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Recently, metasurface-based photodetectors (metaphotodetectors) have been developed and applied in various fields. Metasurfaces are artificial materials with unique properties that have emerged over the past decade, and photodetectors are powerful tools used to quantify incident electromagnetic wave information by measuring changes in the conductivity of irradiated materials. Through an efficient microstructural design, metasurfaces can effectively regulate numerous characteristics of electromagnetic waves and have demonstrated unique advantages in various fields, including holographic projection, stealth, biological image enhancement, biological sensing, and energy absorption applications. Photodetectors play a crucial role in military and civilian applications; therefore, efficient photodetectors are essential for optical communications, imaging technology, and spectral analysis. Metaphotodetectors have considerably improved sensitivity and noise-equivalent power and miniaturization over conventional photodetectors. This review summarizes the advantages of metaphotodetectors based on five aspects. Furthermore, the applications of metaphotodetectors in various fields including military and civil applications, are systematically discussed. It highlights the potential future applications and developmental trends of metasurfaces in metaphotodetectors, provides systematic guidance for their development, and establishes metasurfaces as a promising technology.

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As humans increasingly modify the natural world, many animals have responded by changing their behaviour. Understanding and predicting the extent of these responses is a key step in conserving these species. For example, the tendency for some species of birds to incorporate anthropogenic items-particularly plastic material-into their nests is of increasing concern, as in some cases, this behaviour has harmful effects on adults, young and eggs. Studies of this phenomenon, however, have to date been largely limited in geographic and taxonomic scope. To investigate the global correlates of anthropogenic (including plastic) nest material use, we used Bayesian phylogenetic mixed models and a data set of recorded nest materials in 6147 species of birds. We find that, after controlling for research effort and proximity to human landscape modifications, anthropogenic nest material use is correlated with synanthropic (artificial) nesting locations, breeding environment and the number of different nest materials the species has been recorded to use. We also demonstrate that body mass, range size, conservation status and brain size do not explain variation in the recorded use of anthropogenic nest materials. These results indicate that anthropogenic materials are more likely to be included in nests when they are more readily available, as well as potentially by species that are more flexible in their nest material choice.

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Spontaneous cerebrospinal fluid (CSF) leakage at the clivus is rare. In previous reports, reconstructive materials used to treat such leakage were typically autografts. Considering the pathology, rigid reconstruction is preferred. We here describe a case of spontaneous CSF leakage at the clivus with multiple bony defects. In this case, in addition to using artificial material instead of autografts, such as fat or fascia, that require additional extranasal invasive harvesting site, a rigid material layer of septal cartilage and bone was also used, enabling more stable multilayer reconstruction. One month postoperatively, computed tomography revealed that the bony defect at the clivus had been well reconstructed. All nasal structures were preserved, and the nasoseptal flap was well engrafted. At eight months post-surgery, the patient remained in good condition. This method allows minimally invasive repair of the leaking clivus, according to the underlying pathophysiology.

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Terahertz (THz) plasmonic metamaterial, based on a metal-wire-woven hole array (MWW-HA), is investigated for the distinct power depletion in the transmittance spectrum of 0.1-2 THz, including the reflected waves from metal holes and woven metal wires. Woven metal wires have four orders of power depletion, which perform sharp dips in a transmittance spectrum. However, only the first-order dip at the metal-hole-reflection band dominates specular reflection with a phase retardation of approximately π. The optical path length and metal surface conductivity are modified to study MWW-HA specular reflection. This experimental modification shows that the first order of MWW-HA power depletion is sustainable and sensitively correlated with a bending angle of the woven metal wire. Specularly reflected THz waves are successfully presented in hollow-core pipe wave guidance specified from MWW-HA pipe wall reflectivity.

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Metal-hole-supported terahertz (THz) waves through the structure of a metal-wire-woven hole array (MWW-HA) present high-frequency-passed transmittance spectra of one plasmonic metamaterial with artificial plasmonic frequencies, which are inversely proportional to metal-hole widths. For the transmitted THz waves of MWW-HA, transverse-electric (TE) and transverse-magnetic (TM) waveguide modes mix within a symmetric metal-hole boundary. THz resonance waves transversely crossing the holes of MWW-HA are experimentally characterized with spectral peaks in the frequency range of 0.1-2 THz that are correlated with aperture sizes, unit-cell-hole widths, metal-wire thicknesses, and wire-bending angles. The metal-hole-transported resonance waves of MWW-HA are dominated by TE waveguide modes instead of TM ones because a hole width of MWW-HA is approximate to the half wavelength of a resonance wave. The round metal edges of the woven metal wires can minimize the effective optical length of a thick metal hole to transmit THz resonance waves, thereby resulting the smallest rotation angle of linear polarization and high transmittance up to 0.94. An MWW-HA structure is therefore reliable for supporting metal-hole resonance waves with low resistance, whereas a metal-slab-perforated hole array cannot achieve the same result.

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Reconstruction of long-bone segmental defects (LBSDs) has been one of the biggest challenges in orthopaedics. Biomaterials for the reconstruction are required to be strong, osteoinductive, osteoconductive, and allowing for fast angiogenesis, without causing any immune rejection or disease transmission. There are four main types of biomaterials including autograft, allograft, artificial material, and tissue-engineered bone. Remarkable progress has been made in LBSD reconstruction biomaterials in the last ten years. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Our aim is to summarize recent developments in the divided four biomaterials utilized in the LBSD reconstruction to provide the clinicians with new information and comprehension from the biomaterial point of view.

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Gain enhancement wideband end-fire antenna is proposed in this paper. The proposed antenna can achieve gain enhancement by loading novel artificial materials structures (Split-ring Resonators) in the end-fire direction while broad bandwidth is realized by using elliptic dipole elements and a microstrip to coplanar balun. The measurements show that the proposed antenna have around 5-8 dB gain in the working band (5-11 GHz), which is around 2 dB more than the unloaded one. This antenna can be used in target recognition systems for its advantages of end-fire radiation broad bandwidth and high gain.

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CONCLUSION: Visualization of mouse induced pluripotent stem (iPS) cells with the use of a fluorescent protein was successfully achieved for evaluation of tracheal regeneration. OBJECTIVES: Tracheal epithelial cells derived from iPS cells are expected to be a useful cell source for tracheal regeneration. Our previous study demonstrated that mouse iPS cells differentiated into tracheal epithelial cells. However, when they are implanted into tracheal defects in experimental animals, it is difficult to determine whether the regenerated tracheal epithelium is in fact derived from iPS cells. The purpose of this study was to develop a visualization technique for iPS cells for evaluation of tracheal regeneration. METHODS: Fluorescent marker tdTomato was transfected into iPS cells. Tracheal epithelial cells were generated from tdTomato-labeled iPS cells using embryoid body formation to detect the expression of tdTomato. The artificial material with tdTomato-labeled iPS cells was implanted into tracheal defects in nude rats. The survival and distribution of tdTomato-labeled iPS cell-derived cells were examined using the IVIS Imaging System and immunostaining. RESULTS: The expression of tdTomato was detected in both undifferentiated cells and tracheal epithelial cells in vitro. tdTomato-labeled iPS cell-derived cells were successfully detected in the tracheal defects by IVIS Imaging System and immunostaining.

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Objective To investigate the clinical effects of transpedicular graft of biological artificial material (BAM) -induced artificial bone and posterior pedicle screw fixation in the treatment of osteoporotic thoracolumbar fractures.Methods A total of 72 patients with osteoporotic thoracolumbar fractures treated by transpedicular reduction by leverage,BMA-induced artificial bone grafting and posterior pedicle screw fixation from 2005 to 2010 were reviewed and followed up.The frontal and lateral X-ray radiograph of the spine was performed before and after operation and during the follow-up.The anterior and posterior height of the injured vertebrae,thoracolumbar kyphotic angle ( Cobb' s angle),ratio of anterior to posterior vertebral height were determined.Also,the America Spinal Injury Association (ASIA) scale was used to evaluate the neurological recovery and the visual analog scale (VAS) was applied to assess the back and waist pain.Results All patients were followed up for a mean period of 18.3 months,ranging from 12 to 28 months.Meanwhile,all the patients obtained bone union,with no rejection of artificial bone graft,breakage or loosening of screws,or obvious loss of both vertebrae height and deformity correction angle.Notable improvement of neurological function was achieved in all patients except for two patients with Frankel A nerve injury.The VAS score descended from pre-operative ( 8.4 ± 2.5 ) points to (2.2 ± 1.6 ) points at latest follow-up,which showed obvious alleviation of back and waist pain.Conclusions Transpedicular bone graft plus internal fixation is an effective,reasonable and easy method for managing osteoporotic thoracolumbar fractures.In addition,the implanted BAM-induced artificial bone is of good biological and mechanical properties.

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With the improvement of living standard, the requirement of artificial joint material is ever increasing. The development of meted artificial joint, high polymer artificial joint and ceramic-made artificial joint, which are widely used in joint replacement, are introduced. Advantages and disadvantages of these materials are discussed, as well as the required improvement to these three materials. Development on metal-to-metal hip resurfacing arthroplasty and its clinical application is introduced. Now that no material with good biocompatibility, good biomechanical compatibility, good biological aasociativity and satisfied life-span has yet been found, compound material artificial joint may be the focus of the research in future.

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This paper discusses the actuality of the artificial bioactive functionally gradient material and its developing trend.