Transplantation of Crossed Fused Renal Ectopia

Crossed fused renal ectopia is a type of congenital fused anomaly of the kidney. This type of kidney, when encountered, can be used as a donor organ to provide useful solution to the critical shortage of available organs for transplantation

Melioidosis and the Vascular Surgeon: Hospital Kuala Lumpur Experience

Bacterial arteritis is relatively uncommon and management of this condition, which carries high morbidity and mortality, is difficult and time-consuming. Common organisms implicated include Salmonella and Staphylococcus. Arteritis as a result of infection by Burkholderia pseudomallei (formerly Pseudomonas pseudomallei) has been rarely reported in the English literature. This organism, which is endemic in our part of the world, is well known to cause a wide spectrum of septic conditions. A review of cases managed at Hospital Kuala Lumpur revealed that bacterial arteritis due to melioidosis is not such a rare entity. We share our experience in the management of this condition using three cases as examples

MOCVD growth of InGaP/GaAs heterojunction bipolar transistors on 200 mm Si wafers for heterogeneous integration with Si CMOS

Heterojunction bipolar transistors (HBTs) with an In0.49Ga0.51P emitter and a GaAs base and collector were fabricated on epitaxial films grown directly onto Si substrates using a thin germanium (100%) buffer layer. All the materials (Ge, GaAs, In0.49Ga0.51P) were grown epitaxially using metal-organic chemical vapor deposition. The thin germanium buffer layer has a threading dislocation density (TDD) of ∼3 × 107 cm-2. The TDD of the active device layers does not worsen and is maintained at ∼2 × 107 cm-2, based on the density of dark spots detected in an electron-beam-induced current plan view image. Although the TDD is high, a DC current gain of 95 can be achieved by the In0.49Ga0.51P/GaAs HBT on a Si substrate. In addition, collector current and base current ideality factors (n c and n b) of 1.07 and 1.23, respectively, and average breakdown voltage (BV cbo) of 14.2 V can be realized. These results enable applications such as power amplifiers for mobile phone handsets and monolithic integration of HBTs with standard Si CMOS transistors on a common Si platform

Monolithic integration of InSb photodetector on silicon for mid-infrared silicon photonics

The InSb photodetector on a Si substrate acts as a signal receiver for the mid-infrared silicon photonics application to overcome the limitation of group IV semiconductors. In this paper, we demonstrated an InSb p–i–n photodetector with an InAlSb barrier layer grown on (100) silicon substrates via a GaAs/Ge buffer by molecular beam epitaxy. The lattice mismatch between InSb and GaAs was accommodated by an interfacial misfit array. The 50% cutoff detectable wavelength of this detector increased from 5.7 μm at 80 K to 6.3 μm at 200 K. An 80 K detectivity of 8.8 × 109 cmHz1/2 W–1 at 5.3 μm was achieved with a quantum efficiency of 16.3%. The dark current generating mechanism of this detector is both generation–recombination and surface leakage above 140 K, while it is only surface leakage from 120 to 40 K.NRF (Natl Research Foundation, S’pore)Accepted versio

Long-term outcomes after reirradiation in nasopharyngeal carcinoma with intensity-modulated radiotherapy: A meta-analysis

10.1002/hed.24993HEAD AND NECK-JOURNAL FOR THE SCIENCES AND SPECIALTIES OF THE HEAD AND NECK403622-63

Accuracy of 18F-flurodeoxyglucosepositron emission tomography/computed tomography in the staging of newly diagnosed nasopharyngeal carcinoma: a systematic review and meta-analysis

Background. The specific role of 18F-flurodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in staging of nasopharyngeal carcinoma (NPC) remains to be validated. A systematic review and meta-analysis were performed to assess the accuracy of staging FDG-PET/CT for newly diagnosed NPC. Methods. We searched various biomedical databases and conference proceedings for relevant studies. We determined the pooled sensitivities and specificities, diagnostic odds ratios (DOR) and constructed summary receiver operating characteristic (SROC) curves using the hierarchical regression model. Results. 15 relevant studies including 851 patients were identified. Five addressed primary tumor (T), nine addressed regional lymph nodes (N) and seven addressed distant metastasis (M). The combined sensitivity estimate for FDG-PET/CT in T classification was 0.77 (95% confidence interval [CI] 0.59-0.95). For N classification, combined sensitivity was 0.84 (95% CI 0.76-0.91), specificity was 0.90 (95% CI 0.83-0.97), DOR was 82.4 (23.2-292.6) and Q*-index was 0.90. For M classification, the combined sensitivity estimate was 0.87 (95% CI 0.74-1.00), specificity was 0.98 (95% CI 0.96-1.00), DOR was 120.9 (43.0-340.0) and Q*-index was 0.89. Conclusion. FDG-PET/CT showed good accuracy in N and M but not T classification for newly diagnosed NPC. FDG-PET/CT, together with Magnetic resonance imaging (MRI) of the nasopharynx, should be part of the routine staging investigation

In0.49Ga0.51P/GaAs heterojunction bipolar transistors (HBTs) on 200 mm Si substrates: Effects of base thickness, base and sub-collector doping concentrations

We report performance of InGaP/GaAs heterojunction bipolar transistors (HBTs) fabricated on epitaxial films directly grown onto 200 mm silicon (Si) substrates using a thin 100% germanium (Ge) buffer layer. Both buffer layer and device layers were grown epitaxially using metalorganic chemical vapor deposition (MOCVD). With the assistance of numerical simulation, we were able to achieve high performance GaAs HBTs with DC current gain of ∼100 through optimizing the base doping concentration (C-doped, ∼ 1.9×1019/cm3), base layer thickness (∼55 nm), and the sub-collector doping concentration (Te-doped, > 5×1018/cm3). The breakdown voltage at base (BVceo) of higher than 9.43 V was realized with variation of < 3% across the 200 mm wafer. These results could enable applications such as power amplifiers for mobile phone handsets and monolithic integration of HBTs with standard Si-CMOS transistors on a common Si platform

CMOS-compatible Ti/TiN/Al refractory ohmic contact for GaAs heterojunction bipolar transistors grown on Ge/Si substrate

In this article, we demonstrate the Ti/TiN/Al (15/50/50 nm) ohmic contact on InGaP/GaAs heterojunction bipolar transistors (HBTs) epitaxially grown on 200-mm Si substrate. We study the rapid thermal annealing (RTA) effect of the metal stack on both n-type InGaAs and p-type GaAs. The dc characteristics of the HBT devices fabricated using the Ti/TiN/Al metal contacts have been analyzed. Contact resistances (R-c)<0.1 Omega. mm for n-InGaAs and 0.8 Omega. mm for p-GaAs can be achieved. A dc current gain of 45 with a collector-base breakdown voltage (BVcbo) of 15.65 V is achieved. The ideality factor of the emitter-base current (n(b)) and base-collector current (n(c)) is 1.03 and 1.44, respectively, after RTA at 450 degrees C. The dc characteristics remain stable upon prolonged annealing at 450 degrees C for 45 min. This high thermal budget non-gold ohmic contact is suitable for Si-CMOS integration and enables the potential for hybrid III-V CMOS technology for 5G and mm-wave applications.This work was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology’s Low Energy Electronic Systems Interdisciplinary Research Group (IRG)

Monolithic Integration of InSb Photodetector on Silicon for Mid-Infrared Silicon Photonics

The InSb photodetector on a Si substrate acts as a signal receiver for the mid-infrared silicon photonics application to overcome the limitation of group IV semiconductors. In this paper, we demonstrated an InSb p–i–n photodetector with an InAlSb barrier layer grown on (100) silicon substrates via a GaAs/Ge buffer by molecular beam epitaxy. The lattice mismatch between InSb and GaAs was accommodated by an interfacial misfit array. The 50% cutoff detectable wavelength of this detector increased from 5.7 μm at 80 K to 6.3 μm at 200 K. An 80 K detectivity of 8.8 × 10⁹ cmHz^1/2 W^–1 at 5.3 μm was achieved with a quantum efficiency of 16.3%. The dark current generating mechanism of this detector is both generation–recombination and surface leakage above 140 K, while it is only surface leakage from 120 to 40 K