This paper reports on experiments that have monitored protein microsecond dynamics with a cantilevered near-field optical glass fiber. In these experiments two photoactive proteins, bacteriorhodopsin ...(bR) and the photosynthetic reaction center (PS I), are used to demonstrate that such probes can measure light-induced microsecond protein dynamics even though the resonance frequencies of the glass cantilevers used are on the order of a few hundred kilohertz. In the case of the light-driven proton pump, bR, the light-induced atomic force sensing (AFS) signal is negative (indicating contraction) in the microsecond time domain of the L photointermediate and becomes positive (corresponding to expansion) in the subsequent M intermediate that lives for milliseconds. Double pulse experiments from M to bR show that the latter process reverses the AFS signal. Thus, the AFS structural changes are coupled with the (optical) photocycle intermediates. Light-induced contraction and expansion phenomena are also observed in the case of PS I. In both systems the time regime of the dynamic phenomena that have been measured with AFS is five orders of magnitude faster than the fastest previously recorded atomic force detection of dynamic phenomena. This advance portends a new era in dynamic imaging of protein conformational changes.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
OBJECTIVE To evaluate central and peripheral retinal function in patients treated with vigabatrin, an antiepileptic drug associated with peripheral visual field constriction (VFC). METHODS Six ...patients with epilepsy treated with vigabatrin as add-on therapy for at least 3 years were included in this observational case series. All patients underwent a clinical ophthalmologic examination, color vision testing, standard perimetry, and full-field and focal foveal cone electroretinography. Four patients, 3 of whom had VFC, completed specialized computerized static light- and dark-adapted perimetry. RESULTS In 9 of 11 eyes tested, foveal cone electroretinographic amplitudes were at or below the lower limit of normal. Dark-adapted perimetry demonstrated abnormal rod-derived visual fields in the 3 patients with vigabatrin-attributed VFC, whereas rod-derived thresholds were within normal limits throughout the visual field in the patient who did not have VFC. CONCLUSIONS Our results suggest that vigabatrin not only impairs peripheral cone-derived function as manifested by VFC but also affects foveal cone electroretinographic amplitudes and rod-derived visual fields. The clinical dilemma regarding the use of vigabatrin therapy is further complicated since central as well as peripheral visual function seems to be adversely affected.Arch Ophthalmol.2003;121:811-816
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The XENON1T experiment is currently in the commissioning phase at the Laboratori Nazionali del Gran Sasso, Italy. In this article we study the experiment's expected sensitivity to the ...spin-independent WIMP-nucleon interaction cross section, based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds. The total electronic recoil background in \(1\) tonne fiducial volume and (\(1\), \(12\)) keV electronic recoil equivalent energy region, before applying any selection to discriminate between electronic and nuclear recoils, is \((1.80 \pm 0.15) \cdot 10^{-4}\) (\(\rm{kg} \cdot day \cdot keV)^{-1}\), mainly due to the decay of \(^{222}\rm{Rn}\) daughters inside the xenon target. The nuclear recoil background in the corresponding nuclear recoil equivalent energy region (\(4\), \(50\)) keV, is composed of \((0.6 \pm 0.1)\) (\(\rm{t} \cdot y)^{-1}\) from radiogenic neutrons, \((1.8 \pm 0.3) \cdot 10^{-2}\) (\(\rm{t} \cdot y)^{-1}\) from coherent scattering of neutrinos, and less than \(0.01\) (\(\rm{t} \cdot y)^{-1}\) from muon-induced neutrons. The sensitivity of XENON1T is calculated with the Profile Likelihood Ratio method, after converting the deposited energy of electronic and nuclear recoils into the scintillation and ionization signals seen in the detector. We take into account the systematic uncertainties on the photon and electron emission model, and on the estimation of the backgrounds, treated as nuisance parameters. The main contribution comes from the relative scintillation efficiency \(\mathcal{L}_\mathrm{eff}\), which affects both the signal from WIMPs and the nuclear recoil backgrounds. After a \(2\) y measurement in \(1\) t fiducial volume, the sensitivity reaches a minimum cross section of \(1.6 \cdot 10^{-47}\) cm\(^2\) at m\(_\chi\)=\(50\) GeV/\(c^2\).
We present our observations of SN 2010mb, a Type Ic SN lacking spectroscopic signatures of H and He. SN 2010mb has a slowly-declining light curve (\(\sim600\,\)days) that cannot be powered by ...\(^{56}\)Ni/\(^{56}\)Co radioactivity, the common energy source for Type Ic SNe. We detect signatures of interaction with hydrogen-free CSM including a blue quasi-continuum and, uniquely, narrow oxygen emission lines that require high densities (\(\sim10^9\)cm\(^{-3}\)). From the observed spectra and light curve we estimate that the amount of material involved in the interaction was \(\sim3\)M\(_{\odot}\). Our observations are in agreement with models of pulsational pair-instability SNe described in the literature.
We studied the effects of prone immersion on pulmonary function in children with asthma. Twelve children with asthma were subjected to prone immersion (WET) and standing upright on land (DRY) under ...controlled conditions regarding temperature and relative humidity of the inhaled air, minute ventilation, respiratory frequency, tidal volume, and the concentration of carbon dioxide in the exhaled air. Eight minutes of isocapnic hyperpnea was performed in random order either in the swimming pool (prone) or on land (upright), with the temperature and relative humidity of the inhaled air kept at 20 +/- 2 degrees C and 10 +/- 2%, respectively. The average accumulated ventilation for the 8 min of hyperpnea was 3151 for the WET treatment and 3101 for the DRY (P > 0.1). Average heart rates were 101 +/- 11 and 115 +/- 17 beats.min-1 for the WET and DRY treatments, respectively (P < 0.05). The decrease in FEV1 (delta FEV1) was 26.3 +/- 16.7% after the WET treatment (compared with pretreatment FEV1), and 26.4 +/- 11.3% after the DRY treatment (P > 0.1 between WET and DRY delta FEV1), with similar trend (insignificant differences between treatments), for delta FVC, delta PEF 50%, and delta PEF 25-75%. It is concluded that airway hyperactivity is not alleviated by whole body prone immersion.
On May 31, 2011 UT a supernova (SN) exploded in the nearby galaxy M51 (the Whirlpool Galaxy). We discovered this event using small telescopes equipped with CCD cameras, as well as by the Palomar ...Transient Factory (PTF) survey, and rapidly confirmed it to be a Type II supernova. Our early light curve and spectroscopy indicates that PTF11eon resulted from the explosion of a relatively compact progenitor star as evidenced by the rapid shock-breakout cooling seen in the light curve, the relatively low temperature in early-time spectra and the prompt appearance of low-ionization spectral features. The spectra of PTF11eon are dominated by H lines out to day 10 after explosion, but initial signs of He appear to be present. Assuming that He lines continue to develop in the near future, this SN is likely a member of the cIIb (compact IIb; Chevalier and Soderberg 2010) class, with progenitor radius larger than that of SN 2008ax and smaller than the eIIb (extended IIb) SN 1993J progenitor. Our data imply that the object identified in pre-explosion Hubble Space Telescope images at the SN location is possibly a companion to the progenitor or a blended source, and not the progenitor star itself, as its radius (~10^13 cm) would be highly inconsistent with constraints from our post-explosion photometric and spectroscopic data.
Colletotrichum species are fungal pathogens that devastate crop plants worldwide. Host infection involves the differentiation of specialized cell types that are associated with penetration, growth ...inside living host cells (biotrophy) and tissue destruction (necrotrophy). We report here genome and transcriptome analyses of Colletotrichum higginsianum infecting Arabidopsis thaliana and Colletotrichum graminicola infecting maize. Comparative genomics showed that both fungi have large sets of pathogenicity-related genes, but families of genes encoding secreted effectors, pectin-degrading enzymes, secondary metabolism enzymes, transporters and peptidases are expanded in C. higginsianum. Genome-wide expression profiling revealed that these genes are transcribed in successive waves that are linked to pathogenic transitions: effectors and secondary metabolism enzymes are induced before penetration and during biotrophy, whereas most hydrolases and transporters are upregulated later, at the switch to necrotrophy. Our findings show that preinvasion perception of plant-derived signals substantially reprograms fungal gene expression and indicate previously unknown functions for particular fungal cell types.
Colletotrichum species are fungal pathogens that devastate crop plants worldwide. Host infection involves the differentiation of specialized cell types that are associated with penetration, growth ...inside living host cells (biotrophy) and tissue destruction (necrotrophy). We report here genome and transcriptome analyses of Colletotrichum higginsianum infecting Arabidopsis thaliana and Colletotrichum graminicola infecting maize. Comparative genomics showed that both fungi have large sets of pathogenicity-related genes, but families of genes encoding secreted effectors, pectin-degrading enzymes, secondary metabolism enzymes, transporters and peptidases are expanded in C. higginsianum. Genome-wide expression profiling revealed that these genes are transcribed in successive waves that are linked to pathogenic transitions: effectors and secondary metabolism enzymes are induced before penetration and during biotrophy, whereas most hydrolases and transporters are upregulated later, at the switch to necrotrophy. Our findings show that preinvasion perception of plant-derived signals substantially reprograms fungal gene expression and indicate previously unknown functions for particular fungal cell types.
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