[Advances in the treatment of anti-HER-2 antibody drug conjugates in pan-tumor with low HER-2 expression]

Antibody-drug conjugates (ADCs) are drugs that combine monoclonal antibody drugs targeting specific antigens and small molecule cytotoxic drugs through linker molecules. ADCs combine the advantages of high specificity targeting and potent killing effects, achieving precise and efficient targeting of cancer cells. Nowadays, ADCs are one of the hotspots in cancer drug development. Human epidermal growth factor receptor 2 (HER-2) is a known oncogene that can drive the occurrence and development of various types of tumors. HER-2 is also an important tumor target for ADCs approved for solid tumors. Anti-HER-2 ADCs can not only be used to treat HER-2-positive tumors but also effectively target HER-2-low tumors. The emergence of ADCs has broken the traditional classification of HER-2 in tumors, bringing significant treatment breakthroughs for HER-2-low tumors. Anti-HER-2 ADCs are widely used in the treatment of solid tumors and have substantial evidence for HER-2-low tumors. This article presents the progress of various anti-HER-2 ADCs in HER-2-low tumors including breast cancer, gastrointestinal malignancies, urothelial carcinoma, lung cancer. And this article summarizes the current status of preclinical studies, clinical studies, and safety of anti-HER-2 ADCs in order to provide reference for the clinical use of HER-2-low tumors.

Quasi van der Waals Epitaxy of Single Crystalline GaN on Amorphous SiO2/Si(100) for Monolithic Optoelectronic Integration

The realization of high quality (0001) GaN on Si(100) is paramount importance for the monolithic integration of Si-based integrated circuits and GaN-enabled optoelectronic devices. Nevertheless, thorny issues including large thermal mismatch and distinct crystal symmetries typically bring about uncontrollable polycrystalline GaN formation with considerable surface roughness on standard Si(100). Here a breakthrough of high-quality single-crystalline GaN film on polycrystalline SiO2/Si(100) is presented by quasi van der Waals epitaxy and fabricate the monolithically integrated photonic chips. The in-plane orientation of epilayer is aligned throughout a slip and rotation of high density AlN nuclei due to weak interfacial forces, while the out-of-plane orientation of GaN can be guided by multi-step growth on transfer-free graphene. For the first time, the monolithic integration of light-emitting diode (LED) and photodetector (PD) devices are accomplished on CMOS-compatible SiO2/Si(100). Remarkably, the self-powered PD affords a rapid response below 250 µs under adjacent LED radiation, demonstrating the responsivity and detectivity of 2.01 × 105 A/W and 4.64 × 1013 Jones, respectively. This work breaks a bottleneck of synthesizing large area single-crystal GaN on Si(100), which is anticipated to motivate the disruptive developments in Si-integrated optoelectronic devices.

Damping Properties of Selective Laser-Melted Medium Manganese Mn-xCu Alloy

In this work, selective laser melting (SLM) technology was applied to directly realize the in situ synthesis of medium manganese Mn-xCu (x = 30-40 wt.%) alloys based on the blended elemental powders. The effects of heat treatment on the microstructural evolution and damping properties of the SLMed Mn-xCu alloys were investigated. The metastable miscibility gap was studied by thermodynamic modeling and microhardness measurement. The results showed that γ-(Mn, Cu) phase with dendritic arm spacing (DAS) of 0.9-1.2 μm was the main constituent phase in the as-SLMed alloys, which was one to two orders of magnitude finer than those of the as-cast samples. Aging at 400-480°C for the Mn-30%Cu or 430°C for Mn-40%Cu alloys can induce spinodal decomposition, martensitic transformation, and α-phase precipitation, whose direct evidence was provided for the first time by transmission electron microscopy and 3D atom probe tomography in the work. The miscibility gap obtained from thermodynamics calculation was basically consistent with the microhardness results for the SLMed Mn-xCu alloys. Solution and aging (SA) treatment can improve the microstructure, tensile and damping properties of the SLMed Mn-xCu alloys more obviously than aging treatment. A 2.3-2.8 and 4.3-4.5 times increase was produced in damping capacity in the aged SLMed and SLMed+SAed Mn-xCu samples, respectively.

Wafer-Scale Transferrable GaN Enabled by Hexagonal Boron Nitride for Flexible Light-Emitting Diode

Epitaxy growth and mechanical transfer of high-quality III-nitrides using 2D materials, weakly bonded by van der Waals force, becomes an important technology for semiconductor industry. In this work, wafer-scale transferrable GaN epilayer with low dislocation density is successfully achieved through AlN/h-BN composite buffer layer and its application in flexible InGaN-based light-emitting diodes (LEDs) is demonstrated. Guided by first-principles calculations, the nucleation and bonding mechanism of GaN and AlN on h-BN is presented, and it is confirmed that the adsorption energy of Al atoms on O2 -plasma-treated h-BN is over 1 eV larger than that of Ga atoms. It is found that the introduced high-temperature AlN buffer layer induces sufficient tensile strain during rapid coalescence to compensate the compressive strain generated by the heteromismatch, and a strain-relaxation model for III-nitrides on h-BN is proposed. Eventually, the mechanical exfoliation of single-crystalline GaN film and LED through weak interaction between multilayer h-BN is realized. The flexible free-standing thin-film LED exhibits ≈66% luminescence enhancement with good reliability compared to that before transfer. This work proposes a new approach for the development of flexible semiconductor devices.

Phosphor-free micro-pyramid InGaN-based white light-emitting diode with a high color rendering index on a β-Ga2O3 substrate

We demonstrate the InGaN/GaN-based monolithic micro-pyramid white (MPW) vertical LED (VLED) grown on (-201)-oriented β-Ga2O3 substrate by selective area growth. The transmission electron microscopy (TEM) reveals an almost defect-free GaN pyramid structure on (10-11) sidewalls, including stacked dual-wavelength multi-quantum wells (MQWs). From the electroluminescence (EL) spectra of the fabricated MPW VLED, a white light emission with a high color rendering index (CRI) of 97.4 is achieved. Furthermore, the simulation shows that the light extraction efficiency (LEE) of the MPW VLED is at least 4 times higher compared with the conventional planar LED. These results show that the MPW VLED grown on β-Ga2O3 has great potential for highly efficient phosphor-free white light emission.

Rationale and Design of a Phase II Trial of Combined Serplulimab and Chemotherapy in Patients with Histologically Transformed Small Cell Lung Cancer: a Prospective, Single-arm and Multicentre Study

AIMS

Transformed small cell lung cancer (T-SCLC) is a highly aggressive clinical disease with a notably poor prognosis. It most often arises from epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) following treatment. To date, no standard treatment has been established for T-SCLC. Platinum-etoposide was the most commonly used regimen, but progression-free survival remains unsatisfactory. Therefore, there is an urgent unmet need to develop novel and effective strategies for this population. Our study, a multicentre, open-label, single-arm phase II clinical trial (NCT05957510), aims to evaluate the efficacy and safety of serplulimab plus chemotherapy in untreated T-SCLC patients after histological transformation.

MATERIALS AND METHODS

In total, 36 eligible participants experiencing SCLC transformation from EGFR-mutant NSCLC will be enrolled to receive combination therapy of serplulimab, etoposide and carboplatin for four to six cycles, followed by maintenance therapy with serplulimab for up to 2 years. The primary endpoint is progression-free survival; secondary endpoints include objective response rate, overall survival and safety.

RESULTS

Enrolment started in July 2023 and is ongoing, with an estimated completion date of December 2025.

CONCLUSIONS

This study aims to provide valuable insights into the efficacy and safety of combining serplulimab with chemotherapy for treating patients with T-SCLC originating from EGFR-mutant NSCLC.

Plasmon-enhanced deep ultraviolet Micro-LED arrays for solar-blind communications

Localized surface plasmon resonance (LSPR)-enhanced deep ultraviolet (DUV) Micro-light emitting diodes (Micro-LEDs) using Al nanotriangle arrays (NTAs) are reported for improving the -3 dB modulation bandwidth. Through self-assembled nanospheres, the high-density Al NTAs arrays are transferred into the designated p-AlGaN region of the Micro-LEDs, realizing the effect of LSPR coupling. A 2.5-fold enhancement in photoluminescence (PL) intensity is demonstrated. Combined with the PL intensity ratio at 300 K and 10 K, internal quantum efficiency (IQE) may be increased about 15-20% by the plasmonic effect and the carrier lifetime decreases from 1.15 ns to 0.82 ns, suggesting that LSPR accelerates the spontaneous emission rate. Resulting from the improvement of the IQE, the electroluminescence intensity of Micro-LED arrays with LSPR is obviously increased. Meanwhile, the -3 dB bandwidth of 6 × 6 Micro-LED arrays is increased from 180 MHz to 300 MHz at a current density of 200 A/cm². A potential way is proposed to further increase both the IQE and the modulation bandwidth of DUV Micro-LEDs.

A High-Reliability RF MEMS Metal-Contact Switch Based on Al-Sc Alloy

This paper presents a new metal-contact RF MEMS switch based on an Al-Sc alloy. The use of an Al-Sc alloy is intended to replace the traditional Au-Au contact, which can greatly improve the hardness of the contact, and thus improve the reliability of the switch. The multi-layer stack structure is adopted to achieve the low switch line resistance and hard contact surface. The polyimide sacrificial layer process is developed and optimized, and the RF switches are fabricated and tested for pull-in voltage, S-parameters, and switching time. The switch shows high isolation of more than 24 dB and a low insertion loss of less than 0.9 dB in the frequency range of 0.1-6 GHz.

Quasi-van der Waals Epitaxy of a Stress-Released AlN Film on Thermally Annealed Hexagonal BN for Deep Ultraviolet Light-Emitting Diodes

The heteroepitaxy of high-quality aluminum nitride (AlN) with low stress is essential for the development of energy-efficient deep ultraviolet light-emitting diodes (DUV-LEDs). In this work, we realize that quasi-van der Waals epitaxy growth of a stress-released AlN film with low dislocation density on hexagonal boron nitride (h-BN)/sapphire suffered from high-temperature annealing (HTA) treatment and demonstrate its application in a DUV-LED. It is revealed that HTA effectively improves the crystalline quality and surface morphology of monolayer h-BN. Guided by first-principles calculations, we demonstrate that h-BN can enhance lateral migration of Al atoms due to the ability to lower the surface migration barrier (less than 0.14 eV), resulting in the rapid coalescence of the AlN film. The HTA h-BN is also proved to be efficient in reducing the dislocation density and releasing the large strain in the AlN epilayer. Based on the low-stress and high-quality AlN film on HTA h-BN, the as-fabricated 290 nm DUV-LED exhibits 80% luminescence enhancement compared to that without h-BN, as well as good reliability with a negligible wavelength shift under high current. These findings broaden the applications of h-BN in favor of III-nitride and provide an opportunity for further developing DUV optoelectronic devices on large mismatched heterogeneous substrates.

A nomogram and risk classification system for predicting cancer-specific survival in tall cell variant of papillary thyroid cancer: a SEER-based study

BACKGROUND

Tall cell variant (TCV) of papillary thyroid cancer (PTC) is the most common aggressive subtype of PTC. The factors that affect survival of patients with TCV remain unclear. We aimed to develop a model to predict the cancer-specific survival (CSS).

METHODS

A total of 1615 patients diagnosed with TCV between 2004 and 2016 were identified from the Surveillance, Epidemiology, and End Results (SEER) database and randomized into training and validation cohorts (7:3). A predictive nomogram for predicting CSS was constructed by Cox proportional hazards regression and validated by concordance index (C-index), calibration curve, and decision curve analyses (DCA). A risk classification system was built based on the total nomogram scores of each case.

RESULTS

A nomogram was constructed including five independent prognostic factors (age, tumor size, T stage, M stage, and extent of surgery) associated with CSS in TCV patients. Various validations proved that the nomogram model had good consistency and discrimination for TCV prognosis. The risk classification system could perfectly classify TCV patients into three risk groups with significantly different CSS. Compared with traditional AJCC TNM staging system, the nomogram could better predict CSS in TCV patients.

CONCLUSIONS

A nomogram and corresponding risk classification system were developed for predicting CSS in TCV patients. The model has excellent performance and can be used to help clinicians make accurate prognostic assessment and individualized treatment.

Nonfood Probiotic, Prebiotic, and Synbiotic Use Reduces All-Cause and Cardiovascular Mortality Risk in Older Adults: A Population-Based Cohort Study

OBJECTIVES

Pro-, pre-, and synbiotic supplements improve cardiovascular risk factors. However, the association between nonfood pro-, pre-, and synbiotics (NPPS) and long-term all-cause and cardiovascular mortality has not been studied. Thus, our objective was to determine the impact of nonfood pro-, pre-, and synbiotics on all-cause and cardiovascular mortality.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective, cohort study of 4837 nationally representative American participants aged 65 years or older with a median follow-up duration of 77 months.

MEASUREMENTS

All-cause and cardiovascular mortality were measured.

RESULTS

A total of 1556 participants died during the median 77-month follow-up, and 517 died from cardiovascular disease. Compared with participants without NPPS use, participants who used NPPS experienced a reduced risk of all-cause mortality by nearly 41% (hazard ratio 0.59, 95% CI 0.43 to 0.79) and cardiovascular mortality by 52% (HR 0.48, 95% CI 0.30 to 0.76). Such an effect persisted in most subgroup analyses and complete-case analyses.

CONCLUSION AND RELEVANCE

In this study, we found a protective effect of NPPS against all-cause and cardiovascular mortality in Americans aged 65 years or older. Nonfood pro-, pre-, and synbiotics can be a novel, inexpensive, low-risk treatment addition for all-cause and cardiovascular mortality for older individuals.

[Accuracy of two different registration methods of dynamic navigation system for dental implant placement]

Objective: To compare cusp and U-tube registration methods of dynamic navigation system in dental implant placement. Methods: Twenty resin mandible models and 40 implants were utilized, with implants being placed by a single researcher using one of the two registration methods selected at random. Accuracy was measured through the superimposition of the final and planned implant positions. Angular deviation, three-dimensional (3D) entry deviation, and 3D apex deviation were analyzed. Results: The 3D entry deviation, and 3D apex deviation and angular deviation of cusp group and U-tube group were (1.07±0.46) and (0.93±0.54) mm, (1.16±0.55) and (1.03±0.53) mm, 2.06°±0.98°and 1.62°±0.97°. No significant differences (t=0.91, P=0.368; t=0.79, P=0.436; t=1.42, P=0.164) were observed when comparing these two registration methods. Conclusions: Both the cusp and U-tube registration methods are highly accurate when implemented in vitro. The cusp registration technique can also overcome several of the limitations of the U-tube approach, and it is convenient for clinic.

Strain modulated luminescence in green InGaN/GaN multiple quantum wells with microwire array by piezo-phototronic effect

We have demonstrated piezo-phototronic enhanced modulation in green InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) with a microwire array (MWA) structure. It is found that an a-axis oriented MWA structure induces more c-axis compressive strain than a flat structure when a convex bending strain is applied. Moreover, the photoluminescence (PL) intensity exhibits a tendency to increase first and then decrease under the enhanced compressive strain. Specifically, light intensity reaches a maximum of about 123% accompanied by 1.1-nm blueshift, and the carrier lifetime comes to the minimum simultaneously. The enhanced luminescence characteristics are attributed to strain-induced interface polarized charges, which modulate the built-in field in InGaN/GaN MQWs and could promote the radiative recombination of carriers. This work opens a pathway to drastically improve InGaN-based long-wavelength micro-LEDs with highly efficient piezo-phototronic modulation.

Continuous Single-Crystalline GaN Film Grown on WS2 -Glass Wafer

Use of 2D materials as buffer layers has prospects in nitride epitaxy on symmetry mismatched substrates. However, the control of lattice arrangement via 2D materials at the heterointerface presents certain challenges. In this study, the epitaxy of single-crystalline GaN film on WS₂ -glass wafer is successfully performed by using the strong polarity of WS₂ buffer layer and its perfectly matching lattice geometry with GaN. Furthermore, this study reveals that the first interfacial nitrogen layer plays a crucial role in the well-constructed interface by sharing electrons with both Ga and S atoms, enabling the single-crystalline stress-free GaN, as well as a violet light-emitting diode. This study paves a way for the heterogeneous integration of semiconductors and creates opportunities to break through the design and performance limitations, which are induced by substrate restriction, of the devices.

Predictive capability of material screening by fast neutron activation analysis using laser-driven neutron sources

Bright, short-pulsed neutron beams from laser-driven neutron sources (LANSs) provide a new perspective on material screening via fast neutron activation analysis (FNAA). FNAA is a nondestructive technique for determining material elemental composition based on nuclear excitation by fast neutron bombardment and subsequent spectral analysis of prompt γ-rays emitted by the active nuclei. Our recent experiments and simulations have shown that activation analysis can be used in practice with modest neutron fluences on the order of 10⁵ n/cm², which is available with current laser technology. In addition, time-resolved γ-ray measurements combined with picosecond neutron probes from LANSs are effective in mitigating the issue of spectral interference between elements, enabling highly accurate screening of complex samples containing many elements. This paper describes the predictive capability of LANS-based activation analysis based on experimental demonstrations and spectral calculations with Monte Carlo simulations.

Three dimensional truncated-hexagonal-pyramid vertical InGaN-based white light emitting diodes based on β-Ga2O3

In this Letter, we describe the fabrication of three dimensional (3D) truncated-hexagonal-pyramid (THP) vertical light emitting diodes (VLEDs) with white emission grown on β-Ga₂O₃ substrate. In the 3D n-GaN layer, it is noted that the longitudinal growth rate of the 3D n-GaN layer increases as the flow rate of N₂ decreases and H₂ increases. Moreover, the 3D THP VLED can effectively suppress the quantum-confined Stark effect (QCSE) compared with planar VLEDs due to the semipolar facets and strain relaxation. Thus, the internal quantum efficiency (IQE) of the 3D THP VLED has been doubled and the V-shaped pits have been greatly reduced. In particular, the 3D THP VLED enables multi-wavelength emission (448.0 nm and 498.5 nm) and also shows better light extraction efficiency (LEE), which presents an effective way for the realization of phosphor-free white LED devices.

Hydrogen sulphide regulates the growth of tomato root cells by affecting cell wall biosynthesis under CuO NPs stress

Copper oxide nanoparticles (CuO NPs) show strong nano-toxic effects on organisms. Hydrogen sulphide (H₂ S) plays a pivotal role in plant response to abiotic stress. In this study, we examine the crucial role of the cell wall as regulated by H₂ S in response to CuO NPs stress. The digestion method was employed to determine Cu content using atomic absorption spectrometry. The TraKine pro-tubulin staining kit was used to investigate the microtubule cytoskeleton using confocal laser-scanning microscopy. Cell wall component analysis utilized the ICS-3000 HPLC system. Application of H₂ S reduced growth inhibition caused by CuO NPs. Furthermore, most of the CuO NPs accumulates in roots, indicating a low transfer rate, and H₂ S significantly decreased CuO NPs content in roots, leaves and stems. Subcellular distribution analysis implied most Cu accumulated in root cell walls, and that H₂ S reduced the content of Cu in root cell walls. Cortical microtubules in the plasma membrane, guide cell wall biosynthesis. H₂ S obviously alleviated microtubule cytoskeleton disorders caused by CuO NPs. In addition, the content of cellulose, hemicellulose, pectin and other monosaccharides in root cell walls was reduced by CuO NPs treatment. H₂ S enhanced the monosaccharide and polysaccharide contents compared with that after CuO NPs treatment. In conclusion, H₂ S regulates cell wall development in response to CuO NPs stress by stabilizing microtubules. H₂ S affected Cu distribution and alleviated growth inhibition of tomato seedlings. The research results provide a theoretical basis for further study of nano-toxicity regulation in plants.

GaN-based parallel micro-light-emitting diode arrays with dual-wavelength InxGa1-xN/GaN MQWs for visible light communication

The dual-wavelength In_xGa_1-xN/GaN micro light emitting diode (Micro-LED) arrays are fabricated by flip-chip parallel connection. It is noted that the Micro-LED arrays with smaller diameter present considerably bigger light output power density (LOPD). For all Micro-LEDs, the LOPD increases continuously with increasing injection current density until it "turns over". It also can be observed that the maximum value of LOPD is determined by the blue quantum well (QW) for the broad area LED. In comparison, the green peak intensity dominates the change of LOPD in the Micro-LEDs. In addition, the enhancement of the green peak intensity value for the Micro-LEDs are considered as a consequence of the combined effects of the reduction in the quantum-confined Stark effect (QCSE) and the crowding effect, high LEE as well as geometric shape. Moreover, -3dB modulation bandwidths of the four different kinds of Micro-LEDs increase with the decrease of the device diameter in the same injected current density, higher than that of the broad area LED. The -3dB modulation bandwidth of the 60 µm Micro-LED shows 1.4 times enhancement compared to that of the broad area LED under the current density of 300 mA/cm². Evidently, the dual-wavelength In_xGa_1-xN/GaN Micro-LEDs have great potential in both solid-state lighting (SSL) and the visible light communication (VLC) in the future fabrication.

Semipolar (112̅2) AlGaN-Based Solar-Blind Ultraviolet Photodetectors with Fast Response

The high-quality semipolar (112̅2) AlGaN epitaxial films have been obtained on m-plane sapphire by metal-organic chemical vapor deposition. X-ray rocking curve measurements show the full-width at half-maximums of semipolar (112̅2)-oriented AlGaN films are 0.357° and 0.531° along [112̅3̅]_AlGaN and [11̅00]_AlGaN, respectively. The fabricated semipolar AlGaN metal-semiconductor-metal solar-blind ultraviolet (UV) photodetector (PD) exhibits a high responsivity of 1842 A/W. The fast response and reliability of the UV PD are ensured via fast switching with a rise and decay time of 90 ms and 53(720) ms, respectively. The UV PD exhibits a significant reduction in the dark current, that is, from 100 μA to 780 fA at 10 V, using a simple wet chemical etching to modify the surface properties of materials. The photo-to-dark-current ratio value of the etched UV PD reaches 4 orders of magnitude higher than the unetched UV PD under 270 nm illumination. These are attributed to the fact that KOH wet etching assists in eliminating the surface states and reconstructing the surface oxides. This work might provide a new potential for the development of solar-blind UV PDs with high performance.

[Clinical efficacy of transjugular intrahepatic portosystemic shunt for gastrointestinal hemorrhage in patients with idiopathic noncirrhotic portal hypertension]

Objective: To explore the medium-long term efficacy of transjugular intrahepatic portosystemic shunt (TIPS) for gastrointestinal hemorrhage in patients with idiopathic non-cirrhotic portal hypertension (INCPH). Methods: From March 2013 to July 2018, clinical data of 13 INCPH patients, including 5 males, 8 females,with gastrointestinal hemorrhage were retrospectively analyzed, who were diagnosed at the First Affiliated Hospital of Zhengzhou University, Anyang Fifth People' s Hospital and Yuncheng Central Hospital. All patients received TIPS treatment. The general information, postoperative survival rate, the incidence of rebleeding, shunt dysfunction rate, and incidence of hepatic encephalopathy were analyzed. Results: All 13 patients with INCPH completed TIPS successfully with an average age of 45±8 (33 to 59) years. The hepatic venous pressure gradient (HVPG) decreased from 20.0-26.0 (22.6±1.9) mmHg before procedure to 8.0-14.0 (9.4±3.2) mmHg after. The median follow-up time was 44±7 (31 to 53) months. One patient died of liver failure 27 months after TIPS. Hepatic encephalopathy occurred cumulatively in 1 case (1/13), 1 case (1/13) and 1 case (1/13) in 12, 24 and 36 months after TIPS. Stent restenosis occurred cumulatively in 2 cases (2/13), 3 cases (3/13) and 3 cases (3/13) in 12, 24 and 36 months after TIPS. Portal vein thrombosis occurred cumulatively in 2 cases (2/13), and no primary liver cancer developed. Conclusions: TIPS is safe and effective in the treatment of INCPH with gastrointestinal bleeding with favorable medium-long term outcome.

Atomic Mechanism of Strain Alleviation and Dislocation Reduction in Highly Mismatched Remote Heteroepitaxy Using a Graphene Interlayer

Remote heteroepitaxy is known to yield semiconductor films with better quality. However, the atomic mechanisms in systems with large mismatches are still unclear. Herein, low-strain single-crystalline nitride films are achieved on highly mismatched (∼16.3%) sapphire via graphene-assisted remote heteroepitaxy. Because of a weaker interface potential, the in-plane compressive strain at the interface releases by 30%, and dislocations are prevented. Meanwhile, the lattice distortions in the epilayer disappear when the structure climbs over the atomic steps on substrates because graphene renders the steps smooth. In this way, the density of edge dislocations in as-grown nitride films reduces to the same level as that of the screw dislocations, which is rarely observed in heteroepitaxy. Further, the indium composition in In_xGa_1-xN/GaN multiquantum wells increases to ∼32%, enabling the fabrication of a yellow light-emitting diode. This study demonstrates the advantages of remote heteroepitaxy for bandgap tuning and opens opportunities for photoelectronic and electronic applications.

Graphene-driving strain engineering to enable strain-free epitaxy of AlN film for deep ultraviolet light-emitting diode

The energy-efficient deep ultraviolet (DUV) optoelectronic devices suffer from critical issues associated with the poor quality and large strain of nitride material system caused by the inherent mismatch of heteroepitaxy. In this work, we have prepared the strain-free AlN film with low dislocation density (DD) by graphene (Gr)-driving strain-pre-store engineering and a unique mechanism of strain-relaxation in quasi-van der Waals (QvdW) epitaxy is presented. The DD in AlN epilayer with Gr exhibits an anomalous sawtooth-like evolution during the whole epitaxy process. Gr can help to enable the annihilation of the dislocations originated from the interface between AlN and Gr/sapphire by impelling a lateral two-dimensional growth mode. Remarkably, it can induce AlN epilayer to pre-store sufficient tensile strain during the early growth stage and thus compensate the compressive strain caused by hetero-mismatch. Therefore, the low-strain state of the DUV light-emitting diode (DUV-LED) epitaxial structure is realized on the strain-free AlN template with Gr. Furthermore, the DUV-LED with Gr demonstrate 2.1 times enhancement of light output power and a better stability of luminous wavelength compared to that on bare sapphire. An in-depth understanding of this work reveals diverse beneficial impacts of Gr on nitride growth and provides a novel strategy of relaxing the vital requirements of hetero-mismatch in conventional heteroepitaxy.

Atomic-Scale Mechanism of Spontaneous Polarity Inversion in AlN on Nonpolar Sapphire Substrate Grown by MOCVD

The performance of nitride devices is strongly affected by their polarity. Understanding the polarity determination and evolution mechanism of polar wurtzite nitrides on nonpolar substrates is therefore critically important. This work confirms that the polarity of AlN on sapphire prepared by metal-organic chemical vapor deposition is not inherited from the nitrides/sapphire interface as widely accepted, instead, experiences a spontaneous polarity inversion during the growth. It is found that at the initial growth stage, the interface favors the nitrogen-polarity, rather than the widely accepted metal-polarity or randomly coexisting. However, the polarity subsequently converts into the metal-polar situation, at first locally then expanding into the whole area, driven by the anisotropy of surface energies, which results in universally existing inherent inverse grain boundaries. Furthermore, vertical two-dimensional electron accumulation originating from the lattice symmetry breaking at the inverse grain boundary is first revealed. This work identifies another cause of high-density defects in nitride epilayers, besides lattice mismatch induced dislocations. These findings also offer new insights into atomic structure and determination mechanism of polarity in nitrides, providing clues for its manipulation toward the novel hetero-polarity devices.

[Clinical analysis of pulmonary nocardiosis associated with bronchiectasis]

Objective: To better understand the clinical characteristics of pulmonary nocardiosis associated with bronchiectasis. Methods: Patients diagnosed as bronchiectasis complicated with pulmonary nocardiosis in 9 tertiary general hospitals in China were enrolled from March 2016 to March 2020, with the record of general data, imaging performance and pathogen. The literature was reviewed. Results: Totally 17 patients were included. There were 12 females and 5 males. The ages ranged from 45 to 79 years, with an average of (63±9) years. There were 15 nonsmokers and 2 smokers, all of whom with chronic course. The clinical manifestations were mostly cough, expectoration, hemoptysis, fever, and dyspnea. The imaging manifestation was bronchiectasis in both lungs, with the most common involvement in the left lower lung, right middle lobe and left lingual lobe. Sputum cultures were positive in 10 cases, bronchoalveolar lavage fluid (BALF) cultures were positive in 6 cases, and next generation gene sequencings were positive in 4 cases, including 2 cases of Nocardia gelsenkii, 2 cases of Nocardia abscess, 2 cases of Nocardia stellate, 1 case of Nocardia mexicana, 1 case of Nocardia otitis caviae, and 9 cases of undetermined Nocardia. There were 3 cases of Klebsiella pneumoniae, 2 cases of Pseudomonas aeruginosa and 2 cases of Aspergillus. The symptoms and imaging of all patients were improved after anti Nocardia therapy. Conclusions: Bronchiectasis combined with nocardiosis is more common in middle-aged and elderly women without smoking, which is similar to the clinical manifestations of Lady Windermere syndrome. Bronchiectasis often involves the left lower lobe, right middle lobe and left lingual lobe. Nocardia infection might further precipitate the initiation and progression of bronchiectasis.

Transfer-Enabled Fabrication of Graphene Wrinkle Arrays for Epitaxial Growth of AlN Films

Formation of graphene wrinkle arrays can periodically alter the electrical properties and chemical reactivity of graphene, which is promising for numerous applications. However, large-area fabrication of graphene wrinkle arrays remains unachievable with a high density and defined orientations, especially on rigid substrates. Herein, relying on the understanding of the formation mechanism of transfer-related graphene wrinkles, the graphene wrinkle arrays are fabricated without altering the crystalline orientation of entire graphene films. The choice of the transfer medium that has poor wettability on the corrugated surface of graphene is proven to be the key for the formation of wrinkles. This work provides a deep understanding of formation process of transfer-related graphene wrinkles and opens up a new way for periodically modifying the surface properties of graphene for potential applications, including direct growth of AlN epilayers and deep ultraviolet light emitting diodes.

Upper Limb Lymphedema Impacts the Risk of Peripherally Inserted Central Catheter-Related Thrombosis in Patients with Breast Cancer

There is little information on the risk for catheter-related thrombosis in patients with upper limb lymphedema following breast cancer treatment. We investigated the association between upper limb lymphedema and the risk of peripherally inserted central catheterrelated thrombosis (PICC-RT) occurring in the contralateral limb of patients with breast cancer. A retrospective review analyzed all patients with breast cancer who underwent PICC insertion at a cancer hospital in Hunan Province from 2015 to 2019. Upper limb lymphedema was indexed from hospital information system (HIS) before the occurrence of PICC-RT developed in the contralateral limb. Cox regression analysis was used to evaluate the association of factors with outcome. A total of 1,262 patient records were found and 50 cases of PICC-RT were identified. Forty of these occurred in patients without lymphedema (n=1,236) and 10 in patients with upper limb lymphedema (n=26). After adjustment for various co-variables, Cox regression analysis showed that upper limb lymphedema was significantly associated with increased risk of PICC-RT (hazard ratio=12.128, 95% confidence interval=5.551-26.501; P<0.001). In breast cancer patients, upper limb lymphedema may be an important predictor for PICC-RT in the contralateral limb and information should be provided to patients.

Van der Waals epitaxy of nearly single-crystalline nitride films on amorphous graphene-glass wafer

Van der Waals epitaxy provides a fertile playground for the monolithic integration of various materials for advanced electronics and optoelectronics. Here, a previously unidentified nanorod-assisted van der Waals epitaxy is developed and nearly single-crystalline GaN films are first grown on amorphous silica glass substrates using a graphene interfacial layer. The epitaxial GaN-based light-emitting diode structures, with a record internal quantum efficiency, can be readily lifted off, becoming large-size flexible devices. Without the effects of the potential field from a single-crystalline substrate, we expect this approach to be equally applicable for high-quality growth of nitrides on arbitrary substrates. Our work provides a revolutionary technology for the growth of high-quality semiconductors, thus enabling the hetero-integration of highly mismatched material systems.

Graphene-Nanorod Enhanced Quasi-Van Der Waals Epitaxy for High Indium Composition Nitride Films

The nitride films with high indium (In) composition play a crucial role in the fabrication of In-rich InGaN-based optoelectronic devices. However, a major limitation is In incorporation requiring a low temperature during growth at the expense of nitride dissociation. Here, to overcome this limitation, a strain-modulated growth method, namely the graphene (Gr)-nanorod (NR) enhanced quasi-van der Waals epitaxy, is proposed to increase the In composition in InGaN alloy. The lattice transparency of Gr enables constraint of in-plane orientation of nitride film and epitaxial relationships at the heterointerface. The Gr interlayer together with NRs buffer layer substantially reduces the stress of the GaN film by 74.4%, from 0.9 to 0.23 GPa, and thus increases the In incorporation by 30.7%. The first principles calculations confirm that the release of strain accounts for the dramatic improvement. The photoluminescence peak of multiple quantum wells shifts from 461 to 497 nm and the functionally small-sized cyan light-emitting diodes of 7 × 9 mil² are demonstrated. These findings provide an efficient approach for the growth of In-rich InGaN film and extend the applications of nitrides in advanced optoelectronic, photovoltaic, and thermoelectric devices.

Survival of Clostridioides difficile in finished dairy compost under controlled conditions

AIM

The survival of Clostridioides difficile (previously Clostridium difficile) vegetative cells and endospores was compared at different levels of indigenous microflora using autoclaved and unautoclaved dairy composts with different moisture contents (MCs).

METHODS AND RESULTS

Both types of composts adjusted to 20, 30 and 40% MCs were inoculated with a suspension of C. difficile that contained both vegetative cells (c. 5-6 log CFU per gram) and endospores (c. 5·0 CFU per gram), and then stored aerobically inside a humidity-controlled chamber at room temperature 22·5 ± 0·8°C for 1 year. The level of indigenous microflora was very stable during the storage after day 7 in both types of compost. The greatest reductions of C. difficile vegetative cell counts occurred during the first 24 h of storage in autoclaved and unautoclaved composts, which had 4·7 and 5·5 log CFU per gram with 20% MC, 1·8 and 2·1 log CFU per gram with 30% MC, and 2·3 and 1·3 log CFU per gram with 40% MC, respectively. Both MC and the duration of storage have significant (P < 0·05) effects on the survival of vegetative cells for first 120 days of storage. The slow inactivation of C. difficile vegetative cells at higher MCs during aerobic storage was confirmed by exponentially decaying modelling data during the early stage of aerobic exposure. The reduction of endospore counts (<1·0 log CFU per gram) during the storage for both types of compost at all MCs was not significant (P > 0·05) except for the autoclaved compost with 30% MC.

CONCLUSION

The highly resistant C. difficile endospores to the unfavourable environmental conditions survived for more than a year while vegetative cells died off exponentially upon the initial aerobic exposure.

SIGNIFICANCE AND IMPACT OF THE STUDY

The long-term survival of C. difficile endospores in contaminated compost may transmit the pathogen to fresh produce, animals or water in pre-harvest conditions.

Primary intraosseous squamous cell carcinoma arising from an odontogenic keratocyst: case series and literature review

Background

The aim of this study was to investigate the clinicopathologic features of primary intraosseous squamous cell carcinoma arising from an odontogenic keratocyst (PIOSCC ex OKC) and comprehensively improve the understanding of this disease.

Material and Methods

We retrospectively investigated five cases of PIOSCC ex OKC at Peking University School and Hospital of Stomatology. We also conducted a systematic review of studies on PIOSCC ex OKC by using online databases from their inception until February 2020.

Results

In our series of five cases, all lesions were located in the mandible. Three cases (60%) showed recurrent OKCs and two cases (40%) showed primary OKCs. During the follow-up period, one patient died of local relapse. No patients developed metastasis. On the basis of our literature survey, we selected 22 articles reporting 29 patients with PIOSCC ex OKC. Seven of these patients (24.1%) showed local recurrence, three patients (10.3%) developed cervical metastasis, three patients (10.3%) developed distant metastasis (in the pleura in one case and in the lung in two cases), and seven patients died from the disease during the follow-up period. The disease-specific 5-year survival rate in the study group was 53.2%. Through univariate and multivariate analysis, local recurrence was identified as the only significant independent prognostic factor for survival (P < 0.05).

Conclusions

The results suggest that PIOSCC ex OKC is a rare intermediate-grade malignancy. Although elective neck dissection is typically unnecessary, adequate therapy should be applied to achieve the lowest local recurrence rate possible to ensure a favorable survival rate.

Key words:Primary intraosseous squamous cell carcinoma, odontogenic keratocyst, prognosis.

Quasi-2D Growth of Aluminum Nitride Film on Graphene for Boosting Deep Ultraviolet Light-Emitting Diodes

Efficient and low-cost production of high-quality aluminum nitride (AlN) films during heteroepitaxy is the key for the development of deep ultraviolet light-emitting diodes (DUV-LEDs). Here, the quasi-2D growth of high-quality AlN film with low strain and low dislocation density on graphene (Gr) is presented and a high-performance 272 nm DUV-LED is demonstrated. Guided by first-principles calculations, it is found that AlN grown on Gr prefers lateral growth both energetically and kinetically, thereby resulting in a Gr-driven quasi-2D growth mode. The strong lateral growth mode enables most of dislocations to annihilate each other at the AlN/Gr interface, and therefore the AlN epilayer can quickly coalesce and flatten the nanopatterned sapphire substrate. Based on the high quality and low strain of AlN film grown on Gr, the as-fabricated 272 nm DUV-LED shows a 22% enhancement of output power than that with low-temperature AlN buffer, following a negligible wavelength shift under high current. This facile strategy opens a pathway to drastically improve the performance of DUV-LEDs.

Graphene-Assisted Quasi-van der Waals Epitaxy of AlN Film on Nano-Patterned Sapphire Substrate for Ultraviolet Light Emitting Diodes

This protocol demonstrates a method for graphene-assisted quick growth and coalescence of AlN on nano-pattened sapphire substrate (NPSS). Graphene layers are directly grown on NPSS using catalyst-free atmospheric-pressure chemical vapor deposition (APCVD). By applying nitrogen reactive ion etching (RIE) plasma treatment, defects are introduced into the graphene film to enhance chemical reactivity. During metal-organic chemical vapor deposition (MOCVD) growth of AlN, this N-plasma treated graphene buffer enables AlN quick growth, and coalescence on NPSS is confirmed by cross-sectional scanning electron microscopy (SEM). The high quality of AlN on graphene-NPSS is then evaluated by X-ray rocking curves (XRCs) with narrow (0002) and (10-12) full width at half-maximum (FWHM) as 267.2 arcsec and 503.4 arcsec, respectively. Compared to bare NPSS, AlN growth on graphene-NPSS shows significant reduction of residual stress from 0.87 GPa to 0.25 Gpa, based on Raman measurements. Followed by AlGaN multiple quantum wells (MQWS) growth on graphene-NPSS, AlGaN-based deep ultraviolet light-emitting-diodes (DUV LEDs) are fabricated. The fabricated DUV-LEDs also demonstrate obvious, enhanced luminescence performance. This work provides a new solution for the growth of high quality AlN and fabrication of high performance DUV-LEDs using a shorter process and less costs.

Enhanced Emission of Deep Ultraviolet Light-Emitting Diodes through Using Work Function Tunable Cu Nanowires as the Top Transparent Electrode

Deep ultraviolet light-emitting diodes (DUV LEDs) (<280 nm) have been important light sources for broad applications in, e.g., sterilization, purification, and high-density storage. However, the lack of excellent transparent electrodes in the DUV region remains a challenging issue. Here, we demonstrate an architectural engineering scheme to flexibly tune the work function of Cu@shell nanowires (NWs) as top transparent electrodes in DUV LEDs. By fast encapsulation of shell metals on Cu NWs and a shift of electron binding energy, the electronic work function could be widely tailored down to 4.37 eV and up to 5.73 eV. It is revealed that the high work function of Cu@Ni and Cu@Pt NWs could overcome the interfacial barrier to p-AlGaN and achieve direct ohmic contact with high transparency (91%) in 200-400 nm. Completely transparent DUV LED chips are fabricated and successfully lighted with sharp top emission (wall-plug efficiency reaches 3%) under a turn-on voltage of 6.4 V. This architectural strategy is of importance in providing highly transparent ohmic electrodes for optoelectronic devices in broad wavelength regions.

High-effective biosynthesis of baccatin Ⅲ by using the alternative acetyl substrate, N-acetyl-d-glucosamine

AIMS

Paclitaxel is a type of broad-spectrum anticancer drug in short supply. The price of acetyl-CoA (17 709 677·4 USD mol^-1 ), which is the acetyl group donor for the enzymatic synthesis of the intermediate, baccatin Ⅲ, is still the bottleneck of the mass production of paclitaxel. This study reports a novel acetyl group donor, which could substantially reduce the cost of production.

METHODS AND RESULTS

In this study, a substrate spectrum with 14 kinds of representative acetyl-donor substitutes predicted by computer-aided methods was tested in a 10-deacetylbaccatin Ⅲ-10-O-acetyltransferase (DBAT) heterogeneous-expressed open-whole-cell catalytic system. The results of computer prediction and experimental analysis revealed the rule of the acetyl-donor compounds based on this substrate spectrum. N-acetyl-d-glucosamine (30·95 USD mol^-1 , about 572 202-fold cheaper than acetyl-CoA) is selected as a suitable substitute under the rule. The yield when using N-acetyl-d-glucosamine as acetyl donor in open-whole-cell catalytic system was 2·13-fold of that when using acetyl-CoA. In the in vivo system, the yield increased 24·17%, which may indicate its cooperation with acetyl-CoA.

CONCLUSION

The success of open-whole-cell synthesis and in vivo synthesis of baccatin Ⅲ by adding N-acetyl-d-glucosamine as acetyl substrate demonstrates that it is a useful substrate to improve the yield of baccatin Ⅲ.

SIGNIFICANCE AND IMPACT OF THE STUDY

All these findings provided a potential acetyl-donor substitute for acetyl-CoA, as well as a low cost and efficient method of preparing paclitaxel through baccatin Ⅲ semi-synthesis.

(100)-Oriented gallium oxide substrate for metal organic vapor phase epitaxy for ultraviolet emission

High-quality low-stress GaN and MQWs emitting in the UV region were grown on (100) β-Ga₂O₃ by MOVPE using a pulsed-flow method.

Enhancing wastewater remediation by drinking water treatment residual-augmented floating treatment wetlands

In this study, the involvement of aluminum-based drinking water treatment residual (DWTR) as substrate in floating treatment wetland (FTW) to enhance its treatment performance was firstly proposed and trialed. A laboratory scale DWTR-FTW fed with synthetic wastewater containing COD, nitrogen (N), phosphorus (P) and mineral salts was operated in three stages of unplanted (1-30 days), planted (31-60 days) and aerated (61-135 days) modes. The results showed that the average removal rates of COD, total nitrogen (TN), total phosphorus (TP) in stage 3 were 88%, 85%, and 90.2%, respectively, indicating the outstanding purification performance of DWTR-FTW in comparison of traditional FTWs. The embedded DWTR enriches the biomass and robustly adsorbs P, while aeration supplies sufficient dissolved oxygen for the microorganism. The results revealed that 7.022 g P was accumulated in DWTR, which is 400 times higher than that in sediment and plants during the experimental period, reflecting that DWTR adsorption is the major P removal pathway in DWTR-FTW. Overall, DWTR-FTW could significantly remove pollutants, especially P, and provide an alternative pathway to enhance purification performance of FTW.

[Effects of smoking cessation on the risk of hypertension: a meta-analysis]

Objective: To estimate the effect of smoking cessation on the risk of hypertension. Methods: Literature search of PubMed, Embase, Vip and CNKI between 2001 and 2016 was performed to retrieve prospective cohort studies assessing the relative risks (RR) of smoking cessation and current smoking on hypertension. The pooled RR with 95% confidence intervals (CI) were calculated using random effects models, and subgroup analyses were employed based on participants and study characteristics. Results: A total of 8 eligible prospective cohort studies with 70 130 participants and 21 238 incident cases of hypertension were retrieved. The individuals aged 25-84 years, among them, 53.64% (37 618/70 130) were men and the follow-up period were 4-14.5 years. The pooled RR of hypertension was 1.08 (95%CI: 0.94-1.20) for comparing smoking cessation with current smoking and the pooled adjusted RR was 0.91 (95%CI: 0.33-2.50) (both P>0.05). Conclusions: Smoking cessation did not increased risks of hypertension. Therefore, effective strategies are needed to encourage smokers to quit.

Enhancement of Heat Dissipation in Ultraviolet Light-Emitting Diodes by a Vertically Oriented Graphene Nanowall Buffer Layer

For III-nitride-based devices, such as high-brightness light-emitting diodes (LEDs), the poor heat dissipation of the sapphire substrate is deleterious to the energy efficiency and restricts many of their applications. Herein, the role of vertically oriented graphene (VG) nanowalls as a buffer layer for improving the heat dissipation in AlN films on sapphire substrates is studied. It is found that VG nanowalls can effectively enhance the heat dissipation between an AlN film and a sapphire substrate in the longitudinal direction because of their unique vertical structure and good thermal conductivity. Thus, an LED fabricated on a VG-sapphire substrate shows a 37% improved light output power under a high injection current (350 mA) with an effective 3.8% temperature reduction. Moreover, the introduction of VG nanowalls does not degrade the quality of the AlN film, but instead promotes AlN nucleation and significantly reduces the epilayer strain that is generated during the cooling process. These findings suggest that the VG nanowalls can be a good buffer layer candidate in III-nitride semiconductor devices, especially for improving the heat dissipation in high-brightness LEDs.

Improved Epitaxy of AlN Film for Deep-Ultraviolet Light-Emitting Diodes Enabled by Graphene

The growth of single-crystal III-nitride films with a low stress and dislocation density is crucial for the semiconductor industry. In particular, AlN-derived deep-ultraviolet light-emitting diodes (DUV-LEDs) have important applications in microelectronic technologies and environmental sciences but are still limited by large lattice and thermal mismatches between the epilayer and substrate. Here, the quasi-van der Waals epitaxial (QvdWE) growth of high-quality AlN films on graphene/sapphire substrates is reported and their application in high-performance DUV-LEDs is demonstrated. Guided by density functional theory calculations, it is found that pyrrolic nitrogen in graphene introduced by a plasma treatment greatly facilitates the AlN nucleation and enables fast growth of a mirror-smooth single-crystal film in a very short time of ≈0.5 h (≈50% decrease compared with the conventional process), thus leading to a largely reduced cost. Additionally, graphene effectively releases the biaxial stress (0.11 GPa) and reduces the dislocation density in the epilayer. The as-fabricated DUV-LED shows a low turn-on voltage, good reliability, and high output power. This study may provide a revolutionary technology for the epitaxial growth of AlN films and provide opportunities for scalable applications of graphene films.

High-performance nanoporous-GaN metal-insulator-semiconductor ultraviolet photodetectors with a thermal oxidized β-Ga2O3 layer

We report on the high-performance nanoporous (NP) GaN-based metal-insulator-semiconductor (MIS) ultraviolet (UV) photodetectors (PDs) with a thermal oxidized β-Ga₂O₃insulating layer. The devices show a high responsivity of 4.5×10⁵  A/W and maximum external quantum efficiency of 1.55×10⁸% at 360 nm under a 10 V applied bias, which are attributed to the trap-assisted tunneling induced internal gain mechanism. Correspondingly, a specific detectivity of 8.27×10¹⁵ Jones and excellent optical switching repeatability are also observed in our fabricated PDs. The NP-GaN/β-Ga₂O₃ MIS UV PD may act as an excellent candidate for the application in UV photodetection due to the high performance and simple fabrication process.

Thermal resistance of Clostridium difficile endospores in dairy compost upon exposure to wet and dry heat treatments

AIM

Thermal resistance of Clostridium difficile endospores in finished dairy compost was compared at 55 and 65°C under wet and dry heat conditions.

METHODS AND RESULTS

A three-strain cocktail of C. difficile endospores was inoculated into dairy compost to a final concentration of c. 5·5 log CFU per gram and the moisture content (MC) of the compost was adjusted to be 20, 30 and 40%. For the dry heat treatment at 55 and 65°C, the compost samples were placed in an environmental chamber, whereas for the wet heat treatment, the inoculated compost samples were placed in a tray submerged in a water bath. The MCs of composts were maintained well throughout the wet heat treatment while the dry heat treatment reduced the MCs of composts to <10% by the end of come-up time. During the come-up time, the log endospore reductions at a selected temperature were not significantly different in compost with three selected MCs, in each heat treatment. During the holding time, endospore counts reduced by <0·5 log CFU per gram at 55 and 65°C of dry heat treatment, whereas 0·7-0·8 and 0·6-3·0 log CFU per gram reductions were observed at 55 and 65°C in wet heat treatment respectively.

CONCLUSION

The recommended minimum composting guidelines were not sufficient to reduce C. difficile endospore counts to an undetectable level (five endospores per gram). Increasing the temperature of thermophilic phase to 65°C, and maintaining higher MCs of composting feedstocks have significant (P < 0·05) effects on the endospore inactivation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our study identified factors that significantly affecting the thermal resistance of C. difficile endospores during composting, and the results suggest the current composting guidelines need to be amended in order to reduce the dissemination of C. difficile endospores in agricultural environment.

[HIV-1 gene subtypes among newly reported HIV/AIDS cases in two border areas of Yunnan province]

Objective: To explore the features of distribution on HIV-1 gene subtypes among newly reported HIV/AIDS cases in the border areas of Yunnan province. Methods: A total of 233 newly reported HIV/AIDS cases aged 18 or more were consecutively included in the border counties of Dehong Dai and Jingpo autonomous prefecture (Dehong prefecture), Honghe Hani and Yi autonomous prefecture (Honghe prefecture) of Yunnan province from November 2015 to October 2016. HIV-1 RNA was extracted with pol and env genes amplified. HIV-1 gene subtypes were determined through phylogenetic analysis. Results: A total of 146 out of 233 specimens were genotyped successfully. HIV-1 was found to have had 8 gene subtypes in Dehong prefecture, with the unique recombinant forms (URFs) as the predominant (52.8%, 57/108) type, including 56.8% (21/37) of the cases with Chinese ethnicity and another 50.7% (36/71) were Myanmar citizens. Four HIV-1 gene subtypes were detected in Honghe prefecture, with CRF01_AE as predominant (71.1%, 27/38), including 81.0% (17/21) Vietnamese and 58.8% (10/17) Chinese. Differences on the distribution of HIV-1 gene subtypes were seen statistically significant between Dehong prefecture and Honghe prefecture (χ(2)=61.072, P<0.001). Conclusions: The distribution of HIV-1 gene subtypes showed big difference in the two border areas of Yunnan province, suggesting that both Chinese or non- Chinese citizens living in the area should be taken good care of, in terms of HIV/AIDS prevention and control.

Horizontal GaN nanowires grown on Si (111) substrate: the effect of catalyst migration and coalescence

Here, we demonstrate the growth of horizontal GaN nanowires (NWs) on silicon (111) by a surface-directed vapor-liquid-solid growth. The influence of the Au/Ni catalysts migration and coalescence on the growth of the NWs has been systematically studied. 2D root-like branched NWs were gown spontaneously through catalyst migration. Furthermore, a novel phenomenon that a catalyst particle is embedded in a horizontal NW was observed and attributed the destruction of growth steady state due to the catalysts coalescence. The transmission electron microscopy and photoluminescence, cathodoluminescence measurement demonstrated that the horizontal NWs exhibit single crystalline structures and good optical properties. Our work sheds light on the horizontal NWs growth and should facilitate the development of highly integrated III-V nanodevices on silicon.