Local modulation of Au/MoS2 Schottky barriers using a top ZnO nanowire gate for high-performance photodetection

Schottky junctions are commonly used for fabricating heterojunction-based 2D transition metal dichalcogenide (TMD) photodetectors, characteristically offering a wide detection range, high sensitivity and fast response. However, these devices often suffer from reduced detectivity due to the high dark current, making it challenging to discover a simple and efficient universal way to improve the photoelectric performances. Here, we demonstrate a novel approach for integrating ZnO nanowire gates into a MoS2-Au Schottky junction to improve the photoelectric performances of photodetectors by locally controlling the Schottky barrier. This strategy remarkably reduces the dark current level of the device without affecting its photocurrent and the Schottky detectivity can be modified to a maximum detectivity of 1.4 × 1013 Jones with -20 V NG bias. This work provides potential possibilities for tuning the band structure of other materials and optimizing the performance of heterojunction photodetectors.

Artificial Intelligence Meets Flexible Sensors: Emerging Smart Flexible Sensing Systems Driven by Machine Learning and Artificial Synapses

The recent wave of the artificial intelligence (AI) revolution has aroused unprecedented interest in the intelligentialize of human society. As an essential component that bridges the physical world and digital signals, flexible sensors are evolving from a single sensing element to a smarter system, which is capable of highly efficient acquisition, analysis, and even perception of vast, multifaceted data. While challenging from a manual perspective, the development of intelligent flexible sensing has been remarkably facilitated owing to the rapid advances of brain-inspired AI innovations from both the algorithm (machine learning) and the framework (artificial synapses) level. This review presents the recent progress of the emerging AI-driven, intelligent flexible sensing systems. The basic concept of machine learning and artificial synapses are introduced. The new enabling features induced by the fusion of AI and flexible sensing are comprehensively reviewed, which significantly advances the applications such as flexible sensory systems, soft/humanoid robotics, and human activity monitoring. As two of the most profound innovations in the twenty-first century, the deep incorporation of flexible sensing and AI technology holds tremendous potential for creating a smarter world for human beings.

High-speed directional transport of condensate droplets on superhydrophobic saw-tooth surfaces

HYPOTHESIS

Most droplets on high-efficiency condensing surfaces have radii of less than 100 μm, but conventional droplet transport methods (such as wettability-gradient surfaces and structural-curvature-gradient surfaces) that rely on the unbalanced force of three-phase lines can only transport millimeter-sized droplets efficiently. Regulating high-speed directional transport of condensate droplets is still challenging. Therefore, we present a method for condensate droplet transportation, based on the reaction force of the superhydrophobic saw-tooth surfaces to the liquid bridge, the condensate droplets could be transported at high speed and over long distances.

EXPERIMENTS

The superhydrophobic saw-tooth surfaces are fabricated by femtosecond laser ablation and chemical etching. Condensation experiments and luminescent particle characterization experiments on different surfaces are conducted. Aided by the theoretical analysis, we illustrate the remarkable performance of condensate droplet transportation on saw-tooth surfaces.

FINDINGS

Compared with conventional methods, our method improves the transport velocity and relative transport distance by 1-2 orders of magnitude and achieves directional transport of the smallest condensate droplet of about 2 μm. Furthermore, the superhydrophobic saw-tooth surfaces enable multi-hop directional jumping of condensate droplets, leading to cross-scale increases in transport distances from microns to decimeters.

Switching ultra-stretchability and sensitivity in metal films for electronic skins: a pufferfish-inspired, interlayer regulation strategy

The booming development of electronic skins necessitates stretchable electrodes and flexible sensors that exhibit distinctly opposite requirements of electromechanical properties, both of which are difficult to be fulfilled on a single material. Here, a pufferfish-inspired, interlayer regulation strategy is proposed that realizes the above opposite properties in simple metal films, exhibiting either ultra-stretchability (295% strain) or sensitivity (maximum GF: ∼5500) on demand. It is revealed that the stretchability of the intrinsically strain-sensitive metal films can be improved by ∼20-fold via regulating the surface morphology of the inserted interlayer, accompanied by an intriguing transition in film cracking behavior from cut-through cracks to network patterns. By featuring these two antithetical but valuable properties, common metal films can be applied as diverse sensors and stretchable electrodes in electronic skins, showing application prospects in healthcare monitoring, human-machine interaction, and engineering services. Our proposed strategy substantially advances the application of metal film conductors in flexible electronics and broadens the horizons for developing more sophisticated electronic skins by interlayer engineering.

High performance 1D-2D CuO/MoS2 photodetectors enhanced by femtosecond laser-induced contact engineering

The integration of 2D materials with other dimensional materials opens up rich possibilities for both fundamental physics and exotic nanodevices. However, current mixed-dimensional heterostructures often suffer from interfacial contact issues and environment-induced degradation, which severely limits their performance in electronics/optoelectronics. Herein, we demonstrate a novel BN-encapsulated CuO/MoS₂ 2D-1D van der Waals heterostructure photodetector with an ultrahigh photoresponsivity which is 10-fold higher than its previous 2D-1D counterparts. The interfacial contact state and photodetection capabilities of 2D-1D heterojunctions are significantly improved via femtosecond laser irradiation induced MoS₂ wrapping and contamination removal. These h-BN protected devices show highly sensitive, gate-tunable and robust photoelectronic properties. By controlling the gate and bias voltages, the device can achieve a photoresponsivity as high as 2500 A W^-1 in the forward bias mode, or achieve a high detectivity of 6.5 × 10¹¹ Jones and a typical rise time of 2.5 ms at reverse bias. Moreover, h-BN encapsulation effectively protects the mixed-dimensional photodetector from electrical depletion by gas molecules such as O₂ and H₂O during fs laser treatment or the operation process, thus greatly improving the stability and service life in harsh environments. This work provides a new way for the further development of high performance, low cost, and robust mixed-dimensional heterostructure photodetectors by femtosecond laser contact engineering.

Venation-Mimicking, Ultrastretchable, Room-Temperature-Attachable Metal Tapes for Integrated Electronic Skins

Future electronic skin systems require stretchable conductors and low-temperature integration of external components, which remains challenging for traditional metal films. Herein, a bioinspired design concept is reported to endow metal films with 200% stretchability as well as room-temperature integration capability with diverse components. It is revealed that by controllable implantation of defects, distinctive venation-mimicking cracking modes can be induced in strained metal films, leading to profound stretchability regulation. An intriguing exponential-to-linear transition of the film electromechanical performance is observed, which is elucidated by a unified model covering the essence of all modes. Combined with room-temperature integration capability, an integrated electronic skin is constructed with metal films serving as stretchable electrodes, diverse sensors, and "tapes" to attach subcomponents, showing prospects in helping disabled people. This one-step, defect implantation strategy is applicable to common metals without special substrate treatments, which enables fascinating ultrastretchable metal film conductors with low-temperature integration capability to spark more sophisticated flexible electronic systems.

Locally Thinned, Core-Shell Nanowire-Integrated Multi-gate MoS2 Transistors for Active Control of Extendable Logic

Field-effect transistor (FET) devices with multi-gate coupled structures usually exhibit special electrical properties and are suitable for fabricating multifunctional devices. Among them, the 1D nanowire gate configuration has become a promising gate design to tailor 2D FET performances. However, due to possible short circuiting induced by nanowire contact and the high requirement for precision manipulation, the integration of multi-nanowires as gates in a single 2D electronic system remains a grand challenge. Herein, local laser--thinned multiple core-shell SiC@SiO₂ nanowires are successfully integrated into MoS₂ transistors as multi-gates for active control of extendable logic applications. Nanowire gates (NGs) locally enhance the carrier transportation, and the use of multiple NGs can achieve designed band structures to tune the performance of the device. For core-shell structures, a semiconducting core is used to introduce a gate bias, and the insulating shell provides protection against short circuiting between NGs, facilitating nanowire assembly. Furthermore, a global control gate is introduced to co-tune the overall electrical characteristics, while active control of logic devices and extendable inputs are achieved based on this model. This work proposes a novel nanowire multi-gate configuration, which provides possibilities for localized, precise control of band structures and the fabrication of highly integrated, multifunctional, and controllable nano-devices.

POS0259 A RANDOMIZED CLINICAL TRIAL OF 2-WEEK METHOTREXATE DISCONTINUATION IN RHEUMATOID ARTHRITIS PATIENTS VACCINATED WITH INACTIVATED SARS-COV-2 VACCINE

Background

Patients with rheumatoid arthritis (RA) on methotrexate have reduced vaccine responses. Temporary discontinuation has improved immunogenicity of anti-influenza vaccine, but this strategy has not been evaluated in anti-SARS-CoV-2 vaccines.

Objectives

To evaluate the effect on immunogenicity and safety of 2-week methotrexate (MTX) discontinuation after each dose of the Sinovac-CoronaVac vaccine versus MTX maintenance in rheumatoid arthritis (RA) patients.

Methods

This was a single-center, prospective, randomized, investigator-blinded, intervention study (#NCT04754698, CoronavRheum), including adult RA patients (stable CDAI≤10, prednisone ≤7.5mg/day), randomized (1:1) to withdraw MTX (MTX-hold) for 2 weeks after each vaccine dose or maintain MTX (MTX-maintain), evaluated at D0, D28 and D69. Co-primary outcomes were anti-SARS-CoV-2 S1/S2 IgG seroconversion(SC) and neutralizing antibody (NAb) positivity at D69. Secondary outcomes were geometric mean titers (GMT) and flare rates. For immunogenicity analyses, we excluded patients with baseline positive IgG/NAb, and, for safety reasons, those who flared at D28 (CDAI>10) and did not withdraw MTX twice.

Results

Randomization included 138 patients with 9 exclusions (5 COVID-19, 4 protocol violations). Safety evaluation included 60 (MTX-hold) and 69 (MTX-maintain) patients. Further exclusions: 27 patients [13 (21.7%) vs. 14 (20.3%), p=0.848] with positive baseline IgG/NAb and 10 patients (21.3%) in MTX-hold with CDAI>10 at D28. At D69, MTX-hold (n=37) had a higher rate of seroconversion than MTX-maintain (n=55) group [29 (78.4%) vs 30 (54.5%), p=0.019], with parallel augmentation in GMT [34.2 (25.2-46.4) vs 16.8 (11.9-23.6), p=0.006]. No differences were observed for NAb positivity [23 (62.2%) vs 27 (49.1%), p=0.217]. At D28 flare, rates were comparable in both groups (CDAI, p=0.122; DAS28-CRP, p=0.576), whereas CDAI>10 was more frequent in MTX-hold at D69 (p=0.024).

Figure 1.

Conclusion

We provide novel data that 2-week MTX withdrawal after each Sinovac-CoronaVac vaccine dose improves anti-SARS-CoV-2 IgG response. The increased flare rates after second MTX withdrawal may be attributed to the short-term interval between vaccine doses. This strategy requires close surveillance and shared decision making due to the possibility of flares.

References

[1]​​Jara A, Undurraga EA, González C, et al. Effectiveness of an inactivated SARS-CoV-2 vaccine in Chile. N Eng J Med. 2021 Sep 2;385(10):875-84. doi: 10.1056/NEJMoa2107715

[2]Furer V, Eviatar T, Zisman D, et al. Lb0003 Immunogenicity and Safety of the BNT162B2 mRNA Covid-19 Vaccine in Adult Patients with Autoimmune Inflammatory Rheumatic Diseases and General Population: a Multicenter Study. Ann Rheum Dis. 2021;80:200-201. doi: 10.1136/annrheumdis-2021-220647

[3]Medeiros-Ribeiro AC, Aikawa NE, Saad CG, et al. Immunogenicity and safety of the CoronaVac inactivated vaccine in patients with autoimmune rheumatic diseases: a phase 4 trial. Nat. Med. 2021 Jul 30:1-8. doi: 10.1038/s41591-021-01469-5.

[4]Park JK, Lee MA, Lee EY, et al. Effect of methotrexate discontinuation on efficacy of seasonal influenza vaccination in patients with rheumatoid arthritis: a randomised clinical trial. Ann Rheum Dis. 2017 Sep 1;76(9):1559-65. http://dx.doi.org/10.1136/annrheumdis-2017-211128

[5]Park JK, Lee YJ, Shin K, et al. Impact of temporary methotrexate discontinuation for 2 weeks on immunogenicity of seasonal influenza vaccination in patients with rheumatoid arthritis: a randomised clinical trial. Ann Rheum Dis. 2018 Jun 1;77(6):898-904. http://dx.doi.org/10.1136/annrheumdis-2018-213222

Acknowledgements

This protocol is part of a larger study of immunosuppressed patients with ARD (Clinicaltrials.gov#NCT04754698)

Disclosure of Interests

None declared

Wilcoxon-Mann-Whitney odds ratio: A statistical measure for ordinal outcomes such as EDSS

BACKGROUND

In many clinical situations, ordinal scales afford the primary method of semi-quantifying patient outcomes. In the field of multiple sclerosis, the primary ordinal scale is the Expanded Disability Status Scale. Predominant methods of ordinal scale statistical analysis provide a p-value without effect size or rely heavily on the assumption of proportionality of odds, subjecting them to lack of power and error. The Wilcoxon-Manny-Whitney Odds is a statistical method which provides significant information such as p-value, effect size, number needed to treat, confidence intervals, and is largely assumption-free. However, its utility has not been demonstrated in the field of multiple sclerosis.

METHODS

Three clinical studies in the field of multiple sclerosis were selected which utilized ordinal scale outcomes at group or individual levels. Data from these studies was extracted using WebPlotDigitizer, and a custom Wilxocon-Mann-Whitney Odds software was applied to each dataset to re-analyze the main outcomes of the studies.

RESULTS

Re-analysis of the manuscript by Muraro et al., 2017 demonstrated that autologous stem cell transplantation for relapsing remitting multiple sclerosis resulted in a 65% chance of improving from any Expanded Disability Status Scale category, although not significant. Re-analysis of the manuscript by Songthammawat et al., 2019 demonstrated chance of improvement with intravenous methylprednisolone and concurrent plasma exchange was 185% versus 32% in intravenous methylprednisolone with add-on plasma exchange, although not significant. Re-analysis of Kister et al., 2012 demonstrated the chances of mobility or cognition scores generally favored decline at every 5-year increment of study, and although statistically significant, these were smaller effect sizes ranging from an 11% chance of improvement to a 66% chance of decline over a 5-year interval.

DISCUSSION

The Wilcoxon-Mann-Whitney Odds simplifies ordinal data analysis with its robust largely assumption-free nature. In the place of numerous statistical tests, this single test provides effect size estimate, number needed to treat, p-values, and confidence intervals. Importantly, the Wilcoxon-Mann-Whitney Odds effect size calculation is intuitively applicable to both individual and population-levels. Further, the Wilcoxon-Mann-Whitney Odds allows intuitive description of the progression of large cohorts over time, and we were able to clearly convey the odds of mobility and cognitive decline over 30 years in a large multiple sclerosis cohort. Overall, the Wilcoxon-Mann-Whitney Odds is a powerful and robust statistical test with significant promise within the field of multiple sclerosis.

Femtosecond Laser Irradiation-Mediated MoS2-Metal Contact Engineering for High-Performance Field-Effect Transistors and Photodetectors

2D materials exhibit intriguing electrical and optical properties, making them promising candidates for next-generation nanoelectronic devices. However, the high contact resistance of 2D materials to electrode material often limits the ultimate performance and potential of 2D materials and devices. In this work, we demonstrate a localized femtosecond (fs) laser irradiation process to substantially minimize the resistance of MoS₂-metal contacts. A reduction of the contact resistance exceeding three orders of magnitude is achieved for mechanically exfoliated MoS₂, which remarkably improves the overall FET performance. The underlying mechanisms of resistance reduction are the removal of organic contamination induced by the transfer process, as well as the lowering of Schottky barrier resistance (R_SB) attributed to interface Fermi level pinning (FLP) by Au diffusion, and the lowering of interlayer resistance (R_int) due to interlayer coupling enhancement by Au intercalation under fs laser irradiation. By taking advantage of the improved MoS₂-metal contact behavior, a high-performance MoS₂ photodetector was developed with a photoresponsivity of 68.8 A W^-1 at quite a low V_ds of 0.5 V, which is ∼80 times higher than the pristine multilayer photodetector. This contamination-free, site-specific, and universal photonic fabrication technique provides an effective tool for the integration of complex 2D devices, and the mechanism of MoS₂-metal interface modification reveals a new pathway to engineer the 2D material-metal interface.

Bioinspired Color Switchable Photonic Crystal Silicone Elastomer Kirigami

Bioinspired dynamic structural color has great potential for use in dynamic displays, sensors, cryptography, and camouflage. However, it is quite rare for artificial structural color devices to withstand thousands of cycles. Male hummingbird's crowns and gorgets are brightly colored, demonstrating frequent color switching that is induced by regulating the orientation of the feathers through movement of skin or joints. Inspired by this unique structural color modulation, we demonstrate a flexible, mechanically triggered color switchable sheet based on a photonic crystal (PhC)-coated polydimethylsiloxane (PDMS) kirigami (PhC-PDMS kirigami) made by laser cutting. Finite element modeling (FEM) simulation reveals that the thickness of PDMS kirigami and the chamfer at the incision induced by laser cutting both dominate the out-of-plane deformation through in-plane stretching. The bioinspired PhC-PDMS kirigami shows precisely programmable structural color and keeps the color very well after recycling over 10 000 times. This bioinspired PhC-PDMS kirigami also shows excellent viewability even in bright sunlight, high readability, robust functionality, technical flexibility, and mechanical durability, which are readily exploitable for applications, such as chromic mechanical monitors for the sports industry or for medical applications, wearable camouflage, and security systems.

Solar anti-icing surface with enhanced condensate self-removing at extreme environmental conditions

The inhibition of condensation freezing under extreme conditions (i.e., ultra-low temperature and high humidity) remains a daunting challenge in the field of anti-icing. As water vapor easily condensates or desublimates and melted water refreezes instantly, these cause significant performance decrease of most anti-icing surfaces at such extreme conditions. Herein, inspired by wheat leaves, an effective condensate self-removing solar anti-icing/frosting surface (CR-SAS) is fabricated using ultrafast pulsed laser deposition technology, which exhibits synergistic effects of enhanced condensate self-removal and efficient solar anti-icing. The superblack CR-SAS displays superior anti-reflection and photothermal conversion performance, benefiting from the light trapping effect in the micro/nano hierarchical structures and the thermoplasmonic effect of the iron oxide nanoparticles. Meanwhile, the CR-SAS displays superhydrophobicity to condensed water, which can be instantly shed off from the surface before freezing through self-propelled droplet jumping, thus leading to a continuously refreshed dry area available for sunlight absorption and photothermal conversion. Under one-sun illumination, the CR-SAS can be maintained ice free even under an ambient environment of -50 °C ultra-low temperature and extremely high humidity (ice supersaturation degree of ∼260). The excellent environmental versatility, mechanical durability, and material adaptability make CR-SAS a promising anti-icing candidate for broad practical applications even in harsh environments.

[Feasibility and safety of fetal intravascular transfusion via the intrahepatic vein in the treatment of fetal anemia]

Objective: To investigate the feasibility and safety of fetal intravascular transfusion via the intrahepatic vein in the treatment of fetal anemia. Methods: This was a retrospective analysis of all fetuses requiring intrauterine transfusion (IUT) in the Shanghai First Maternity and Infant Hospital between January 2010 and December 2019. According to the different ways of IUT, they were divided into intrahepatic venous transfusion group and umbilical venous transfusion group, fetal outcomes and the incidence of procedure-related complications between the two groups were compared. Results: A total of 97 IUTs were performed on 48 fetuses. Among them, 16 cases were performed in the intrahepatic vein (31 transfusions), 32 cases were performed in the cord of the umbilical vein (66 transfusions).There were no significant differences between the two groups in age, labor history and the proportion of fetal hydrops before the first transfusion. In the intrahepatic venous transfusion group, the posterior placenta was 14/16, which was significantly higher than 78% (25/32) in the umbilical venous transfusion group (P<0.01). The live-birth rates of the two groups were 13/16 and 75% (24/32). There was no significant difference between the two groups (P>0.05). Before intrahepatic venous transfusion, the proportion of fetal hydrops was significantly higher than that of umbilical venous transfusion [55% (17/31) vs 24% (16/66), P<0.05]. Puncture success rate of intrahepatic venous transfusion and umbilical venous transfusion were both 100%. In the umbilical venous transfasion group, the incidence of needle slippage (5%, 3/66) and the abnormality of fetal heart rate (11%, 7/66) were higher than those in the intrahepatic venous transfasion group [0 and 3% (1/31)], but there were no significant differences between the two groups (all P>0.05). There were no cases of fetal loss within 24 hours, premature rupture of membranes, infection within 7 days and emergency cesarean section after IUT in both groups. Conclusions: Fetal intravascular transfusion via the intrahepatic vein is safe and feasible in the treatment of fetal anemia. But the requirements of puncture technique are relatively high, so it is recommended to be carried out in experienced fetal treatment center.

Protein-protein interaction network and potential drug target candidates of Streptococcus suis

AIMS

This study aimed to explore potential drug targets of Streptococcus suis at the system level.

METHODS AND RESULTS

A homologous protein mapping method was used in the construction of a protein-protein interaction (PPI) network of S. suis, which presented 1147 non-redundant interaction pairs among 286 proteins. The parameters of PPI networks were calculated and showed scale-free network properties. In all, 41 possibly essential proteins identified from 47 highly connected proteins were selected as potential drug target candidates. Of these proteins, 30 were already regarded as drug targets in other bacterial species. Six transporters with high connections to other functional proteins were identified as probably not essential but important functional proteins. Afterward, the subnetwork centred with cell division protein FtsZ was used in confirming the PPI network through bacterial two-hybrid analysis.

CONCLUSIONS

The predicted PPI network covers 13·04% of the proteome in S. suis. The selected 41 potential drug target candidates are conserved between S. suis and several model bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

The predictions included proteins known to be drug targets, and a verifying experiment confirmed the reliability of predicted interactions. This work is the first to present systematic computational PPI data for S. suis and provides potential drug targets, which are valuable in exploring novel anti-streptococcus drugs.

Moisture-Enabled Electricity Generation: From Physics and Materials to Self-Powered Applications

The exploration of the utilization of sustainable, green energy represents one way in which it is possible to ameliorate the growing threat of the global environmental issues and the crisis in energy. Moisture, which is ubiquitous on Earth, contains a vast reservoir of low-grade energy in the form of gaseous water molecules and water droplets. It has now been found that a number of functionalized materials can generate electricity directly from their interaction with moisture. This suggests that electrical energy can be harvested from atmospheric moisture and enables the creation of a new range of self-powered devices. Herein, the basic mechanisms of moisture-induced electricity generation are discussed, the recent advances in materials (including carbon nanoparticles, graphene materials, metal oxide nanomaterials, biofibers, and polymers) for harvesting electrical energy from moisture are summarized, and some strategies for improving energy conversion efficiency and output power in these devices are provided. The potential applications of moisture electrical generators in self-powered electronics, healthcare, security, information storage, artificial intelligence, and Internet-of-things are also discussed. Some remaining challenges are also considered, together with a number of suggestions for potential new developments of this emerging technology.

Nanoporous silver using pulsed laser deposition for high-performance oxygen reduction reaction and hydrogen peroxide sensing

Silver (Ag)-based materials have shown great application potential in the oxygen reduction reaction (ORR) and hydrogen peroxide (H2O2) detection. The porous structures of Ag have attracted a lot of research interest due to their large specific surface area and high electrochemical activity. In this work, nanoporous Ag structures composed of nano-sized particles were prepared by a one-step pulsed laser deposition (PLD) under controlled background gas pressure. The porous PLD-Ag showed a high ORR performance (Eonset: 1.007 V vs. RHE, E1/2: 0.863 V vs. RHE), high sensitivity (613.1 μA cm-2 mM-1 at -0.2 V vs. SCE) and selectivity for H2O2 detection. The PLD technique provided a new, yet universal approach to producing high-performance, metal-based electrochemical electrodes.

Influence of lymph node dissection in patients undergoing radical nephrectomy for non-metastatic renal cell carcinoma: a systematic review and meta-analysis

OBJECTIVE

Whether lymph node dissection (LND) should be performed concomitantly with radical nephrectomy (RN) for non-metastatic renal carcinoma has still been controversial recently. We conducted a meta-analysis assessing oncologic outcomes of radical nephrectomy with lymph node dissection (LND) and without lymph node dissection (non-LND) in non-metastatic renal cell carcinoma (NMRCC).

PATIENTS AND METHODS

A systematic review was performed until April 2018 using a comprehensive search in PubMed, EMBASE, and Cochrane Library databases to identify eligible comparative studies. A formal meta-analysis was performed for studies comparing radical nephrectomy with LND and radical nephrectomy with non-LND for cT1-T4NxM0 tumors. Furthermore, a subgroup analysis for locally advanced renal cell carcinoma (cT3-T4NxM0) was conducted.

RESULTS

Thirteen studies on patients with LND and non- LND were identified and included in the analysis. LND group did not have a significantly better survival than non-LND group for cT1-T4NxM0 tumors (HR 0.93, 95% CI 0.78-1.11, p=0.45), However, in the subgroup of locally advanced renal cell carcinoma (cT3-T4NxM0), it showed a significantly better OS rate in patients who had undergone LND compared to those without LND (HR 0.73, 95% CI 0.60-0.90; p=0.003).

CONCLUSIONS

LND offers better cancer control and better long-term survival in locally advanced renal cell carcinomas (cT3-T4NxM0). This conclusion should be confirmed by a prospective randomized clinical trial.

MiR-216a-5p act as a tumor suppressor, regulating the cell proliferation and metastasis by targeting PAK2 in breast cancer

OBJECTIVE

Our study aimed to investigate the expression of microRNA-216a-5p (miR-216a-5p) in breast cancer (BC) and its effect on the proliferation and metastasis of BC cells by regulating the expression of p21-activated protein kinase 2 (PAK2) gene.

PATIENTS AND METHODS

A total of 50 cases of cancer tissue specimens and corresponding para-carcinoma normal tissue specimens were collected from the breast surgery department of our hospital from July 2016 to December 2017. BC MCF-7 cell line and normal breast epithelial MCF-10A cells were cultured. MiR-NC (negative control), LV-p21-activated protein kinase 2 (PAK2) and/or miR-216a-5p mimics were synthesized and transfected. The protein and mRNA expression level in BC tissues and cells were detected by Western blot and quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) assay, respectively. Additionally, the Luciferase Reporter Assays, cell proliferation detection, clone formation assays and transwell migration and invasion assay were performed to determine the functional alteration of BC cells, respectively.

RESULTS

The results of qRT-PCR demonstrated that miR-216a-5p was decreased in both BC tissues and cells compared with that in normal controls. Online target gene prediction software and Dual-Luciferase reporter assay were used for target identification, and PAK2 was identified as a functional target of miR-216a-5p in BC cells. The results were further clarified with the Western blot (WB) experiment. In vitro, cell functions were detected by Cell Counting Kit-8 (CCK-8), crystal violet staining and transwell experiment, respectively. The results indicated that decreased expression of PAK2 resulting from the up-regulation of miR-216a-5p could restrain the proliferation, clone formation, invasion and migration abilities of BC cells.

CONCLUSIONS

We showed that miR-216a-5p played a role as antioncogene in BC, which provides a new therapeutic target for the treatment of BC.

A wireless, implantable optoelectrochemical probe for optogenetic stimulation and dopamine detection

Physical and chemical technologies have been continuously progressing advances in neuroscience research. The development of research tools for closed-loop control and monitoring neural activities in behaving animals is highly desirable. In this paper, we introduce a wirelessly operated, miniaturized microprobe system for optical interrogation and neurochemical sensing in the deep brain. Via epitaxial liftoff and transfer printing, microscale light-emitting diodes (micro-LEDs) as light sources and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-coated diamond films as electrochemical sensors are vertically assembled to form implantable optoelectrochemical probes for real-time optogenetic stimulation and dopamine detection capabilities. A customized, lightweight circuit module is employed for untethered, remote signal control, and data acquisition. After the probe is injected into the ventral tegmental area (VTA) of freely behaving mice, in vivo experiments clearly demonstrate the utilities of the multifunctional optoelectrochemical microprobe system for optogenetic interference of place preferences and detection of dopamine release. The presented options for material and device integrations provide a practical route to simultaneous optical control and electrochemical sensing of complex nervous systems.

Rationally designed surface microstructural features for enhanced droplet jumping and anti-frosting performance

The accretion of frost on heat exchanging surfaces through the freezing of condensed water in cold and humid environments significantly reduces the operating efficiency of air-source heat pumps, refrigerators and other cryogenic equipment. The construction of hierarchical micro-nanostructured SHSs, with the ability to timely remove condensed water before freezing via self-propelled droplet jumping, serves as a promising anti-frosting strategy. However, the actual relationship between microstructural features and water removal capability through droplet jumping is still not clear, hindering the further optimization of anti-frosting SHSs. Herein, a series of aluminum SHSs with different micro-cone arrays is designed and fabricated via ultrafast laser processing and chemical etching. The effect of microstructural features on water removal capability is elucidated by statistically analyzing the condensation process. As compared to nanostructured SHSs with the micro-cone size ranging from 10 to 40 μm, the water removal through droplet jumping is remarkably enhanced from 3.42 g m-2 to as much as 13.91 g m-2 over 10 minutes of condensation experiments due to the effective transition of condensed microdroplets from the initial high-adhesion partial wetting (PW) state to low-adhesion Cassie state, leading to significantly reduced water accumulation and improved anti-frosting performance. However, a further increase in the micro-cone size decreased the water removal amount due to greater droplet adhesion to the surface, which results in higher chances for immobile coalescence and the formation of large droplets. Herein, by rationally tuning the size scale of the structured micro-cones, the optimal SHSs display the least water accumulation and render excellent frosting delay of over 90 minutes under simulated harsh operating conditions.

Sintering Mechanism of a Supersaturated Ag-Cu Nanoalloy Film for Power Electronic Packaging

Ag-Cu bimetallic nanoparticles, combining the advantages of both Ag and Cu, are a promising material for power electronic packaging. In this work, a supersaturated Ag-7.3 wt % Cu alloy nanoparticle film was developed by using pulsed laser deposition. Unlike Cu nanoparticles, the supersaturated Ag-Cu alloy nanoparticles can conduct bonding in air without the assistance of a reduction agent. The shear strength was >20 MPa when the bonding temperature reached 300 °C, which was above the die shear standard (MIL-STD-883 K, 7.8 MPa) and compatible with the typical die attach process. The Cu separating behavior was accompanied by the bonding process at 250-400 °C, which was discussed systematically. Neck formation was delayed to about 250 °C because of the hindering effect of the thin oxide shell of the Ag-Cu alloy. The necking networks provide volume diffusion paths despite the growth of surface oxide, resulting in compact densification. The bondline under the SiC die consisted of a porous Ag-Cu alloy matrix with a dispersed secondary phase of Cu₂O/CuO, which is supposed to have improved electrochemical migration resistance.

Contact engineering of single core/shell SiC/SiO2 nanowire memory unit with high current tolerance using focused femtosecond laser irradiation

Single nanowire memory units are of particular interest in the design of high-density nanoelectronic circuits, but the performance due to weak contact state remains a major problem. In this paper, bonding between core/shell SiC/SiO2 nanowire and Au electrodes can be improved via local contact engineering with femtosecond (fs) laser irradiation. An optimized heterojunction (Au-SiO2-SiC) is possible since plasmonic enhanced optical absorption can be localized at the metal-oxide (Au-SiO2) interface. Electron transport across the barrier and charge accumulation at the oxide-semiconductor (SiO2-SiC) interface are improved in nanowire circuits. A fast and stable resistance change can be achieved after only one biasing cycle ('write') and the written state can be read/extracted at a low voltage (∼ 0.5 V). Unlike other as-built nanowire circuits, the resistance state can be retained for 10 min in the absence of external power, indicating that these devices can be used for short-term memory units. High current tolerance is also provided in the circuit by the surface oxide shell which acts to protect the inner SiC core. The current density carried by the single SiC/SiO2 nanowire circuit can be as high as ∼3 × 106 A cm-2 before break down, and that breakdown occurs as a two-stage process.

Competing Effects between Condensation and Self-Removal of Water Droplets Determine Antifrosting Performance of Superhydrophobic Surfaces

Preventing condensation frosting is crucial for air conditioning units, refrigeration systems, and other cryogenic equipment. Coalescence-induced self-propelled jumping of condensed microdroplets on superhydrophobic surfaces serves as a favorable strategy against condensation frosting. In previous reports, efforts were dedicated to enhance the efficiency of self-propelled jumping by constructing appropriate surface structures on superhydrophobic surfaces. However, the incorporation of surface structures results in larger area available for condensation to occur, leading to an increase in total amount of condensed water on the surface and partially counteracts the effect of promoted jumping on removing condensed water from the surface. In this paper, we focus on the competing effects between condensing and self-propelled jumping on promoting and preventing water accumulation, respectively. A series of micro- and nanostructured superhydrophobic surfaces are designed and prepared. The condensation process and self-propelled jumping behavior of microdroplets on the surfaces are investigated. Thousands of jumping events are statistically analyzed to acquire a comprehensive understanding of antifrosting potential of superhydrophobic surfaces with self-propelled jumping of condensed microdroplets. Further frosting experiments shows that the surface with the lowest amount of accumulated water exhibits the best antifrosting performance, which validates our design strategy. This work offers new insights into the rational design and fabrication of antifrosting materials.

Self-powered, flexible and remote-controlled breath monitor based on TiO2 nanowire networks

Smart breath monitor devices with high stretchability, fast response/recovery times and self-powered characteristic are essential in the wearable medical and life science applications. In this work, we report on the development of a versatile high-performance humidity sensor based on TiO₂ nanowire networks for self-powered sensing application of human breath monitoring. These sensors, with typical response times of ∼3.6 s and recovery times of ∼14 s, exhibit high sensitivity to water vapor and can yield an output voltage that is directly proportional to the humidity level of ambient environment. The structure of nanowire networks is highly flexible and maintains the output voltage even after 10 000 times bending. By combining this type of sensor with a commercial signal transmission and processing system, it shows the good basis for real-time/remote-controlled monitoring and analysis of human breath under a variety of respiratory conditions. Our results suggest a new class of humidity sensing for self-powered biomedical devices and open to new technologies in energy, electronics, and sensor applications.

Experimental and Theoretical Investigation of Laser Pretreatment on Strengthening the Heterojunction between Carbon Fiber-Reinforced Plastic and Aluminum Alloy

Besides aluminum alloys, lightweight carbon fiber-reinforced plastics (CFRPs) have been adopted progressively in automobiles to save energy and reduce emission, so constructing a reliable heterojunction between aluminum alloys and CFRPs has come to be the key issue. In this study, ultrafast picosecond infrared (IR) and excimer ultraviolet (UV) lasers were introduced to pretreat the joint surface to enhance the adhesive strength. Scanning electron microscopy, white light interferometry, and X-ray photoelectron spectroscopy examinations indicated that because the energy absorptivities for the two lasers were different, the variation of the roughness, wettability, and chemical composition were a little different for the patterned surface. Correspondingly, the shear strengths of the adhesive joints were increased from 5.6 to 24.8 and 21.9 MPa for IR and UV laser-pretreated samples, respectively. Furthermore, finite element analysis was adopted to evaluate the effects of strengthened mechanical interlocking and fortified chemical bonding force on the enhancement of joint strength. It was shown that chemical bonding, instead of mechanical interlocking, played the dominant role in reinforcing the heterogeneous joints. As a whole, the picosecond IR laser was more preferable for surface pretreatment in adhesive heterojunctions due to its higher processing and enhancing efficiency.

Structure Inheritance in Nanoparticle Ink Direct-Writing Processes and Crack-Free Nano-Copper Interconnects Printed by a Single-Run Approach

When nanoparticle conductive ink is used for printing interconnects, cracks and pores are common defects that deteriorate the electrical conductivity of the printed circuits. Influences of the ink solvent, the solid fraction of the ink, the pre-printing treatment and the sintering parameters on the interconnect morphology and conductivity were investigated. It was found that the impacts of all these factors coupled with each other throughout the whole procedure, from the pre-printing to the post-printing processes, and led to a structure inheritance effect. An optimum process route was developed for producing crack-free interconnects by a single-run direct-writing approach using home-made nano-copper ink. A weak gel was promoted in the ink before printing in the presence of long-chain polymers and bridging molecules by mechanical agitation. The fully developed gel network prevented the phase separation during ink extrusion and crack formations during drying. With the reducing agents in the ink and slow evaporation of the ink solvent, compact packing and neck joining of copper nanoparticles were obtained after a two-step sintering process. The crack-free interconnects successfully produced have a surface roughness smaller than 1.5 μm and the square resistances as low as 0.01 Ω/□.

Cooperative Bilayer of Lattice-Disordered Nanoparticles as Room-Temperature Sinterable Nanoarchitecture for Device Integrations

Decreasing the interconnecting temperature is essential for 3D and heterogeneous device integrations, which play indispensable roles in the coming era of "more than Moore". Although nanomaterials exhibit a decreased onset temperature for interconnecting, such an effect is always deeply impaired because of organic additives in practical integrations. Meanwhile, current organic-free integration strategies suffer from roughness and contaminants at the bonding interface. Herein, a novel bilayer nanoarchitecture simultaneously overcomes the drawbacks of organics and is highly tolerant to interfacial morphology, which exhibits universal applicability for device-level integrations at even room temperature, with the overall performance outperforming most counterparts reported. This nanoarchitecture features a loose nanoparticle layer with unprecedented deformability for interfacial gap-filling, and a compact one providing firm bonding with the component surface. The two distinct nanoparticle layers cooperatively enhance the interconnecting performance by 73-357%. Apart from the absence of organics, the internal abundant lattice disorders profoundly accelerate the interconnecting process, which is supported by experiments and molecular dynamics simulation. This nanoarchitecture is successfully demonstrated in diversified applications including paper-based light-emitting diodes, Cu-Cu micro-bonding, and SiC power modules. The strategy proposed here can open a new paradigm for device integrations and provide a fresh understanding on interconnecting mechanisms.

Self-Powered, Rapid-Response, and Highly Flexible Humidity Sensors Based on Moisture-Dependent Voltage Generation

Most advanced humidity sensors are powered by batteries that need regular charging and replacement, causing environmental problems and complicated management issues. This paradigm has been overcome through the development of new technology based on the concept of simple, self-powered, rapid-response, flexible humidity sensors enabled by the properties of densely packed titanium dioxide (TiO₂) nanowire networks. These sensors eliminate the need for an external power source and produce an output voltage that can be readily related to ambient humidity level over a wide range of ambient conditions. They are characterized by rapid response and relaxation times (typically 4.5 and 2.8 s, respectively). These units are mechanically flexible and maintain a constant voltage output after 10 000 bending cycles. This new type of humidity sensor is easily attached to a human finger for use in the monitoring of ambient humidity level in the environment around human skin, near wet objects, or in the presence of moist materials. The unique properties of this new self-powered wearable humidity sensor technology open up a variety of new applications, including the development of electronic skin, personal healthcare products, and smart tracking in the future Internet-of-things.

Plasmon-Induced Heterointerface Thinning for Schottky Barrier Modification of Core/Shell SiC/SiO2 Nanowires

In this work, plasmon-induced heterointerface thinning for Schottky barrier modification of core/shell SiC/SiO₂ nanowires is conducted by femtosecond (fs) laser irradiation. The incident energy of polarized fs laser (50 fs, 800 nm) is confined in the SiO₂ shell of the nanowire due to strong plasmonic localization in the region of the electrode-nanowire junction. With intense nonlinear absorption in SiO₂, the thickness of the SiO₂ layer can be thinned in a controllable way. The tuning of the SiO₂ barrier layer allows the promotion of electron transportation at the electrode-nanowire interface. The switching voltage of the rectifying junction made by the SiC/SiO₂ nanowire can be significantly tuned from 15.7 to 1 V. When selectively thinning at source and drain electrodes and leaving the SiO₂ barrier layer at the gate electrode intact, a metal/oxide/semiconductor (MOS) device is fabricated with low leakage current. This optically controlled interfacial engineering technology should be applicable for MOS components and other heterogeneous integration structures.

Ambroxol as a novel disease-modifying treatment for Parkinson's disease dementia: protocol for a single-centre, randomized, double-blind, placebo-controlled trial

BACKGROUND

Currently there are no disease-modifying treatments for Parkinson's disease dementia (PDD), a condition linked to aggregation of the protein α-synuclein in subcortical and cortical brain areas. One of the leading genetic risk factors for Parkinson's disease is being a carrier in the gene for β-Glucocerebrosidase (GCase; gene name GBA1). Studies in cell culture and animal models have shown that raising the levels of GCase can decrease levels of α-synuclein. Ambroxol is a pharmacological chaperone for GCase and is able to raise the levels of GCase and could therefore be a disease-modifying treatment for PDD. The aims of this trial are to determine if Ambroxol is safe and well-tolerated by individuals with PDD and if Ambroxol affects cognitive, biochemical, and neuroimaging measures.

METHODS

This is a phase II, single-centre, double-blind, randomized placebo-controlled trial involving 75 individuals with mild to moderate PDD. Participants will be randomized into Ambroxol high-dose (1050 mg/day), low-dose (525 mg/day), or placebo treatment arms. Assessments will be undertaken at baseline, 6-months, and 12-months follow up times. Primary outcome measures will be the Alzheimer's disease Assessment Scale-cognitive subscale (ADAS-Cog) and the ADCS Clinician's Global Impression of Change (CGIC). Secondary measures will include the Parkinson's disease Cognitive Rating Scale, Clinical Dementia Rating, Trail Making Test, Stroop Test, Unified Parkinson's disease Rating Scale, Purdue Pegboard, Timed Up and Go, and gait kinematics. Markers of neurodegeneration will include MRI and CSF measures. Pharmacokinetics and pharmacodynamics of Ambroxol will be examined through plasma levels during dose titration phase and evaluation of GCase activity in lymphocytes.

DISCUSSION

If found effective and safe, Ambroxol will be one of the first disease-modifying treatments for PDD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02914366, 26 Sep 2016/retrospectively registered.

Hierarchically Mesostructured Aluminum Current Collector for Enhancing the Performance of Supercapacitors

Aluminum (Al) current collector is one of the most important components of supercapacitors, and its performance has vital effects on the electrochemical performance and cyclic stability of supercapacitors. In the present work, a scalable and low-cost, yet highly efficient, picosecond laser processing method of Al current collectors was developed to improve the overall performance of supercapacitors. The laser treatment resulted in hierarchical micro-nanostructures on the surface of the commercial Al foil and reduced the surface oxygen content of the foil. The electrochemical performance of the Al foil with the micro-nanosurface structures was examined in the symmetrical activated carbon-based coin supercapacitors with an organic electrolyte. The results suggest that the laser-treated Al foil (laser-Al) increased the capacitance density of supercapacitors up to 110.1 F g^-1 and promoted the rate capability due to its low contact resistance with the carbonaceous electrode and high electrical conductivity derived from its larger specific surface areas and deoxidized surface. In addition, the capacitor with the laser-Al current collector exhibited high cyclic stability with 91.5% capacitance retention after 10 000 cycles, 21.3% higher than that with pristine-Al current collector due to its stronger bonding with the carbonaceous electrode that prevented any delamination during aging. Our work has provided a new strategy for improving the electrochemical performance of supercapacitors.

Self-Powered Wearable Electronics Based on Moisture Enabled Electricity Generation

Most state-of-the-art electronic wearable sensors are powered by batteries that require regular charging and eventual replacement, which would cause environmental issues and complex management problems. Here, a device concept is reported that can break this paradigm in ambient moisture monitoring-a new class of simple sensors themselves can generate moisture-dependent voltage that can be used to determine the ambient humidity level directly. It is demonstrated that a moisture-driven electrical generator, based on the diffusive flow of water in titanium dioxide (TiO₂ ) nanowire networks, can yield an output power density of up to 4 µW cm^-2 when exposed to a highly moist environment. This performance is two orders of magnitude better than that reported for carbon-black generators. The output voltage is strongly dependent on humidity of ambient environment. As a big breakthrough, this new type of device is successfully used as self-powered wearable human-breathing monitors and touch pads, which is not achievable by any existing moisture-induced-electricity technology. The availability of high-output self-powered electrical generators will facilitate the design and application of a wide range of new innovative flexible electronic devices.

Ultrasonic effect mechanism on transient liquid phase bonding joints of SiCp reinforced Mg metal matrix composites using Zn-Al-Zn multi-interlayer

The effect of ultrasound on transient liquid phase bonding of SiC_p reinforced Mg metal matrix composites was investigated based on microstructure evolution, phase composition, SiC particles redistribution, mechanical properties and fracture path of the bonded joint. The results indicate the joint of full solid solution without SiC particles aggregation was obtained by inducing the secondary ultrasonic-assisted holding process at 430 °C for 30 s and the joint shear strength reach to 175.5 MPa (87.5% base material strength). The time needed for the isothermal solidification process was significantly shortened to several second time, which is mainly ascribed to the ultrasonic vibration can squeeze out a large fraction of residual liquid phase and facilitate the atomic diffusion in grain boundary.

Reliability of histologic assessment in patients with eosinophilic oesophagitis

BACKGROUND

The validity of the eosinophilic oesophagitis (EoE) histologic scoring system (EoEHSS) has been demonstrated, but only preliminary reliability data exist.

AIM

Formally assess the reliability of the EoEHSS and additional histologic features.

METHODS

Four expert gastrointestinal pathologists independently reviewed slides from adult patients with EoE (N = 45) twice, in random order, using standardised training materials and scoring conventions for the EoEHSS and additional histologic features agreed upon during a modified Delphi process. Intra- and inter-rater reliability for scoring the EoEHSS, a visual analogue scale (VAS) of overall histopathologic disease severity, and additional histologic features were assessed using intra-class correlation coefficients (ICCs).

RESULTS

Almost perfect intra-rater reliability was observed for the composite EoEHSS scores and the VAS. Inter-rater reliability was also almost perfect for the composite EoEHSS scores and substantial for the VAS. Of the EoEHSS items, eosinophilic inflammation was associated with the highest ICC estimates and consistent with almost perfect intra- and inter-rater reliability. With the exception of dyskeratotic epithelial cells and surface epithelial alteration, ICC estimates for the remaining EoEHSS items were above the benchmarks for substantial intra-rater, and moderate inter-rater reliability. Estimation of peak eosinophil count and number of lamina propria eosinophils were associated with the highest ICC estimates among the exploratory items.

CONCLUSION

The composite EoEHSS and most component items are associated with substantial reliability when assessed by central pathologists. Future studies should assess responsiveness of the score to change after a therapeutic intervention to facilitate its use in clinical trials.

Investigation of impact and spreading of molten nanosized gold droplets on solid surfaces

Understanding the impact dynamics and spreading of molten nanosized droplets on a solid surface is a crucial step towards the design and control of nano-fabrication in many novel applications of nanotechnology. In this context, molecular dynamic (MD) simulations have been conducted to compute temperature and dynamic contact angles of nano-droplets during impact. The evolution of the morphology of a molten metallic nano-droplet impacting on a substrate has been studied using a combination of experimental and simulation techniques. Femtosecond lasers have been used to transfer nanosized gold droplets. Droplet morphology calculated in MD simulations is found to be in good agreement with that seen in scanning electron microscopy (SEM) images. It is found that the spreading of nanoscale molten gold droplets upon impact is enhanced by increasing the droplet impact energy. As observed in experimental data, MD simulation results show that a high droplet-substrate heat transfer rate together with increased wettability of the substrate facilitates spreading and results in a thinner metal deposit after solidification.

Scalable High-Performance Ultraminiature Graphene Micro-Supercapacitors by a Hybrid Technique Combining Direct Writing and Controllable Microdroplet Transfer

Miniaturization of energy storage devices can significantly decrease the overall size of electronic systems. However, this miniaturization is limited by the reduction of electrode dimensions and the reproducible transfer of small electrolyte drops. This paper reports first a simple scalable direct writing method for the production of ultraminiature microsupercapacitor (MSC) electrodes, based on femtosecond laser reduced graphene oxide (fsrGO) interlaced pads. These pads, separated by 2 μm spacing, are 100 μm long and 8 μm wide. A second stage involves the accurate transfer of an electrolyte microdroplet on top of each individual electrode, which can avoid any interference of the electrolyte with other electronic components. Abundant in-plane mesopores in fsrGO induced by a fs laser together with ultrashort interelectrode spacing enables MSCs to exhibit a high specific capacitance (6.3 mF cm^-2 and 105 F cm^-3) and ∼100% retention after 1000 cycles. An all graphene resistor-capacitor (RC) filter is also constructed by combining the MSC and a fsrGO resistor, which is confirmed to exhibit highly enhanced performance characteristics. This new hybrid technique combining fs laser direct writing and precise microdroplet transfer easily enables scalable production of ultraminiature MSCs, which is believed to be significant for practical application of micro-supercapacitor microelectronic systems.

Interactions at the planar Ag3Sn/liquid Sn interface under ultrasonic irradiation

The interactions at the interface between planar Ag₃Sn and liquid Sn under ultrasonic irradiation were investigated. An intensive thermal grooving process occurred at Ag₃Sn grain boundaries due to ultrasonic effects. Without ultrasonic application, planar shape of Ag₃Sn layer gradually evolved into scalloped morphology after the solid-state Sn melting, due to a preferential dissolution of the intermetallic compounds from the regions at grain boundaries, which left behind the grooves embedding in the Ag₃Sn layer. Under the effect of ultrasonic, stable grooves could be rapidly generated within an extremely short time (<10s) that was far less than the traditional soldering process (>10min). In addition, the deepened grooves leaded to the formation of necks at the roots of Ag₃Sn grains, and further resulted in the strong detachment of intermetallic grains from the substrate. The intensive thermal grooving could promote the growth of Ag₃Sn grains in the vertical direction but restrain their coarsening in the horizontal direction, consequently, an elongated morphology was presented. All these phenomena could be attributed to the acoustic cavitation and streaming effects of ultrasonic vibration.

Improving the electrical contact at a Pt/TiO2 nanowire interface by selective application of focused femtosecond laser irradiation

In this paper, we show that tightly focused femtosecond laser irradiation is effective in improving nanojoining of an oxide nanowire (NW) (TiO₂) to a metal electrode (Pt), and how this process can be used to modify contact states. Enhanced chemical bondings are created due to localized plasmonically enhanced optical absorption at the Pt/TiO₂ interface as confirmed by finite element simulations of the localized field distribution during irradiation. Nano Auger electron spectroscopy shows that the resulting heterojunction is depleted in oxygen, suggesting that a TiO_2-x layer is formed between the Pt electrode and the TiO₂ NW. The presence of this redox layer at the metal/oxide interface plays an important role in decreasing the Schottky barrier height and in facilitating chemical bonding. After laser irradiation at the cathode for 10 s at a fluence of 5.02 mJ cm^-2, the Pt/TiO₂ NW/Pt structure displays different electrical properties under forward and reverse bias voltage, respectively. The creation of this asymmetric electrical characteristic shows the way in which modification of the electronic interface by laser engineering can replace the electroforming process in resistive switching devices and how it can be used to control contact states in a metal/oxide interface.

Randomised non-inferiority trial: 1600 mg versus 400 mg tablets of mesalazine for the treatment of mild-to-moderate ulcerative colitis

BACKGROUND

High concentration mesalazine formulations are more convenient than conventional low concentration formulations for the treatment of ulcerative colitis (UC).

AIM

To compare the efficacy and safety of 1600 mg and 400 mg tablet mesalazine formulations.

METHODS

Patients with mild-to-moderate active UC (Mayo Clinic Score >5; N=817) were randomised to 3.2 g of oral mesalazine, administered as two 1600 mg tablets once, or four 400 mg tablets twice daily. We hypothesised that treatment with the 1600 mg tablet was non-inferior (within a 10% margin) to the 400 mg tablet for induction of clinical and endoscopic remission at week 8. Open-label treatment with the 1600 mg tablet continued for 26-30 weeks based on induction response. Predictors of treatment response were also explored.

RESULTS

At week 8, remission occurred in 22.4% and 24.6% of patients receiving the 1600 mg and 400 mg tablets, respectively (absolute difference -2.2%, 95% CI: -8.1% to 3.8%, non-inferiority P=.005). Endoscopic and histopathologic disease activity, leucocyte concentration and age were significantly associated with clinical remission (P=.022, .042, .014 and .023, respectively). At week 38, 43.9% (296/675) of patients who continued treatment with the 1600 mg formulation were in remission, including 70.3% (142/202) of patients who received a reduced dose of mesalazine (1.6 g/d). The overall incidence of serious adverse events was low.

CONCLUSIONS

Induction therapy with 3.2 mg mesalazine using two 1600 mg tablets once-daily was statistically and clinically non-inferior to a twice-daily regimen using four 400 mg tablets (NCT01903252).

Rapid Ag/Sn/Ag transient liquid phase bonding for high-temperature power devices packaging by the assistance of ultrasound

Rapid transient liquid phase (TLP) bonding process on Ag/Sn/Ag system is achieved in air by the assistance of ultrasonic, which has great potential to be applied to high-temperature power devices packaging. In this study, the influence of ultrasonic effect on the morphology and growth kinetics of Ag₃Sn grains, and the joint microstructure, mechanical property and thermal reliability were systematically investigated. Experimental results indicated that the rapid consumption of the "dynamic" transient liquid phase was attributed to the accelerated dissolution of Ag substrate and the extrusion of liquid Sn, which were entirely induced by the complex sonochemical effects on the liquid/solid intermetallic compounds (IMCs) interface. An elongated scallop-like morphology of Ag₃Sn grains was developed during Ag/Sn interfacial reaction with ultrasonic, accompanied by widening of grooves between neighbored grains. This phenomenon is called as a strengthening thermal grooving, in which the grooves at grain boundaries provide stable molten channels for Ag atoms diffusion from the substrate. Consequently, the improved elemental diffusion was evaluated through the growth kinetics of Ag₃Sn IMCs, with conservative estimation of 6-16.5 times faster than the traditional TLP process. In addition, both excellent mechanical property and thermal reliability of the Ag-Sn intermetallic joint were experimentally verified by shear test and high-temperature storage test, respectively.