Effect of interdiffusion of quantum well infrared photodetector

The intersubband infrared photodetector performance is theoretically analyzed for various stages of interdiffusion in AlGaAs/GaAs quantum well. The absorption strength and responsivity are enhanced for certain extents of interdiffusion and the peak detection wavelength red shifts continuously with a large tunable range from 7 to 38.4 µm. The dark current is at an acceptable value for small diffusion extent. ©1996 American Institute of Physics.published_or_final_versio

Diffused quantum well solar cell

An alternative multi-bandgap solar cell made of diffused quantum well (DFQW) as the absorber is proposed here. The modeling of the spectral response and energy conversion efficiency of the solar cell will be shown. Significant enhancement in energy conversion efficiency is demonstrated when compared to that of the single bandgap cells.published_or_final_versio

Thermal interdiffusion in InGaAs/GaAs strained multiple quantum well infrared photodetector

RTA at 850 °C for 5 and 10 s is carried out to study the effect of interdiffusion on the optical and electrical properties of strained InGaAs/GaAs quantum well infrared photodetector. Photoluminescence measurement at 4.5 K shows that no strain relaxation or misfit dislocation formation occurs throughout the annealing process. Absorption and responsivity peak wavelengths are red shifted continuously without appreciable degradation in absorption strength. The normal incident absorption, which is believed to be the result of band-mixing effects induced by the coupling between the conduction and valence and is usually forbidden in conventional polarization selection rule, is preserved after interdiffusion. Responsivity spectra of both 0° and 90° polarization are of compatible amplitude and the shape of the annealed spectra becomes narrower. Dark current of the annealed devices is not very sensitive to temperature variation and is found to be an order of magnitude larger than the as-grown one at 77K.published_or_final_versio

The reasons of dropout of sport in Hong Kong school athletes

domains. The aim of this study was to identify the potential dropout reasons of school athletes and to examine if their perception of dropout was affected by the previous dropout experience. There were 50 subjects who were divided into two groups based on their previous dropout experience (Dropout Group=22, No Dropout Group=28). They filled a questionnaire about potential dropout reasons of the current sport. Coach and teammates were two predominated reasons of dropout; Influence of parent and training seemed to affect the termination of the sport to a lesser extent. Moreover, the perception of social value and lost focus were significantly different between two groups. Character of coach and teammates affect the engagement of training in school athletes. However, the parental influence had less influence than expected. Training intensity played little role as the dropout reason. Previous experience of dropout had an impact of potential dropout reasons on their current sport training

MicroRNA-210 and endoplasmic reticulum chaperones in the regulation of chemoresistance in glioblastoma

Glioblastoma multiforme (GBM) is the commonest primary brain tumour in adults characterized by relentless recurrence due to resistance towards the standard chemotherapeutic agent temozolomide (TMZ). Prolyl 4-hydroxylase, beta polypeptide (P4HB), an endoplasmic reticulum (ER) chaperone, is known to be upregulated in TMZ-resistant GBM cells. MicroRNAs (miRNAs) are non-protein-coding transcripts that may play important roles in GBM chemoresistance. We surmised that miRNA dysregulations may contribute to P4HB upregulation, hence chemoresistance.We found that miRNA-210 (miR-210) was P4HB-targeting and was highly downregulated in TMZ-resistant GBM cells. Forced overexpression of miR-210 led to P4HB downregulation and a reduction in TMZ-resistance. A reciprocal relationship between their expressions was also verified in clinical glioma specimens. Our study is the first to demonstrate a potential link between miR-210 and ER chaperone in determining chemosensitivity in GBM. The findings have important translational implications in suggesting new directions of future studies.published_or_final_versio

Validity and Reliability of Timed Up and Go Test on Dynamic Balance in 3-5 Years Old Preschool Children

Objective: The purpose of this study was to investigate the validity and reliability of the Timed Up and Go Test (TUG) among normal 3-5 years old preschool children in Hong Kong. Methods: Cross-sectional design was applied to this study. Sixty (30 female, 30 male) preschool children aged from 3 to 5 years old (mean age=4.22 ± 0.85) from local normal preschool was recruited using convenient sampling to perform three dynamic balance tests: Timed Up and Go Test (TUG), Star Excursion Balance Test (SEBT) and the Pediatric Balance Scale Test (PBS). A simple self-administrative questionnaire survey was also conducted with their parents. Results: Positive correlation (r=0.74, p<0.05) was found between TUG results obtained at two time points when assessing the test-retest reliability. Moderated negative correlations were found between TUG and SEBT or PBS, which indicated children with longer reaching distance or higher PBS score tend to use shorter time to complete TUG. Conclusion: TUG was a valid and reliable tool for assessing dynamic balance of preschool children aged between 3 and 5 years old. This can also be used for screening or early detection of developmental coordination disorder (DCD) for children aged 6 years old or younger

Developments in the negative-U modelling of the cuprate HTSC systems

The paper deals with the many stands that go into creating the unique and complex nature of the HTSC cuprates above Tc as below. Like its predecessors it treats charge, not spin or lattice, as prime mover, but thus taken in the context of the chemical bonding relevant to these copper oxides. The crucial shell filling, negative-U, double-loading fluctuations possible there require accessing at high valent local environment as prevails within the mixed valent, inhomogeneous two sub-system circumstance of the HTSC materials. Close attention is paid to the recent results from Corson, Demsar, Li, Johnson, Norman, Varma, Gyorffy and colleagues.Comment: 44 pages:200+ references. Submitted to J.Phys.:Condensed Matter, Sept 7 200

Test of lepton universality in b→sℓ+ℓ−b \rightarrow s \ell^+ \ell^- decays

The first simultaneous test of muon-electron universality using $B^{+}\rightarrow K^{+}\ell^{+}\ell^{-}$ and $B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-}$ decays is performed, in two ranges of the dilepton invariant-mass squared, $q^{2}$. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 $\mathrm{fb}^{-1}$. Each of the four lepton universality measurements reported is either the first in the given $q^{2}$ interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-046.html (LHCb public pages