Polarimetric interferometer for nanoscale positioning applications

We propose and demonstrate a displacement control method at the subnanometric scale based on a Michelson interferometer combined with a polarimeter and a phase-locked loop electronic board. Step by step displacements with a step value of 5 nm are presented. A repeatability of 0.47 nm is obtained from back and forth displacements over 1 mum range. We show that a residual ellipticity of less than 10 degrees on the polarization state leads to a positioning error of less than 1 nm. Such system could be used over millimeter range displacements in a controlled surrounding environment leading to numerous applications in nanometrology.

Optical coherence tomographic characteristics and surgical outcome of eyes with myopic foveoschisis

AIM

To describe the optical coherence topographic (OCT) characteristics and outcome of vitrectomy with triamcinolone acetonide (TA)-assisted epiretinal tissue removal and gas tamponade in eyes with myopic foveoschisis (MF).

METHODS

We examined 101 myopic eyes, and the OCT characteristics of 18 eyes (18%) with an MF were studied. Six eyes underwent vitrectomy with TA-assisted epiretinal tissue removal and gas tamponade. The postoperative outcome measures were best-corrected visual acuity (BCVA), resolution of the MF as determined by OCT, and complications.

RESULTS

OCT scans showed an isolated MF in three (17%) eyes, and the MF were associated with two or more macular anomalies in 15 (83%) eyes. A foveal detachment was found in 13 (72%), lamellar macular hole in 4 (22%), and a tractional epimacular membrane in 11 (61%) of the 18 eyes. Six eyes underwent surgery, in which the epiretinal tissue was made visible by intravitreal TA and completely removed. The median BCVA significantly improved from 20/400 preoperatively (range, 20/1000-20/160) to 20/160 postoperatively (range, 20/200-20/40; P=0.03, Wilcoxon signed-rank test). The mean VA improved by 5.6 lines. OCT showed a complete reattachment of the fovea in four (67%) eyes and a small subfoveal or parafoveal detachment in two (33%) eyes.

CONCLUSIONS

MF is commonly observed in highly myopic eyes and most are associated with one or more macular anomalies. Vitrectomy with TA-assisted complete removal of all tractional premacular structures followed by gas tamponade resulted in good visual and anatomical outcomes for treating MF.

Non-radially polarized THz pulse emitted from femtosecond laser filament in air

Femtosecond laser filament could produce THz wave in forward direction. In our experiment, THz pulse emitted from a femtosecond laser filament has been investigated. It was found that the polarization of the studied THz pulse mainly appears as elliptical. This observation supplements the previous conclusion obtained by C. D'Amico et al. that THz wave emitted by a filament is radially polarized. The mechanism of generating elliptically polarized THz wave has been interpreted by either four-wave optical rectification or second order optical rectification inside the filament zone where centro-symmetry of the air is broken by the femtosecond laser pulse.

Metabolic activation of a pentafluorophenylethylamine derivative: Formation of glutathione conjugatesin vitroin the rat

The aim was to investigate the metabolic activation potential of a pentafluorophenylethylamine derivative (compound I) in vitro in the rat and to identify the cytochrome P450 (CYP) enzymes that catalyse these metabolic activation processes. Reduced glutathione (GSH) was fortified in rat hepatocytes and liver microsomes to trap possible reactive intermediates. Four glutathione conjugates (M1-4) were identified by LC-MS(n) following incubation of compound I in GSH-enriched rat hepatocytes and liver microsomes. Three of these conjugates (M2-4) have not been reported previously for pentafluorophenyl derivatives. Elemental composition analysis of these conjugates was obtained using high-resolution quadrupole time-of-flight mass spectrometry. The formation of GSH conjugate M1 was rationalized as a direct nucleophilic replacement of fluoride by glutathione, whereas the formation of the GSH conjugates M2-4 was proposed to occur by NADPH-dependent metabolic activation of the pentafluorophenyl ring via arene oxide, quinone and/or quinoneimine reactive intermediates. Formation of these conjugates was enhanced three- to five-fold in liver microsomes obtained from phenobarbital- and dexamethasone-treated rats. In incubations with pooled rat liver microsomes and recombinant rat CYP3A1 and CYP3A2, troleandomycin (TAO) reduced the formation of GSH conjugates M2-4 by 80-90%, but it had no effect on the formation of M1. Incubation of compound I with rat supersomes indicated that only CYP3A1 and CYP3A2 were capable of mediating these metabolic activation processes.

Transient expression of hepatitis B virus surface antigen (HBsAg) and human erythropoietin (hEPO) genes in milk after direct introduction into ewe

The ability to deliver nonviral DNA directly into animals would provide major practical and economic benefits. To pursue this potential, as a preliminary approach, the expression in mammary epithelial cells with nonviral DNA ending HBsAg and hEPO was investigated by in vivo delivery directly into mammary gland Either the bovine asl-casein-HBsAg or the WAE-hEPO gene construct was introduced into mammary glands of dm by mammary artery injection. A single injection of 10(11) copies of DNA construct was implemented for a doe. Transient expression of the constructs in milk collected from milk letdown by induction up to 19 d after injection was measured with an hEPO ELISA kit from Boehringer Mannheim (Cat. No. 1 693 417) for rhEPO, and a HBsAg-ELISA kit (Abbott Lab. USA) for rHBsAg. The treated animals showed mean concentration of recombinant molecules at 16 microg/L for rHBsAg, and 2 mg/L for rhEPO in milk.

A Fisher scoring algorithm for the weighted regression method of QTL mapping

An improved weighted least square (LS) method for quantitative trait loci (QTL) mapping using the estimating equation (EE) algorithm was developed recently. The method is more efficient than both the LS and the weighted LS methods and slightly less efficient than the mixture model maximum likelihood (ML) method. The iteration process of the EE algorithm is implicit. We developed a Fisher-scoring algorithm for the weighted LS method. The iteration process is explicit and easy to program. In addition, the method automatically provides an approximate variance-covariance matrix for the estimated QTL parameters as a by-product of the iteration process. As a consequence, a W-test statistic can be used for testing the significance of QTL. To compare the Fisher scoring algorithm with the expectation maximization (EM)-based ML method, we also developed a slightly simplified method to compute the variance-covariance matrix of the estimated parameters under the EM algorithm.

Negative words on surgical wards result in therapeutic failure of patient-controlled analgesia and further release of cortisol after abdominal surgeries

BACKGROUND

The perception of pain is germane to the environmental stimuli. Nurses on surgical wards are the main contributor in influencing patients' psychophysiological fettle. The aim of the study was to investigate the effect of different words, negative or positive, from nurses on postoperative pain therapy with patient-controlled analgesia (PCA).

METHODS

1500 ASA I-II patients, who underwent abdominal hysterectomy, were screened and 771 were randomized into one of four groups. In the no words group (NW, N.=35), no words was delivered. The positive (PW, N.=248), partially negative (NW1, N.=241) and totally negative (NW2, N.=247) groups received corresponding words when treating with morphine PCA, the words were given singly at the 3(rd), 6(th), 12(th), 18(th) h and repeatedly at the 3(rd) and 6(th) h, and each group was redivided into six subgroups according to varying time points. Pain intensity, morphine consumption, side effects, overall sedation and satisfaction scores were recorded and plasma cortisol was tested.

RESULTS

A total of 614 patients completed the study. Negative words expressed significant influence on pain therapy at the 3(rd) and 6(th) h after surgeries (P<0.01), and this effect was more convenient in repeatedly treated patients (P<0.001). Positive and the 12(th) and 18(th) h negative words displayed little role in pain management. Morphine consumption, side effects, satisfaction and cortisol level converted with the change of the pain intensity. No intergroup differences were observed in patients' overall conditions.

CONCLUSION

Negative words on surgical wards influenced postoperative pain management at the earlier period of time after abdominal surgeries associated with the HPA axis activation.

Novel double-superior-trunk injury of the brachial plexus: a case report

Brachial plexus injuries are generally rare and a double-superior-trunk injury of the brachial plexus has never been reported before. We report the first case of a brachial plexus injury in a 43-year-old Chinese male with a double superior trunk. This was observed incidentally during an operation 1 month after initial traction injury sustained in a car accident. The double superior trunk of the brachial plexus was formed by the double roots of C5 and C6, respectively. Six months after discharge, the patient reported the recovery of most of the function of his left arm except the muscles innervated by the radial nerve. Two years after discharge, he reported almost full functional recovery of his left arm. We discuss what is known about anatomical variations of the brachial plexus, and the possible association between this novel brachial plexus anatomy and the almost complete functional recovery of the arm.

Preparation of TEM samples of ferritic alloys

We describe techniques for electropolishing irradiated ferritic specimens for examination under the TEM in situations where the foil quality is of utmost importance. First, we describe some modifications to the standard technique for making plan-view specimens aimed at optimizing the foil quality. Second, we describe a technique for making plan-view specimens from a region of buried damage in a specimen irradiated with 2 MeV Fe(+) ions.

A simple method for calculating the statistical power for detecting a QTL located in a marker interval

We developed a simple method for calculating the statistical power for detecting a QTL located in an interval flanked by two markers. The statistical method for QTL detection is assumed to be the Haley and Knott's simple regression method of interval mapping. This method allows us to answer one of the fundamental questions in designing a QTL mapping experiment: What is the minimum marker density required to detect a QTL explaining a certain heritable proportion of the phenotypic variance (denoted by h(2)) with a power gamma under a Type I error alpha in an F(2) or other mating designs with a sample size n? Computing the statistical power only requires the ability to evaluate a non-central F-distribution function and the inverse function of this distribution.

Zero-field remote detection of NMR with a microfabricated atomic magnetometer

We demonstrate remote detection of nuclear magnetic resonance (NMR) with a microchip sensor consisting of a microfluidic channel and a microfabricated vapor cell (the heart of an atomic magnetometer). Detection occurs at zero magnetic field, which allows operation of the magnetometer in the spin-exchange relaxation-free (SERF) regime and increases the proximity of sensor and sample by eliminating the need for a solenoid to create a leading field. We achieve pulsed NMR linewidths of 26 Hz, limited, we believe, by the residence time and flow dispersion in the encoding region. In a fully optimized system, we estimate that for 1 s of integration, 7 x 10(13) protons in a volume of 1 mm(3), prepolarized in a 10-kG field, can be detected with a signal-to-noise ratio of approximately 3. This level of sensitivity is competitive with that demonstrated by microcoils in 100-kG magnetic fields, without requiring superconducting magnets.

Homogeneous nanocrystalline cubic silicon carbide films prepared by inductively coupled plasma chemical vapor deposition

Silicon carbide films with different carbon concentrations x(C) have been synthesized by inductively coupled plasma chemical vapor deposition from a SiH(4)/CH(4)/H(2) gas mixture at a low substrate temperature of 500 °C. The characteristics of the films were studied by x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transform infrared absorption spectroscopy, and Raman spectroscopy. Our experimental results show that, at x(C) = 49 at.%, the film is made up of homogeneous nanocrystalline cubic silicon carbide without any phase of silicon, graphite, or diamond crystallites/clusters. The average size of SiC crystallites is approximately 6 nm. At a lower value of x(C), polycrystalline silicon and amorphous silicon carbide coexist in the films. At a higher value of x(C), amorphous carbon and silicon carbide coexist in the films.

Mechanisms of the reactions of W AND W+ with H2O: computational studies

The mechanism of the reactions of W and W(+) with the water molecule have been studied for several lower-lying electronic states of tungsten centers at the CCSD(T)/6-311G(d,p)+SDD and B3LYP/6-31G(d,p)+SDD levels of theory. It is shown that these reactions are essentially multistate processes, during which lower-lying electronic states of the systems cross several times. They start with the formation of initial prereaction M(H(2)O) complexes with M-H(2)O bonding energies of 9.6 and 48.2 kcal/mol for M = W and W(+), followed by insertion of the metal center into an O-H bond with 20.0 and 53.3 kcal/mol barriers for neutral and cationic systems, respectively. The overall process of M + H(2)O --> t-HM(OH) is calculated to be highly exothermic, 48.4 and 48.8 kcal/mol for M = W and W(+). From the HM(OH) intermediate the reaction may proceed via several different channels, among which the stepwise HM(OH) --> HMO + H --> (H)(2)MO and concerted HM(OH) --> (H)(2)MO pathways are more favorable and can compete (energetically) with each other. For the neutral system (M = W), the concerted process is the most favorable, whereas for the charged system (M = W(+)), the stepwise pathway is slightly more favorable. From the energetically most favorable intermediate (H)(2)MO the reactions proceed via H(2)-molecule formation with a 53.1 kcal/mol activation barrier for the neutral system. For the cationic system, H-H formation and dissociation is an almost barrierless process. The overall reaction of W and W(+) with the water molecule leading to H(2) + MO formation is found to be exothermic by 48.2 and 39.8 kcal/mol, respectively. In the gas phase with the collision-less conditions the reactions W((7)S) + H(2)O --> H(2) + WO((3)Sigma(+)), and W(+)((6)D) + H(2)O --> H(2) + WO(+)((4)Sigma(+)) are expected to proceed via a 10.4 and 5.1 kcal/mol overall energy barrier corresponding to the first O-H dissociation at the TS1. On the basis of these PESs, we predict kinetic rate constants for the reactions of W and W(+) with H(2)O.

The effects of force inhibition by sodium vanadate on cross-bridge binding, force redevelopment, and Ca2+ activation in cardiac muscle

Strongly bound, force-generating myosin cross-bridges play an important role as allosteric activators of cardiac thin filaments. Sodium vanadate (Vi) is a phosphate analog that inhibits force by preventing cross-bridge transition into force-producing states. This study characterizes the mechanical state of cross-bridges with bound Vi as a tool to examine the contribution of cross-bridges to cardiac contractile activation. The K(i) of force inhibition by Vi was approximately 40 microM. Sinusoidal stiffness was inhibited with Vi, although to a lesser extent than force. We used chord stiffness measurements to monitor Vi-induced changes in cross-bridge attachment/detachment kinetics at saturating [Ca(2+)]. Vi decreased chord stiffness at the fastest rates of stretch, whereas at slow rates chord stiffness actually increased. This suggests a shift in cross-bridge population toward low force states with very slow attachment/detachment kinetics. Low angle x-ray diffraction measurements indicate that with Vi cross-bridge mass shifted away from thin filaments, implying decreased cross-bridge/thin filament interaction. The combined x-ray and mechanical data suggest at least two cross-bridge populations with Vi; one characteristic of normal cycling cross-bridges, and a population of weak-binding cross-bridges with bound Vi and slow attachment/detachment kinetics. The Ca(2+) sensitivity of force (pCa(50)) and force redevelopment kinetics (k(TR)) were measured to study the effects of Vi on contractile activation. When maximal force was inhibited by 40% with Vi pCa(50) decreased, but greater force inhibition at higher [Vi] did not further alter pCa(50). In contrast, the Ca(2+) sensitivity of k(TR) was unaffected by Vi. Interestingly, when force was inhibited by Vi k(TR) increased at submaximal levels of Ca(2+)-activated force. Additionally, k(TR) is faster at saturating Ca(2+) at [Vi] that inhibit force by > approximately 70%. The effects of Vi on k(TR) imply that k(TR) is determined not only by the intrinsic properties of the cross-bridge cycle, but also by cross-bridge contribution to thin filament activation.