3D printed modules for integrated microfluidic devices

Direct 3d printing for functional modules and their assembly into an integrated microfluidic device.

Relationship between socioeconomic status and anemia prevalence in adolescent girls based on the fourth and fifth Korea National Health and Nutrition Examination Surveys

BACKGROUND/OBJECTIVES

We studied the relationship between socioeconomic status (SES), represented by household income, and the prevalence of anemia and iron deficiency anemia (IDA) among adolescent girls in Korea.

SUBJECTS/METHODS

The samples were based on the data from a four-year (2008-2011) collection for the Korea National Health and Nutrition Examination Survey (1312 girls, age 10-18 years). The survey included demographic, anthropometric, biochemical and nutritional parameters. A multiple regression analysis after adjusting for age, body mass index (BMI), red blood cell count, white blood cell count and red meat intake was performed. Anemia was defined as hemoglobin level lower than 11.5 g/dl for ages 10-11 years and 12.0 g/dl for ages 12-14 years. Iron deficiency was defined as serum ferritin level below 15 μg/l.

RESULTS

The prevalences of anemia and IDA in Korean girls were 5.3 and 4.2%, respectively. Girls with anemia were older, taller, weighed more, had higher BMI, had higher portion of menarche experience and consumed less red meat than girls without anemia. Girls with higher income had lower anemia prevalence and consumed more iron and vitamins. Logistic regression analysis showed a decreasing trend in anemia prevalence as household income increased. Correlation analysis demonstrated that there is a relationship between household income and serum hemoglobin and ferritin levels (P=0.003 and P=0.026, respectively).

CONCLUSIONS

Higher SES leads to lower prevalence of anemia and IDA in Korean adolescent girls. This may be due to the fact that higher SES individuals consume more iron and vitamin C.

Existence of orbital order and its fluctuation in superconducting Ba(Fe(1-x)Co(x))2As2 single crystals revealed by x-ray absorption spectroscopy

We performed temperature dependent x-ray linear dichroism (XLD) experiments on an iron pnictide system, Ba(Fe(1-x)Co(x))2As2 with x=0.00, 0.05, 0.08, and 0.10 to experimentally verify the existence of orbital ordering (OO). Substantial XLD was observed in polarization dependent x-ray absorption spectra of Fe L edges. By exploiting the difference in the temperature dependent behaviors, OO, and structure contributions to XLD could be clearly separated. The observed OO signal indicates different occupation numbers for d(yz) and d(zx) orbitals and supports the existence of ferro-OO. The results are also consistent with the theoretical prediction. Moreover, we find substantial OO signal well above the structural and magnetic transition temperatures, which suggests the existence of strong OO fluctuations up to high temperatures.

Anomalous dressing of Dirac fermions in the topological surface state of Bi2Se3, Bi2Te3, and Cu-doped Bi2Se3

Quasiparticle dynamics on the topological surface state of Bi(2(3), Bi(2)Te(3), and superconducting Cu(x)Bi(2)Se(3) are studied by 7 eV laser-based angle resolved photoemission spectroscopy. We find strong mode couplings in the Dirac-cone surface states at energies of ~3 and ~15-20 meV associated with an exceptionally large coupling constant λ of ~3, which is one of the strongest ever reported for any material. This result is compatible with the recent observation of a strong Kohn anomaly in the surface phonon dispersion of Bi(2)Se(3), but it appears that the theoretically proposed "spin-plasmon" excitations realized in helical metals are also playing an important role. Intriguingly, the ~3 meV mode coupling is found to be enhanced in the superconducting state of Cu(x)Bi(2)Se(3).

Anomalous doping variation of the nodal low-energy feature of superconducting (Bi,Pb)2(Sr,La)2CuO(6+δ) crystals revealed by laser-based angle-resolved photoemission spectroscopy

The nodal band dispersion in (Bi,Pb)(2)(Sr,La)(2)CuO(6+δ) (Bi2201) is investigated over a wide range of doping by using 7-eV laser-based angle-resolved photoemission spectroscopy. We find that the low-energy band renormalization ("kink"), recently discovered in Bi(2)Sr(2)CaCu(2)O(8+δ) (Bi2212), also occurs in Bi2201, but at a binding energy around half that in Bi2212. Surprisingly, the coupling energy dramatically increases with a decrease of carrier concentration, showing a sharp enhancement across the optimal doping. These properties (material and doping dependence of the coupling energy) demonstrate the significant correlation among the mode coupling, the energy gap close to the node, and the strong electron correlation. Our results suggest forward scattering arising from the interplay between the electrons and in-plane polarized acoustic phonon branch as the origin of the low-energy renormalization.

Strongly spin-orbit coupled two-dimensional electron gas emerging near the surface of polar semiconductors

We investigate the two-dimensional highly spin-polarized electron accumulation layers commonly appearing near the surface of n-type polar semiconductors BiTeX (X=I, Br, and Cl) by angular-resolved photoemission spectroscopy. Because of the polarity and the strong spin-orbit interaction built in the bulk atomic configurations, the quantized conduction-band subbands show giant Rashba-type spin splitting. The characteristic 2D confinement effect is clearly observed also in the valence bands down to the binding energy of 4 eV. The X-dependent Rashba spin-orbit coupling is directly estimated from the observed spin-split subbands, which roughly scales with the inverse of the band-gap size in BiTeX.

The effect of oral prostaglandin analogue on painful diabetic neuropathy: a double-blind, randomized, controlled trial

This study was performed to assess the efficacy of beraprost sodium (BPS) in painful diabetic peripheral neuropathy (DPN) in type 2 diabetes mellitus (T2DM) patients. In this randomized clinical trial, 99 T2DM patients (41% male, age 60 ± 6 years) with DPN but without evidence of peripheral artery disease were randomized to receive either BPS (40 µg, tid) or placebo for 8 weeks. The primary end point was the improvement of the total symptom score (TSS), temperature rebound (TR) and nadir to peak (NP) above baseline. After 8 weeks treatment, the change of TSS in the BPS group showed a significant improvement compared to the placebo group (2.80 ± 2.48 vs. 1.60 ± 1.94 points, p = 0.009). Furthermore, the number of patients who showed signs of improvement in TSS and the proportion of patients with 50% relief of symptom was also significantly greater in the BPS group than in the placebo group (83.7 vs. 62%, p = 0.015, 36.2 vs. 14%, p = 0.009, respectively). In conclusion, treatment with BPS significantly improved TSS over an 8-week period.

Evidence for a cos(4φ) modulation of the superconducting energy gap of optimally doped FeTe(0.6)Se(0.4) single crystals using laser angle-resolved photoemission spectroscopy

We study the superconducting-gap anisotropy of the Γ-centered hole Fermi surface in optimally doped FeTe(0.6)Se(0.4) (T(c)=14.5 K), using laser-excited angle-resolved photoemission spectroscopy. We observe sharp superconducting (SC) coherence peaks at T=2.5 K. In contrast to earlier angle-resolved photoemission spectroscopy studies but consistent with thermodynamic results, the momentum dependence shows a cos(4φ) modulation of the SC-gap anisotropy. The observed SC-gap anisotropy strongly indicates that the pairing interaction is not a conventional phonon-mediated isotropic one. Instead, the results suggest the importance of second-nearest-neighbor electronic interactions between the iron sites in the framework of s(±)-wave superconductivity.

The Xpert® MTB/RIF assay evaluation in South Korea, a country with an intermediate tuberculosis burden

SETTING

A central hospital laboratory in South Korea.

OBJECTIVE

To evaluate the usefulness of the Xpert® MTB/RIF assay in a country with an intermediate tuberculosis burden.

DESIGN

A total of 71 real-time polymerase chain reaction-positive sputum sediments were tested within 24 h by the Xpert MTB/RIF assay. Mycobacterium tuberculosis detection was compared with smear microscopy and culture. Rifampicin (RMP) resistance was compared with a culture-based method and rpoB gene sequencing. We also assessed the limit of detection for mutant proportions and time savings in diagnosis.

RESULTS

The Xpert MTB/RIF assay detected M. tuberculosis in 71 (100%) specimens (32 smear-positive, 39 smear-negative). This assay showed 100% (62/62) concordance with drug resistance confirmed by culture and 98.4% (61/62) concordance with sequencing. A specimen containing approximately 50% of mutant p.His526Tyr was falsely interpreted as wild-type bacilli by this assay. The minimal detection ratio was 5:1 of mutant vs. wild-type cells. The median time saved was 18.5 days (range 9-30) for the diagnosis of M. tuberculosis and 81.5 days (65-136) for RMP susceptibility in smear-negative, culture-positive patients.

CONCLUSIONS

The Xpert MTB/RIF assay showed high sensitivity in detecting M. tuberculosis with information on RMP resistance, and had a more rapid time to diagnosis compared to conventional tests; however, the location and amount of mutation may affect test sensitivity.

Quasiparticles and Fermi liquid behaviour in an organic metal

Many organic metals display exotic properties such as superconductivity, spin-charge separation and so on and have been described as quasi-one-dimensional Luttinger liquids. However, a genuine Fermi liquid behaviour with quasiparticles and Fermi surfaces have not been reported to date for any organic metal. Here, we report the experimental Fermi surface and band structure of an organic metal (BEDT-TTF)(3)Br(pBIB) obtained using angle-resolved photoelectron spectroscopy, and show its consistency with first-principles band structure calculations. Our results reveal a quasiparticle renormalization at low energy scales (effective mass m*=1.9 m(e)) and ω(2) dependence of the imaginary part of the self energy, limited by a kink at ~50 meV arising from coupling to molecular vibrations. The study unambiguously proves that (BEDT-TTF)(3)Br(pBIB) is a quasi-2D organic Fermi liquid with a Fermi surface consistent with Shubnikov-de Haas results.

Measurement of the inclusive jet cross section in pp collisions at √s = 7 TeV

The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the Large Hadron Collider using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 pb(-1). The measurement is made for jet transverse momenta in the range 18-1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet p(T) ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leading-order perturbative QCD predictions.

A one-step electrochemical method for DNA detection that utilizes a peroxidase-mimicking DNAzyme amplified through PCR of target DNA

A novel one-step electrochemical method for DNA detection is described. The procedure utilizes a reaction catalyzed by a peroxidase-mimicking DNAzyme to produce a product, which forms an insoluble precipitation layer on the surface of an electrode. A rationally designed forward primer, conjugated with a peroxidase DNAzyme complementary sequence at its 5'-end, is used for PCR amplification of target DNA. As a result, the DNAzyme sequence is produced by amplification only when the target DNA is present in the sample. The PCR product is then subjected to the precipitation reaction on the electrode surface using an electrolyte assay buffer containing 4-chloronaphthol, hydrogen peroxide, ferrocenemethanol, hemin, and 5'-lambdaexonuclease. Finally, analysis is carried out using Faradaic impedance spectroscopy. The impedance value was found to greatly increase when target DNA is present owing to the formation of a precipitation layer on the electrode surface caused by the catalytic action of the DNAzyme. In contrast, no impedance increase is observed when a control sample not containing target DNA is utilized. By employing this strategy, target DNA from Chlamydia trachomatis was reliably detected within a 10 min period following precipitation without the need for complicated secondary procedures. This effort has led to the development of a highly convenient electrochemical one-step method for DNA detection that utilizes a peroxidase-mimicking DNAzyme, which is specifically designed to undergo amplification during PCR of target DNA.

Non-thermal hot electrons ultrafastly generating hot optical phonons in graphite

Investigation of the non-equilibrium dynamics after an impulsive impact provides insights into couplings among various excitations. A two-temperature model (TTM) is often a starting point to understand the coupled dynamics of electrons and lattice vibrations: the optical pulse primarily raises the electronic temperature T(el) while leaving the lattice temperature T(l) low; subsequently the hot electrons heat up the lattice until T(el) = T(l) is reached. This temporal hierarchy owes to the assumption that the electron-electron scattering rate is much larger than the electron-phonon scattering rate. We report herein that the TTM scheme is seriously invalidated in semimetal graphite. Time-resolved photoemission spectroscopy (TrPES) of graphite reveals that fingerprints of coupled optical phonons (COPs) occur from the initial moments where T(el) is still not definable. Our study shows that ultrafast-and-efficient phonon generations occur beyond the TTM scheme, presumably associated to the long duration of the non-thermal electrons in graphite.