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We reported the fabrication of a highly sensitive, fast, and thermally switchable humidity sensor based on a β-Ga2O3–amorphous-SnO2 core–shell microribbon, which was synthesized via a simple one-step chemical vapour deposition. The as-grown microribbons were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) and the results indicated that the microribbon has a well-defined core–shell structure with β-Ga2O3 in the core and amorphous SnO2 in the shell. At 25 °C, the conductivity of the humidity sensor at 75% relative humidity (RH) was three orders of magnitude larger than that in dry air (5% RH). The response time and recovery time were ∼28 and ∼7 s, respectively, when RH was switched between 5 and 75%. Interestingly, by changing the temperature between 12 and 40 °C at 75% RH, the sensitivity can be tuned between ∼105 (12 °C) and ∼102 (40 °C). Typical thermally switchable properties of β-Ga2O3–amorphous-SnO2 core–shell microribbons at 75% RH were demonstrated using a heating–cooling cycle between 20 and 30 °C. The possible mechanisms have been proposed based on the novel core–shell structures and water adsorption–desorption processes. Our findings pave the way for new types of humidity sensors and thermal switches.

Conventional photolithography-based microfabrication techniques are widely used to create microscale structures and devices nowadays. However, these techniques are limited to two-dimensional fabrication and also to particular materials. Excimer laser micromachining enables us to overcome those limitations and facilitates three-dimensional (3D) microfabrication. This paper presents a comprehensive characterization study for excimer laser micromachining of micro-electro-mechanical system (MEMS) materials. By using a 248 nm KrF excimer laser and four representative MEMS materials (Si, soda-lime glass, SU-8 photoresist and poly-dimethysiloxane (PDMS)), the relations between laser ablation parameters (fluence, frequency and number of laser pulses) and etch performance such as the etch rates in the vertical and lateral directions, aspect ratio, and surface quality were obtained. The etch rate increased almost linearly for all four materials as the fluence increased but no significant variation in etch rate was observed as the frequency of laser pulses was changed. The etch rate was also inversely proportional to the number of laser pulses. Physical deformation in the laser-machined sites on PDMS and SU-8 was investigated using SEM imaging. In order to demonstrate the 3D microfabrication capability of an excimer laser and the utility of this characterization study, two novel implantable biomedical microscale devices made of SU-8 and PDMS were successfully fabricated using the optimized laser ablation parameters obtained in this study.

We report the optical and magnetic properties of ZnO, Zn0.97In0.03O, and Zn0.94In0.06O nanowires (NWs). All samples have similar wirelike shape with an average diameter of about 70 nm and a length of about 10 μm. The comparison of photoluminescence (PL) spectra at 10 K indicated that a new broad emission band appeared after indium doping, which is associated with donor-acceptor-pair recombination. Additionally, the intensity of oxygen-vacancies-induced visible emission increased with increasing In content, indicating that In doping can induce many oxygen vacancies. Furthermore, magnetic measurements revealed that pure ZnO NWs are diamagnetic, while indium-doped ZnO NWs exhibit intrinsic ferromagnetism at room temperature. With the increase in In content, the coercive field and the magnetic moment for indium-doped ZnO NWs increase largely. Ferromagnetic ordering can be interpreted as being due to O vacancies induced by In doping, which is in good agreement with PL results.

We investigated the photoluminescence (PL) properties of ZnO nanowires with and without covering with polymethyl methacrylate (PMMA). Low temperature PL spectra of as-grown ZnO nanowires are dominated by near band edge (NBE) emission due to donor bound excitons and free-to-bound recombination (FB). FB emission persists till 300 K and together with free exciton emission governs the lineshape of the PL spectra. After covering with PMMA, the integral intensity of NBE emission increases about three times, indicating significantly improved excitonic emission efficiency. A model based on surface states and energy bands theory was proposed to interpret this emission enhancement.

The aim of this study was to evaluate the predictive value of the polymorphism Glutathione S-transferase P1 (GSTP1) Ile(105)Val on oxaliplatin/5-FU-based chemotherapy in advanced gastric cancer. Patients with advanced gastric cancer accepted oxaliplatin/5-FU-based chemotherapy as first-line chemotherapy were investigated. GSTP1 Ile(105)Val polymorphism was detected by TaqMan-MGB probe allelic discrimination method. Response to treatment was assessed by disease controlled rate. Time to progression, overall survival and toxicities were recorded. Final patient outcomes were as follows: the allele frequencies of GSTP1 were (105)Ile/(105)Ile 52%, (105)Ile/(105)Val 41% and (105)Val/(105)Val 7%. For patients with (105)Ile/(105)Ile and those with at least one (105)Val allele, disease control rate was 39% and 71% (P=0.026), respectively; median time to progression was 4.0 and 7.0 months (P=0.002); median overall survival time was 7.0 and 9.5 months (P=0.002). Neurological toxicity was more frequently occurred in patients with two (105)Ile alleles (P=0.005). In conclusion, patients with at least one (105)Val allele have better prognosis and response to oxaliplatin/5-FU-based regimen as first-line treatment for patients with advanced gastric cancer.

We investigate the photoconductivity properties of ZnO thin films prepared by pulsed laser deposition with and without metals (Au or Pt) on the surface. The covering of nanostructured metals can largely enhance the photocurrent. Meanwhile, the dark currents have been increased significantly due to the increase in carrier concentration and mobility near the surface of ZnO thin film. Although plasmonic effect was observed by the photoluminescence enhancement, the main mechanism of the increase in the dark current and photoresponsivity for ZnO photoconductors has been interpreted by surface states, interface states, and persistent photoconductivity.

The authors report the enhancement of the bandgap emission from ZnO thin films by surface modification and surface plasmon cross-coupling. 12-fold and twofold enhancements of bandgap emission from the metal side of ZnO film were observed by sputtering Pt nanopattern and Pt film onto ZnO film, respectively. Time-resolved photoluminescence indicates that the decay time is slowed down by Pt capping, contrary to common observations. The “abnormal” phenomena are interpreted by considering both the surface modification and surface plasmon coupling. Published version

ZnMgO films are prepared by RF magnetron sputtering using a composite target and the Mg composition of the samples can be controlled easily even at a high growth temperature. The metal?semiconductor?metal photodetector based on the wurtzite Zn0.6Mg0.4O film exhibits a very low dark current (5?pA at |Vbias| = 3?V) and a high UV/visible rejection ratio (more than three orders of magnitude). The peak responsivity of the photodetector is at around 270?nm and a very sharp cutoff wavelength is at a wavelength of about 295?nm corresponding to the absorption edge of the Zn0.6Mg0.4O film.

In this work, MgxZn1−xO (MZO) thin films were grown on quartz by rf magnetron sputtering technology. It was found that MZO films possess preferred c-axis orientation and exhibit hexagonal wurtzite structure up to a Mg composition of 44.26 mol%. Furthermore, the band gap determined by absorption spectra was smaller than the theoretical calculation for the as-grown MZO thin film. The band gap blueshifted initially and then redshifted with increasing the annealing temperature of the MZO films. The reason for the shift was attributed to the displacement, effusion of Mg atoms in the films and phase separation at different annealing temperatures.

Zn0.76Mg0.24O p-n photodiode was fabricated on (000l) Al2O3 substrate by plasma-assisted molecular beam epitaxy. Ni∕Au and In metals deposited using vacuum evaporation were used as p-type and n-type contacts, respectively. Current-voltage measurements on the device showed weak rectifying behavior. The photodetectors exhibited a peak responsivity at around 325nm. The ultraviolet-visible rejection ratio (R325nm∕R400nm) of four orders of magnitude was obtained at 6V bias. The photodetector showed fast photoresponse with a rise time of 10ns and fall time of 150ns. In addition, the thermally limited detectivity was calculated as 1.8×1010cmHz1∕2∕W at 325nm, which corresponds to a noise equivalent power of 8.4×10−12W∕Hz1∕2 at room temperature.

FeSe film was prepared on GaAs (001) substrate by low pressure metal-organic chemical vapor deposition. The x-ray diffraction measurement indicated that the sample was preferentially oriented with tetragonal structure. The structure relationship between FeSe epilayer and GaAs (001) substrate has been studied. The critical behavior in the temperature-dependent resistivity at ∼290K is close to the Curie temperature, which confirmed that the transformation from ferromagnetism to paramagnetism could be responsible for the critical behavior.

The optical and electrical properties of FeSe thin films are studied by both optical absorption and Hall measurements, which suggest that ferromagnetic FeSe is a metal instead of a semiconductor. No absorption gap is observed in the whole spectrum range from far infrared to ultraviolet. Temperature dependent transport measurement indicates that FeSe has a resistivity about 10−3Ωcm. It is also found that there is a transition from n-type conductivity at low temperatures to p-type conductivity at higher temperatures in FeSe, which is attributed to the two-carrier transport nature and the thermal activation of localized carriers in the thin film.

Granular thin film samples composed of Fe clusters embedded in CdFeS were prepared with using low pressure metal organic chemical vapor deposition. Temperature dependence of the resistivity of the granular film follows well the relationship for the tunneling transport between the iron granules. A large negative magnetoresistance of about 2.2% at 0.1T was observed at room temperature due to the presence of Fe clusters. The hysteresis behavior observed in the magnetoresistance corresponded exactly to those of the hysteresis loop in the magnetization measurement, which evidently showed the correlation between the magnetoresistance and global magnetization in the sample.

Cd1−xFexS thin films with different Fe contents were grown on c-plane sapphire by low-pressure metal organic chemical vapor deposition. The resistivity of the thin films was found to increase with the addition of more Fe contents into the Cd1−xFexS thin films by elevating the growth temperature, which was attributed to the ionization of holes from trivalent Fe ions. High density Fe doping eventually reversed the conductivity of Cd1−xFexS thin film from n to p type. With increasing Fe content, the band-to-band transition at 2.5eV was suppressed while the emission from the donor-acceptor pairs at 2.0–2.4eV finally dominated the photoluminescence spectra.

Staphylococcus epidermidis ( S. epidermidis ) plays a critical role in modulating cutaneous inflammatory responses in skin. Although S. epidermidis has been shown to co-colonize with Propionibacterium acnes ( P. acnes ) in acne lesions, it is unclear whether S. epidermidis is involved in the regulation of P. acnes- induced inflammatory responses. In this study, we demonstrated that S. epidermidis inhibited P. acnes -induced inflammation in skin. P. acnes induced the expression of interleukin-6 and tumor necrosis factor-α via the activation of toll-like receptor (TLR) 2 in both keratinocytes and mouse ears. Staphylococcal lipoteichoic acid activated TLR2 to induce miR-143 in keratinocytes, and miR-143, in turn, directly targeted 3′ UTR of TLR2 to decrease the stability of TLR2 mRNA and then decreased TLR2 protein, thus inhibiting P. acnes -induced proinflammatory cytokines. The inhibitory effect of miR-143 was further confirmed in vivo as the administration of miR-143 antagomir into mouse ears abrogated the inhibitory effect of lipoteichoic acid on P. acnes -induced inflammation in skin. Taken together, these observations demonstrate that staphylococcal lipoteichoic acid inhibits P. acnes -induced inflammation via the induction of miR-143, and suggest that local modulation of inflammatory responses by S. epidermidis at the site of acne vulgaris might be a beneficial therapeutic strategy for management of P. acnes -induced inflammation.

In this paper, we investigate the stability of a class of nonlinear fractional neutral systems. We extend the Lyapunov-Krasovskii approach to nonlinear fractional neutral systems. Necessary and sufficient conditions for stability are obtained for the nonlinear fractional neutral systems. MSC:34K20, 34K37, 34K40.