Experiments on Quantum and Thermal Desorption from ^4He Films

Desorption of He atoms from thin films may be resolved experimentally into quantum and thermal components. We show that quantum desorption becomes the dominant part of the signal in submonolayer films. We also show that, when all effects of collisions between desorbed atoms are eliminated, quantum desorption is not focused normal to the surface of optically polished sapphire crystals

Links between core promoter and basic gene features influence gene expression

<p>Abstract</p> <p>Background</p> <p>Diversity in rates of gene expression is essential for basic cell functions and is controlled by a variety of intricate mechanisms. Revealing general mechanisms that control gene expression is important for understanding normal and pathological cell functions and for improving the design of expression systems. Here we analyzed the relationship between general features of genes and their contribution to expression levels.</p> <p>Results</p> <p>Genes were divided into four groups according to their core promoter type and their characteristics analyzed statistically. Surprisingly we found that small variations in the TATA box are linked to large differences in gene length. Genes containing canonical TATA are generally short whereas long genes are associated with either non-canonical TATA or TATA-less promoters. These differences in gene length are primarily determined by the size and number of introns. Generally, gene expression was found to be tightly correlated with the strength of the TATA-box. However significant reduction in gene expression levels were linked with long TATA-containing genes (canonical and non-canonical) whereas intron length hardly affected the expression of TATA-less genes. Interestingly, features associated with high translation are prevalent in TATA-containing genes suggesting that their protein production is also more efficient.</p> <p>Conclusion</p> <p>Our results suggest that interplay between core promoter type and gene size can generate significant diversity in gene expression.</p

Physical Therapy for Hospitalized COVID-19 Patients in Isolation: Feasibility and pilot implementation of telehealth for delivering individualized therapy.

Objective To optimize the ability of hospitalized patients isolated due to COVID-19 to participate in physical therapy. Design This was a prospective, quality improvement trial of the feasibility and acceptability of a hybrid in-person and telerehabilitation platform to deliver physical therapy to hospitalized adults. Setting Inpatient wards of a tertiary care, multi-specialty academic medical center in the greater New York City metropolitan area. Participants A convenience sample of 39 COVID-19+ adults, mean age 57.3 years, 69% male, all previously community dwelling agreed to participate in a combination of in-person and telerehabilitation sessions (TR). Intervention Initial in-person evaluation by physical therapist followed by twice daily PT sessions, one in-person and one via a telehealth platform meeting Health Insurance Portability and Accountability Act (HIPAA) confidentiality requirements. The communication platform was downloaded to each participant\u27s personal smart device to establish audiovisual contact with the Physical Therapist. Measures The 6-clicks Activity Measure for Post-Acute Care (AM-PAC) was used to score self-reported functional status pre-morbidly by, and by the therapist at baseline and discharge. Results Functional status measured by AM-PAC 6-clicks demonstrated improvement from admission to discharge. Barriers to participation were identified and strategies are planned to facilitate use of the platform in future. Conclusions A consistent and structured protocol for engaging patient participation in PT delivered via a telehealth platform was successfully developed. A process was put in place to allow for further development, recruitment and testing in a randomized trial

Sticking probability of ^4He on solid surfaces at low temperature

The first low-temperature (<4 K) determination of the sticking probability S of a 4He atom on a solid surface is presented. It is found that 2/3~<VS<1 for a thermal distribution of incident atoms with beam temperature 10 to 20 K. This result is not affected by the presence of a preadsorbed, ~< 1-monolayer He film

All-optical silicon simplified passive modulation

In this paper we present an all-optical silicon based modulator suggested also for high power operation and for pulse picker application being used as part of fiber lasers system. The paper theoretically and experimentally investigates several new and important insights involving the dependence of the relative transmission on the pump pulse energy for different finesse values of the constructed cavity as well as the dependence of the response rate of the device to the pump wavelength due to coexistence of two physical recombination processes: fast surface effect and slow bulk recombination. To adapt the constructed silicon based cavity to be used in lasers applications, we aligned the pump and the signal beams to co-propagate through the device while the usage of a cavity allowed a low power pump to yield a significant extinction ratio at the output of the device

Desorption of helium atoms from thin films

Investigation is made of the desorption of He atoms from thin films. Three different experimental geometries are used to study the dependence on substrate material, film temperature, and duration of the heat pulse. The major conclusions are that (a) the speed distribution is similar to a Maxwellian, (b) the angular distribution is strongly focused about the normal direction, (c) desorption time constants differ systematically from estimates, and (d) a phonoatomic effect analogous to the photoelectric effect is observed. The measurements are analyzed in terms of several theoretical models. Conclusions are drawn about the time evolution of the film thickness and temperature

Unique translation initiation of mRNAs-containing TISU element

Translation Initiator of Short 5′ UTR (TISU) is a unique regulatory element of both transcription and translation initiation. It is present in a sizable number of genes with basic cellular functions and a very short untranslated region (5′ UTR). Here, we investigated translation initiation from short 5′ UTR mRNAs with AUG in various contexts. Reducing 5′ UTR length to the minimal functional size increases leaky scanning from weak and strong initiators but hardly affects translation initiation and ribosomal binding directed by TISU. Ribosome interaction with TISU mRNA is cap dependent and involves AUG downstream nucleotides that compensate for the absent 5′ UTR contacts. Interestingly, eIF1 inhibits cap-proximal AUG selection within weak or strong contexts but not within TISU. Furthermore, TISU-directed translation is unaffected by inhibition of the RNA helicase eIF4A. Thus, TISU directs efficient cap-dependent translation initiation without scanning, a mechanism that would be advantageous when intracellular levels of eIF1 and eIF4A fluctuate