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Two-dimensional (2D) crystals have renewed opportunities in design and assembly of artificial lattices without the constraints of epitaxy. However, the lack of thickness control in exfoliated van der Waals (vdW) layers prevents realization of repeat units with high fidelity. Recent availability of uniform, wafer-scale samples permits engineering of both electronic and optical dispersions in stacks of disparate 2D layers with multiple repeating units. Here we present optical dispersion engineering in a superlattice structure comprising alternating layers of 2D excitonic chalcogenides and dielectric insulators. By carefully designing the unit cell parameters, we demonstrate greater than 90% narrow band absorption in less than 4 nm of active layer excitonic absorber medium at room temperature, concurrently with enhanced photoluminescence in square-centimetre samples. These superlattices show evidence of strong light–matter coupling and exciton–polariton formation with geometry-tuneable coupling constants. Our results demonstrate proof of concept structures with engineered optical properties and pave the way for a broad class of scalable, designer optical metamaterials from atomically thin layers. Square-centimetre scale, multilayer superlattice structures based on atomically thin two-dimensional chalcogenide monolayers enable the realization of excitonic metamaterials.

Background This study aimed to evaluate the clinical efficacy of femoral head and neck fenestration combined with autologous bone mixed with β-tricalcium phosphate porous bioceramic bone (light bulb procedure) through Orthopdische Chirurgie München approach (OCM approach) for pre-collapse non-traumatic osteonecrosis of the femoral head(ONFH). Methods The clinical data of 47 patients (47 hips) with ONFH were retrospectively reviewed. The Harris hip score (HHS) was used to evaluate the clinical outcomes. Imaging was assessed by X-ray. Clinical failure was defined as postoperative total hip arthroplasty (THA) or the HHS was poor ( Results All the 47 hips were followed up for 24–58 months, with an average of 45 months. The Harris score (76.29 ± 10.38) at the last follow-up was significantly higher than the preoperative HHS (64.45 ± 2.93) (P P P Conclusions The head and neck fenestration and bone grafting via the OCM approach in the treatment of non-traumatic ONFH in the pre-collapse stage can achieve good clinical outcomes. 25(OH)D deficient patients and ARCO IIIA patients had a higher failure rate of bone graft using this approach.

Integrated optics is at the heart of a wide range of systems from remote sensing and communications to computing and quantum information processing. Demand for smaller and more energy efficient str...

Wearable and implantable pressure sensors are in great demand for personalized health monitoring. Pressure sensors with low operation voltage and low power-consumption are desired for energy-saving devices. Organic iontronic devices, such as organic electrochemical transistors (OECTs), have demonstrated great potential for low power-consumption bioelectronic sensing applications. The ability to conduct both electrons and ions, in addition to their low-operation voltage has enabled the widespread use of OECTs in different biosensing fields. However, despite these merits, OECTs have not been demonstrated for pressure sensing applications. This is because most OECTs are gated with aqueous electrolyte, which fails to respond to external pressure. Here, a low power-consumption iontronic pressure sensor is presented based on an OECT, in which an ionic hydrogel is used as a solid gating medium. The resultant iontronic device operated at voltages less than 1 V, with a power-consumption between ~ 101– $10^{3} \mu \text{W}$ , while maintaining a tunable sensitivity between 1 ~ 10 kPa−1. This work places OECTs on the frontline for developing low power-consumption iontronic pressure sensors and for biosensing applications.

Animal models and traditional cell cultures are essential tools for drug development. However, these platforms can show striking discrepancies in efficacy and side effects when compared to human trials. These differences can lengthen the drug development process and even lead to drug withdrawal from the market. The establishment of preclinical drug screening platforms that have higher relevancy to physiological conditions is desirable to facilitate drug development. Here, a heart-on-a-chip platform, incorporating microgrooves and electrical pulse stimulations to recapitulate the well-aligned structure and synchronous beating of cardiomyocytes (CMs) for drug screening, is reported. Each chip is made with facile lithographic and laser-cutting processes that can be easily scaled up to high-throughput format. The maturation and phenotypic changes of CMs cultured on the heart-on-a-chip is validated and it can be treated with various drugs to evaluate cardiotoxicity and cardioprotective efficacy. The heart-on-a-chip can provide a high-throughput drug screening platform in preclinical drug development.

BackgroundThis study aimed to evaluate the clinical efficacy of autologous bone mixed with tricalcium phosphate porous bioceramic bone grafting via Orthopdische Chirurgie München approach (OCM approach) with fenestration of the femoral head-neck in patients with pre-collapse non-traumatic osteonecrosis of the femoral head (ONFH).MethodsThe clinical data of 47 patients (47 hips) with ONFH were retrospectively reviewed. The Harris hip score (HHS) was used to evaluate the clinical outcomes. Imaging was assessed by X-ray. Clinical failure was defined as postoperative total hip arthroplasty (THA) or the HHS was poor (

To investigate the clinical efficacy and safety of two different bone graft materials in the minimally invasive treatment of early and middle stage femoral head necrosis. A total of 36 patients (39 hips) with avascular necrosis of the femoral head were divided into autologous iliac bone group (ABG) and bioceramics bone group (BBG). Both groups were treated with minimally invasive thick channel decompression to remove dead bone of femoral head. The ABG was treated with autologous iliac bone graft, and BBG was treated with β-tricalcium phosphate bone graft. The operation time, intra-operative blood loss, haemoglobin, and haematocrit were recorded at three and seven days post-operatively. The clinical efficacy and safety were evaluated by Harris score and imaging examination before, and after treatment and at follow-up stages. The patients were followed up for 24 to 45 (average 29.27 ± 3.56) months. The BBG was significantly better than the ABG in terms of operation time, intra-operative blood loss, haemoglobin, and haematocrit value at three days. Compared with pre-operative, the Harris score of the two groups at 12 months after operation was significantly improved. The Harris score and the imaging evaluation of the last follow-up exhibited significantly better outcome in BBG than those of ABG. Bioceramics and autologous iliac bone minimally invasive treatment of early and medium-term femoral head necrosis exhibited satisfactory clinical efficacy in the short and medium-term. The bioceramics graft materials have the advantages of reducing trauma, bleeding, operation time, and quick recovery of post-operative functions.

As the Internet is developing rapidly and people are becoming increasingly dependent on e-commerce, whether the users can be provided with accurate recommendation information has become the key to attracting users. Under this background, corresponding personalized recommendation systems have been proposed, and collaborative filtering algorithm is one of the algorithms commonly used in the recommendation systems. Collaborative filtering recommends the information in which the user is interested through analyzing the preferences of a group with similar interests and common experience. With the increasing number of users and items in the e-commerce system, the collaborative filtering algorithm is limited by data sparsity in operation, which will influence the quality of the recommendation results. This paper studied the collaborative filtering recommendation algorithm based on the prediction for item rating, and enhanced the accuracy of the recommendation algorithm by designing an improved similarity-based algorithm for predicting ratings based on the Pearson correlation coefficient.

Minimally invasive biosensors are emerging as powerful tools to enable personalized healthcare and precision medicine. Recent advances in biotechnology, wireless communication, and flexible electronics have offered unprecedented opportunity to develop minimally invasive biosensors for commercial applications. In this chapter, we discuss emerging technologies of minimally invasive biosensing and their working principle, applications, and challenges. We also present areas where further endeavors are needed and future directions in this field.

Three-dimensional (3D) printing technology has received great attention in the past decades in both academia and industry because of its advantages such as customized fabrication, low manufacturing cost, unprecedented capability for complex geometry, and short fabrication period. 3D printing of metals with controllable structures represents a state-of-the-art technology that enables the development of metallic implants for biomedical applications. This review discusses currently existing 3D printing techniques and their applications in developing metallic medical implants and devices. Perspective about the current challenges and future directions for development of this technology is also presented. Keywords: 3D printing, Biometals, Biocompatibility, Medical devices, Clinical application