Reduced Transmission Efficiency Research Articles

Effect of tapered roller bearing supports on the dynamic behaviour of hypoid gear pair differentials

Noise and vibration refinement and energy efficiency are the key drivers in powertrain development. The final drive (the differential) is a source of vibration concern and also contributes to the powertrain inefficiency. To optimise differential characteristics for the key objectives of refinement and efficiency, detailed models of the gear interactions as well as the support bearing dynamics are required. This study reports the integrated lubricated bearing and gear contacts with an eight-degree-of-freedom dynamic analysis (a tribo-dynamic model). Non-Newtonian shear behaviour of thin lubricant-film conjunctions is taken into account in the integrated tribo-dynamic analysis, which has not hitherto been reported in the literature. The results show that the transmitted vibration spectra from the system onto the differential casing are dominated by the bearing frequencies rather than by those due to the meshing of gears. It is also shown that a sufficiently high bearing preload improves the vibration refinement but can lead to a marginally reduced transmission efficiency.

A magnetic rotary optical fiber connector for optogenetic experiments in freely moving animals

Performing optogenetic experiments in a behaving animal presents a unique technical challenge. In order to provide an optical path between a fixed light source and a chronically implanted fiber in a freely moving animal, a typical experimental setup includes a detachable connection between the light source and the head of the animal, as well as a rotary joint to relieve torsional stress during movement. We have combined the functionality of the head mounted connector and the rotary joint into a single integrated device that is inexpensive, simple to build, and easy to use. A typical rotary connector has a transmission efficiency of 80% with a rotational variability of 4%, but can be configured to have a rotational variability of 2% at the expense of a reduced transmission efficiency. Depending on configuration, rotational torque ranges from 14 to 180μNm, making the rotary connector suitable for use with small animals such as mice. Benchmark tests demonstrate that our connectors perform similarly to commercially available solutions in terms of transmission efficiency, rotational variability, and torque but at a fraction of the cost. Unlike currently available solutions, our unique design requires a single optical junction which significantly reduces overall light loss. In addition, magnets allow the connectors and caps to "snap into place" for quick yet reliable connection and disconnection. Our rotary connector system offers superior performance, reduced cost, and is easily incorporated into existing optogenetic setups.

Apoptosis Induction Influences Reovirus Replication and Virulence in Newborn Mice

Apoptosis is a type of controlled cell death that is essential for development and tissue homeostasis. It also serves as a robust host response against infection by many viruses. The capacity of neurotropic viruses to induce apoptosis strongly correlates with virulence. However, the precise function of apoptosis in viral infection is not well understood. Reovirus is a neurotropic virus that induces apoptosis in a variety of cell types, including central nervous system neurons, leading to fatal encephalitis in newborn mice. To determine the effect of apoptosis on reovirus replication in the host, we generated two otherwise isogenic viruses that differ in a single amino acid in viral capsid protein μ1 that segregates with apoptotic capacity. Apoptosis-proficient and apoptosis-deficient viruses were compared for replication, dissemination, tropism, and tissue injury in newborn mice and for the capacity to spread to uninfected littermates. Our results indicate that apoptotic capacity enhances reovirus replication in the brain and consequent neurovirulence but reduces transmission efficiency. The replication advantage of the apoptosis-proficient strain is limited to the brain and correlates with enhanced infectivity of neurons. These studies reveal a new cell type-specific determinant of reovirus virulence.

WE-G-103-04: X-Ray Scatter in Differential Phase-Contrast Breast Imaging Using Gratings-Based Interferometer

Purpose: To determine the x-ray scatter content in differential phase-contrast imaging of the breast using a gratings-based interferometer. Methods: X-ray scatter during small field-of-view (9.6×5-cm) differential phase-contrast breast imaging with a gratings-based interferometer (25-keV design) was determined using GEANT4 Monte Carlo (MC) toolkit. The duty-cycles of source (G0), phase (G1) and analyzer (G2) gratings were 0.25, 0.5 and 0.5, respectively. All gratings were planar and fabricated from 0.675-mm thick silicon wafers. MC estimated transmission efficiencies of the gratings in parallel-beam geometry were validated with theoretical estimates. After validation, their transmission efficiencies were determined in cone-beam geometry. Position-independent estimates of scatter and primary photons at the detector plane were obtained with 2 to 8 cm thick adipose and fibroglandular breasts and without the breast in the x-ray beam. The recorded x-ray scatter was analyzed after classification as photons that underwent at least one Compton interaction (incoherent scatter) and as photons that underwent Rayleigh interaction alone (coherent scatter). While G2 is needed in practice, simulations were conducted without G2 to determine its role in scatter reduction. Results: In parallel-beam geometry, Monte Carlo estimated transmission efficiencies showed good correspondence (r2>0.99) with theory. In cone-beam geometry, the transmission efficiencies of G0, G1 and G2 gratings were 0.16, 0.7 and 0.25, respectively. Position-independent estimates of scatter-to-primary ratio were 0.08 without the breast, and increased from 0.13 (0.15) to 0.25 (0.31) for 2 to 8 cm thick adipose (fibroglandular) breasts. Coherent scatter was the dominant contributor to total scatter with coherent-to-incoherent scatter ratio ranging from 1.65 (1.94) to 1.8 (2.04) for adipose (fibroglandular) breasts. The G2 grating reduced incoherent scatter by ∼5% to 24% for 2 to 8-cm breasts. Conclusion: The 0.675-mm thick silicon wafer contributed to ∼30% reduction in transmission efficiency for each grating. The G2 grating reduces the incoherent scatter at the detector plane. Supported in part by the National Institutes of Health (NIH) grants R01 CA128906 and R21 CA134128. The contents are solely the responsibility of the authors and do not represent the official views of the NIH or NCI.

A single base-pair change in 2009 H1N1 hemagglutinin increases human receptor affinity and leads to efficient airborne viral transmission in ferrets.

The 2009 H1N1 influenza A virus continues to circulate among the human population as the predominant H1N1 subtype. Epidemiological studies and airborne transmission studies using the ferret model have shown that the transmission efficiency of 2009 H1N1 viruses is lower than that of previous seasonal strains and the 1918 pandemic H1N1 strain. We recently correlated this reduced transmission efficiency to the lower binding affinity of the 2009 H1N1 hemagglutinin (HA) to α2→6 sialylated glycan receptors (human receptors). Here we report that a single point mutation (Ile219→Lys; a base pair change) in the glycan receptor-binding site (RBS) of a representative 2009 H1N1 influenza A virus, A/California/04/09 or CA04/09, quantitatively increases its human receptor-binding affinity. The increased human receptor-affinity is in the same range as that of the HA from highly transmissible seasonal and 1918 pandemic H1N1 viruses. Moreover, a 2009 H1N1 virus carrying this mutation in the RBS (generated using reverse genetics) transmits efficiently in ferrets by respiratory droplets thereby reestablishing our previously observed correlation between human receptor-binding affinity and transmission efficiency. These findings are significant in the context of monitoring the evolution of the currently circulating 2009 H1N1 viruses.

Single-Carrier Transmission Using Overlap Frequency Domain Equalizing and Coherent Averaging

This paper proposes a single-carrier transmission method based on an overlap frequency-domain equalizing (FDE) and a coherent averaging. FDE is a block-based equalizing technique using discrete Fourier transform. A cyclic prefix is often used to avoid inter-block interference under multipath channel conditions, which reduces transmission efficiency. An overlap FDE is a technique to avoid the cyclic prefix insertion, but the residual interferences often exist after the FDE processing according to the channel conditions. The method proposed in this paper suppresses the residual interferences by applying a coherent averaging to the FDE outputs and improve the equalization performances. Computer simulation shows the effect of the proposed technique over the multipath channels.

Resistance to Artesunate + Mefloquine does not incurin fitness cost in malaria parasites

Background Resistance to almost all available anti-malarials poses a large threat for the effective control of Malaria. The only remaining exceptions are the artemisinin (ART) derivatives. However, there is now evidence that appearance of resistance to ART either administered alone or in combination with other anti-malarials may become a reality. Although resistance to treatment is an obstacle for controlling the disease, in many biological models increased drug resistance is often associated with a biological cost. Similarly, in malaria parasites, resistance to anti-malarial drugs such as chloroquine (CQ) [1] and mefloquine (MF) [2] has been reported as causing a reduction in parasite’s fitness associated with lower asexual growth rates and/or reduced transmission efficiency. By using an artesunate (ATN)-resistant parasite, AS-ATN, we have selected a parasite clone (ASATNMF-1) which is resistance to the artesunate + mefloquine (ATN + MF) version of Artemisinin Combination Therapy [3]. AS-ATNMF-1 is also resistant to each component of the combination when administered separately. AS-ATNMF-1 was obtained after twentyseven consecutive sub-inoculations of AS-ATN in mice treated with the ATN + MF combination. Since consecutive sub-inoculations into mice have been shown to cause increased virulence in malaria parasites [4], ASATN was also sub-inoculated twenty-seven times into untreated mice in parallel. The resulting line was named AS-ATN27P. In order to assess the fitness cost associated with resistance to the combination ATN + MF, AS-ATNMF1 parasites were grown with the AS-ATN parental clone or with AS-ATN27P within the same host in absence of drug pressure, for 14 days. The proportions of each parasite parasite within were determined along time by Proportional Sequencing [5].

Fishing out marine parasites? Impacts of fishing on rates of parasitism in the ocean

Among anthropogenic effects on the ocean, fishing is one of the most pervasive and extends deepest into the past. Because fishing reduces the density of fish (reducing transmission efficiency of directly transmitted parasites), selectively removes large fish (which tend to carry more parasites than small fish), and reduces food web complexity (reducing transmission efficiency of trophically transmitted parasites), the removal of fish from the world's oceans over the course of hundreds of years may be driving a longterm, global decline in fish parasites. There has been growing recognition in recent years that parasites are a critical part of biodiversity and that their loss could substantially alter ecosystem function. Such a loss may be among the last major ecological effects of industrial fishing to be recognized by scientists.

What does the report of the USMHRP Phase III study in Thailand mean for HIV and for vaccine developers?

What does the report of the USMHRP Phase III study in Thailand mean for HIV and for vaccine developers?

ソーラーパネルやレンズに堆積するルナダストの静電クリーニング機構

Introduction: Because a cleaning system of lunar dust on the solar panel and optical lens is of great importance for the lunar exploration, we are developing a self-cleaning device of lunar dust utilizing electrostatic force.[1]-[4] Although it has been demonstrated that particles can be transported by the traveling-wave electric field formed by the parallel electrodes, some specific issues must be overcome to utilize this system for the lunar exploration. In this study, we have developed the electrostatic cleaner system that can be used in the lunar environment. System Configuration: The developed cleaner system is shown in Fig. 1. The conveyer consists of transparent ITO electrodes printed on a glass substrate. The surface of the conveyer is covered with an insulating film to prevent from electrical breakdown between electrodes. Traveling-wave propagation was achieved utilizing a set of positive and negative amplifiers controlled by a microcomputer. Four-phase rectangular voltage was applied to electrodes because it was most efficient compared to the sine or triangular wave. The power system is designed simple, small, and lightweight for the space application. Lunar soil simulant FJS-1 (Shimiz Corp.) and JSC1A (PLANET LLC.) were used for experiments. Results and Discussion: The cleaning rate of more than 90% was realized with this system under conditions of 700 V voltage and less than 100 Hz frequency. The reduced transmission efficiency of light and the reduced generation efficiency of the solar cell after cleaning were both only several %. Figure 2 shows photograph of the demonstration. Although some fraction of large particles larger than 0.5 mm were not transported, they were cleaned by the application of

Molecular species composition of rat liver phospholipids by ESI-MS/MS: the effect of chromatography

Using electrospray ionization tandem mass spectrometry (ESI-MS/MS) this study shows that the loss of glycerophospholipid (GPL) after chromatography was unevenly distributed across the GPL molecular species. Both TLC and HPLC caused a preferential loss of GPL with 0 to 3 double bonds: 20% and 7.2% for choline glycerophosphates (PC) and 19.7% and 7.5% for ethanolamine glycerophosphates (PE), respectively. A consequence of these losses was that GPLs containing fatty acids with four or more double bonds had a greater contribution to the total after chromatography. ESI-MS/MS analysis also showed that PC molecular species with four or more double bonds migrated at the front of the TLC band of PCs. GPLs extracted from TLC plates occasionally contained PCs that were smaller than those in the original extract. These low molecular mass PCs were easily reduced to alcohols and formed derivatives with 2,4-dinitrophenylhydrazine, suggesting that aldehydes were generated by the oxidation of unsaturated fatty acids. Directly analyzing lipid extracts by ESI-MS/MS without preliminary chromatographic separation gives an accurate distribution of GPL molecular species in lipid mixtures. However, the ionization of the phospholipids in the electrospray jet maximized at relatively low concentrations of GPL. There was a linear response between phospholipid mass and ion intensity for concentrations around 1-2 nmol/ml for both PC and PE. The total ion intensity continued to increase with concentrations above 1-2 nmol/ml, but the response was non-linear.

Comparison of the application of higher mass resolution and cool plasma conditions to avoid spectral interferences in Cr(III)/Cr(VI) speciation by means of high-performance liquid chromatography – inductively coupled plasma mass spectrometry

In Cr(III)/Cr(VI) speciation by means of high-performance liquid chromatography – inductively coupled plasma mass spectrometry (HPLC–ICPMS), accurate quantification is often jeopardised as a result of spectral overlap to be attributed to the occurrence of C- ( 40 Ar 12,13 C + ) and/or Cl-based ( 37 Cl 16 O + and 35 Cl 16 OH + ) molecular ions. In the present work, a microbore anion exchange column, hyphenated to a sector field ICP — mass spectrometer by means of a microconcentric nebuliser, was used for a challenging ‘real-life’ application: Cr speciation in industrial process solutions, characterised by a heavy matrix. The capabilities of both high mass resolution ( R=3000) and cool plasma conditions (at R=300) to overcome the aforementioned spectral interferences were studied and compared to one another and the effect of both approaches on the analytical figures of merit was evaluated. Under cool plasma conditions, the occurrence of ArC + ions, which interfere with the determination of Cr(VI) with the anion exchange column used (co-elution of Cr(VI) and HCO 3 −), can be sufficiently reduced to permit reliable Cr(VI) determination. The presence of ClO(H) + ions, which interfere with the determination of Cr(III) on the other hand (co-elution of Cr(III) and Cl −), cannot be avoided by cool plasma conditions. Increasing the mass resolution is an elegant way to avoid the detrimental influence of both interferences, but leads to a 15-fold reduction in transmission efficiency (sensitivity). Nevertheless, for both species involved, sub-μg limits of detection — 50 ng/l for Cr(III) and 120 ng/l for Cr(VI) — could be obtained. As a result, application of a higher mass resolution ( R=3000) was preferred for the analysis of industrial process solutions by means of HPLC–ICPMS. The accuracy of the results obtained was demonstrated by the good agreement between (i) the sum of the concentrations of Cr(III) and Cr(VI) and (ii) the total Cr content, determined by means of pneumatic nebulisation ICPMS.

Estimation of the amount of Venezuelan equine encephalomyelitis virus transmitted by a single infected Aedes aegypti (Diptera: Culicidae).

The transmission of Venezuelan equine encephalomyelitis (VEE) virus by Aedes aegypti to mice was studied in relation to the course of the biting process. The amounts of virus transmitted increased with the duration of the penetration period. Mosquitoes averaged 14 s of undisturbed skin penetration to transmit 1 mouse-infective dose. Prolonged blood feeding considerably reduced transmission efficiency. This effect was probably related to the length of the feeding period. Only a small fraction of the virus material introduced during the infective bite appears to contribute to the establishment of an infection in mice.

Some Effects of Temperature on the Transmission of Pea Enation Mosaic Virus and on the Biology of the Pea Aphid Vector1

The transmission of pea enation mosaic virus to sweet pea, Lathyrus odoratus , by the pea aphid, Acyrthosiphon pisum (Harris), was compared at 10°, 20°, and 30°C. Temperature affected virus acquisition more than it did inoculation. Most of the reduction in virus acquisition occurred at 10°C with acquisition access periods of more than 3 hours. The effect of temperature on inoculation was almost entirely associated with reduced transmission efficiency in inoculation access periods equal to or less than 30 minutes at 10°C. The median latent period decreased from 70 hours at 10°C to 25 and 14 hours at 20° and 30°C, respectively. There was evidence that the efficiency of virus transmission was negatively correlated with the length of the latent period. The probability of transmission, after completion of the latent period, decreased with time in serial-transmission experiments. The weighted mean period of retention of inoculativity varied from 29.5 days at 10°C to 13.7 and 4.3 days at 20° and 30°C, respectively. Infective aphids had net reproductive rates and generation times that were similar to noninfective aphids.