On the origin of carrier localization in AlInAsSb digital alloy

We compared the photoluminescence(PL)properties of Al In As Sb digital alloy samples with different periods grown on Ga Sb(001)substrates by molecular beam epitaxy.Temperature-dependent S-shape behavior is observed and explained using a thermally activated redistribution model within a Gaussian distribution of localized states.There are two different mechanisms for the origin of the PL intensity quenching for the Al In As Sb digital alloy.The high-temperature activation energy E_(1)is positively correlated with the interface thickness,whereas the low-temperature activation energy E_(2)is negatively correlated with the interface thickness.A quantitative high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)study shows that the interface quality improves as the interface thickness increases.Our results confirm that E_(1)comes from carrier trapping at a state in the In Sb interface layer,while E_(2)originates from the exciton binding energy due to the roughness of the Al As interface layer.

Bioreductive prodrugs as cancer therapeutics:targeting tumor hypoxia

Hypoxia, a state of low oxygen, is a common feature of solid tumors and is associated with disease progression as well as resistance to radiotherapy and certain chemotherapeutic drugs. Hypoxic regions in tumors, therefore, represent attractive targets for cancer therapy. To date, five distinct classes of bioreactive prodrugs have been developed to target hypoxic cells in solid tumors. These hypoxia-activated prodrugs, including nitro compounds, N-oxides, quinones, and metal complexes, generally share a common mechanism of activation whereby they are reduced by intracellular oxidoreductases in an oxygensensitive manner to form cytotoxins. Several examples including PR-104, TH-302, and EO9 are currently undergoing phase II and phase III clinical evaluation. In this review, we discuss the nature of tumor hypoxia as a therapeutic target, focusing on the development of bioreductive prodrugs. We also describe the current knowledge of how each prodrug class is activated and detail the clinical progress of leading examples.

First-principles study of structural stability and elastic properties of MgPd_(3) and its hydride

Theoretical study of structural stability and elastic properties ofα-andβ-MgPd_(3)intermetallic compounds as well as their hydrides have been carried out based on density functional theory.The results indicateα-MgPd_(3)is more stable thanβphase with increased stability in their hydrides.The calculated elastic constants ofα-MgPd_(3)are overall larger thanβphase.After hydrogenation,the elastic constants are enlarged.And the elastic moduli exhibit similar tendency.The anisotropy ofα-MgPd_(3)is larger thanβphase,and the hydrides demonstrate larger anisotropy.Their ductility follows the order ofα-MgPd_(3)H_(0.5)<α-MgPd_(3)<β-MgPd_(3)H<β-MgPd_(3).Compared withβphase,higher Debye temperature ofα-MgPd_(3)implies stronger covalent interaction,and the Debye temperature of hydrides increases slightly.The electronic structures demonstrate that the Pd-Pd interaction is stronger than Pd-Mg,and Pd-H bonds play a significant role in the phase stability and elastic properties of hydrides.

EVALUATION OF EFFICACY AND SAFETY OF DIACEREIN IN KNEE OSTEOARTHRITIS IN CHINESE PATIENTS

Objective To evaluate the efficacy and safety of diacerein in patients with knee osteoarthritis (OA). Methods A total of 223 patients satisfying the American College of Rheumatology criteria for knee OA were chosen for this 17-week, randomized, double-dummy, diclofenac sodium-controlled trial, with diacerein dosage of 100 mg/d and diclofenac sodium of 75mg/d. Efficacy and safety of both drugs were evaluated. Results Totally 106 patients in the diacerein group and 107 patients in the diclofenac group were considered qualified for the evaluation. After 12 weeks of treatment, the total effective rates of patients/physicians’ overall assessment in diacerein and diclofenac groups were 65.4%/61.6% and 61.2%/61.2%, respectively (P>0.05). The primary efficacy parameter [visual analog scale (VAS) assessment of pain on 20 metres walking] and the secondary efficacy parameters [tenderness on palpation, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short-Form (SF-36) Health Survey] significantly improved compared with baseline in both groups (P<0.05). In the follow-up period, there were no obvious changes in above parameters in diacerein group. However, in diclofenac group, pain on 20 metres walking, tenderness on palpation, and WOMAC became aggravated after withdrawing the drug for 4 weeks (P<0.05). Moreover, the consumption of paracetamol was significantly lower in diacerein group than in diclofenac group during follow-up (P<0.001). The incidences of related adverse events were 35.7% in diacerein and 45.1% in diclofenac group, respectively. Mild-to-moderate gastrointestinal disorders were the most frequent adverse events. Conclusions Diacerein is as effective as diclofenac sodium in treating patients with knee OA. Furthermore, it has better extended effect and a good safety profile. It is generally well tolerated and has no severe adverse effect.

Wet etching and passivation of GaSb-based very long wavelength infrared detectors

The etching and passivation processes of very long wavelength infrared(VLWIR)detector based on the InAs/GaSb/AlSb type-II superlattice have been studied.By studying the effect of each component in the citric acid solution(citric acid,phosphoric acid,hydrogen peroxide,deionized water),the best solution ratio is obtained.After comparing different passivation materials such as sulfide+SiO_(2),Al_(2)O_(3),Si_(3)N_(4) and SU8,it is found that SU8 passivation can reduce the dark current of the device to a greater degree.Combining this wet etching and SU8 passivation,the of VLWIR detector with a mesa diameter of 500μm is about 3.6Ω·cm^(2) at 77 K.