With the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is an urgent need for more rapid and simple detection technologies at the forefront of medical care worldwide.In this study, we evaluated the effectiveness of the Loopamp® 2019-SARSCoV-2 Detection Reagent Kit, which uses loop-mediated isothermal amplification (LAMP) technology. In this protocol, cDNA is synthesized from SARS-CoV-2 RNA using reverse transcriptase, followed by DNA amplification under isothermal conditions in one step. The RT-LAMP test kit amplified the targeted RNA of a SARS-CoV-2 isolate with a detection limit of 1.0 × 101 copies/μL, which was comparable to the detection sensitivity of quantitative reverse transcription PCR (RT-qPCR).Comparison with the results of RT-qPCR for 76 nasopharyngeal swab samples from patients with suspected COVID-19 showed a sensitivity of 100 % and a specificity of 97.6 %. In the 24 RNA specimens derived from febrile Japanese patients with or without influenza A, no amplification was observed using RT-LAMP. RT-LAMP could be a simple and easy-to-use diagnostic tool for the detection of SARS-CoV-2.
Further improving complementary metal oxide semiconductor performance beyond the 22 nm generation likely requires the use of high mobility channel materials, such as Ge for p-type metal oxide semiconductor (pMOS) and III/V for n-type metal oxide semiconductor devices. The complementary integration of both materials on Si substrates can be realized with selective epitaxial growth. We present two fabrication schemes for Ge virtual substrates using Si wafers with standard shallow trench isolation (STI). This reduces the fabrication cost of these virtual substrates as the complicated isolation scheme in blanket Ge can be omitted. The low topography enables integration of ultrathin high-
k
gate dielectrics. The fabrication schemes are also compatible with uniaxial stress techniques. Both modules include an annealing step at
850°C
to reduce the threading dislocation densities down to
4×108
and
1×107cm−2
, respectively. We are able to fabricate high quality Ge virtual substrates for pMOS devices as well as suitable starting surfaces for selective epitaxial III/V growth. The latter are illustrated by preliminary results of selective epitaxial InGaAs growth on virtual Ge substrates.
Although conclusive evidence has not yet been obtained, SITS is more minimally invasive in regard to postoperative wound pain compared with c-VATS. This procedure should be considered as a treatment option for early-stage lung cancer.
We have investigated Sn precipitation and strain relaxation behaviors in the growth of Ge1−xSnx layers on virtual Ge substrates (v-Ge) for strain engineering of Ge. By varying misfit strain at Ge1−xSnx∕v-Ge and Ge1−ySny∕Ge1−xSnx interfaces, we found that a critical misfit strain controls the onset of Sn precipitation at a given thickness of the Ge1−xSnx layer. A compositionally step-graded method, in which the critical misfit strain is taken into account, was applied to the growth of strain-relaxed Ge1−xSnx layers on v-Ge. Postdeposition annealing at each growth step led to lateral propagation of threading dislocations preexisting in the layer and originating from v-Ge, which resulted in high degree of strain relaxation. An epitaxial Ge layer was grown on the strain-relaxed Ge1−xSnx layer and an in-plane tensile strain of 0.68% was achieved.
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