48 research outputs found
Experimental investigation of ball bearing lubrication conditions by shock pulse method
Lubricant (grease) is a vital requirement of ball bearing system. Grease not only protects ball bearing from wear and tear but performs various other functions that are essential for proper functioning of ball bearings. The lubricant (grease) under different conditions attains different properties which in turn affect the performance of the ball bearings. The effect of the condition of the lubricants on the performance of the ball bearings is well documented. the work reports about the investigation of ball bearing using shock pulse method by using two different instruments (Tester T2000 Model and Shock Pulse Meter 43A) of different operating conditions of ball bearing the condition such as used the quantity of grease as different percentage (0%, 25%, 50%, 75%, 100%) and bad quality grease (burn grease) at different rpm at a fixed load (10kg) and compare the normalized shock pulse value (dB) at different operating conditions. This method uses a piezo-electric accelerometer superimposed electrically as well as mechanically to about 32 kHz of resonant frequency. The result will help in bearing related to quantity as well as quality condition based maintenance choosing the optimum conditions for detecting the lubricant problem in ball bearing
Bochdalek Hernia with Incarceration of Large Bowel
Congenital Diaphragmatic Hernia (CDH) is a
condition characterized by developmental defect in the
diaphragm with herniation of the abdominal contents
through the defect into the thorax. Late presentation of
CDH is around 5 to 25%. This is a report of a young
female presenting with acute abdomen and left- sided
chest pain. Laparotomy revealed a Bochdalek Hernia
with incarceration of large bowel. The contents were
reduced, gangrenous bowel and omentum resected and
intestinal continuity restored. Acute intestinal
obstruction with respiratory embarrassment warrants a
high index of suspicion. An adequate resuscitative
measure with urgent surgical intervention and
ventilatory support is the key to a successful outcome
Probing the dynamics of an optically trapped particle by phase sensitive back focal plane interferometry
The dynamics of an optically trapped particle are often determined by
measuring intensity shifts of the back-scattered light from the particle using
position sensitive detectors. We present a technique which measures the phase
of the back-scattered light using balanced detection in an external Mach-Zender
interferometer scheme where we separate out and beat the scattered light from
the bead and that from the top surface of our trapping chamber. The technique
has improved axial motion resolution over intensity-based detection, and can
also be used to measure lateral motion of the trapped particle. In addition, we
are able to track the Brownian motion of trapped 1 and 3 m diameter beads
from the phase jitter and show that, similar to intensity-based measurements,
phase measurements can also be used to simultaneously determine displacements
of the trapped bead as well as the spring constant of the trap. For lateral
displacements, we have matched our experimental results with a simulation of
the overall phase contour of the back-scattered light for lateral displacements
by using plane wave decomposition in conjunction with Mie scattering theory.
The position resolution is limited by path drifts of the interferometer which
we have presently reduced to obtain a displacement resolution of around 2 nm
for 1.1 m diameter probes by locking the interferometer to a frequency
stabilized diode laser.Comment: 10 pages, 7 figure
Prevalence of vitamin D deficiency and its relationship with thyroid autoimmunity in Asian Indians: a community-based survey
25-Hydroxy vitamin D (25(OH)D) deficiency is linked with predisposition to autoimmune type 1 diabetes and multiple sclerosis. Our objective was to assess the relationship between serum 25(OH)D levels and thyroid autoimmunity. Subjects included students, teachers and staff aged 16-60 years (total 642, 244 males, 398 females). Serum free thyroxine, thyroid-stimulating hormone (TSH), and thyroid peroxidase autoantibodies (TPOAb), intact parathyroid hormone and 25(OH)D were measured by electrochemiluminescence and RIA, respectively. Thyroid dysfunction was defined if (1) serum TSH ≥ 5 μ U/ml and TPOAb>34 IU/ml or (2) TSH ≥ 10 μ U/ml but normal TPOAb. The mean serum 25(OH)D of the study subjects was 17.5 (SD 10.2) nmol/l with 87 % having values ≤ 25 nmol/l. TPOAb positivity was observed in 21 % of subjects. The relationship between 25(OH)D and TPOAb was assessed with and without controlling for age and showed significant inverse correlation (r - 0.08, P = 0.04) when adjusted for age. The prevalence of TPOAb and thyroid dysfunction were comparable between subjects stratified according to serum 25(OH)D into two groups either at cut-off of ≤ 25 or >25 nmol/l or first and second tertiles. Serum 25(OH)D values show only weak inverse correlation with TPOAb titres. The presence of such weak association and narrow range of serum 25(OH)D did not allow us to interpret the present results in terms of quantitative cut-off values of serum 25(OH)D. Further studies in vitamin D-sufficient populations with wider range of serum 25(OH)D levels are required to substantiate the findings of the current study
Spin selection rule for {\it S} level transitions in atomic rubidium under paraxial and nonparaxial two-photon excitation
We report on an experimental test of the spin selection rule for two-photon
transitions in atoms. In particular, we demonstrate that the transition rate in a rubidium gas follows a quadratic dependency on
the helicity parameter linked to the polarization of the excitation light. For
excitation via a single Gaussian beam or two counterpropagating beams in a hot
vapor cell, the transition rate scales as the squared degree of linear
polarization. The rate reaches zero when the light is circularly polarized. In
contrast, when the excitation is realized via an evanescent field near an
optical nanofiber, the two-photon transition cannot be completely extinguished
(theoretically, not lower than 13\% of the maximum rate, under our experimental
conditions) by only varying the polarization of the fiber-guided light. Our
findings lead to a deeper understanding of the physics of multiphoton processes
in atoms in strongly nonparaxial light
EvDNeRF: Reconstructing Event Data with Dynamic Neural Radiance Fields
We present EvDNeRF, a pipeline for generating event data and training an
event-based dynamic NeRF, for the purpose of faithfully reconstructing
eventstreams on scenes with rigid and non-rigid deformations that may be too
fast to capture with a standard camera. Event cameras register asynchronous
per-pixel brightness changes at MHz rates with high dynamic range, making them
ideal for observing fast motion with almost no motion blur. Neural radiance
fields (NeRFs) offer visual-quality geometric-based learnable rendering, but
prior work with events has only considered reconstruction of static scenes. Our
EvDNeRF can predict eventstreams of dynamic scenes from a static or moving
viewpoint between any desired timestamps, thereby allowing it to be used as an
event-based simulator for a given scene. We show that by training on varied
batch sizes of events, we can improve test-time predictions of events at fine
time resolutions, outperforming baselines that pair standard dynamic NeRFs with
event generators. We release our simulated and real datasets, as well as code
for multi-view event-based data generation and the training and evaluation of
EvDNeRF models (https://github.com/anish-bhattacharya/EvDNeRF).Comment: 16 pages, 20 figures, 2 table
H11-induced immunoprotection is predominantly linked to N-glycan moieties during Haemonchus contortus infection
Nematodes are one of the largest groups of animals on the planet. Many of them are major pathogens of humans, animals and plants, and cause destructive diseases and socioeconomic losses worldwide. Despite their adverse impacts on human health and agriculture, nematodes can be challenging to control, because anthelmintic treatments do not prevent re-infection, and excessive treatment has led to widespread drug resistance in nematode populations. Indeed, many nematode species of livestock animals have become resistant to almost all classes of anthelmintics used. Most efforts to develop commercial anti-nematode vaccines (native or recombinant) for use in animals and humans have not succeeded, although one effective (dead) vaccine (Barbervax) has been developed to protect animals against one of the most pathogenic parasites of livestock animals – Haemonchus contortus (the barber’s pole worm). This vaccine contains native molecules, called H11 and H-Gal-GP, derived from the intestine of this blood-feeding worm. In its native form, H11 alone consistently induces high levels (75-95%) of immunoprotection in animals against disease (haemonchosis), but recombinant forms thereof do not. Here, to test the hypothesis that post-translational modification (glycosylation) of H11 plays a crucial role in achieving such high immunoprotection, we explored the N-glycoproteome and N-glycome of H11 using the high-resolution mass spectrometry and assessed the roles of N-glycosylation in protective immunity against H. contortus. Our results showed conclusively that N-glycan moieties on H11 are the dominant immunogens, which induce high IgG serum antibody levels in immunised animals, and that anti-H11 IgG antibodies can confer specific, passive immunity in naïve animals. This work provides the first detailed account of the relevance and role of protein glycosylation in protective immunity against a parasitic nematode, with important implications for the design of vaccines against metazoan parasites.Peer Reviewe
Observation of the 87Rb 5S1/2 to 4D3/2 electric quadrupole transition at 516.6 nm mediated via an optical nanofibre
Light guided by an optical nanofibre has a very steep evanescent field gradient extending from the fibre surface. This gradient can be exploited to drive electric quadrupole transitions in nearby quantum emitters. In this paper, we report on the observation of the 5S 1/2 →4D 3/2 electric quadrupole transition at 516.6 nm (in vacuum) in laser-cooled 87Rb atoms using only a few μW of laser power propagating through an optical nanofibre embedded in the atom cloud. This work extends the rangeof applications for optical nanofibres in atomic physics to include more fundamental tests such as high-precision measurements of parity non-conservation
All-d-Enantiomer of β-Amyloid Peptide Forms Ion Channels in Lipid Bilayers
Alzheimer’s disease (AD) is the most common type
of senile
dementia in aging populations. Amyloid β (Aβ)-mediated
dysregulation of ionic homeostasis is the prevailing underlying mechanism
leading to synaptic degeneration and neuronal death. Aβ-dependent
ionic dysregulation most likely occurs either directly via unregulated
ionic transport through the membrane or indirectly via Aβ binding
to cell membrane receptors and subsequent opening of existing ion
channels or transporters. Receptor binding is expected to involve
a high degree of stereospecificity. Here, we investigated whether
an Aβ peptide enantiomer, whose entire sequence consists of d-amino acids, can form ion-conducting channels; these channels
can directly mediate Aβ effects even in the absence of receptor–peptide
interactions. Using complementary approaches of planar lipid bilayer
(PLB) electrophysiological recordings and molecular dynamics (MD)
simulations, we show that the d-Aβ isomer exhibits
ion conductance behavior in the bilayer indistinguishable from that
described earlier for the l-Aβ isomer. The d isomer forms channel-like pores with heterogeneous ionic conductance
similar to the l-Aβ isomer channels, and the d-isomer channel conductance is blocked by Zn2+, a known
blocker of l-Aβ isomer channels. MD simulations further
verify formation of β-barrel-like Aβ channels with d- and l-isomers, illustrating that both d- and l-Aβ barrels can conduct cations. The calculated
values of the single-channel conductance are approximately in the
range of the experimental values. These findings are in agreement
with amyloids forming Ca2+ leaking, unregulated channels
in AD, and suggest that Aβ toxicity is mediated through a receptor-independent,
nonstereoselective mechanism