Valley filtering and spatial maps of coupling between silicon donors and quantum dots

Exchange coupling is a key ingredient for spin-based quantum technologies since it can be used to entangle spin qubits and create logical spin qubits. However, the influence of the electronic valley degree of freedom in silicon on exchange interactions is presently the subject of important open questions. Here we investigate the influence of valleys on exchange in a coupled donor/quantum dot system, a basic building block of recently proposed schemes for robust quantum information processing. Using a scanning tunneling microscope tip to position the quantum dot with sub-nm precision, we find a near monotonic exchange characteristic where lattice-aperiodic modulations associated with valley degrees of freedom comprise less than 2~\% of exchange. From this we conclude that intravalley tunneling processes that preserve the donor's $\pm x$ and $\pm y$ valley index are filtered out of the interaction with the $\pm z$ valley quantum dot, and that the $\pm x$ and $\pm y$ intervalley processes where the electron valley index changes are weak. Complemented by tight-binding calculations of exchange versus donor depth, the demonstrated electrostatic tunability of donor/QD exchange can be used to compensate the remaining intravalley $\pm z$ oscillations to realise uniform interactions in an array of highly coherent donor spins.Comment: 6 pages, 4 figures, 6 pages Supplemental Materia

Analisis dan Desain Sistem Monitoring dan Evaluasi Koperasi pada Dinas Koperasi Kabupaten Sidoarjo

Cooperatives are considered the most suitable to be developed in Indonesia because of their role in building the national economic order. Currently Sidoarjo District Cooperative Office for Institutional especially tasked to monitor and oversee the development of the cooperative experience problems. The problem of cooperative is, late submission of monthly reports that resulted in the manufacture of quarterly progress reports as a co-operative evaluation is also inhibited. The delay makes data to be processed to work on a progress report becomes inaccurate. Last problems in the progress report results only in the form of tables with figures that chart the development of cooperatives in the previous month are not visible. After analysis and design of monitoring and evaluation systems of cooperative development document can be produced in the form of Software Requirement Specification (SRS) and the Software Architecture Document (SAD). The document can be used as the basis for monitoring and evaluation of software development at the Department of Cooperative cooperative Sidoarjo Regenc

Proximate Composition, Phytochemical and Elemental Analysis of Some Organic Solvent Extract of The Wild Mushroom- Ganoderma lucidum.

Brief about the title: The crude extract powder of Ganoderma lucidum harvested from Lafia, Nassarawa State of Nigeria during the rainy season was analyzed for proximate contents, phytochemical constituents and mineral composition using various standard methods. Description of the experiment and procedures: The harvested Ganoderma lucidum was air dried at 370C and grinded to powder; this was preliminary analyzed for proximate contents, phytochemical constituents. The crude powder was subjected to soxhlet extraction at 400C using Methanol, Ethylacetate and N-butanol to obtain different organic solvent fractions, these were then concentrated in vacuo at 240C for 48 hours to obtain different solvent extract fractions. These extracts were then analyzed for phytochemical contents using standards methods. Results: Analysis for proximate constituent showed Moisture contents was 10.54%, Total ash 5.93%, Protein 17.55%, Crude Fats 2.60%, Crude Fiber 30.25%, Carbohydrates 33.13%, and Nitrogen 23.52%. Phytochemical screening from unprocessed G.lucidum powder reveals the presence of:  Alkaloids, Flavonoids, Reducing sugars, Tannins, Cardiac glycosides, Anthraquinones, Saponins, Volatile oils and Steroids. However, variations in the presence and concentrations of these phytochemicals were observed in the partitioned portions separated by Methanol, Ethyl acetate and N-butanol. Analysis of Total ash reveals in (mg/kg) the presence of Ca (322.6), K (317.1), P (197.1), and Na (193.5) in high quantity, while C (68.2), Fe (44.6), and Zn (14.65) and Mg (8.7.0), were found to be in moderate quantity. However, Si (4.10), Mn (1.83), As (1.23), Cu (0.84), Cr (0.14), Pb (0.106), Mo (0.09), Ni (0.095), F (0.0039), Al (0.20) and Co (0.026) are very low in concentration, but Se (0.00) was completely not detected. Conclusion: The presence of these essential nutrients and minerals found in G.lucidum implies that it can be utilized for its medicinal values in healthcare delivery systems, and the medicinal importance are thus highlighted in this work. Keywords: Ganoderma lucidum, Fruiting body, proximate analysis, Phytochemical and Mineral, Healthcar

Quantitative Excited State Spectroscopy of a Single InGaAs Quantum Dot Molecule through Multi-million Atom Electronic Structure Calculations

Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum [12] is quantitatively reproduced, and the correct energy states are identified based on a previously validated atomistic tight binding model. The extended devices are represented explicitly in space with 15 million atom structures. An excited state spectroscopy technique is presented in which the externally applied electric field is swept to probe the ladder of the electronic energy levels (electron or hole) of one quantum dot through anti-crossings with the energy levels of the other quantum dot in a two quantum dot molecule. This technique can be applied to estimate the spatial electron-hole spacing inside the quantum dot molecule as well as to reverse engineer quantum dot geometry parameters such as the quantum dot separation. Crystal deformation induced piezoelectric effects have been discussed in the literature as minor perturbations lifting degeneracies of the electron excited (P and D) states, thus affecting polarization alignment of wave function lobes for III-V Heterostructures such as single InAs/GaAs quantum dots. In contrast this work demonstrates the crucial importance of piezoelectricity to resolve the symmetries and energies of the excited states through matching the experimentally measured spectrum in an InGaAs quantum dot molecule under the influence of an electric field. Both linear and quadratic piezoelectric effects are studied for the first time for a quantum dot molecule and demonstrated to be indeed important. The net piezoelectric contribution is found to be critical in determining the correct energy spectrum, which is in contrast to recent studies reporting vanishing net piezoelectric contributions.Comment: Accepted for publication in IOP Nanotechnology Journa

Analysis of the Impact of Relative Humidity and Mineral Nuclei Mode Aerosols Particle Concentration on the Visibility of Desert Aerosols

This paper presents the results of the Analysis of the Impact of relative humidity and water-soluble aerosol particle concentrations on the visibility and particle size distribution of desert aerosols based on microphysical properties of desert aerosols. The microphysical properties (the extinction coefficients, volume mix ratios, dry mode radii and wet mode radii) were extracted from Optical Properties of Aerosols and Clouds (OPAC 4.0) at eight relative humidities (00 to 99%RH) and at the spectral range of 0.4-0.8 mm. the concentrations of mineral nuclie component (MINN) were varied to obtain five different models. The angstrom exponent (a), the turbidity (b), the curvature (a2), humidification factor (g), the mean exponent of aerosol growth curve (µ) and the mean exponent of aerosol size distributions (n) were determined from the regression analysis of some standard equations. It was observed that the values of (a) are less than 1 throughout the 5 models which signifies the dominance of coarse mode particles over fine mode particles. It was observed that the curvature (a2) has both monomodal and bimodal types of distributions all through the 5 models and this signifies the dominance of coarse mode particles with some traces of fine mode particles. The visibility was observed to decrease with the increase in RH and increased with wavelength. The analysis further found that there is an inverse power law relationship between humidification factor, the mean exponent of the aerosol size distribution with the mean exponent of the aerosol growth curve (as the magnitude of (µ) decreases across the five models, the magnitudes of (g) and (n) increase, but the magnitude of both (g) and (n) increases for a given (µ) across the individual models). The mean exponent of aerosol size distribution (µ) being less than 3 indicate hazy condition of the desert atmosphere

Control over phase separation and nucleation using a laser-tweezing potential

Control over the nucleation of new phases is highly desirable but elusive. Even though there is a long history of crystallization engineering by varying physicochemical parameters, controlling which polymorph crystallizes or whether a molecule crystallizes or forms an amorphous precipitate is still a poorly understood practice. Although there are now numerous examples of control using laser-induced nucleation, the absence of physical understanding is preventing progress. Here we show that the proximity of a liquid–liquid critical point or the corresponding binodal line can be used by a laser-tweezing potential to induce concentration gradients. A simple theoretical model shows that the stored electromagnetic energy of the laser beam produces a free-energy potential that forces phase separation or triggers the nucleation of a new phase. Experiments in a liquid mixture using a low-power laser diode confirm the effect. Phase separation and nucleation using a laser-tweezing potential explains the physics behind non-photochemical laser-induced nucleation and suggests new ways of manipulating matter

BIOADHESIVE MULTIPARTICULATE (MICROSPHERS) DRUG DELIVERY SYSTEM: A REVIEW

The concept of controlled drug delivery has been traditionally used to obtain specific release rates or targeting of active ingredients. The phenomenon of bioadhesion has been studied extensively in the last decade and applied to improve the performance of these drug delivery systems. Recent advances in polymer science and drug carrier technologies have promulgated the development of novel drug carriers such as bioadhesive microspheres that have boosted the use of “bioadhesion†in drug delivery. This article presents the spectrum of potential applications of bioadhesive microspheres in controlled drug delivery ranging from the small molecules, to peptides, and to the macromolecular drugs such as proteins, oligonucleotides and even DNA. The development of mucus or cell-specific bioadhesive polymers and the concepts of cytoadhesion and bioinvasion provide unprecedented opportunities for targeting drugs to specific cells or intracellular compartments. Developments in the techniques for in vitro and in vivo evaluation of bioadhesive microspheres have also been discussed. Keywords: - Bioadhesion, Bioadhesive Microspheres, Development, Polymers

Iron minerals inhibit the growth of <i>Pseudomonas brassicacearum</i> J12 via a free-radical mechanism: implications for soil carbon storage

Natural minerals in soil can inhibit the growth of bacteria that protect organic carbon from decay. However, the mechanism inhibiting the bacterial growth remains poorly understood. Here, using a series of cultivation experiments and biological, chemical and synchrotron-based spectral analyses, we showed that kaolinite, hematite, goethite and ferrihydrite had a significant inhibitory effect on the growth of the model bacteria Pseudomonas brassicacearum J12, which was more prominent with a concentration of 25&thinsp;mg&thinsp;mL−1 than it was with either 10 or 5&thinsp;mg&thinsp;mL−1. In contrast, montmorillonite promoted the growth of J12. Compared to Al-containing minerals, Fe(III)-containing minerals produced more hydroxyl radical (HO⚫) that has high efficiency for the inhibition of J12. Moreover, a significant positive correlation between HO⚫ radical and Fe(II) was found, suggesting that Fe(II) contributes to the generation of HO⚫. Furthermore, both micro X-ray fluorescence and X-ray photoelectron spectroscopies indicated that surface Fe(III) was reduced to Fe(II), which can produce HO⚫ through the well-known Fenton reaction series. Together, these findings indicate that the reduced surface Fe(II) derived from Fe(III)-containing minerals inhibits the growth of Pseudomonas brassicacearum J12 via a free-radical mechanism, which may serve as a ubiquitous mechanism between iron minerals and all of the heterotrophic bacteria in view of taxonomically and ecologically diverse heterotrophic bacteria from terrestrial environments as a vast source of superoxide.</p

Fingerprint White Line Counts: An Upcoming Forensic Tool for Sex Determination

Abstract Fingerprints are one of the common forensic tools used in personal identification. However, the associated secondary epidermal creases of fingerprints, fingerprint white line count (FWLC), has received less attention within the forensic community. This study was conducted with an aim to determine the potential of FWLC in sex inference among adult Nigerians. A cross sectional study was carried out with 150 males and 150 females with age range of 18-30 and 18-33 years, respectively. Live scanner (Digita persona, China) was used to capture the plain fingerprint for FWLC. Mann Whitney, Kruskal Wallis and logistic regression analyses were employed for determination of digit variation (based on side and type), sexual dimorphism and prediction models, respectively. Likelihood ratio and posterior probability were used to determine the favour odd for sex inference from FWLC. A significant higher mean value of FWLC was observed in females (2.24 ± 2.03) compared to males (0.85 ± 1.29). Absence of white line was indicative of male origin in all the digits except for left index digit (favor odd of 0.72 for females and 0.29 for males). However, FWLC from 5 to 11 were more likely to be of female origin. The best discriminator of sex was the left FWLC with a percentage accuracy of discrimination of 72%. The percentage contribution of the left FWLC in the discrimination of the sexes was observed to range from 23.0 to 30.20%. The FWLC was found to be a potential predictor of sex among adult Nigerians of Hausa ethnic origin

Synthesis, Purification and Crystallization of Guanine-rich RNA Oligonucleotides

Guanine-rich RNA oligonucleotides display many novel structural motifs in recent crystal structures. Here we describe the procedures of the chemical synthesis and the purification of such RNA molecules that are suitable for X-ray crystallographic studies. Modifications of the previous purification methods allow us to obtain better yields in shorter time. We also provide 24 screening conditions that are very effective in crystallization of the guanine-rich RNA oligonucleotides. Optimal crystallization conditions are usually achieved by adjustment of the concentration of the metal ions and pH of the buffer. Crystals obtained by this method usually diffract to high resolution