Quantum Simulation of the Universal Features of the Polyakov Loop.

Lattice gauge theories are fundamental to our understanding of high-energy physics. Nevertheless, the search for suitable platforms for their quantum simulation has proven difficult. We show that the Abelian Higgs model in 1+1 dimensions is a prime candidate for an experimental quantum simulation of a lattice gauge theory. To this end, we use a discrete tensor reformulation to smoothly connect the space-time isotropic version used in most numerical lattice simulations to the continuous-time limit corresponding to the Hamiltonian formulation. The eigenstates of the Hamiltonian are neutral for periodic boundary conditions, but we probe the nonzero charge sectors by introducing either a Polyakov loop or an external electric field. In both cases we obtain universal functions relating the mass gap, the gauge coupling, and the spatial size, which are invariant under the deformation of the temporal lattice spacing. We propose to use a physical multileg ladder of atoms trapped in optical lattices and interacting with Rydberg-dressed interactions to quantum simulate the model and check the universal features. Our results provide a path to the analog quantum simulation of lattice gauge theories with atoms in optical lattices.

Indoor air quality in hairdressing salons in Taipei.

To improve indoor air quality and to protect public health, Taiwan has enacted the "Indoor Air Quality Act (IAQ Act)" in 2012. For the general public, the indoor air quality in hair salons is important because it is a popular location that people will often visit for hair treatments. However, only a few exposure assessments regarding air pollutants have previously been performed in hair salons. To assess the air quality of hairdressing environments in Taipei, ten hairdressing salons were included for a walk-through survey in this study. In addition, the airborne concentrations of formaldehyde, volatile organic compounds (VOCs), CO2 , and phthalate esters were also determined in 5 salons. Charcoal, XAD-2, and OVS-Tenax tubes were used for the air sampling, while the samples were analyzed with gas chromatography/mass spectrometer. It was found that the products used in hair salons contained various chemicals. In fact, from the walk-through survey, a total of 387 different ingredients were found on 129 hair product labels. The hair salons were not well ventilated, with CO2 levels of 600 to 3576 ppm. The formaldehyde concentrations determined in this study ranged from 12.40 to 1.04 × 103  µg m-3 , and the maximum level was above the permissible exposure limit (PEL) of US Occupational Safety and Health Administration (US OSHA). Additionally, 83% of the samples were with levels higher than the standard regulated by Taiwan's IAQ Act. The concentrations of VOCs and phthalate esters were below the occupational exposure limits (OELs), but higher than what was found in general residential environments. The hair products were considered as the major source of air pollutants because significantly higher concentrations were found around the working areas. The number of perming treatments, the number of workers, and the frequency of using formaldehyde releasing products, were found to be associated with the levels of formaldehyde. This study indicates that efforts are needed to improve the indoor air quality in hairdressing salons in Taipei.

Time-weighted average sampling of airborne propylene glycol ethers by a solid-phase microextraction device.

A solid-phase microextraction (SPME) device was used as a diffusive sampler for airborne propylene glycol ethers (PGEs), including propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), and dipropylene glycol monomethyl ether (DPGME). Carboxen-polydimethylsiloxane (CAR/PDMS) SPME fiber was selected for this study. A polytetrafluoroethylene (PTFE) tubing was used as the holder, and the SPME fiber assembly was inserted into the tubing as a diffusive sampler. The diffusion path length and area of the sampler were 0.3 cm and 0.00086 cm(2), respectively. The theoretical sampling constants at 30°C and 1 atm for PGME, PGMEA, and DPGME were 1.50 × 10(-2), 1.23 × 10(-2) and 1.14 × 10(-2) cm(3) min(-1), respectively. For evaluations, known concentrations of PGEs around the threshold limit values/time-weighted average with specific relative humidities (10% and 80%) were generated both by the air bag method and the dynamic generation system, while 15, 30, 60, 120, and 240 min were selected as the time periods for vapor exposures. Comparisons of the SPME diffusive sampling method to Occupational Safety and Health Administration (OSHA) organic Method 99 were performed side-by-side in an exposure chamber at 30°C for PGME. A gas chromatography/flame ionization detector (GC/FID) was used for sample analysis. The experimental sampling constants of the sampler at 30°C were (6.93 ± 0.12) × 10(-1), (4.72 ± 0.03) × 10(-1), and (3.29 ± 0.20) × 10(-1) cm(3) min(-1) for PGME, PGMEA, and DPGME, respectively. The adsorption of chemicals on the stainless steel needle of the SPME fiber was suspected to be one of the reasons why significant differences between theoretical and experimental sampling rates were observed. Correlations between the results for PGME from both SPME device and OSHA organic Method 99 were linear (r = 0.9984) and consistent (slope = 0.97 ± 0.03). Face velocity (0-0.18 m/s) also proved to have no effects on the sampler. However, the effects of temperature and humidity have been observed. Therefore, adjustments of experimental sampling constants at different environmental conditions will be necessary.

Theory of scanning tunneling spectroscopy of magnetic adatoms in graphene.

We examine theoretically the signatures of magnetic adatoms in graphene probed by scanning tunneling spectroscopy (STS). When the adatom hybridizes equally with the two graphene sublattices, the broadening of the local adatom level is anomalous and can scale with the cube of the energy. In contrast to ordinary metal surfaces, the adatom local moment can be suppressed by the proximity of the probing scanning tip. We propose that the dependence of the tunneling conductance on the distance between the tip and the adatom can provide a clear signature for the presence of local magnetic moments. We also show that tunneling conductance can distinguish whether the adatom is located on top of a carbon atom or in the center of a honeycomb hexagon.

Preparation and evaluation of a hyaluronate-collagen film for preventing post-surgical adhesion.

Post-surgical adhesion occurs when fibrous strands of scar tissue form, leading to the abnormal joining of anatomical structures. Patients undergoing abdominal surgery are at risk of the complications associated with intraperitoneal adhesions. Hyaluronic acid (HA) is a biocompatible, biodegradable and non-toxic natural polymer, which is gaining popularity as a barrier agent for preventing post-surgical adhesions. As HA is water-soluble and rapidly degraded in vivo, chemical modification is required to produce a non-soluble sheet that might be used to prevent tissue adhesion. We developed a range of biocompatible cross-linked HA-collagen composites and then evaluated them in a rat model of post-surgical adhesion. The results showed that cross-linked HA-collagen was almost totally resistant to hyaluronidase digestion. HA-collagen membranes induced minimal tissue reactions and were bioresorbed within 14 days post-surgery. These results suggest that cross-linked HA-collagen membrane may be a valuable anti-adhesion material to prevent post-surgical intraperitoneal adhesion.

Expression and characterization of a 159 amino acid, N-terminal fragment of human complement component C1s.

A 159 residue, N-terminal fragment of the human C1s complement component, C1s alpha(159), was expressed in the baculovirus, insect cell system. The protein was abundantly produced 3 days after infection, reaching levels as high as 40 microg/ml in cell culture media. It had a molecular weight of 18,100 (+/-4.9) Da by laser desorption mass spectrometry, close to the theoretical value of 18,111 Da, confirmed by sequencing. Sedimentation equilibrium and gel filtration column chromatography showed that C1s alpha(159) was a monomer in the presence of EDTA, and a dimer in the presence of Ca2+. The C1s alpha(159)2 dimer had a sedimentation coefficient of 3.1 S. When the C1s alpha(159)2 was mixed with Clq, there was little or no interaction. Likewise, unactivated C1r2 dimer had a sedimentation coefficient of 6.8 S, and when mixed with C1q little or no interaction was observed. When C1s alpha(159)2 was mixed with the 6.8 S C1r2 in Ca2+, a 7.5 S complex was formed, presumably the C1s alpha(159) x C1r x C1r x C1s alpha(159) tetramer. When C1q, which migrated at 10.1 S was mixed with C1s alpha(159)2 and C1r2 in the presence of Ca2+, a C1-like complex, but containing C1s alpha(159) instead of C1s, was formed which migrated at 14.0 S. This C1-like molecule remained unactivated unless challenged with an ovalbumin-antiovalbumin immune complex. In the presence of immune complex, the C1r became activated. This suggested that the presence of the 159 amino acid C1s alpha domain, which held the C1r to the C1q, was sufficient to permit activation by an immune complex, even though the catalytic domains of C1s were not present.

Mechanical stretch promotes alveolar epithelial type II cell differentiation.

Functional maturation of pulmonary alveolar epithelial cells is crucial for extrauterine survival. Mechanical distension and mesenchymal-epithelial interactions play important roles in this process. We hypothesized that mechanical stretch simulating fetal breathing movements is an important regulator of pulmonary epithelial cell differentiation. Using a Flexercell Strain Unit, we analyzed effects of stretch on primary cultures of type II cells and cocultures of epithelial and mesenchymal cells isolated from fetal rat lungs during late development. Cyclic stretch of isolated type II cells increased surfactant protein (SP) C mRNA expression by 150 +/- 30% over controls (P < 0.02) on gestational day 18 and by 130 +/- 30% on day 19 (P < 0.03). Stretch of cocultures with fibroblasts increased SP-C expression on days 18 and 19 by 170 +/- 40 and 270 +/- 40%, respectively, compared with unstretched cocultures. On day 19, stretch of isolated type II cells increased SP-B mRNA expression by 50% (P < 0.003). Unlike SP-C, addition of fibroblasts did not produce significant additional effects on SP-B mRNA levels. Under these conditions, we observed only modest increases in cellular immunoreactive SP-B, but secreted saturated phosphatidylcholine rose by 40% (P < 0.002). These results indicate that cyclic stretch promotes developmentally timed differentiation of fetal type II cells, as a direct effect on epithelial cell function and via mesenchymal-epithelial interactions. Expression of the SP-C gene appears to be highly responsive to mechanical stimulation.

Distributions of p53 codon 72 polymorphism in primary open angle glaucoma.

BACKGROUND: Glaucomatous neuropathy is a type of cell death by apoptosis. The p53 gene is one of the regulatory genes of apoptosis. Recently, p53 codon 72 polymorphism has been extensively studied to determine the risk factors responsible for many diseases. In the p53 gene, a single base change from G to C causes the alternation of amino acid residue 72 from arginine to proline. In this study the association between p53 codon 72 polymorphism and primary open angle glaucoma (POAG) patients was evaluated. METHODS: 58 POAG patients and 59 healthy volunteers were enrolled in this study. Polymerase chain reaction based analysis was used to resolve the p53 codon 72 polymorphism. RESULTS: There were significant differences in the distribution of the polymorphism between the control subjects and the POAG patients (p = 0.00782) The proline form of p53 gene codon 72 appears to be a significant risk factor in the development of POAG (odds ratio 2.389, 95% confidence interval: 1.14 to 5.01). CONCLUSIONS: Retinal ganglion cells die during POAG by apoptosis. The tumour suppressor protein, p53, is one of the primary regulators steps of apoptosis, and the results of our study are compatible with this concept.

Time-weighted average sampling of airborne n-valeraldehyde by a solid-phase microextration device.

A solid-phase microextraction (SPME) device was used as a time-weighted average sampler for n-valeraldehyde. The SPME device was first modified to improve the wearer's acceptance as a passive sampler. Then a poly(dimethylsiloxane)-divinylbenzene fiber was used and O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was loaded onto the fiber. Vapors of known concentrations around the threshold limit values time-weighted average of n-valeraldehyde and specific relative humidities (RHs) were generated by syringe pumps in a dynamic generation system. n-Valeraldehyde vapors in gas bags were also generated. An exposure chamber was designed to allow measurement of face velocities, temperatures, exposing vapor concentrations, and RHs. Gas chromatography with flame ionization detection was used for sample analysis. The appropriate adsorption time for SPME coating PFBHA was determined to be 2 min and the desorption time for oxime formed after sampling was optimized to be 2 min. The experimental sampling constant was found to be (3.86+/-0.13) x 10(-2) cm3/min and face velocity was not expect to have effect on the sampler.

Enantioselective synthesis of (S)-ibuprofen ester prodrug in cyclohexane by Candida rugosa lipase immobilized on Accurel MP1000.

An enantioselective esterification process was developed for the synthesis of 2-N-morpholinoethyl (S)-ibuprofen ester prodrug from racemic ibuprofen by using Candida rugosa lipase immobilized on Accurel MP1000 in cyclohexane. Compared with the performance of Lipase MY, the immobilized lipase possesses a higher enzyme activity and thermal stability, but with a slightly suppressed enantioselectivity. A kinetic model was proposed and confirmed from experiments, for the simulation of time-course conversions of both enantiomers at various combinations of substrate concentrations in a batch reactor. Preliminary results of employing the proposed model and the immobilized lipase in a continuous packed-bed reactor were also reported and discussed.

Effects of 3'-phosphoadenosine 5'-phosphate on the activity and folding of phenol sulfotransferase.

Known spectroscopic and kinetic data are used to formulate pathways of the physiological and transfer reactions and the substrate inhibition of phenol sulfotransferase. Kinetic mechanisms indicate that release of PAP from enzyme complex is required for the physiological reaction but not for the transfer reaction. The pathways explain rate difference between the physiological and transfer reactions since the release of PAP is the rate-limiting step of the former reaction. Two enzyme species of phenol sulfotransferase which distinguish the physiological and transfer reaction were found to involve the binding of PAP. Differences between two forms of phenol sulfotransferase, alpha and beta, indicate that they assemble through different folding process. It is demonstrated that only alpha enzyme renatures in the presence of PAP and beta enzyme renatures only in the absence of PAP in vitro. In the over-expressed system, formation of alpha and beta phenol sulfotransferase is also dependent on the availability of PAP in Escherichia coli. It is concluded that folding of phenol sulfotransferase is assisted by PAP to form alpha enzyme. In the absence of PAP, beta form of phenol sulfotransferase is produced.

Effects of mechanical forces on lung-specific gene expression.

Fetal breathing movements (FBM) are necessary for fetal lung growth and maturation. The authors analyzed fetal rat lungs cultured with or without lung distension and tracheal ligation, and examined the effects of mechanical stretch on a human pulmonary epithelial cell line (NCI-H441) that shows regulated expression of surfactant proteins (SP-A, SP-B). Cells were grown on silastic membranes and mounted in a Flexercell Strain Unit. Cyclic deformation simulating FBM was achieved by applying a vacuum of 22 kPa (5%-15% radial deformation) at 50 cycles per minute for 2 to 24 hours. Results indicate that static distension for as little as 4 hours decreased steady-state SP-A and SP-B mRNA levels in whole lung (n = 5-6, P < .01). In contrast, cyclic stretching of H441 cells for 24 hours increased SP-B and SP-A expression 2- to 4-fold over controls. Cyclic deformation also significantly enhanced 3H-choline incorporation into saturated phosphatidylcholine. Dynamic mechanodeformation may be a critical stimulus for fetal lung development.

Enantioselective esterification of racemic naproxen by lipases in organic solvent.

Enantioselective esterification of naproxen, 2-(6-methoxy-2-naphthyl) propionic acid, was attempted by lipases in nearly anhydrous isooctane. The nature of the alcohol affects the reactivity and enantioselectivity of the lipase from Candida cylindracea. Alcohols containing a trimethylsilyl group are highly reactive and enantioselective to the S-isomer of the acid. An optimal temperature around 65 degrees C and an enzyme concentration less than 7 mg ml-1 were proposed to resolve the racemate, with trimethylsilyl methanol as nucleophile, from a consideration of the enantiomeric ratio, the ester formation, and the resistance of mass transfer for the substrate.

Surfactant effect on enhancing (S)-naproxen prodrug production from racemic naproxen by lipase.

In the enantioselective esterification of racemic naproxen with 4-(2-hydroxyethyl) morpholine by Lipase MY in organic solvents, a productivity improvement of the desired (S)-naproxen ester from 0.42 to 0.72 mM at the reaction time of 130 h was observed, when the surfactant bis (2-ethylhexyl) sodium sulfosuccinate (AOT) was added in the reaction mixture. The presence of a small amount of exogenously added water dramatically activated the enzyme in AOT/cyclohexane-reversed micelles. Desorption of the surfactant molecule from the enzyme mass and solubilization of the enzyme into reversed micelles were used to elucidate an existing maximum of the initial rate of (S)-naproxen synthesis with the water content. Moreover, the effects of alcohol and surfactant concentration on the enzyme activity are reported.

Lipase-catalyzed synthesis of (S)-naproxen ester prodrug by transesterification in organic solvents.

A lipase-catalyzed enantioselective transesterification process was developed for the synthesis of (S)-naproxen 2-N-morpholinoethyl ester prodrug from racemic 2,2,2-trifluoroethyl naproxen ester in organic solvents. By selecting isooctane and 37 degrees C as the best solvent and temperature, the apparent fits of the initial conversion rates for transesterification and hydrolysis side reaction suggest a ping-pong Bi-Bi enzymatic mechanism with the alcohol as a competitive enzyme inhibitor. Improvements in the initial conversion rate and the productivity for the desired (S)-ester product were obtained after comparing with the result of an enantioselective esterification process. Studies of water content in isooctane and alcohol containing various N,N-dialkylamino groups on the enzyme activity and enantioselectivity, as well as the recovery of (S)-ester product by using extraction, were also reported.

Mathematical modelling and simulation of a recycle dialysis membrane reactor in a reversed micellar system.

A mathematical framework was developed for the evaluation of a recycle dialysis membrane reactor (RDMR). The lipase-catalyzed hydrolysis of olive oil in an AOT-iso-octane reversed micellar system was employed as a model. Three specific operational strategies have been considered, namely batch, fed-batch, and fed-batch--bleed. Simulation shows the conversion of substrate to be strongly dependent on efficient use of the substrate, since the permeability coefficients of both substrate and product are quite similar. Sensitivity analyses were performed to assess the influences of various parameters (membrane area, substrate feed rate, solvent bleed rate and permeability) on the performance of the reactor in different modes of operation. The analyses presented are useful to assist the optimization of the operational strategy used for the RDMR system.

Application of a recycle dialysis system in a reversed micellar reactor.

A recycle dialysis stirred cell has been successfully used for integrating the reaction and product recovery of the lipase-catalyzed hydrolysis of olive oil in bis(2-ethylhexyl) sodium sulfosuccinate (AOT)-iso-octane reversed micelles. The resistance of membrane to reversed micelles was monitored by the water content and found to be 95.9% rejection after 24 h and 93.4% rejection after 48 h. The resistance of the membrane to free surfactants, by monitoring the UV absorption, was found to be 98.5% rejection after 10 h and 97.3% rejection after 24 h. Mathematical formulations involving the enzymatic reaction coupled with mass transfer were developed for predicting the performance of a membrane reactor. Theoretical predictions in terms of time course of oleic acid concentrations were found to be in agreement with the experimental results.

New applications of the renormalization group method in physics: a brief introduction.

The renormalization group (RG) method developed by Ken Wilson more than four decades ago has revolutionized the way we think about problems involving a broad range of energy scales such as phase transitions, turbulence, continuum limits and bifurcations in dynamical systems. The Theme Issue provides articles reviewing recent progress made using the RG method in atomic, condensed matter, nuclear and particle physics. In the following, we introduce these articles in a way that emphasizes common themes and the universal aspects of the method.

The association between lumican gene polymorphisms and high myopia.

PURPOSES: Lumican (LUM) is one of the major extracellular matrix components of the sclera. Increasing evidence suggests that changes in the structure and composition of the sclera are major factors in regulating scleral integrity and axial elongation of the eye, as in myopia. PATIENTS AND METHODS: Patients (n=182; age range, 17-24 years) were with a myopic spherical equivalent (SE)>6.5 diopters (D) and the control group comprised individuals (n=78; age range, 17-25 years) were with a myopic SE<0.5 D. The DNA fragments were separated by horizontal electrophoresis on 3% agarose gels. The forward primer was labelled with a 5' FAM and the reaction products were detected using a 3100 Genetic Analyzer. RESULTS: The polymorphisms detected in this study were LUMc.601, LUM-59, LUM-628, and LUM-1554. Moreover, the haplotype distributions of Ht1 (C/A/CC/T), Ht2 (C/A/--/T), Ht3 (T/A/CC/C), Ht4 (T/--/CC/T), Ht5 (T/--/CC/C), and Ht6 (T/--/--/C) of these polymorphisms were compared between the two groups. The haplotype frequencies of Ht1, Ht2, Ht5, and Ht6 differed significantly between the two groups (P=2.08x10(-5), odds ratio (OR): 2.19, 95% confidence interval (CI): 1.52-3.15; P=2.2x10(-5), OR: 0.39, 95% CI: 0.25-0.61; P=2.7x10(-5), OR: 0.36, 95% CI: 0.22-0.59; P=3.7x10(-5), OR: 4.71, 95% CI: 2.12-10.5, respectively). CONCLUSIONS: These observations suggest that the four polymorphisms of the LUM promoter contribute to the pathogenesis of high myopia. Understanding the functions of LUM in myopia helps us design new methods in treating and preventing myopia.