Monolithic integration of a 10 µm cut-off wavelength InAs/GaSb type-II superlattice diode on GaAs platform.

At room temperature, a 10 µm cut-off wavelength coincides with an infrared spectral window and the peak emission of blackbody objects. We report a 10 µm cut-off wavelength InAs/GaSb T2SL p-i-n diode on a GaAs substrate with an intentional interfacial misfit (IMF) array between the GaSb buffer layer and GaAs substrate. Transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed that the heterostructure on GaSb-on-GaAs is epitaxial, single-crystalline but with a reduced material homogeneity, extended lattice defects and atomic segregation/intermixing in comparison to that on the GaSb substrate. Strain-induced degradation of the material quality is observed by temperature-dependent current-voltage measurements. The T2SL with the IMF array appears as a potentially effective route to mitigate the impact of the lattice mismatch once its fabrication is fully optimized for these systems, but additional strain compensating measures can enable a low cost, scalable manufacturing of focal plane arrays (FPA) for thermal imaging cameras for spectroscopy, dynamic scene projection, thermometry, and remote gas sensing.

[Practice guideline for patients with osteoporosis].

In recent years, osteoporosis (OP) has become one of the main diseases affecting the health of middle-aged and elderly people in China, and the prevalence of OP has increased significantly. The clinical diagnosis and treatment guidelines for this disease are also constantly updated. The overall principles speciallyemphasise that doctors and patients need to work together to negotiate the details of the diagnosis and treatment guidelines, in order to improve the OP clinical diagnosis and treatment rate. Therefore, patients' knowledge of the disease, understanding of clinical guidelines, and cooperation with doctors to implement diagnosis and treatment plans are very important. In this study, from the most concerned issues of the patients, we established the OP patient practice guideline working group. 14 recommendations, as the OP patient practice guidelines, are proposed in accordance with the relevant principles of the "World Health Organization guidelines development manual" and the international normative process.

[Practice guideline for patients with ankylosing spondylitis/spondyloarthritis].

In recent years, the clinical experts consensuses or guidelines of ankylosing spondylitis (AS)/spondyloarthritis (SpA) have been constantly updated, but to better understand and practice, patient self-participation management is one of the key points to improve the level of diagnosis and treatment. Through questionnaire survey of these patients, we screened out the most concerned issues, and established the AS/SpA patient practice guideline working group with multidisciplinary physicians and patients. Fifteen opinions, as the AS/SpA patient practice guidelines, are proposed in accordance with the relevant principles of the "WHO guidelines development manual" , and with the international normative process.

Ischemia-reperfusion injury in an aortic dissection patient.

Aortic dissection is a life-threatening emergency. Well-established risk factors include systemic hypertension, hereditary connective tissue diseases (Marfan syndrome and Ehlers-Danlos syndrome), coarctation of the aorta, bicuspid aortic valve, aortitis, and arch hypoplasia. Ischemia of the viscera, the kidneys, the spinal cord, or the lower extremities due to malperfusion constitutes life-threatening complications that have to be considered in the treatment strategy.We report a rare case of symptomatic ischemia of the lower extremities due to aortic dissection. This case demonstrates that the treating physician needs to be vigilant for ischemia reperfusion injuries such as osteofascial compartment syndrome and acute renal failure in aortic dissection.

Initial experiences with laparoscopy and flexible ureteroscopy combination pyeloplasty in management of ectopic pelvic kidney with stone and ureter-pelvic junction obstruction.

To demonstrate the safety and efficacy of combine laparoscopy and flexible ureteroscopy to treat ectopic pelvic kidneys with ureteropelvic junction obstruction (UPJO) and stones. 16 patients of ectopic pelvic kidneys with ureteropelvic junction obstruction and stones were treated with laparoscopy and flexible ureteroscopy (FURS). The operative time, required dose of tramadol, visual analog pain scale (VAPS), postoperative day, stone-free rates (SFRs), perioperative complications, and serum creatinine were evaluated. The SFRs were evaluated with noncontrasted renal computed tomography (CT). Intravenous pyelography (IVP) and CT scan were used to evaluate the UPJO. Stone-free status was defined as absence of stone fragments in kidney or the size of that is less than 3 mm. Operation time from 118 to 225 min, average time (171 ± 28) min; lithotomy time from 16 to 45 min, average time (32 ± 6) min. Average tramadol required at the first day postoperation was (118 ± 49.6) mg; at the second day was (78 ± 24.8) mg. VAPS score at 24 h (5.0 ± 0.7), VAPS score at 48 h (2.5 ± 0.8). Postoperative day (3.9 ± 0.6) days. Stone-free rate was 100%. Average serum creatinine was (88.7 ± 24.3) mol/L before surgery and (92.8 ± 21.6) mol/L after surgery. No major complication. No stone and obstruction recurrence in the follow-up of average 29.3 months. Combined FUR and LC is a good option for patient of ectopic pelvic kidney with renal stone and UPJO. From our initial experience, the SFRs and the effect of pyeloplasty are satisfactory and without major complication, the operative time is acceptable.

Propagation characteristics of a focused laser beam in a strontium barium niobate photorefractive crystal under reverse external electric field.

The propagation characteristics of a focused laser beam in a SBN:75 photorefractive crystal strongly depend on the signal-to-background intensity ratio (R=Is/Ib) under reverse external electric field. In the range 20>R>0.05, the laser beam shows enhanced self-defocusing behavior with increasing external electric field, while it shows self-focusing in the range 0.03>R>0.01. Spatial solitons are observed under a suitable reverse external electric field for R=0.025. A theoretical model is proposed to explain the experimental observations, which suggest a new type of soliton formation due to "enhancement" not "screening" of the external electrical field.

Triptolide inhibits the multidrug resistance in prostate cancer cells via the downregulation of MDR1 expression.

Triptolide (TPL) is a diterpenoid triepoxide derived from the Chinese herb Tripterygium wilfordii and possesses anti-tumor activity against a range of cancer cells. However, the effect of TPL on prostate cancer cells and its potential to overcome multidrug resistance (MDR) have not been explored. Therefore, in this study we used prostate cancer cell line DU145 as the experimental model and established DU145/ADM cell line resistant to adriamycin (ADM). Our results showed that TPL inhibited the proliferation and induced the cell cycle arrest and apoptosis of DU145 cells in a dose and time dependent manner. TPL decreased the levels of Cyclin D1 and anti-apoptotic protein Bcl-2, and increased the levels of pro-apoptotic proteins Fas and Bax. Furthermore, we found that TPL restored the sensitivity DU145/ADM cells to ADM in a dose dependent manner, and this was accompanied by the inhibition of MDR1 expression at both mRNA and protein levels. Taken together, these results provide strong evidence that TPL overcomes MDR in prostate cancer cells by downregulating MDR1 expression, and suggest that TPL is a promising agent for prostate cancer therapy, especially for chemoresistant prostate cancer.

Genitourinary toxicity of ketamine.

Ketamine is a relatively new recreational drug used by youngsters in recent decades. Its toxic effects on the genitourinary system were first reported in 2007, and now attract extensive attention from urologists, pharmacologists, and toxicologists all over the world. As many front-line health professionals and medical social workers are still unaware of this new clinical entity and an increasing number of the drug users seek help for urological symptoms, this mini-review aimed to summarise the clinical features and possible mechanisms of ketamine-induced genitourinary toxicity. By raising public awareness of these toxic effects, the authors hope that the contents of this review will be widely disseminated not only to medical professionals, but also to relevant government departments and the general public.

Strong passivation effects on the properties of an InAs surface quantum dot hybrid structure.

We report on an InAs quantum dot (QD) hybrid structure with a top surface QD layer coupled to two buried QD layers that is highly sensitive to surface passivation. After 180 min of passivation, the photoluminescence (PL) peak of the surface QDs shifts from 1545 to 1275 nm while its intensity decreases by one order of magnitude. Time-resolved PL reveals a significant decrease of carrier tunneling between the QD layers because of the surface state modification by chemical treatment. A simple model with rate equations is used to explain the observed optical performance. Our results show that the optical performance of this hybrid structure is very sensitive to the surface environment, making it a potential candidate for sensing applications.

Anisotropic Confinement, Electronic Coupling and Strain Induced Effects Detected by Valence-Band Anisotropy in Self-Assembled Quantum Dots.

A method to determine the effects of the geometry and lateral ordering on the electronic properties of an array of one-dimensional self-assembled quantum dots is discussed. A model that takes into account the valence-band anisotropic effective masses and strain effects must be used to describe the behavior of the photoluminescence emission, proposed as a clean tool for the characterization of dot anisotropy and/or inter-dot coupling. Under special growth conditions, such as substrate temperature and Arsenic background, 1D chains of In0.4Ga0.6 As quantum dots were grown by molecular beam epitaxy. Grazing-incidence X-ray diffraction measurements directly evidence the strong strain anisotropy due to the formation of quantum dot chains, probed by polarization-resolved low-temperature photoluminescence. The results are in fair good agreement with the proposed model.

Lateral interdot carrier transfer in an InAs quantum dot cluster grown on a pyramidal GaAs surface.

InAs quantum dot clusters (QDCs), which consist of three closely spaced QDs, are formed on nano-facets of GaAs pyramidal structures by selective-area growth using metal-organic chemical vapor deposition. Photoluminescence (PL) and time-resolved PL (TRPL) experiments, measured in the PL linewidth, peak energy and QD emission dynamics indicate lateral carrier transfer within QDCs with an interdot carrier tunneling time of 910 ps under low excitation conditions. This study demonstrates the controlled formation of laterally coupled QDCs, providing a new approach to fabricate patterned QD molecules for optical computing applications.

Band alignment tailoring of InAs1-xSbx/GaAs quantum dots: control of type I to type II transition.

We report the growth of InAs(1-x)Sb(x) self-assembled quantum dots (QDs) on GaAs (100) by molecular beam epitaxy. The optical properties of the QDs are investigated by photoluminescence (PL) and time-resolved photoluminescence (TRPL). A type I to type II band alignment transition is demonstrated by both power-dependent PL and TRPL in InAs(1-x)Sb(x) QD samples with increased Sb beam flux. Results are compared to an eight-band strain-dependent k x p model incorporating detailed QD structure and alloy composition. The calculations show that the conduction band offset of InAs(1-x)Sb(x)/GaAs can be continuously tuned from 0 to 500 meV and a flat conduction band alignment exists when 60% Sb is incorporated into the QDs. Our study offers the possibility of tailoring the band structure of GaAs based InAsSb QDs and opens up new means for device applications.

Fabrication and characteristics of broad-area light-emitting diode based on nanopatterned quantum dots.

The device fabrication and integration of nanopatterned quantum dots (PQDs) are realized through the demonstration of a broad-area light-emitting diode with PQD active region. The device involves two growth processes, first to form PQDs by selective-area epitaxy on an SiO(2) mask and then to complete the device structure after mask removal. Linear current-voltage characteristics are observed with sharp turn-on, low leakage current and low forward resistance. Electroluminescence spectra show PQD intraband structure and low quenching of emission from 77 K to room temperature. Light-current measurements demonstrate external quantum efficiency per PQD comparable to self-assembled QDs, thus providing a possible route toward individually addressable single QD devices.

InAs quantum dot clusters grown on GaAs droplet templates: surface morphologies and optical properties.

GaAs nano-mounds formed by droplet epitaxy are used as templates for growth of self-assembled InAs quantum dot clusters (QDCs). These QDCs are found to contain an average of thirteen dots per cluster, of which there are two families of different sized quantum dots. Excitation intensity-dependent photoluminescence (PL) demonstrates that there is no lateral coupling between the two different size quantum dots. Lateral transfer of carriers is observed between different size quantum dots due to thermal activation as seen in their different temperature-dependent optical behaviors.

Time-resolved photoluminescence of type-II Ga(As)Sb/GaAs quantum dots embedded in an InGaAs quantum well.

Optical properties and carrier dynamics in type-II Ga(As)Sb/GaAs quantum dots (QDs) embedded in an InGaAs quantum well (QW) are reported. A large blueshift of the photoluminescence (PL) peak is observed with increased excitation densities. This blueshift is due to the Coulomb interaction between physically separated electrons and holes characteristic of the type-II band alignment, along with a band-filling effect of electrons in the QW. Low-temperature (4 K) time-resolved PL measurements show a decay time of [Formula: see text] ns from the transition between Ga(As)Sb QDs and InGaAs QW which is longer than that of the transition between Ga(As)Sb QDs and GaAs two-dimensional electron gas ([Formula: see text] ns).

Improved photoluminescence efficiency of patterned quantum dots incorporating a dots-in-the-well structure.

InAs quantum dots embedded in InGaAs quantum well (DWELL: dots-in-the-well) structures grown on nanopatterned GaAs pyramids and planar GaAs(001) surface are comparatively investigated. Photoluminescence (PL) measurements demonstrate that the DWELL structure grown on the GaAs pyramids exhibits a broad quantum well PL band (full width at half-maximum ∼ 90 meV) and a higher quantum dot emission efficiency than the DWELL structure grown on the planar GaAs(001) substrate. These properties are attributed to the InGaAs quantum well with distributed thickness profile on the faceted GaAs pyramids, which introduces a tapered energy band structure and enhances carrier capture into the quantum dots.

Tuning the optical performance of surface quantum dots in InGaAs/GaAs hybrid structures.

GaAs spacer thicknesses are varied to tune the coupling between InGaAs surface quantum dots (QDs) and multilayers of buried QDs. Temperature and excitation intensity dependence of the photoluminescence together with time resolved photoluminescence reveal that coupling between layers of QDs and consequently the optical properties of both the surface and the buried QDs significantly depend on the GaAs spacer. This work provides an experimental method to tune and control the optical performance of surface QDs.

Morphologic analysis of normal human lumbar dorsal root ganglion by 3D MR imaging.

BACKGROUND AND PURPOSE: The dorsal root ganglion (DRG) of the spinal nerve has been considered a key structure in the mechanism of low-back pain and radicular symptoms. The purpose of this study was to clarify the normal morphologic features and variations of the lumbar DRGs in a healthy population by using 3D MR imaging. METHODS: 3D fast-field echo (FFE) with water selective excitation coronal MR images of lumbar spine obtained in 115 healthy volunteers were further reconstructed into a radial stack of 15 coronal images by using maximum intensity projection technique. The DRGs from L1 through L5 were assessed for the location, signal intensity, architecture, and dimensions. RESULTS: Most DGRs were foraminal in location. Only 5.7% of the L5 DGRs were located intraspinally. The sizes of L1, L2, and L5 DRGs in men were larger than those in women (P < .05). The dimensions of the DRGs gradually increased from L1 to L5 (P < .0001). The biganglia (2 ganglial components) frequently occurred in the L4 and L3 DRGs, whereas the singular ganglion (1 ganglial component), in the L5 and L1 DRGs. CONCLUSION: The normal anatomy and variants of the lumbar DRG could be better demonstrated by 3D MR imaging with water selective excitation technique. The relatively larger and more proximally located DRGs in the lower lumbar region may be more susceptible to compression. An appreciation of normal anatomy and variants of DRGs radiologically is helpful for the diagnosis and proper treatment for radiculopathy.

Enhancement of Two-Wave Coupling in a Ce:KNSBN Crystal with Optimum Polarization of the Writing Beams.

We have improved the two-wave coupling amplification and the signal-to-noise ratio of an amplified signal with photorefractive cerium-doped potassium sodium strontium barium niobate (Ce:KNSBN) by employing optimum polarization orientation of the pump beam while the signal beam retains extraordinary polarization. The optimum polarization angle of the pump beam was found experimentally to be 30 degrees with respect to the extraordinary polarization direction in a symmetrically incident system. Nearly 1.9-times enhancement of the gain and nearly 3-times enhancement of the signal-to-noise ratio were achieved at a signal-to-pump beam intensity ratio of 1:40. At a beam intensity ratio of 1:2000, a two-wave coupling gain of nearly 500 was obtained, which is much higher than the gain previously reported. Modified coupled-wave equations that involve beam fanning with certain assumptions concerning the fanning parameters were used. The numerical solution is in good agreement with the experimental data. The results are compared with those obtained with a 45 degrees -cut BaTiO(3) crystal.

Holographic recording with orthogonally polarized beams in a cesium-doped (K0.5Na0.5)0.2(Sr0.75Ba0.25)0.9Nb2O6 crystal.

Holographic recording with orthogonally polarized beams in a cesium-doped KNSBN [(K0.5Na0.5)0.2(Sr0.75Ba0.25)0.9Nb2O6] crystal has been studied. It was found that this kind of photorefractive crystal possesses high linear dichroism, which makes it suitable for use in polarization holography. The diffraction efficiency as a function of the polarization orientation of the reference beam and as a function of the fringe modulation at the optimum polarization orientation of the reference beam is experimentally investigated. Theoretical fitting based on Kahmann models was performed and agrees well with the experimental data. In the experiments, both polarization holography and conventional holography are used to record a binary object. The reconstruction shows that polarization holography with Ce:KNSBN is highly effective, exhibiting high diffraction efficiency and reduced fanning noise.