Multifocal multilevel diffractive lens by wavelength multiplexing.

Flat lenses with focal length tunability can enable the development of highly integrated imaging systems. This work explores machine learning to inverse design a multifocal multilevel diffractive lens (MMDL) by wavelength multiplexing. The MMDL output is multiplexed in three color channels, red (650 nm), green (550 nm), and blue (450 nm), to achieve varied focal lengths of 4 mm, 20 mm, and 40 mm at these three color channels, respectively. The focal lengths of the MMDL scale significantly with the wavelength in contrast to conventional diffractive lenses. The MMDL consists of concentric rings with equal widths and varied heights. The machine learning method is utilized to optimize the height of each concentric ring to obtain the desired phase distribution so as to achieve varied focal lengths multiplexed by wavelengths. The designed MMDL is fabricated through a direct-write laser lithography system with gray-scale exposure. The demonstrated singlet lens is miniature and polarization insensitive, and thus can potentially be applied in integrated optical imaging systems to achieve zooming functions.

Machine learning enables the design of a bidirectional focusing diffractive lens.

Machine learning can efficiently empower the inverse design of cascaded diffractive optical elements. In this work, we explore the inverse design of a bidirectional focusing diffractive lens in a cascaded configuration through the diffractive optical neural network (DONN) machine learning method. The bidirectional focusing diffractive lens consists of two on-axially cascaded multi-level diffractive lenses. Each lens consists of concentric rings with equal widths and varying heights. The height of each concentric ring is optimized as part of the design algorithm. The diffractive lens has a focal length f+ as light propagates in the forward (Z+) direction. As light propagates in the backward (Z-) direction, the focal length changes to f-. The designed lens is fabricated through a two-photon polymerization 3D printing technique. The proposed design is polarization insensitive and miniature and can be readily applied in future functional optical imaging systems.

Modified xiaoyao san combined with chemotherapy for breast cancer: A systematic review and meta-analysis of randomized controlled trials.

Background: Breast cancer is a common cause of cancer-related death worldwide. Chemotherapy plays an indispensable role in the conventional treatment of breast cancer, bringing some physical burdens and discomfort on cancer patients. Consequently, more and more patients turn to seeking the help of Complementary and Alternative Medicine (CAM), mainly traditional Chinese medicine (TCM). Xiaoyao san (XYS), a classical formula, has been shown to improve symptoms of breast cancer. An increasing number of researches suggest that compared to chemotherapy alone, Chinese herbal medicine combined with chemotherapy could increase effectiveness and reduce toxicity caused by chemotherapy. Emerging experimental research continuously demonstrated some of the components in XYS could stop breast cancer tumor cells from growing. However, the efficacy and safety of modified XYS combined with chemotherapy remain to be determined. Therefore, it is essential to evaluate the comparative effectiveness and safety of modified XYS combined with chemotherapy in-depth, thus providing clinicians and policymakers with evidence-based guidance and new treatment options. Objective: To comprehensively evaluate the efficacy and safety of modified XYS in conjunction with chemotherapy in treating breast cancer by conducting a meta-analysis. Methods: 8 databases were systemically searched until April 3, 2022, including Web of Science PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Scientific Journals Database (VIP), and Chinese Biological Medical Database (CBM). Relevant randomized controlled trials (RCTs) comparing modified XYS in combination with chemotherapy versus chemotherapy alone were included. For the evaluation of methodological quality, Cochrane Collaboration was considered. Software Review Manager (version 5.4) was used for data analysis. Software STATA (version 15.0) was employed for sensitivity analysis and publication bias. Results: Altogether, 17 RCTs involving 1207 patients were investigated in the current review. The findings revealed that modified XYS combined with chemotherapy could lead to beneficial improvements compared to chemotherapy alone. More specifically, the combined therapy could enhance the short-term efficacy in the treatment of solid tumors (OR: 1.74; 95% CI 1.27 to 2.39; P = 0.0006; I2 = 0%); improve QOL (quality of life) (OR: 3.75; 95% CI 2.58 to 5.44; P < 0.00001; I2 = 0%); reduce clinical symptoms (OR: 3.69; 95% CI 1.43 to 9.49; P = 0.007; I2 = 53%); ease depression (MD: -12.96; 95% CI -16.09 to -9.83; P < 0.00001; I2 = 0%); increase leukocytes (OR: 0.32; 95% CI 0.20 to 0.50; P < 0.00001; I2 = 0%) and platelets (OR: 0.37; 95% CI 0.20 to 0.67; P = 0.001; I2 = 0%); reduce nausea and vomiting (OR: 0.26; 95% CI 0.15 to 0.44; P < 0. 00001; I2 = 0%); mitigate cardiotoxicity (OR: 0.16; 95% CI 0.07 to 0.36; P<0.00001; I2 = 0%); prolong survival time (OR: 2.19; 95% CI 1.03 to 4.66; P = 0.04; I2 = 0%), compared to chemotherapy alone. Unfortunately, there was no statistically significant difference in damage to the liver and kidney (OR: 0.59; 95% CI 0.29 to 1.21; P = 0.15; I2 = 0%). Conclusion: The existing evidence suggests modified XYS combined with chemotherapy leads to beneficial improvements in the management of breast cancer, which may serve as a promising therapy for breast cancer in clinical practice. Given the limited number of high quality RCTs, more rigorous, scientific, double-blinded, large-scale, multi-center clinical trials are warranted further. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022357860.

CNN-assisted SERS enables ultra-sensitive and simultaneous detection of Scr and BUN for rapid kidney function assessment.

Kidney disease is highly prevalent and may result in severe clinical outcomes. Serum creatinine (Scr) and blood urea nitrogen (BUN) are the most widely used biomarkers for kidney function assessment, yet when measured alone, the result can be affected by a variety of parameters such as age, gender, protein consumption, etc. Measuring Scr and BUN simultaneously can eliminate most of the external influences and greatly improve the assessment of kidney function. In this study, a real-time kidney function assessment system based on dual biomarker detection was proposed. Scr and BUN were determined using surface-enhanced Raman scattering (SERS) within the concentration range of 10-1 to 10-6 M and 0.28 to 100 mg dl-1, respectively. A one-dimensional convolutional neural network (1D-CNN) model was employed to quantitatively analyze the concentration of biomarkers from the SERS spectral measurements. Moreover, we simulated a variety of kidney health conditions with 16 groups of mixed Scr and BUN in serum. The proposed CNN-assisted SERS method was used to quantify both biomarkers and provide diagnostic results. The Au core-Ag shell nanoprobes provided ultra-sensitive SERS detection and the CNN model achieved excellent regression results with an R2 of 0.9871 in the testing dataset. The system demonstrated a rapid and robust evaluation for the assessment of kidney function, providing a promising idea for medical diagnosis with the help of spectroscopy and deep learning methods.

Three-dimensional direct lithography of stable perovskite nanocrystals in glass.

Material composition engineering and device fabrication of perovskite nanocrystals (PNCs) in solution can introduce organic contamination and entail several synthetic, processing, and stabilization steps. We report three-dimensional (3D) direct lithography of PNCs with tunable composition and bandgap in glass. The halide ion distribution was controlled at the nanoscale with ultrafast laser-induced liquid nanophase separation. The PNCs exhibit notable stability against ultraviolet irradiation, organic solution, and high temperatures (up to 250°C). Printed 3D structures in glass were used for optical storage, micro-light emitting diodes, and holographic displays. The proposed mechanisms of both PNC formation and composition tunability were verified.

Why are pollution damages lower in developed countries? Insights from high-Income, high-particulate matter Hong Kong.

Conventional wisdom suggests that marginal damages from particulate matter pollution are high in less-developed countries because they are highly polluted. Using administrative data on the universe of births and deaths, we explore birthweight and mortality effects of gestational particulate matter exposure in high-pollution yet high-income Hong Kong. The marginal effects of particulates on birthweight are large but we fail to detect an effect on neonatal mortality. We interpret our stark mortality results in a comparative analysis of pollution-mortality relationships across studies. We provide early evidence that marginal mortality damages from pollution are high in less-developed countries because they are less developed, not because they are more polluted.

768-ary Laguerre-Gaussian-mode shift keying free-space optical communication based on convolutional neural networks.

Beyond orbital angular momentum of Laguerre-Gaussian (LG) modes, the radial index can also be exploited as information channel in free-space optical (FSO) communication to extend the communication capacity, resulting in the LG- shift keying (LG-SK) FSO communications. However, the recognition of radial index is critical and tough when the superposed high-order LG modes are disturbed by the atmospheric turbulences (ATs). In this paper, the convolutional neural network (CNN) is utilized to recognize both the azimuthal and radial index of superposed LG modes. We experimentally demonstrate the application of CNN model in a 10-meter 768-ary LG-SK FSO communication system at the AT of Cn2 = 1e-14 m-2/3. Based on the high recognition accuracy of the CNN model (>95%) in the scheme, a colorful image can be transmitted and the peak signal-to-noise ratio of the received image can exceed 35 dB. We anticipate that our results can stimulate further researches on the utilization of the potential applications of LG modes with non-zero radial index based on the artificial-intelligence-enhanced optoelectronic systems.

Anomalous transport and magnetic properties induced by slight Cu valence alternation in layered oxytelluride BiCuTeO.

In this paper, we report on the transport and magnetic properties of layered oxytelluride BiCuTeO polycrystals with slight mixed valence of Cu. The temperature-dependent electrical resistivity reveals degenerate semiconductor behavior (similar to metals). Under the action of an external magnetic field, the BiCuTeO polycrystal sample exhibits unsaturated magnetic resistance (MR) of about 8% at 2 K and 9 Tesla. The Hall resistivities show nonlinear behavior, suggesting the coexistence of both electrons and holes in the sample. When the temperature is decreased to around 110 K, the dominant carriers are changed from electrons to holes from the viewpoint of electrical transport, which is supported by the calculated temperature-dependent Fermi energy. Meanwhile, at low temperatures (<100 K), the impurity magnetic moment formed by a small amount of positive divalent copper exhibits short-range magnetism (a spin-glass-like feature), which gives rise to a narrow magnetic hysteresis loop. Our work may benefit in-depth understanding of physical properties of BiCuTeO-based materials.

Opioid Deaths and Local Healthcare Intensity: A Longitudinal Analysis of the U.S. Population, 2003-2014.

INTRODUCTION: This study examines the association between local healthcare intensity and drug death rates. METHODS: County-level drug death rates were computed for 2003-2014 using vital statistics data adjusted for incomplete reporting of drug involvement. A county-level healthcare intensity index was constructed using Dartmouth Atlas of Health Care data. Linear regression and dose-response models were estimated for all residents and for population subgroups to analyze the relationship between healthcare intensity and drug death rates, as well as for 7 indicators of healthcare quality. Data collection and analysis were conducted in 2018 and 2019. RESULTS: Linear estimates indicated a positive correlation between healthcare intensity and opioid-involved drug death rates. Dose-response models revealed that the association was especially pronounced for the 2 highest healthcare intensity quintiles. Moving from the lowest to the highest healthcare intensity quintile was associated with a 2.14 (95% CI=1.56, 2.72) per 100,000 rise in opioid-involved drug death rates and a 25.1% (95% CI=18.3%, 31.9%) increase from the base rate of 8.54 per 100,000. Corresponding associations were larger in absolute terms for individuals who were male, white, aged 20-44 years, and not college educated than for their counterparts, but similar in percentages, except for 2 minority racial groups and seniors. Non-opioid drug death rates were unrelated to healthcare intensity. High healthcare intensity was associated with worse healthcare quality for 6 of 7 indicators. CONCLUSIONS: In the U.S., between 2003 and 2014, high medical care intensity was associated with elevated opioid death rates and lower healthcare quality.

Laplacian-Uniform Mixture-Driven Iterative Robust Coding With Applications to Face Recognition Against Dense Errors.

Outliers due to occlusion, pixel corruption, and so on pose serious challenges to face recognition despite the recent progress brought by sparse representation. In this article, we show that robust statistics implemented by the state-of-the-art methods are insufficient for robustness against dense gross errors. By modeling the distribution of coding residuals with a Laplacian-uniform mixture, we obtain a sparse representation that is significantly more robust than the previous methods. The nonconvex error term of the implemented objective function is nondifferentiable at zero and cannot be properly addressed by the usual iteratively reweighted least-squares formulation. We show that an iterative robust coding algorithm can be derived by local linear approximation of the nonconvex error term, which is both effective and efficient. With iteratively reweighted l1 minimization of the error term, the proposed algorithm is capable of handling the sparsity assumption of the coding errors more appropriately than the previous methods. Notably, it has the distinct property of addressing error detection and error correction cooperatively in the robust coding process. The proposed method demonstrates significantly improved robustness for face recognition against dense gross errors, either contiguous or discontiguous, as verified by extensive experiments.

Breastfeeding, schooling, and income: Insights from the Indonesian Family Life Survey.

Recent research has highlighted associations of breastfeeding with IQ, schooling, and income, but uncertainty about such links remains. The Indonesian Family Life Survey, representative of 83% of the Indonesian population, provides data on breastfeeding, parents' years of schooling, wealth, and other family characteristics in 1993-1994, as well as schooling and income in 2014-2015 for 5,421 children of those families. Using linear regressions and controlling for village or neighbourhood, as well as propensity score matching, we analysed breastfeeding associations for boys and girls separately, when regularly fed foods/beverages other than breast milk is significantly associated with years of schooling in 2014-2015 for girls, but not for boys, after controlling for the village or neighbourhood of residence in 1993-1994. For girls, ages 1 to 1.9, 2 to 2.9, 3 to 3.9, and >4 months, relative to ages <1 month, are associated with an additional 0.41 to 0.46 years of schooling, with p values of 0.086, 0.071, 0.043, and 0.026, respectively. No comparable estimate for boys attains statistical significance. Using propensity score matching yields similar results. Associations with annual income in 2014-2015 are not statistically significant, either for all children, or for either sex. Our finding suggests that delaying regular feeding of foods/beverages other than breast milk beyond 1 month may help girls' schooling but has no observable association with annual income, perhaps because of lower labour force participation by women. Also, the inclusion of controls for village or neighbourhood of residence reduces confounding.

Hydrothermal treatment and butylphosphonic acid derived self-assembled monolayers for improving the surface chemistry and corrosion resistance of AZ61 magnesium alloy.

The hydrothermal treatment followed by a self-assembled monolayer (SAM) of 1-butylphosphonic acid through the tethering by aggregation and growth (T-BAG) method was employed to produce protective surface coatings on the Mg-6Al-1Zn alloy (AZ61) for reducing the degradation rate in physiological environments. Potentiodynamic polarization measurements revealed that the organic self-assembled monolayer and Mg(OH)2 coating can further enhance the surface chemical stability and corrosion resistance of Mg alloys. SAM-treated Mg(OH)2 coatings can be served as a more passive surface layer as a result of their much higher charge transfer resistance and the presence of Warburg impedance in electrochemical impedance spectroscopy measurement.

Phenolic Modified Ceramic Coating on Biodegradable Mg Alloy: The Improved Corrosion Resistance and Osteoblast-Like Cell Activity.

Magnesium alloys have great potential for developing orthopedic implants due to their biodegradability and mechanical properties, but the rapid corrosion rate of the currently-available alloys limits their clinical applications. To increase the corrosion resistance of the substrate, a protective ceramic coating is constructed by a micro-arc oxidation (MAO) process on ZK60 magnesium alloy. The porous ceramic coating is mainly composed of magnesium oxide and magnesium silicate, and the results from cell cultures show it can stimulate osteoblastic cell growth and proliferation. Moreover, gallic acid, a phenolic compound, was successfully introduced onto the MAO coating by grafting on hydrated oxide and chelating with magnesium ions. The gallic acid and rough surface of MAO altered the cell attachment behavior, making it difficult for fibroblasts to adhere to the MAO coating. The viability tests showed that gallic acid could suppress fibroblast growth and stimulate osteoblastic cell proliferation. Overall, the porous MAO coating combined with gallic acid offered a novel strategy for increasing osteocompatibility.

Composition and temperature-dependent phase transition in miscible Mo1-xWxTe2 single crystals.

Transition metal dichalcogenides (TMDs) WTe2 and MoTe2 with orthorhombic Td phase, being potential candidates as type-II Weyl semimetals, are attracted much attention recently. Here we synthesized a series of miscible Mo1-xWxTe2 single crystals by bromine vapor transport method. Composition-dependent X-ray diffraction and Raman spectroscopy, as well as composition and temperature-dependent resistivity prove that the tunable crystal structure (from hexagonal (2H), monoclinic (ß) to orthorhombic (Td) phase) can be realized by increasing W content in Mo1-xWxTe2. Simultaneously the electrical property gradually evolves from semiconductor to semimetal behavior. Temperature-dependent Raman spectroscopy proves that temperature also can induce the structural phase transition from ß to Td phase in Mo1-xWxTe2 crystals. Based on aforementioned characterizations, we map out the temperature and composition dependent phase diagram of Mo1-xWxTe2 system. In addition, a series of electrical parameters, such as carrier type, carrier concentration and mobility, have also been presented. This work offers a scheme to accurately control structural phase in Mo1-xWxTe2 system, which can be used to explore type-II Weyl semimetal, as well as temperature/composition controlled topological phase transition therein.

Dramatically decreased magnetoresistance in non-stoichiometric WTe2 crystals.

Recently, the layered semimetal WTe2 has attracted renewed interest owing to the observation of a non-saturating and giant positive magnetoresistance (~10(5)%), which can be useful for magnetic memory and spintronic devices. However, the underlying mechanisms of the giant magnetoresistance are still under hot debate. Herein, we grew the stoichiometric and non-stoichiometric WTe2 crystals to test the robustness of giant magnetoresistance. The stoichiometric WTe2 crystals have magnetoresistance as large as 3100% at 2 K and 9-Tesla magnetic field. However, only 71% and 13% magnetoresistance in the most non-stoichiometry (WTe1.80) and the highest Mo isovalent substitution samples (W0.7Mo0.3Te2) are observed, respectively. Analysis of the magnetic-field dependent magnetoresistance of non-stoichiometric WTe2 crystals substantiates that both the large electron-hole concentration asymmetry and decreased carrier mobility, induced by non-stoichiometry, synergistically lead to the decreased magnetoresistance. This work sheds more light on the origin of giant magnetoresistance observed in WTe2.

Microstructure-modified biodegradable magnesium alloy for promoting cytocompatibility and wound healing in vitro.

The microstructure of biomedical magnesium alloys has great influence on anti-corrosion performance and biocompatibility. In practical application and for the purpose of microstructure modification, heat treatments were chosen to provide widely varying microstructures. The aim of the present work was to investigate the influence of the microstructural parameters of an Al-free Mg-Zn-Zr alloy (ZK60), and the corresponding heat-treatment-modified microstructures on the resultant corrosion resistance and biological performance. Significant enhancement in corrosion resistance was obtained in Al-free Mg-Zn-Zr alloy (ZK60) through 400 °C solid-solution heat treatment. It was found that the optimal condition of solid-solution treatment homogenized the matrix and eliminated internal defects; after which, the problem of unfavorable corrosion behavior was improved. Further, it was also found that the Mg ion-release concentration from the modified ZK60 significantly induced the cellular activity of fibroblast cells, revealing in high viability value and migration ability. The experimental evidence suggests that this system can further accelerate wound healing. From the perspective of specific biomedical applications, this research result suggests that the heat treatment should be applied in order to improve the biological performance.

Heat treatment mechanism and biodegradable characteristics of ZAX1330 Mg alloy.

Heat treatments are key processes in the development of biodegradable magnesium implants. The aim of this study is to investigate the factors of microstructures and metallurgical segregation on the functionality of biodegradable magnesium alloy. The solid solution heat treatment and strain induced melting activation heat treatment were employed to alter the microstructures of ZAX1330 alloy in this study. Heat treatments caused a significant change on grain size and distribution of secondary phases. The fine-grained microstructure enhanced the mechanical strength, corrosion resistance and achieved the lowest degradation rate in simulated body fluid solution. In coarse-grained microstructure systems, grain growth followed liquid phase formation. The corrosion rate increased due to a larger cathodic region. The status of micro-alloyed calcium (in solid solution or segregated) influenced the microstructural evolution mechanisms, mechanical strength, and degradation properties. A cytotoxicity test and a live/dead assay showed that ZAX1330 had good cytocompatibility, which varied with heat treatment, and no cell toxicity. The results suggest that heat treatment should be controlled precisely in order to improve the cytocompatibility of magnesium alloys for application in orthopedic implants.

The effect of dynamic culture conditions on endothelial cell seeding and retention on small diameter polyurethane vascular grafts.

Due to the limited number of cells available in endothelial cell (EC) seeding of small diameter vascular grafts, high seeding rate and ideal proliferation are normally required and can be achieved by optimizing the EC seeding and culture procedures. In this study, by using rotational seeding at 0.16 rpm for 12 h in an incubator, 90% cells were successfully seeded on the polyurethane vascular grafts. Following a period of 72 h of static culture, the cell retention after 6 h of flushing could reach 90%. The retention was further enhanced after perfuse culture (9 cm/s). The optimal procedures to prepare a polyurethane vascular graft (4-mm i.d., 4 cm long) populated with firmly attached EC were therefore: (1) seeding the graft with 0.5 ml of cell suspension containing approximately 10(5) cells rotated at 0.16 rpm for 12 h; (2) culturing the seeded graft in static for 72 h; and (3) culturing the graft by perfusion (9 cm/s) for another 72 h to 7 days. These procedures consistently resulted in a graft covered with confluent vein EC that fully retained on the surface after 6 h of in vitro flushing.