Maskless photolithography based on ultraviolet micro-LEDs and direct writing method for improving pattern resolution.

Ultraviolet micro-LEDs show great potential as a light source for maskless photolithography. However, there are few reports on micro-LED based maskless photolithography systems, and the studies on the effects of system parameters on exposure patterns are still lacking. Hence, we developed a maskless photolithography system that employs micro-LEDs with peak wavelength 375 nm to produce micrometer-sized exposure patterns in photoresists. We also systematically explored the effects of exposure time and current density of micro-LED on static direct writing patterns, as well as the effects of stage velocity and current pulse width on dynamic direct writing patterns. Furthermore, reducing the size of micro-LED pixels enables obtaining high-resolution exposure patterns, but this approach will bring technical challenges and high costs. Therefore, this paper proposes an oblique direct writing method that, instead of reducing the micro-LED pixel size, improves the pattern resolution by changing the tilt angle of the sample. The experimental results show that the linewidths of the exposed lines decreased by 4.0% and 15.2%, respectively, as the sample tilt angle increased from 0° to 15° and 30°, which confirms the feasibility of the proposed method to improve the pattern resolution. This method is also expected to correct the exposure pattern error caused by optical distortion of the lens in the photolithography system. The system and method reported can be applied in various fields such as PCBs, photovoltaics, solar cells, and MEMS.

Two-dimensional Keitz method for the radiant power measurement of planar ultraviolet excilamps.

Planar X e B r ∗ and X e C l ∗ excilamps emitting noncoherent narrowband UVB light (280-315 nm) are now widely used to cure psoriasis and vitiligo as well as to improve vitamin D synthesis. The two-dimensional integral formula has been deducted in this study, which is a good method and has great practical significance to calculate the total radiant power and assess the energy efficiency of a planar UV lamp. The measured radiant power of planar white LED lamps through a two-dimensional Keitz formula has been compared to that of gonio-photometer, verifying the applicability of the formula. The optimum measurement distance is dependent on the lamp length (1.5L≤D≤3.5L) for which the derivation from the two methods can be controlled within 10%. The planar X e B r ∗ excilamps have been measured and compared to coaxial excilamps, which show similar patterns of change for the radiant characteristics. Since the planar radiant power formula only needs to measure normal illuminance at a certain distance from the symmetric center of the lamp, it is more convenient to use and is a low-cost method to promote the development of large-sized planar ultraviolet lamps.

QTY code designed thermostable and water-soluble chimeric chemokine receptors with tunable ligand affinity.

Chemokine receptors are of great interest as they play a critical role in many immunological and pathological processes. The ability to study chemokine receptors in aqueous solution without detergent would be significant because natural receptors require detergents to become soluble. We previously reported using the QTY code to design detergent-free chemokine receptors. We here report the design of 2 detergent-free chimeric chemokine receptors that were experimentally unattainable in detergent solution. We designed chimeric receptors by switching the N terminus and 3 extracellular (EC) loops between different receptors. Specifically, we replaced the N terminus and 3 EC loops of CCR5QTY with the N terminus and 3 EC loops of CXCR4. The ligand for CXCR4; namely CXCL12, binds to the chimeric receptor CCR5QTY (7TM)-CXCR4 (N terminus+3 EC loops), but with lower affinity compared to CXCR4; the CCL5 ligand of CCR5 binds the chimeric receptor with ∼20× lower affinity. The chimeric design helps to elucidate the mechanism of native receptor-ligand interaction. We also show that all detergent-free QTY-designed chemokine receptors, expressed in Escherichia coli, bind to their respective chemokines with affinities in the nanomolar (nM) range, similar to the affinities of native receptors and SF9-produced QTY variants. These QTY-designed receptors exhibit remarkable thermostability in the presence of arginine and retain ligand-binding activity after heat treatment at 60 °C for 4 h and 24 h, and at 100 °C for 10 min. Our design approach enables affordable scale-up production of detergent-free QTY variant chemokine receptors with tunable functionality for various uses.

Photosynthetic spectral response curves of saffron leaves.

Saffron (Crocus sativus L.) is an herb with outstanding medicinal functions and commercial value. Light is an important factor in plant growth, and the sensitivity of plant photosynthesis to light quality can be characterized by photosynthetic spectral response curves. This study aims to measure the spectral response curves of saffron leaves so as to provide theoretical guidance for a supplemental lighting spectrum to increase saffron production. The measurement results show the peaks of spectral response curves of saffron leaves are at 480 nm and 660 nm, which provides a reference for the peak wavelengths of supplemental lighting spectrum. Full-spectrum white light with low color temperature or red light mixed with a little blue light might be most beneficial for saffron biomass accumulation.

Implications of Zika virus and congenital Zika syndrome for the number of live births in Brazil.

An increase in microcephaly, associated with an epidemic of Zika virus (ZIKV) in Brazil, prompted the World Health Organization to declare a Public Health Emergency of International Concern in February 2016. While knowledge on biological and epidemiological aspects of ZIKV has advanced, demographic impacts remain poorly understood. This study uses time-series analysis to assess the impact of ZIKV on births. Data on births, fetal deaths, and hospitalizations due to abortion complications for Brazilian states, from 2010 to 2016, were used. Forecasts for September 2015 to December 2016 showed that 119,095 fewer births than expected were observed, particularly after April 2016 (a reduction significant at 0.05), demonstrating a link between publicity associated with the ZIKV epidemic and the decline in births. No significant changes were observed in fetal death rates. Although no significant increases in hospitalizations were forecasted, after the ZIKV outbreak hospitalizations happened earlier in the gestational period in most states. We argue that postponement of pregnancy and an increase in abortions may have contributed to the decline in births. Also, it is likely that an increase in safe abortions happened, albeit selective by socioeconomic status. Thus, the ZIKV epidemic resulted in a generation of congenital Zika syndrome (CZS) babies that reflect and exacerbate regional and social inequalities. Since ZIKV transmission has declined, it is unlikely that reductions in births will continue. However, the possibility of a new epidemic is real. There is a need to address gaps in reproductive health and rights, and to understand CZS risk to better inform conception decisions.

LED light with enhanced color saturation and improved white light perception.

The light emitting diodes (LEDs) with high light quality were investigated to enhance the color appearance of the illuminated objects and increase the white light perception of the ambience. The spectral power distributions of the LED lights were optimized by addition of the RGB components and by shifting the color coordinate below the blackbody line to get desired color rendering index (CRI) and high gamut area index (GAI). The results of the human factor study reveal that the "perfect" white light can be achieved to both enhance color saturation and improve light visual impression. The effects of observer metamerism were studied to clarify the observed phenomenon that the white lights with the same color coordinates were perceived differently by real observers.

Mutli-modal straight flow matching for accelerated MR imaging.

Diffusion models have garnered great interest lately in Magnetic Resonance (MR) image reconstruction. A key component of generating high-quality samples from noise is iterative denoising for thousands of steps. However, the complexity of inference steps has limited its applications. To solve the challenge in obtaining high-quality reconstructed images with fewer inference steps and computational complexity, we introduce a novel straight flow matching, based on a neural ordinary differential equation (ODE) generative model. Our model creates a linear path between undersampled images and reconstructed images, which can be accurately simulated with a few Euler steps. Furthermore, we propose a multi-modal straight flow matching model, which uses relatively easily available modalities as supplementary information to guide the reconstruction of target modalities. We introduce the low frequency fusion layer and the high frequency fusion layer into our multi-modal model, which has been proved to produce promising results in fusion tasks. The proposed multi-modal straight flow matching (MMSflow) achieves state-of-the-art performances in task of reconstruction in fastMRI and Brats-2020 and improves the sampling rate by an order of magnitude than other methods based on stochastic differential equations (SDE).

Effects of total daily light integral from blue and broad-band red LEDs on flowering of saffron (Crocus sativus L.).

Present indoor cultivation of saffron (Crocus sativus L.) only depends on artificial planting experience, so that flower number and stigma yield are seriously affected in case of cloudy or rainy days and temperature changes. In this study, a luminaire was used at 10-h photoperiod combined 450 nm blue LEDs with 660 nm broad-band red LEDs, which respectively had full width at half maximum (FWHM) of 15 nm and 85 nm, in a ratio of blue: red: far-red light = 20%: 62%: 18%. The influence of total daily light integral (TDLI) was evaluated on flowering characteristics, stigma quality, as well as leaf morphological characteristics. The results showed that flower number, daily flowering proportion, stigma dry weight and crocetin esters content were significantly correlated with TDLI (P < 0.01). The increasing TDLI could slightly promote leaf width and leaf area beyond buds, but had no significant effect on bud length and leaf length. Both the average flower number per corm and dried stigma yield was the highest under the 150 mol m-2 TDLI treatment, up to 3.63 and 24.19 mg respectively. The former was 0.7 more than that under original natural light treatment, while the later was 50% higher. Totaling, combining blue LEDs with a broad-band red LEDs of the 150 mol m-2 TDLI was the most favorable condition for flower number and stigma quality of saffron in this study.

Effects of Electrical Pulse Width and Output Irradiance on Intense Pulse Light Inactivation.

The effects of electrical pulse width and output irradiance on the inactivation effect of intense pulse light (IPL) are studied in this paper. The measured radiant efficiency of pulsed xenon lamp can be more than 50%, and its irradiance can reach levels 100-times greater than that of a low-pressure mercury lamp. Staphylococcus aureus is used in inactivation experiments. When the irradiance and dose are both constant, there is no significant difference in inactivation efficiency when the pulse width is changed. However, a narrow pulse width corresponding to high irradiance at the same single-pulsed dose displays better inactivation effect. Experimental results are compared between the xenon lamp and low-pressure mercury lamp. The reduction factor (RF) value of the xenon lamp is more than 1.0 higher under the condition of both the same dose and irradiance. In order to achieve the same RF value, the dose of continuous-wave light must be at least three-times greater than that of pulsed light. The spectral action of the pulsed light is also studied. It is confirmed that UVC plays a major role across the whole spectrum. The experimental results show that extreme high-pulsed irradiance presents the main contributing factor behind the excellent bactericidal effect of IPL.

Non-full-length Water-Soluble CXCR4QTY and CCR5QTY Chemokine Receptors: Implication for Overlooked Truncated but Functional Membrane Receptors.

It was posited that functionalities of GPCRs require full-length sequences that are negated by residue deletions. Here we report that significantly truncated nfCCR5QTY and nfCXCR4QTY still bind native ligands. Receptor-ligand interactions were discovered from yeast 2-hybrid screening and confirmed by mating selection. Two nfCCR5QTY (SZ218a, SZ190b) and two nfCXCR4QTY (SZ158a, SZ146a) were expressed in E. coli. Synthesized receptors exhibited α-helical structures and bound respective ligands with reduced affinities. SZ190b and SZ158a were reconverted into non-QTY forms and expressed in HEK293T cells. Reconverted receptors localized on cell membranes and functioned as negative regulators for ligand-induced signaling when co-expressed with full-length receptors. CCR5-SZ190b individually can perform signaling at a reduced level with higher ligand concentration. Our findings provide insight into essential structural components for CCR5 and CXCR4 functionality, while raising the possibility that non-full-length receptors may be resulted from alternative splicing and that pseudo-genes in genomes may be present and functional in living organisms.

Photo-dissociation of dimethylamine by KrBr* excilamp.

A study of dimethylamine photo-dissociation in the gas phase has been conducted using UV radiation delivered from a KrBr(*) excilamp, driven by a sinusoidal electronic control gear with maximum emission at wavelength of 207 nm. The electrical input power and radiant power of the lamp were measured to determine their effects on the degradation. The influence of flow velocity and initial concentration of dimethylamine were also examined. In order to evaluate the photo-dissociation process comprehensively, several parameters were investigated, including removal efficiency, energy yield, carbon balance and CO2 selectivity. It is shown that the removal efficiency increases with enhanced input power and decreased gas flow rate. A high removal efficiency of 68% is achieved for lamp power 102W and flow velocity 15 m(3) h(-1). The optimum dimethylamine initial concentration is around 3520 mg m(-3), for which the energy yield reaches up to 442 gk Wh(-1) when the input power is 65W. In addition, two chain compounds (1,3-bis-dimethylamino-2-propanol; 3-penten-2-one, 4-amino) and three ring organic matters (1-azetidinecarboxaldehyde, 2,2,4,4-tetramethyl; N-m-tolyl-succinamic acid; p-acetoacetanisidide), were identified by GC-MS as secondary products, in order to demonstrate the pathways of the dimethylamine degradation.