Inertia compensation while scanning screw threads on coordinate-measuring machines

Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up measuring process while still maintaining high accuracy. However, in some cases accuracy drasticaly depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of some dynamic effects while scanning screw threads on coordinate-measuring machines

The Optical Gravitational Lensing Experiment. Monitoring of QSO 2237+0305

We present results from 2 years of monitoring of Huchra's lens (QSO 2237+0305) with the 1.3 m Warsaw telescope on Las Campanas, Chile. Photometry in the V band was done using a newly developed method for image subtraction. Reliable subtraction without Fourier division removes all complexities associated with the presence of a bright lensing galaxy. With positions of lensed images adopted from HST measurements it is relatively easy to fit the variable part of the flux in this system, as opposed to modeling of the underlying galaxy. For the first time we observed smooth light variation over a period of a few months, which can be naturally attributed to microlensing. We also describe automated software capable of real time analysis of the images of QSO 2237+0305. It is expected that starting from the next observing season in 1999 an alert system will be implemented for high amplification events (HAE) in this object. Time sampling and photometric accuracy achieved should be sufficient for early detection of caustic crossings.Comment: 8 pages (including 4 figures and table), latex, emulateapj, submitted to ApJ, revised version - minor change

Optical Gravitational Lensing Experiment. OGLE-1999-BUL-32: the Longest Ever Microlensing Event -- Evidence for a Stellar Mass Black Hole?

We describe the discovery of the longest microlensing event ever observed, OGLE-1999-BUL-32, also independently identified by the MACHO collaboration as MACHO-99-BLG-22. This unique event has an Einstein radius crossing time of 641 days. The high quality data obtained with difference image analysis shows a small but significant parallax signature. This parallax effect allows one to determine the Einstein radius projected onto the observer plane as rE^hat ~ 29.2AU. The transverse velocity projected onto the observer plane is about 79km/s. We argue that the lens is likely to be have a mass of at least a few solar masses, i.e., it could be a stellar black hole. The black hole hypothesis can be tested using the astrometric microlensing signature with the soon-to-be installed Advanced Camera for Surveys on board the Hubble Space Telescope. Deep X-ray and radio images may also be useful for revealing the nature of the object.Comment: submitted to Monthly Notice

Ultrastructural aspects of acute pancreatitis induced by 2, 2'-azobis (2-amidinopropane) dihydrochloride (AAPH) in rats

Background. Pathophysiology of acute pancreatitis (AP) has not been clearly established, nevertheless accumulating evidence implicates highly reactive oxygen species (ROS) as important mediators of exocrine tissue damage.Methods. In this study, we used a water-soluble radical initiator, 2,2'-azobis-(2-amidinopropane) dihydrochloride (AAPH), to investigate consequences of oxidative stress insult to rats pancreas. Detailed ultrastructural characterization of exocrine pancreatic changes that involved a time course of AAPH (40 mg/1kg body weight) induction from 3 to 24 hours was performed. Results. Considerable damage to the mitochondria in acinar cells manifested by increased translucence of the matrix, partial destruction of cristae and formation of myelin figures were noted. At the same time, focal dilation, degranulation of rough endoplasmic reticulum (RER), and reduced number of zymogen granules was observed. The most prominent ultrastructural feature was accumulation of highly polymorphic cytoplasmic vacuoles in acinar cells. Different in size and shape double membrane-bound autophagosomes with sequestered organelles, autophagolisosomes, and also large, empty, single-membrane-bound vacuoles were observed within the cytoplasm. Conclusions. The results indicate that intensive but impaired autophagy mediates pathological accumulation of vacuoles in acinar cells. Rat model of acute pancreatitis induced by AAPH  is useful to investigate the early events of oxidative stress insult to pancreas

The first direct detection of a gravitational micro-lens toward the Galactic bulge

We present a direct detection of the gravitational lens that caused the microlensing event MACHO-95-BLG-37. This is the first fully resolved microlensing system involving a source in the Galactic bulge, and the second such system in general. The lens and source are clearly resolved in images taken with the High Resolution Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope (HST) ~9 years after the microlensing event. The presently available data are not sufficient for the final, unambiguous identification of the gravitational lens and the microlensed source. While the light curve models combined with the high resolution photometry for individual objects indicate that the source is red and the lens is blue, the color-magnitude diagram for the line of sight and the observed proper motions strongly support the opposite case. The first scenario points to a metal-poor lens with mass M = ~0.6 M_Sun at the distance D_l = ~4 kpc. In the second scenario the lens could be a main-sequence star with M = 0.8 - 0.9 M_Sun about half-way to the Galactic bulge or in the foreground disk, depending on the extinction.Comment: Accepted for publication in Ap

The Optical Gravitational Lensing Experiment. Short Distance Scale to the LMC

We present {\it UBVI} photometry of the eclipsing binary HV2274 - the system which has been recently used for distance determination to the LMC by Guinan et al. (1998). We determine the interstellar reddening to the star, E(B-V)=0.149+/-0.015 mag, based on observed colors of the star. This value is in excellent agreement with the mean reddening towards HV2274 obtained from photometry of the red clump stars in the surrounding field. The reddening is almost twice as large as determined by Guinan et al. (1998). We discuss the consequences of reddening underestimate. Most likely HV2274 is located much closer with the distance modulus to the star and the LMC: m-M = 18.22+/-0.13 mag supporting the short distance scale to the LMC. Such a distance modulus is in excellent agreement with the recent distance determinations with RR Lyr and red clump stars.Comment: 11 pages, Latex, 2 Figures. Accepted for publication in Astrophysical Journal Letters. New version - trimmed to fit ApJL. Additional determination of the reddening towards HV2274 with OB star

Controlled cholesterol efflux from the aortic smooth muscle cells triggers microheterogeneity of plasma membrane lipids and induces modification of the mitochondrial topology

It is generally accepted that phospholipids of plasma membrane display lateral segregation into small microdomains commonly known as lipid rafts. Such lateral lipid organization is under the control of cholesterol. Cholesterol depletion evolved by methyl-β-cyclodextrin (MCD) has been found to induce further marked perturbation in lateral lipid organization, evidenced in the high field part of electron paramagnetic resonance spectra of plasma membranes labelled with a spectroscopic probe, namely 5-doxyl-stearic acid (5DOXS). Such perturbation of surface lipid topo-logy has been found to induce distinct changes in the mitochondrial morpho-logy, i.e. switch from filamentous form into small granular form

Optical Gravitational Lensing Experiment. OGLE-1999-BUL-19: The First Multi-Peak Parallax Event

We describe a highly unusual microlensing event, OGLE-1999-BUL-19, which exhibits multiple peaks in its light curve. The Einstein radius crossing time for this event is approximately one year, which is unusually long. We show that the motion of the Earth induces these multiple peaks in the light curve, since the relative transverse velocity of the lens projected into the observer plane is very small (v = 12.5 km/s). This is the lowest velocity so far published and we believe that this is the first multiple-peak parallax event ever observed. We also believe that this event may be exhibiting slight binary-source signatures in addition to these parallax-induced multiple peaks. With spectroscopic observations it is possible to test this `parallax plus binary-source' hypothesis and (if this hypothesis turns out to be correct) to simultaneously fit both models and obtain a measurement of the lens mass. Furthermore, spectroscopic observations could also supply information regarding the lens properties, possibly providing another avenue for determining the lens mass. We found that most of the I-band blending is probably caused by light from the lens or a binary companion to the source. However, in the V-band, there appears to be a second blended source 0.35" away from the lensed source. HST observations will be very useful for understanding the nature of the blends. We also suggest that a radial velocity survey of all parallax events will be very useful for further constraining the lensing kinematics and understanding the origins of these events and the excess of long events toward the bulge.Comment: 36 pages, 7 figures. Accepted for publication in MNRA

Spatial Variability in the Ratio of Interstellar Atomic Deuterium to Hydrogen. I. Observations toward delta Orionis by the Interstellar Medium Absorption Profile Spectrograph

Studies of the abundances of deuterium in different astrophysical sites are of fundamental importance to answering the question about how much deuterium was produced during big bang nucleosynthesis and what fraction of it was destroyed later. With this in mind, we used the Interstellar Medium Absorption Profile Spectrograph (IMAPS) on the ORFEUS-SPAS II mission to observe at a wavelength resolution of 4 km/s (FWHM) the L-delta and L-epsilon absorption features produced by interstellar atomic deuterium in the spectrum of delta Ori A. A chi-square analysis indicated that 0.96 < N(D I)< 1.45e15 cm^{-2} at a 90% level of confidence, and the gas is at a temperature of about 6000K. To obtain an accurate value of N(H I) needed for a determination of the atomic ratio of D to H, we measured the L-alpha absorption features in 57 spectra of delta Ori in the IUE archive. From our measurement of N(H I)= 1.56e20 cm^{-2}, we found that N(D I)/N(H I)= 7.4(+1.9,-1.3)e-6 (90% confidence). Our result for D/H contrasts with the more general finding along other lines of sight that D/H is approximately 1.5e-5. The underabundance of D toward delta Ori A is not accompanied by an overabundance of N or O relative to H, as one might expect if the gas were subjected to more stellar processing than usual.Comment: 37 pages, 6 figures. Submitted to the Astrophysical Journa

4-OH-TEMPO prevents the morphological alteration of rat thymocytes primed to apoptosis by oxidative stress inducer ButOOH

Thymocytes exposed to the pro-oxidant tert&#8211;butyl-hydroperoxide (ButOOH) display a number of dramatic changes in morphology similar to those observed in the case of dexamethasone-treated cells. Both reagents induce nuclear chromatin peripheral aggregation below the nuclear membrane. Some nuclei themselves break up producing two or more fragments. ButOOH-treated cells are morphologically characterised by cell shrinkage, extensive surface blebbing and, finally, fragmentation into membrane&#8211;bound apoptotic bodies composed of cytoplasm and tightly packed with or without nuclear fragments. An increased level of lipid hydroxyperoxides was detected after exposure of thymocytes to ButOOH. Both oxidative stress markers and morphological damage to cells were prevented by the antioxidant 4-OH-TEMPO