433 research outputs found
Impact of alloy disorder on the band structure of compressively strained GaBiAs
The incorporation of bismuth (Bi) in GaAs results in a large reduction of the
band gap energy (E) accompanied with a large increase in the spin-orbit
splitting energy (), leading to the condition that
which is anticipated to reduce so-called CHSH Auger
recombination losses whereby the energy and momentum of a recombining
electron-hole pair is given to a second hole which is excited into the
spin-orbit band. We theoretically investigate the electronic structure of
experimentally grown GaBiAs samples on (100) GaAs substrates by
directly comparing our data with room temperature photo-modulated reflectance
(PR) measurements. Our atomistic theoretical calculations, in agreement with
the PR measurements, confirm that E is equal to for
9. We then theoretically probe the inhomogeneous
broadening of the interband transition energies as a function of the alloy
disorder. The broadening associated with spin-split-off transitions arises from
conventional alloy effects, while the behaviour of the heavy-hole transitions
can be well described using a valence band-anticrossing model. We show that for
the samples containing 8.5% and 10.4% Bi the difficulty in identifying a clear
light-hole-related transition energy from the measured PR data is due to the
significant broadening of the host matrix light-hole states as a result of the
presence of a large number of Bi resonant states in the same energy range and
disorder in the alloy. We further provide quantitative estimates of the impact
of supercell size and the assumed random distribution of Bi atoms on the
interband transition energies in GaBiAs. Our calculations support
a type-I band alignment at the GaBiAs/GaAs interface, consistent
with recent experimental findings
UJI EFEK ANALGESIK EKSTRAK ETANOL DAUN KEJI BELING (Strobilanthes crispus L) PADA TIKUS PUTIH GALUR WISTAR (Rattus norvegicus)
ABSTRACT Pain is an unpleasant sensory and emotional experience due to tissue damage both actual and potential. Analgesics are a drug used to relieve pain without losing consciousness. Keji beling leaves (Strobilanthes crispus L) contain glycosidic ester compounds from caffeic acid, which have analgesic effects. This study aims to determine whether there is an analgesic effect on the ethanol extract of keji beling leaves with different doses, namely dose 0.0023g / 200gBW, 0.0047g / 200gBW, and 0.0094g / 200gBW in test animals of wistar strain male rats. This study uses a laboratory experimental research design using wistar strain male white rat as a test animal. The analgesic effect test was carried out by the heat stimulation method using a 53 °C water bath. The rat response was observed in the form of movements of licking the hind legs or jumping from before giving test material and after giving test material at 30, 60, 90 and 120 minutes, respectively. From the results of statistical data analysis with One Way Anova and LSD showed that the extracts keji beling leaves has an analgesic effect. Where among those three doses the best dose was 0.0023g / 200gBW. Keywords: Analgesic, anova, keji beling leaves, white male wistar rats. ABSTRAK Rasa nyeri merupakan pengalaman sensorik dan emosional yang tidak menyenangkan akibat kerusakan jaringan baik aktual maupun potensial. Analgesik ialah suatu obat yang digunakan untuk menghilangkan rasa sakit tanpa menghilangkan kesadaran. Daun keji beling (Strobilanthes crispus L) mengandung senyawa glikosidik ester dari asam caffeic yang memiliki efek analgesik. Penelitian ini bertujuan untuk mengetahui ada tidaknya efek analgesik pada ekstrak etanol daun keji beling dengan dosis berbeda-beda yaitu dosis 0,0023g/200gBB, 0,0047g/200gBB, dan 0,0094g/200gBB pada hewan uji tikus putih jantan galur wistar. Penelitian ini menggunakan Rancangan penelitian eksperimental laboratorium dengan menggunakan hewan uji tikus putih jantan galur wistar. Pengujian efek analgesik dilakukan dengan metode rangsangan panas menggunakan waterbath suhu 53°C. Respon tikus diamati berupa gerakan menjilat kaki belakang atau melompat dari sebelum pemberian bahan uji dan sesudah pemberian bahan uji berturut-turut pada menit ke 30, 60, 90 dan 120. Dari hasil analisis data secara statistika dengan One Way Anova dan LSD menunjukkan bahwa ekstrak daun keji beling memiliki efek analgesik. Dimana antara ketiga dosis tersebut yang paling terbaik ialah dosis 0,0023 g/200gBB. Kata kunci : Analgesik, Anova, Daun Keji Beling, tikus putih jantan galur wista
FORMULASI SEDIAAN KRIM EKSTRAK ETANOL DAUN KALIANDRA (Calliandra surinamensis) DAN UJI AKTIVITAS ANTIBAKTERINYA TERHADAP BAKTERI Staphylococcus aureus
ABSTRACT This study aims to test the antibacterial effectiveness of ethanolic extract of Kaliandra leaf cream and evaluate the preparations using parameters of physical properties, physical stability, and sterility. Kaliandra leaf (Calliandra surinamensis) contains compounds such as flavonoid, saponins and tannins that can inhibit the growth of bacteria. This research uses laboratory experimental methods. Cream preparation formula is made with variations in the concentration of ethanol extract of Kaliandra leaves 2%, 3%, 4%, 5%, 6%. Kaliandra leaf extract was obtained by maceration using 96% ethanol solvent. The study of antibacterial test of ethanol extract of Kaliandra leaf extract using the method of Staphylococcus aures produced inhibitory power of 5.09 ± 0.88 mm at a concentration of 6%. The physical evaluation of the cream preparation includes organoleptic examination (odor, color, shape), homogeneity, pH testing, adhesion, dispersion, cycling test. All tests are carried out before and after the cycling test. The results obtained before and after the cycling test showed that the cream preparations met organoleptic requirements, homogeneity, cream pH 6.07 (4.5-6.5), cream adhesion 4.59 seconds (<4 seconds), cream dispersion 6.19 cm (5-7 cm). Cream sterility testing shows that the cream is sterile. It can be concluded that the ethanol extract of Kaliandra leaves cream meets the physical test parameters, is stable and has moderate antibacterial activity. Keywords : Kaliandra Leaf (Calliandra surinamensis), Cream, Antibacterial, Staphylococcous aureus. ABSTRAK Penelitian ini bertujuan untuk menguji efektivitas antibakteri sediaan krim ekstrak etanol daun Kaliandra dan mengevaluasi sediaan dengan menggunakan parameter uji sifat fisik, stabilitas fisik, dan sterilitas. Daun Kaliandra (Calliandra surinamensis) merupakan tanaman yang mengandung senyawa flavonoid, saponin dan tannin yang mampu menghambat pertumbuhan bakteri. Penelitian ini menggunakan metode eksperimental laboratorium, Formula sediaan krim dibuat dengan variasi konsentrasi ekstrak etanol daun Kaliandra 2%, 3%, 4%, 5%, 6%. Ekstrak daun Kaliandra diperoleh dengan cara maserasi menggunakan pelarut etanol 96%. Penelitian uji antibakteri sediaan krim esktrak etanol daun Kaliandra menggunakan metode sumuran pada bakteri Staphylococcus aures menghasilkan daya hambat 5,09±0,88 mm pada konsentrasi 6%. Evaluasi fisik sediaan krim meliputi pemeriksaan organoleptis (bau, warna, bentuk), homogenitas, pengujian pH, daya lekat, daya sebar, uji cycling test. Semua pengujian dilakukan sebelum dan sesudah cycling test. Hasil penelitian yang didapat sebelum dan sesudah cycling test menunjukkan bahwa sediaan krim memenuhi persyaratan organoleptis, homogenitas, pH krim 6,07 (4,5-6,5), daya lekat krim 4,59 detik (<4 detik), daya sebar krim 6,19 cm (5-7 cm). Pengujian sterilitas krim menunjukan bahwa krim steril. Dapat disimpulkan bahwa sediaan krim ekstrak etanol daun Kaliandra memenuhi parameter uji fisik, stabil dan memiliki aktivitas antibakteri yang sedang. Kata kunci : Daun Kaliandra (Calliandra surinamensis), Krim, Antibakteri, Staphlococcous aureus
Photoluminescence spectroscopy of bandgap reduction in dilute InNAs alloys
Photoluminescence (PL) has been observed from dilute InNxAs1–x epilayers grown by molecular-beam epitaxy. The PL spectra unambiguously show band gap reduction with increasing N content. The variation of the PL spectra with temperature is indicative of carrier detrapping from localized to extended states as the temperature is increased. The redshift of the free exciton PL peak with increasing N content and temperature is reproduced by the band anticrossing model, implemented via a (5×5) k·p Hamiltonian
Internal transport barriers in the National Spherical Torus Experiment
In the National Spherical Torus Experiment [M. Ono , Nucl. Fusion 41, 1435 (2001)], internal transport barriers (ITBs) are observed in reversed (negative) shear discharges where diffusivities for electron and ion thermal channels and momentum are reduced. While neutral beam heating can produce ITBs in both electron and ion channels, high harmonic fast wave heating can also produce electron ITBs (e-ITBs) under reversed magnetic shear conditions without momentum input. Interestingly, the location of the e-ITB does not necessarily match that of the ion ITB (i-ITB). The e-ITB location correlates best with the magnetic shear minima location determined by motional Stark effect constrained equilibria, whereas the i-ITB location better correlates with the location of maximum ExB shearing rate. Measured electron temperature gradients in the e-ITB can exceed critical gradients for the onset of electron thermal gradient microinstabilities calculated by linear gyrokinetic codes. A high-k microwave scattering diagnostic shows locally reduced density fluctuations at wave numbers characteristic of electron turbulence for discharges with strongly negative magnetic shear versus weakly negative or positive magnetic shear. Reductions in fluctuation amplitude are found to be correlated with the local value of magnetic shear. These results are consistent with nonlinear gyrokinetic simulations predicting a reduction in electron turbulence under negative magnetic shear conditions despite exceeding critical gradients.X1128sciescopu
Rodenticide Exposure Among Endangered Kit Foxes Relative to Habitat Use in an Urban Landscape
Endangered San Joaquin kit foxes (Vulpes macrotis mutica) inhabiting Bakersfield, California exhibit a high incidence of exposure to anticoagulant rodenticides (ARs). We examined kit fox habitat use in an effort to determine potential sources of AR exposure. Kit fox capture, den, night, and mortality locations were assigned to one of 10 habitat categories. Using all available locations, foxes that tested positive for second generation anticoagulant rodenticides (SGARs) were located more frequently on golf courses while those testing negative were located more frequently in commercial areas. Foxes that tested positive for first generation anticoagulant rodenticides (FGARs) were located more frequently in industrial areas while those testing negative were located more frequently on golf courses. Based on night locations (when foxes are foraging), foxes that tested positive for SGARs were found more frequently in undeveloped and golf course habitats. Foxes that tested positive for FGARs were found more frequently in undeveloped, campus, and industrial habitats. Although available data were not sufficient to identify specific point-sources of AR exposure for foxes, golf courses appeared to be used more frequently by foxes exposed to SGARs. However, sources of exposure likely are abundant and widespread in the urban environment. Based on the results of this study, we recommend (1) investigating patterns of AR use in Bakersfield, (2) conducting an outreach program to emphasize the risk from ARs to kit foxes and other wildlife, and (3) continuing to monitor the incidence and patterns of AR exposure among kit foxes in Bakersfield
Correlation between excitation of Alfvén modes and degradation of ICRF heating efficiency in TFTR
Recommended from our members
Tritium Experience in Large Tokamaks: Application to ITER
Recent experience with the use of tritium fuel in the Tokamak Fusion Test Reactor and the Joint European Torus, together with progress in developing the technical design of the International Thermonuclear Experimental Reactor has expanded the technical knowledge base for tritium issues in fusion. This paper reports on an IEA workshop that brought together scientists and engineers to share experience and expertise on all fusion-related tritium issues. Extensive discussion periods were devoted to exploring outstanding issues and identifying potential R{ampersand}D avenues to address them. This paper summarizes the presentations, discussions, and recommendations
- …