A centimeter-scale achromatic hybrid metalens with polarization-insensitivity in the visible

Metalenses, featuring ultra-compactness and CMOS compatibility, are limited by the compromise between the diameter, numerical aperture, and working waveband. To address this problem, we propose and numerically demonstrate a centimeter-scale metasurface-refractive hybrid metalens working in the band of 440 - 700 nm. Revisiting the general Snell law, we present the phase profile of a chromatic aberration correction metasurface that can apply to a plano-convex refractive lens of an arbitrary surface type. Simulated by our semi-vector method, the designed achromatic hybrid metalens achieves 81% chromatic aberration suppression and polarization insensitivity. Broadband imaging results of the hybrid metalens are further provided, verifying the achromatism of the designed hybrid metalens. It can find applications in camera lenses and other optical systems that need compact, high-performance lenses.Comment: 10 pages, 5 figures

Revealing the stability, elastic properties and electronic structures of Pd-V intermetallics via first principle calculations

Precious metals and their alloys are promising high-temperature materials due to the high melting point, high strength and thermodynamically stability, in which Pd-V alloys are one kind of important systems. However, the influence of V concentration on structure stability, mechanical and thermodynamic properties and chemical bonding of Pd-V compounds is unknown. The structures, elastic properties, anisotropic of elastic and electronic structures of thirteen Pd-V compounds as a function of V concentration have been investigated by first principle calculations in this work. We have determined all the possible stable phases of Pd-V system for the first time by thermodynamics convex hull and phonon spectrum. The calculated results show that α-Pd2V has the lowest formation enthalpies as -0.34 eV/atom, indicating more thermodynamically stable than other structures. The elastic constants, bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio of the Pd-V compounds are also calculated and the β-Pd3V has the largest shear modulus and Young’s modulus as 107.1 GPa and 275.7 GPa, respectively. The anisotropic mechanical properties of these Pd-V compounds are discussed in detailed by the anisotropic index, three-dimensional (3D) surface contours and the planer projections on (001) and (110) planes of the Young’s modulus. The values of total density of states (TDOS) of all compounds are nonzero at Fermi energy (EF), indicating metallic feature for all the Pd-V compounds

Evolving market-shaping strategies to boost access to essential medical products in developing countries with HIV self-testing as a case study

Abstract The COVID-19 pandemic has exacerbated health inequities among countries in the Global South with limited access to essential medical products, leading to a higher infection and mortality rate, especially among vulnerable populations. Despite tremendous progress in global health financing, the estimated annual financing gap in developing countries is projected to reach US$371 billion per year by 2030. Therefore, developing market-shaping strategies is of great importance in ensuring adequate supply, affordable prices, and equitable access to essential medical products in low-and middle-income countries. We propose a strategic and appropriate market-shaping intervention framework for governments, international organizations, and NGOs to maximize access to essential medical products in developing countries. In the health field, we believe that market shaping strategy could be defined as a set of purposeful activities that market forces may intervene with to advance the development, production, supply, and distribution of global goods for health, making essential medical products more affordable, accessible, innovative, sustainable and quality assured. We argue that when designing a market-shaping strategy, policy or decision-makers must take full advantage of the key drivers to keep the market dynamic, interactive, and constantly evolving to meet the unmet medical needs. In addition, different forms of market-shaping interventions are determined by objectives and specific issues to be addressed. More comprehensive market shaping strategies, including the strategic use of market expansion, market disruption, market maintenance, and market contraction alone or together, deserve to be explored and key stakeholders are also expected to join forces to make the intervention more efficient and productive

First-Principles Calculations of Thermal and Electrical Transport Properties of bcc and fcc Dilute Fe–X (X = Al, Co, Cr, Mn, Mo, Nb, Ni, Ti, V, and W) Binary Alloys

The adiabatic shear sensitivity of ultra-high-strength steels is closely related to their thermal conductivity. Therefore, it is essential to investigate the effects of alloying elements on the thermal conductivity of ultra-high-strength steel. In this study, the variation in the scattering behavior of electrons with respect to temperature and the mechanism of three-phonon scattering were considered for obtaining the contributions of electrons and phonons, respectively, to the thermal conductivity of alloys while solving the Boltzmann transport equation. By predicting the effect of ten alloying elements on the electronic thermal conductivity (κe), it was found that, at 1200 K, the doping of iron with Ni and Cr endowed iron with κe values of 24.9 and 25.7 W/m K, respectively. In addition, the prediction for the lattice thermal conductivity (κL), which was performed without considering point defect scattering, indicated that elements such as Al, Co, Mn, Mo, V, and Cr demonstrate a positive effect on the lattice thermal conductivity, with values of 3.6, 3.7, 3.0, 3.1, 3.9, and 3.8 W/m K, respectively. The contribution of κL is only 5–15% of the total thermal conductivity (κtotal). The alloying elements exhibited a similar effect on κtotal and κe. Δκi; the change in thermal conductivity with respect to κ0 owing to the alloying element i was evaluated according to the total thermal conductivity. These values were used to understand the effect of the concentration of alloying elements on the thermal conductivity of iron. The Δκi values of Ni, Co, and W were 6.44, 6.80, and 6.06, respectively, indicating a reduction in the thermal conductivity of iron. This paper provides theoretical guidance for the design of ultra-high-strength steels with a high thermal conductivity

Factors associated with the utilization of diagnostic tools among countries with different income levels during the COVID-19 pandemic

Abstract Background Disparities in the utilization of essential medical products are a key factor contributing to inequality in health outcomes. We aimed to analyze the trends and influencing factors in using Coronavirus disease 2019 (COVID-19) diagnostic tools and disparities in countries with different income levels. Methods We conducted a cross-sectional study using open and publicly available data sources. Data were mainly collected from the Foundation for Innovative New Diagnostics, "Our World in Data," and the Global Burden of Disease databases. Negative binomial regression model and generalized linear mixed model were employed to investigate into five sets of factors associated with the usage of diagnostics: severity of COVID-19, socioeconomic status, health status, medical service capacity, and rigidity of response. Dominance analysis was utilized to compare the relative importance of these factors. The Blinder–Oaxaca decomposition was used to decompose the difference in the usage of diagnostics between countries. Results The total COVID-19 testing rate ranged from 5.13 to 22,386.63 per 1000 people from March 2020 to October 2022 and the monthly testing rate declined dramatically from January 2022 to October 2022 (52.37/1000 vs 5.91/1000).. The total testing rate was primarily associated with socioeconomic status (37.84%), with every 1 standard deviation (SD) increase in Gross Domestic Product per capita and the proportion of people aged ≥ 70, the total testing rate increased by 88% and 31%. And so is the medical service capacity (33.66%), with every 1 SD increase in health workforce density, the number increased by 38%. The monthly testing rate was primarily associated with socioeconomic status (34.72%) and medical service capacity (28.67%), and the severity of COVID-19 (21.09%). The average difference in the total testing rates between high-income and low-income countries was 2726.59 per 1000 people, and 2493.43 (91.45%) of the differences could be explained through the five sets of factors. Conclusions Redoubling the efforts, such as local manufacturing, regulatory reliance, and strengthening the community health workforce and laboratory capacity in low- and middle-income countries (LMICs) cannot be more significant for ensuring sustainable and equitable access to diagnostic tools during pandemic

Changes of gut microbiota and short chain fatty acids in patients with Peutz–Jeghers syndrome

Abstract Peutz–Jeghers Syndromeis a rare autosomal dominant genetic disease characterized by gastrointestinal hamartomatous polyps and skin and mucous membrane pigmentation. The pathogenesis of PJS remains unclear; however, it may be associated with mutations in the STK11 gene, and there is currently no effective treatment available. The gut microbiota plays an important role in maintaining intestinal homeostasis in the human body, and an increasing number of studies have reported a relationship between gut microbiota and human health and disease. However, relatively few studies have been conducted on the gut microbiota characteristics of patients with PJS. In this study, we analyzed the characteristics of the gut microbiota of 79 patients with PJS using 16 S sequencing and measured the levels of short-chain fatty acids in the intestines. The results showed dysbiosis in the gut microbiota of patients with PJS, and decreased synthesis of short-chain fatty acids. Bacteroides was positively correlated with maximum polyp length, while Agathobacter was negatively correlated with age of onset. In addition, acetic acid, propionic acid, and butyric acid were positively correlated with the age of onset but negatively correlated with the number of polyps. Furthermore, the butyric acid level was negatively correlated with the frequency of endoscopic surgeries. In contrast, we compared the gut microbiota of STK11-positive and STK11-negative patients with PJS for the first time, but 16 S sequencing analysis revealed no significant differences. Finally, we established a random forest prediction model based on the gut microbiota characteristics of patients to provide a basis for the targeted diagnosis and treatment of PJS in the future

Short‐ and medium‐term outcomes of video‐assisted thoracoscopic surgery versus thoracotomy for carinal lung resection combined with carina reconstruction in locally advanced non–small cell lung cancer patients

Abstract Background The application of video‐assisted thoracoscopic surgery (VATS) for complex carina surgeries in treating non–small cell lung cancer (NSCLC) patients with involved carina is controversial. This study compared short‐ and medium‐term outcomes of VATS versus thoracotomy for carinal lung resection with carina reconstruction in treating locally advanced NSCLC, aiming to assess the potential benefit of VATS over thoracotomy for these patients. Methods A total of 37 consecutive NSCLC cases receiving VATS (n = 14) or thoracotomy (n = 23) for carinal lung resection with carina reconstruction from 2016 to 2021 were retrospectively identified. Baseline clinicopathological characteristics, perioperative outcomes, and survival profiles were investigated. Results Patients in the VATS and thoracotomy groups had comparable baseline clinicopathological characteristics (all p > 0.050). VATS decreased postoperative drainage volume compared with thoracotomy (1280 [1170–1510] vs. 1795 [1510–1905] mL, p = 0.012). Regarding surgical‐related pains, VATS reduced numeric rating scale scores on the postoperative day 1 (4 [3, 4] vs. 5 [4, 5], p = 0.021) and day 2 (3 [3, 4] vs. 5 [3–5], p = 0.023) than thoracotomy. No difference was found between the VATS and thoracotomy groups in other perioperative outcomes, postoperative complications, and assessment of lymph nodes (LNs) and LN stations (all p > 0.050). Moreover, patients in the two groups had comparable 3‐year disease‐free survival (DFS), overall survival (OS), and recurrence and mortality patterns. Further subgroup and Cox hazards regression analyses also observed no difference in DFS or OS between the two groups. Conclusions VATS reduced postoperative drainage volume and ameliorated surgical‐related pain, and achieved comparable medium‐term survival compared to thoracotomy for carinal lung resection with carina reconstruction in treating locally advanced NSCLC

A Simple, Low-Cost, and Green Method for Preparing Strong, Tough, and Ductile Poly(lactic acid) Materials with Good Transparency and Heat Resistance

Notwithstanding that unprecedented progress has been achieved in strengthening and toughening PLA materials, it is still a challenge to find a facile and low-cost way to improve poly(lactic acid) (PLA) strength, toughness, and ductility while maintaining transparency and biodegradability. Herein, strong, tough, transparent, and highly heat-resistant PLA materials with a nacre-like lamellar structure were fabricated via a simple, low-cost and additive-free pressure-driven flow process. PLA powders with a size under 500 μm and heterogeneous size distribution obtained from ball milling and size sieving were used to yield a PLA material with a dense and ordered crystalline structure after pressure-driven flow treatment. The newly formed structured PLA material exhibited exceptional mechanical properties, with tensile strength, elongation at break, impact strength, and tensile toughness reaching 88.9 MPa, 102.5%, 45.1 KJ/m2, and 81.2 MJ/m3, respectively. The refined strength, toughness, and ductility were attributed to more particles undergoing uniform plastic deformation during the pressure-driven flow treatment. The interface between particles in the powder was much larger and more tortuous, and the particles were firmer. Additionally, the newly formed tightly stacked crystal structure consisting of densely and orderly arranged nanosized crystals played an important role in improving the mechanical properties of PLA. Moreover, the newly formed structured PLA materials exhibited enhanced heat resistance and retained good transparency, with a visible light transmission of over 80%. Overall, this work presents a simple and efficient method for fabricating high-performance PLA materials that are strong, tough, ductile, transparent, heat-resistant, and easily recyclable

SCARB2 drives hepatocellular carcinoma tumor initiating cells via enhanced MYC transcriptional activity

Abstract CSCs (Cancer stem cells) with distinct metabolic features are considered to cause HCC (hepatocellular carcinoma) initiation, metastasis and therapeutic resistance. Here, we perform a metabolic gene CRISPR/Cas9 knockout library screen in tumorspheres derived from HCC cells and find that deletion of SCARB2 suppresses the cancer stem cell-like properties of HCC cells. Knockout of Scarb2 in hepatocytes attenuates HCC initiation and progression in both MYC-driven and DEN (diethylnitrosamine)-induced HCC mouse models. Mechanistically, binding of SCARB2 with MYC promotes MYC acetylation by interfering with HDCA3-mediated MYC deacetylation on lysine 148 and subsequently enhances MYC transcriptional activity. Screening of a database of FDA (Food and Drug Administration)-approved drugs shows Polymyxin B displays high binding affinity for SCARB2 protein, disrupts the SCARB2-MYC interaction, decreases MYC activity, and reduces the tumor burden. Our study identifies SCARB2 as a functional driver of HCC and suggests Polymyxin B-based treatment as a targeted therapeutic option for HCC