for clean cleavage of a graphitic thin layer was then estimated based upon experimental data. Raman scattering analysis was used to confirm the number of placed graphene layers and the placement of a few layers of graphene was projected to have about five atomic layers.

Focused ion beam-assisted manipulation of single and double beta-SiC nanowires and their thermal conductivity measurements by the four-point-probe 3-omega method.

Control of one-dimensional (1D) nanostructures is demonstrated in this paper by selectively placing and aligning silicon carbide (beta-SiC) nanowires (NWs). We developed a reliable and highly reproducible way of placing a single or double SiC NW on pre-patterned electrodes by using a focused ion beam and a nanomanipulator. 3-omega signals obtained by the four-point-probe method were used in measuring the thermal conductivity of the NWs. The thermal conductivities of the placed single and double beta-SiC NWs were obtained at 82 +/- 6 W mK( - 1) and 73 +/- 5 W mK( - 1), respectively. The proposed technique offers new possibilities for manipulating and evaluating 1D nanoscale materials.

Evaluation of serotyping using monoclonal antibodies and PCR-RFLP for Chlamydia trachomatis serotype identification.

We compared genotyping by restriction fragment length polymorphism (RFLP) analysis of the amplified omp1 gene with serotyping by dot enzyme-linked immunosorbent assay (dot-ELISA) to determine the suitability of RFLP analysis for epidemiologic study. Fifteen prototypes of Chlamydia trachomatis and 30 clinical isolates were used in this study. To serotype with dot-ELISA, chlamydia antigen was spotted onto a series of replicate nitrocellulose membrane patches and reacted with 11 mAbs that distinguish the 15 known serovars of C. trachomatis. For RFLP analysis, the amplified chlamydia omp1 gene was digested with AluI to differentiate serovars A to K and L1 to L3. Serovars of C, H, I, J, and L3 were further typed by RFLP analysis after digestion with HinfI, and a combination of EcoRI and DdeI. PCR-based RFLP could identify serotype of 28 among 30 clinical isolates tested. The remaining two untypical isolates were probably due to double infections or mechanical transferring error. Serotyping of C. trachomatis isolates shows that serovars E, D, F, and H are the most prevalent types found in urogenital samples in Korea. In this study, we show that RFLP analysis of amplified omp1 gene may be useful in genotyping C. trachomatis isolates.

Prevalence of specific antibodies to Chlamydia pneumoniae in Korea.

To clarify the endemic status of Chlamydia pneumoniae in Korea, the incidence of antibodies in 564 serum samples from healthy individuals, patients with respiratory infection, and cord blood specimens was evaluated. We conclude that C. pneumoniae infection is highly endemic in Korea and that this infection is associated with acute respiratory diseases.

Rounding transform and its application for lossless pyramid structured coding.

A new transform, called the rounding transform (RT), is introduced in this paper. This transform maps an integer vector onto another integer vector by using weighted average and difference filters followed by a rounding operation. The RT can be applied to lossless pyramid structured coding with various elementary block sizes and filters. In addition, it generalizes other mean based lossless pyramid structured coding schemes.

Transcriptional regulation of the Drosophila-raf proto-oncogene by the DNA replication-related element (DRE)/DRE-binding factor (DREF) system.

The DRE/DREF system plays an important role in transcription of DNA replication genes such as those encoding the 180 and 73 kDa subunits of DNA polymerase alpha as well as that for encoding PCNA. In this study, we found two sequences homologous to DRE (5'-TATCGATA-3') in the 5'-flanking region (-370 to -357 with respect to the transcription initiation site) of the D-raf gene and confirmed transcriptional activity through gel mobility shift assays, transient CAT assays, and spatial patterns of lacZ expression in transgenic larval tissues carrying D-raf and lacZ fusion genes. Further, we demonstrated that the D-raf gene is another target of the Zerknüllt (Zen) protein with observation of D-raf repression by Zen protein in cultured cells and its ectopic expression in the dorsal region of the homozygous zen mutant embryo. The evidence of DRE/DREF involvement in regulation of the D-raf gene obtained in this study strongly supports the idea that the DRE/DREF system is responsible for the coordinated regulation of cell proliferation-related genes in Drosophila.

Imported CNS schistosomiasis--a case report.

Central nervous system (CNS) involvement may occur in chronic schistosomiasis. It can be produced by any Schistosome species but happens most frequently in chronic Schistosoma japonicum infection. CNS involvement by S. mansoni is relatively rare but it may occur by embolization of eggs or ectopic migration of adult worms. A case of cerebral schistosomiasis caused by S. mansoni in a 40-year-old man, who had worked in Yemen, is reported. Biopsies taken from the cerebellar vermis and the roof of the fourth ventricle, showed granulomatous inflammation due to eggs. S. mansoni was identified by stool examination and ELISA using serum and CSF. This is the first imported case of cerebral schistosomiasis in Korea.

Nosocomial Legionnaire's disease--a case report and review of the literature.

We report a case of nosocomial legionellosis in a 63 year-old man who was managed with neurosurgery under the diagnosis of subarachnoidal hemorrhage and complicated pneumonia in the intensive care unit. A legionella species was reported from sputum culture and direct immunofluorescent antibody test revealed L. pneumophila (serogroup 2). Our patient's pneumonia was cured with medical therapy including erythromycin and was the first case of microbiologically confirmed legionellosis in Korea.

In vitro activities of eight antibiotics against methicillin-resistant S. aureus and S. epidermidis strains isolated in Korea.

Staphylococcus aureus and Staphylococcus epidermidis strains isolated at eight large medical centers in Korea were examined for methicillin resistance and resistance to eight other antibiotics; cefazolin, cefamandole, cefuroxime, cefoxitin, cefotaxime, moxalactam, penicillin G and vancomycin. Methicillin resistance was found in 296 of 1225 strains (24.2%) of S. aureus and 126 of 348 strains (36.2%) of S. epidermidis. Methicillinresistant strains were isolated from all sources with the frequency of isolation ranging from 11% to 60%. From pleural effusion, throat swab and blood, methicillin-resistant strains of S. aureus were more frequently isolated with statistical significance (Chi-squared test, 95% confidence). Almost all of Methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE) strains were multiply resistant to one or more tested eight antibiotics. However only 7(2.4%) of 296 MRSA strains and 2(1.6%) of 126 MRSE strains were resistant to vancomycin. Vancomycin was the most effective antibiotic against staphylococcal isolates as well as MRSA and MRSE.

Hepatitis B vaccination of newborn infants: clinical study of new vaccine formulation and dose regimen.

To investigate the efficacy in anti-HBsAg response with half the recommended adult dose in a standard vaccination schedule or with a full dose in reduced number of vaccination schedule, 201 healthy newborn infants were randomized to receive either 2.5 micrograms Hevac B vaccine at birth [1, 2 and 14 months in Group I (101)] or 5 micrograms at birth [2 and 14 months in Group II (100)]. Anti-HBsAg responses in the two groups were compared. Passively acquired anti-HBsAg positivity rates at birth were 51.5 and 45.0% in Groups I and II, respectively. Cumulative anti-HBsAg seroconversion rates in Group I were 12.2, 76.6, 82.6 and 86.4% at 2, 4, 14 and 16 months, while the rates in Group II were 2.5, 62.5, 73.7 and 91.0%, showing no significant difference (p greater than 0.05). Significant difference in seroconversion rates at the 2-month follow-up stage between passively acquired anti-HBsAg-negative and -positive groups was observed (11.9 vs. 2.6%). Significant rise in anti-HBsAg titer at 16 months following the booster at 14 months was noted: 36.4 mIU per ml before, 546.4 mIU per ml after in Group I and 25.3 mIU per ml before, 782.6 mIU per ml after in Group II. The booster, 12 months after the primary vaccination series, is therefore considered imperative for maximum effectiveness of hepatitis B active immunization.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial susceptibility of bacteria isolated in 1985--with special reference to prevalence of methicillin-resistant staphylococcus aureus and activities of cefazolin, cefotaxime and piperacillin.

Antimicrobial susceptibility of nine species and one group of bacteria isolated from patients at the hospitals of Seoul National University, Severance, Hanyang University, and Kyungpuk University were tested by agar dilution method. S. aureus was most susceptible to cefazolin, methicillin and cotrimoxazole, and enterococci to ampicillin. Isolates of Enterobacteriaceae were most frequently susceptible to aminoglycosides and cefotaxime. Cefazolin susceptibility was markedly different from species to species. Aminoglycosides and piperacillin were more active than others against P. aeruginosa, and amikachin against A. anitratus. A large proportion of strains of several different species were conditionally susceptible to either tetracycline, ampicillin, cefazolin or cotrimoxazole suggesting the usefulness of these drugs for treatment of urinary tract infection. Activity of cefotaxime was highest against E. coli, and K. pneumoniae, while lowest against A. anitratus and P. aeruginosa. Decrease in the proportion of susceptible isolate was noted in E. coli and K. pneumoniae to cefazolin, K. pneumoniae, E. cloacae and S. marcescens to cotrimoxazole, and P. aeruginosa to tobramycin and gentamicin.