Optimization of Ternary InxGa1-xN Quantum Wells on GaN Microdisks for Full-Color GaN Micro-LEDs

Red, green, and blue light In_xGa_1-xN multiple quantum wells have been grown on GaN/γ-LiAlO₂ microdisk substrates by plasma-assisted molecular beam epitaxy. We established a mechanism to optimize the self-assembly growth with ball-stick model for In_xGa_1-xN multiple quantum well microdisks by bottom-up nanotechnology. We showed that three different red, green, and blue lighting micro-LEDs can be made of one single material (In_xGa_1-xN) solely by tuning the indium content. We also demonstrated that one can fabricate a beautiful In_xGa_1-xN-QW microdisk by choosing an appropriate buffer layer for optoelectronic applications.

Growth and Characterization of M-Plane GaN Thin Films Grown on γ-LiAlO2 (100) Substrates

M-plane GaN thin films were grown on LiAlO₂ substrates under different N/Ga flux ratios by plasma-assisted molecular beam epitaxy. An anisotropic growth of M-plane GaN was demonstrated against the N/Ga flux ratio. As the N/Ga flux ratio decreased by increasing Ga flux, the GaN surface trended to a flat morphology with stripes along [11[Formula: see text]0]. According to high-resolution X-ray diffraction analysis, Li₅GaO₄ was observed on the interface between GaN and LiAlO₂ substrate. The formation of Li₅GaO₄ would influence the surface morphology and crystal quality.

Spin-splitting calculation for zincblende semiconductors using an atomic bond-orbital model

We develop a 16-band atomic bond-orbital model (16ABOM) to compute the spin splitting induced by bulk inversion asymmetry in zincblende materials. This model is derived from the linear combination of atomic-orbital (LCAO) scheme such that the characteristics of the real atomic orbitals can be preserved to calculate the spin splitting. The Hamiltonian of 16ABOM is based on a similarity transformation performed on the nearest-neighbor LCAO Hamiltonian with a second-order Taylor expansion k at the Γ point. The spin-splitting energies in bulk zincblende semiconductors, GaAs and InSb, are calculated, and the results agree with the LCAO and first-principles calculations. However, we find that the spin-orbit coupling between bonding and antibonding p-like states, evaluated by the 16ABOM, dominates the spin splitting of the lowest conduction bands in the zincblende materials.

Microstructure of non-polar GaN on LiGaO2 grown by plasma-assisted MBE

We have investigated the structure of non-polar GaN, both on the M - and A-plane, grown on LiGaO2 by plasma-assisted molecular beam epitaxy. The epitaxial relationship and the microstructure of the GaN films are investigated by transmission electron microscopy (TEM). The already reported epi-taxial relationship and for M -plane GaN is confirmed. The main defects are threading dislocations and stacking faults in both samples. For the M -plane sample, the density of threading dislocations is around 1 × 1011 cm-2 and the stacking fault density amounts to approximately 2 × 105 cm-1. In the A-plane sample, a threading dislocation density in the same order was found, while the stacking fault density is much lower than in the M -plane sample.

[Update on the Mali Pharmacy Code: legislative section]

Due to colonization (1895-1960) Mali has been submitted, on the legislative and regulation plan to a corpus of numerous and scattered texts relative to pharmacy. It is essentially the Law AN XI of 21 Germinal or the 11 April 1803 Law; the content of Book V of the Public Health Code relative to pharmacy practice, of which some disposals have been extended to Overseas Territories, Togo and Cameroon in 1953; the 1955 Ministerial Order about the dispatching of the Retail Pharmacy in AOF; the 1960 Law creating the Board of Pharmacists in the Federation of Mali etc. After independence, the new Malian State while renewing the pharmacy legislation issued by the old tutor State which was not opposed to the new fundamental Law, has also set up, according to the political orientations of the moment, some new texts. In the framework of this work, we have collected all the legislative and regulation texts that have been allowed in Mali in the pharmacy area and in that of Studies in Pharmacy. We have examined those texts and proceeded to codify the legislative part. The present Code consists of 189 articles divided in 5 titles layed out in chapters and sections.

[Update on the Mali Pharmacy Code: legislative section]

Due to colonization (1895-1960) Mali has been submitted, on the legislative and regulation plan to a corpus of numerous and scattered texts relative to pharmacy. It is essentially the Law AN XI of 21 Germinal or the 11 April 1803 Law; the content of Book V of the Public Health Code relative to pharmacy practice, of which some disposals have been extended to Overseas Territories, Togo and Cameroon in 1953; the 1955 Ministerial Order about the dispatching of the Retail Pharmacy in AOF; the 1960 Law creating the Board of Pharmacists in the Federation of Mali etc. After independence, the new Malian State while renewing the pharmacy legislation issued by the old tutor State which was not opposed to the new fundamental Law, has also set up, according to the political orientations of the moment, some new texts. In the framework of this work, we have collected all the legislative and regulation texts that have been allowed in Mali in the pharmacy area and in that of Studies in Pharmacy. We have examined those texts and proceeded to codify the legislative part. The present Code consists of 189 articles divided in 5 titles layed out in chapters and sections.

Current development and patents on high-brightness white LED for illumination

In this paper, we reviewed the current development and patents for the application of high-brightness and high-efficiency white light-emitting diode (LED). The high-efficiency GaN nanostructures, such as disk, pyramid, and rod were grown on LiAlO(2) substrate by plasma-assisted molecular-beam epitaxy, and a model was developed to demonstrate the growth of the GaN nanostructures. Based on the results, the GaN disk p-n junction was designed for the application of high brightness and high efficiency white LED.

P-wave-enhanced spin field effect transistor and recent patents

P-wave-enhanced spin field-effect transistor made of AlGaN/GaN heterostructure was designed for the spintronic devices operated at high power and high temperature. The operation theory is based on the spin-polarized field-effect transistor designed by Datta and Das [Appl. Phys. Lett. 56, 665 (1990)]. The mechanism of the p-wave enhancement in AlGaN/GaN heterostructure was investigated. The recent development and related patents in the spin-polarized field-effect transistor were reviewed. In particular, we will focus on the recent patents which could enhance p-wave probability and control of spin precession of 2DEG in the AlGaN/GaN transistor structure.

[Fractionation of the total extract of Khaya senegalensis Barks. Value of the formulation of an anti-inflammatory ointment]

The aim of this work was to compare the anti-inflammatory activity of the total extract of Khaya senegalensis Barks and its different fractions for optimizing the active ingredients which be used in the ointment formulation. For that, a fractionation was performed followed by anti-inflammatory tests based on the method of the croton oil induced oedema. Three fractions were obtained and the comparison of their activity with the one of the total extract has shown the following results: 37.10%, 45.65%, 22.30% and 22.36% respectively for the extract, fraction n1, fraction n2 and fraction n3. The statistical analysis ofthe results (Student Test; p = 0.05) have revealed that the fraction nl is significatively more active than the others. However, there was not a significant difference between the inhibition induced by the fraction n1 and the total extact one, even the mean value of this latter is lower. Therefore, it seems enough to use the total extract as active ingredient for developing an anti-inflammatory ointment.

[Preparation of a syrup with Bakis roots (Tinospora bakis) and evaluation of its choleretic activity in rats]

The aim of this work was to prepare a pharmaceutical using the aqueous extract of bakis roots and to check if the choleretic activity of this latter was maintained in cholestatic rats. So, a sirup was prepared and tested. The obtained results had shown that the aqueous extract maintained its choleretic activity. Indeed, when it was used at a dose of about 7.5 mg/100 g of weight, the sirup induced a significant increase of bilary secretion in healthy rats and cholestatic rats, confirming the results observed with the aqueous extract. Therefore, futher investigations in order to improve the quality of the sirup can be considered before performing clinical trials.

[Anti-inflammatory activity of the bark of Khaya senegalensis (A Juss). Preliminary research of structure/activity relationship]

Some anti-inflammatory tests based on the carrageenan induced oedema rat paw method have been carried out with a freeze-dried aqueous extract and an etheropetrolic extract of Cailcedrat (Khaya senegalensis) barks. Then, a preliminary chemical study to find a relation structure/activity has been done from the etheropetrolic extract, by using various chromatography technicals. The achieved results have shown a decrease of the oedema by 14% when the aqueous extract is used at 1 g.kg-1, 21.5% and 62% with the etheropetrolic extract used at the respecive doses of 0.5 g.kg-1 and 1 g.kg-1. As for the chemical study, it allowed the separation of two compounds which probably take part in noticed activity and are supposed to be methyl angolensate and methyl hydroxyangolensate.

[Inflammatory ointment from shea butter and hydro-alcoholic extract of Khaya senegalensis barks (Cailcederat)]

In a former study, it was proved that the alcoholic solution of hydro-alcoholic extract of Khaya senegalensis barks had an anti-inflammatory activity on animals after a local application. In this work, ointments made from the same extract and three different excipients (vaseline, lanoline and shea butter (crude and refined)) have been prepared and tested by the method of the croton oil inhibited ear oedema. Results showed inhibition percentages of the ear oedema of 58.8%, 66.7% and 75.4% when the hydro-alcoholic extract was tested at respective doses of 1%, 2% and 3% in shea butter. The two other excipients, (vaceline and Lanoline) tested at the dose of 3% showed between 52% and 58% of inhibitions. The interest of this study was to demonstrate the possibility to maintain the anti-inflammatory activity of Khaya senegalensis barks by using them in a galenic form, easy to prepare and which is, in addition, more adapted than the extract to possible clinical trials.

In vitro antisickling activity of a rearranged limonoid isolated from Khaya senegalensis

We previously observed that aqueous extracts of the stem bark and leaves of Khaya senegalensis exhibited a strong antisickling activity. These results prompted us to find out the constituent(s) responsible for these properties using an in vitro bio-guided fractionation. The bioassay was based on sickle cells countings, before and after deoxygenation, in blood samples taken from patients with severe sickle cell anemia and pre-incubated with the drugs to be tested. The main active constituent was identified as a rearranged limonoid whose structure was recently elucidated. In comparison with pentoxifylline used as standard, the in vitro antisickling activity of this limonoid was much higher at any concentrations and incubation conditions. In addition, it did not alter significantly the corpuscular indices.

Combined central slip and volar plate injuries at the PIP joint

PIP joint injuries are common. We describe an unusual injury in which an apparent volar plate avulsion injury was associated with a dorsal, central slip avulsion fracture. We postulate that the mechanism of injury would appear to have been forced flexion with the central slip being avulsed and the volar plate fracture occurring as a secondary impingement fracture. Our two cases were treated with full extension splinting with satisfactory results.

Human papillomavirus in oesophageal squamous cell carcinoma

Thirty seven cases of oesophageal squamous cell carcinoma were studied by applying DNA slot blot analysis and in situ hybridisation using type specific probes for HPV 6, 11, 16 and 18. Cases of condyloma accuminata, cervical carcinoma, and laryngeal papilloma were used as controls. Blocks including areas of invasive carcinoma, intraepithelial neoplasia, and normal epithelium were studied in each case. No HPV genome was detectable in any of the oesophageal cases. It is concluded that these types of HPV do not have an association with oesophageal squamous cell carcinoma.