A Resonance-Sensitive Ultralow-Frequency Raman Mode in Twisted Bilayer Graphene.

Twisted bilayer graphene (tBLG) possesses intriguing physical properties including unconventional superconductivity, enhanced light-matter interaction due to the formation of van Hove singularities (vHS), and a divergence of density of states in the electronic band structures. The vHS energy band gap provides optical resonant transition channels that can be tuned by the twist angle and interlayer coupling. Raman spectroscopy provides rich information on the vHS structure of tBLG. Here, we report the discovery of an ultralow-frequency Raman mode at ∼49 cm-1 in tBLG. This mode is assigned to the combination of ZA (an out-of-plane acoustic phonon) and TA (a transverse acoustic phonon) phonons, and the Raman scattering is proposed to occur at the so-called mini-valley. This mode is found to be particularly sensitive to the change in vHS in tBLG. Our findings may deepen the understanding of Raman scattering in tBLG and help to reveal vHS-related electron-phonon interactions in tBLG.

Deep-Ultraviolet and Helicity-Dependent Raman Spectroscopy for Carbon Nanotubes and 2D Materials.

Recent progress of Raman spectroscopy on carbon nanotubes and 2D materials is reviewed as a topical review. The Raman tensor with complex values is related to the chiral 1D/2D materials without mirror symmetry for the mirror in the propagating direction of light, such as chiral carbon nanotube and black phosphorus. The phenomenon of complex Raman tensor is observed by the asymmetric polar plot of helicity-dependent Raman spectroscopy using incident circularly-polarized lights. First-principles calculations of resonant Raman spectra directly give the complex Raman tensor that explains helicity-dependent Raman spectra and laser-energy-dependent relative intensities of Raman spectra. In deep-ultraviolet (DUV) Raman spectroscopy with 266 nm laser, since the energy of the photon is large compared with the energy gap, the first-order and double resonant Raman processes occur in general k points in the Brillouin zone. First-principles calculation is necessary to understand the DUV Raman spectra and the origin of double-resonance Raman spectra. Asymmetric line shapes appear for the G band of graphene for 266 nm laser and in-plane Raman mode of WS2 for 532 nm laser, while these spectra show symmetric line shapes for other laser excitation. The interference effect on the asymmetric line shape is discussed by fitting the spectra to the Breit-Wigner-Fano line shapes.

Reduced glutathione and raffinose lengthens postharvest storage of cassava root tubers by improving antioxidant capacity and antibiosis.

Cassava is an ideal food security crop in marginal and drought environment. However, the post-harvest storage of cassava is urgent problem to be resolved. In this study, the storage tolerant and non-tolerant cassava were screened by measuring the change of Peroxidase (POD), Superoxide dismutase (SOD), Catalase (CAT) and Malondialdehyde (MDA) in seven cultivars of cassava. Compared with other cultivars, the cultivar of SC14 showed the highest level of SOD, MDA and POD respectively at 0 day, 12 day and 9 day postharvest while exhibited lowest level of CAT at 0 day postharvest, indicating the strongest antioxidant capability and storage tolerance. In contrast, GR15231, termed as storage non-tolerance cultivars, showed lowest SOD and POD at 12 day and kept a relative high level of CAT at 12 day post-harvest. In addition, SC14 has higher level of starch and dry substance than GR15231. Mass spectrum was performed for SC14 and GR15231 to explore the key metabolites regulating the storage tolerance of cassava. The results showed that the expression of glutathione (reduced) and raffinose was significantly decreased at 12 day post-harvest both in tolerant SC14 and non-tolerant GR15231. Compared with GR15231, SC14 showed higher level of raffinose both at 0 and 12 day post-harvest, indicating that raffinose may be the potential metabolites protecting SC14 cultivar from deterioration post-harvest. Additionally, raffinose ratio of SC14a/SC14b was five times less than that of GR15231a/GR15231b, reflecting the slower degradation of raffinose in SC14 cultivar compared with GR15231 cultivar. In conclusion, the antioxidant microenvironment induced by reduced glutathione and higher level of raffinose in SC14 cultivar might be the promising metabolites to improve its antioxidant capacity and antibiosis and thus maintained the quality of Cassava root tubers.

Two-Dimensional Room-Temperature Magnetic Nonstoichiometric Fe7Se8 Nanocrystals: Controllable Synthesis and Magnetic Behavior.

Two-dimensional (2D) magnetic materials have attracted significant attention for promising applications in energy-saving logic and robust memory devices. However, most 2D magnets discovered so far typically feature drawbacks for practical applications due to low critical temperatures. Herein, we synthesize ultrathin room-temperature (RT) magnetic Fe7Se8 nanoflakes via the space-confined chemical vapor deposition method. It is found that the appropriate supply and control of Se concentration in the reaction chamber is crucial for synthesizing high-quality nonstoichiometric Fe7Se8 nanoflakes. Cryogenic electrical and magnetic characterizations reveal the emergence of spin reorientation at ∼130 K and the survival of long-range magnetic ordering up to room temperature. The RT magnetic domain structures with different thicknesses are also uncovered by magnetic force microscopy. Moreover, theoretical calculations confirm the spin configuration and metallic band structure. The outstanding characteristics exhibited by Fe7Se8 nanoflakes, including RT magnetism, spin reorientation property, and good electrical conductivity, make them a potential candidate for RT spintronics.

[Development of Intelligent Management System for High Value Consumable Material in Operating Room].

Operation room is the most important link for carrying out medical activities in hospital whose demand for medical consumable material is also very large. With the increase of types of consumable material, the process of consumable material management in operating room becomes more complicated, and the traditional management mode can not meet the needs. In this paper, the technology of Internet of things and artificial intelligence is used to design an intelligent management system of high value consumable material in operating room which improves the efficiency of operation of high value consumable material in operating room, reduces the cost of manpower and improves the safety.

[Development of Hospital Medical Instrumentation Management System Based on Cloud Computing].

In order to improve the efficiency of medical instrumentation management in hospital, reduce the management cost and save the human cost, this study analyzes the problems in the traditional hospital medical instrumentation management system, and develops a new system based on cloud computing. Through the characters of the SaaS Service Platform, the system improves the flow efficiency of the medical instrumentation in hospital, saves deployment and operating system costs, and improves the people's work efficiency.

[Research and Implementation of Vital Signs Monitoring System Based on Cloud Platform].

Through analyzing the existing problems in the current mode, the vital signs monitoring information system based on cloud platform is designed and developed. The system's aim is to assist nurse carry out vital signs nursing work effectively and accurately. The system collects, uploads and analyzes patient's vital signs data by PDA which connecting medical inspection equipments. Clinical application proved that the system can effectively improve the quality and efficiency of medical care and may reduce medical expenses. It is alse an important practice result to build a medical cloud platform.

Epitaxial Strain Enhanced Ferroelectric Polarization toward a Giant Tunneling Electroresistance.

A substantial ferroelectric polarization is the key for designing high-performance ferroelectric nonvolatile memories. As a promising candidate system, the BaTiO3/La0.67Sr0.33MnO3 (BTO/LSMO) ferroelectric/ferromagnetic heterostructure has attracted a lot of attention thanks to the merits of high Curie temperature, large spin polarization, and low ferroelectric coercivity. Nevertheless, the BTO/LSMO heterostructure suffers from a moderate FE polarization, primarily due to the quick film-thickness-driven strain relaxation. In response to this challenge, we propose an approach for enhancing the FE properties of BTO films by using a Sr3Al2O6 (SAO) buffering layer to mitigate the interfacial strain relaxation. The continuously tunable strain allows us to illustrate the linear dependence of polarization on epitaxial strain with a large strain-sensitive coefficient of ∼27 µC/cm2 per percent strain. This results in a giant polarization of ∼80 µC/cm2 on the BTO/LSMO interface. Leveraging this large polarization, we achieved a giant tunneling electroresistance (TER) of ∼105 in SAO-buffered Pt/BTO/LSMO ferroelectric tunnel junctions (FTJs). Our research uncovers the fundamental interplay between strain, polarization magnitude, and device performance, such as on/off ratio, thereby advancing the potential of FTJs for next-generation information storage applications.

Quantum interference directed chiral raman scattering in two-dimensional enantiomers.

Raman scattering spectroscopy has been a necessary and accurate tool not only for characterizing lattice structure, but also for probing electron-photon and electron-phonon interactions. In the quantum picture, electrons at ground states can be excited to intermediate energy levels by photons at different k-points in the Brillouin zone, then couple to phonons and emit photons with changed energies. The elementary Raman processes via all possible pathways can interfere with each other, giving rise to intriguing scattering effects. Here we report that quantum interference can lead to significant chiral Raman response in monolayer transitional metal dichalcogenide with triclinic symmetry. Large circular intensity difference observed for monolayer rhenium dichalcogenide originates from inter-k interference of Raman scattering excited by circularly polarized light with opposite helicities. Our results reveal chiral Raman spectra as a new manifestation of quantum interference in Raman scattering process, and may inspire induction of chiral optical response in other materials.

Molten-Salt-Assisted Chemical Vapor Deposition Process for Substitutional Doping of Monolayer MoS2 and Effectively Altering the Electronic Structure and Phononic Properties.

Substitutional doping of layered transition metal dichalcogenides (TMDs) has been proved to be an effective route to alter their intrinsic properties and achieve tunable bandgap, electrical conductivity and magnetism, thus greatly broadening their applications. However, achieving valid substitutional doping of TMDs remains a great challenge to date. Herein, a distinctive molten-salt-assisted chemical vapor deposition (MACVD) method is developed to match the volatilization of the dopants perfectly with the growth process of monolayer MoS2, realizing the substitutional doping of transition metal Fe, Co, and Mn. This doping strategy effectively alters the electronic structure and phononic properties of the pristine MoS2. In addition, a temperature-dependent Raman spectrum is employed to explore the effect of dopants on the lattice dynamics and first-order temperature coefficient of monolayer MoS2, and this doping effect is illustrated in depth combined with the theoretical calculation. This work provides an intriguing and powerful doping strategy for TMDs through employing molten salt in the CVD system, paving the way for exploring new properties of 2D TMDs and extending their applications into spintronics, catalytic chemistry and photoelectric devices.

Gate tunable giant anisotropic resistance in ultra-thin GaTe.

Anisotropy in crystals arises from different lattice periodicity along different crystallographic directions, and is usually more pronounced in two dimensional (2D) materials. Indeed, in the emerging 2D materials, electrical anisotropy has been one of the recent research focuses. However, key understandings of the in-plane anisotropic resistance in low-symmetry 2D materials, as well as demonstrations of model devices taking advantage of it, have proven difficult. Here, we show that, in few-layered semiconducting GaTe, electrical conductivity anisotropy between x and y directions of the 2D crystal can be gate tuned from several fold to over 103. This effect is further demonstrated to yield an anisotropic non-volatile memory behavior in ultra-thin GaTe, when equipped with an architecture of van der Waals floating gate. Our findings of gate-tunable giant anisotropic resistance effect pave the way for potential applications in nanoelectronics such as multifunctional directional memories in the 2D limit.

Calcium alginate film used for guided bone regeneration in mandible defects in a rabbit model.

The objective of this research was to study a new bioabsorbable membrane material, calcium alginate film (CAF), used for guided tissue regeneration (GTR) or guided bone regeneration (GBRL). Circular bone defects of five mm diameter were created in the corners of the mandibles in 45 rabbits. The defects covered with calcium alginate film (CAF) served as the experimental sites, and collagen membrane (CM) or no membrane served as the control sites without considering left or right side, just with a mark on the ear of the same side. The healing condition was analyzed by histological studies and histometry analysis after one, two, four, six, and eight weeks. The histological evaluation showed that the bone regeneration pattern was centripetal in growth from the defect rim. The quantitative histometry analysis showed significantly more and faster newly generated bone in CAF defects than that in CM defects or in empty defects (p < 0.01) at two, four, six, and eight weeks postsurgically. Calcium alginate film was more effective for GTR and GBR than the collagen membrane.

Electric-field control of magnetism in a few-layered van der Waals ferromagnetic semiconductor.

Manipulating a quantum state via electrostatic gating has been of great importance for many model systems in nanoelectronics. Until now, however, controlling the electron spins or, more specifically, the magnetism of a system by electric-field tuning has proven challenging1-4. Recently, atomically thin magnetic semiconductors have attracted significant attention due to their emerging new physical phenomena5-13. However, many issues are yet to be resolved to convincingly demonstrate gate-controllable magnetism in these two-dimensional materials. Here, we show that, via electrostatic gating, a strong field effect can be observed in devices based on few-layered ferromagnetic semiconducting Cr2Ge2Te6. At different gate doping, micro-area Kerr measurements in the studied devices demonstrate bipolar tunable magnetization loops below the Curie temperature, which is tentatively attributed to the moment rebalance in the spin-polarized band structure. Our findings of electric-field-controlled magnetism in van der Waals magnets show possibilities for potential applications in new-generation magnetic memory storage, sensors and spintronics.

Application of a new bioresorbable film to guided bone regeneration in tibia defect model of the rabbits.

Aim is to study the effect of calcium alginate film (CAF) on guided bone regeneration (GBR). Circular bone defects with 5 mm diameter were created in both tibias in 60 rabbits. The defects covered with CAF served as the experimental site, and with collagen membrane (CM) or with no membrane both served as the control site. Healing was analyzed by gross, X-ray, electromicroscopy, histology, immuno-histochemical studies, and an image pattern analysis system after 1, 2, 4, 6, and 8 weeks. The CM control sites showed more macrophages, and CM were absorbed more slowly while collecting fewer osteoinductive factors (p < 0.01) in the early weeks. CAF induced dense bone formation, whereas CM induced less new bone, and the blank control sites effected the worst. In conclusion, the effect of CAF group gave better results than blank control group and CM group on GBR in this animal model.

Deep lingual arterial chemoembolization of tongue carcinoma with microcapsuled anticancer drug.

OBJECTIVE: Microcapsule chemoembolism is a promising treatment of tumors. We describe a deep lingual arterial embolization of tongue carcinoma with microcapsuled carboplatinum. METHODS: Lingual artery cast specimens from cadavers were microscopically examined, and 78 patients with tongue cancer were recruited and treated with the deep lingual arterial embolization therapy. RESULTS: Microcapsule embolism occurred approximately at the fifth or sixth level of the deep lingual artery branches. The five-year survival rate was 88.5% (69 out of 78), and the ten-year survival rate 52.6% (41 out of 78). CONCLUSION: The deep lingual arterial embolization of tongue carcinoma with microcapsuled carboplatinum is an effective therapy to treat carcinoma in mid-margin or mid-body of the tongue.

[The application of three dimensional craniomaxillofacial model in the restoration of mandibular bone defects with vascularized fibular autograft].

OBJECTIVE: To evaluate the effect of applying the three dimensional craniomaxillofacial model technique in the restoration of mandibular defects with vascularized fibular autograft. METHODS: Three dimensional craniomaxillofacial models of 24 patients with mandibular defects were achieved by CT scan and rapid prototype technique. Surgery simulation and individual prefabricated titanium board were designed on the models. Vascularized fibular autograft was obtained, remodeled with titanium implant based upon preoperative surgery simulation, and implanted into the site with mandibular defect. RESULTS: By using three-dimensional craniomaxillofacial model, all fibular flaps survived without complication in all 24 patients. Bony union was achieved between the implanted fibula and the mandible. First intention of the wound was achieved. The appearance of the mandibular bone was well recovered shown by 3-dimensional CT scan. CONCLUSION: Based upon the preoperative surgery simulation with three dimensional craniomaxillofacial model, vascularized fibular autograft has many advantages for mandible reconstruction and represents the first choice for the head and neck surgeon.

MiR-340 suppresses cell migration and invasion by targeting MYO10 in breast cancer.

Breast cancer is one of the most common malignant tumors among females, and can seriously affect the physical and mental health and even threaten the lives of women. Recently, research has demonstrated that microRNAs (miRNAs), as a new method of regulation, have been shown to have oncogenic and tumor­suppressive functions in human breast cancer. Detection of their expression may lead to the identification of novel markers for breast cancer. In the present study, we firstly detected miR­340 expression and found lower expression of miR­340 in 6 human breast cancer cell lines by using RT­qPCR. Then by using wound healing assay and Transwell migration and invasion experiments, we focused on the role of miR-340 in the regulation of tumor cell migration and invasion, exploring the relationship between them. The results revealed that induction of miR­340 expression was able to suppress tumor cell migration and invasion, whereas knockdown of miR­340 expression promoted breast cancer cell migration and invasion. At the gene level, MYO10 (myosin X), as a direct miR­340 target gene, mediated the cell migration and invasion. Finally, we verified our research further at the tissue specimen level and in animal experiments. In brief, miR­340 plays an important role in breast cancer progression. Thus, miR­340 may be further explored as a novel biomarker for breast cancer metastasis and prognosis, and potentially a therapeutic target.

Sequential-release of anticancer drugs microcapsulated with ethylcellulose.

OBJECTIVE: To approach the sequential release of antitumor drugs and promote the effect of chemotherapy. METHODS: Adriamycin (ADM) and carboplatin (CBP) were respectively microcapsulated with ethylcellulose by organic phase separation. The morphology and sizes of the microcapsules were observed and measured with light microscope and scanning electromicroscope. The contents and the release rates of ADM and CBP in microcapsules were measured with fluorescence spectrophotometer and high-efficiency phantom chromatic (HPC) spectrum respectively. The antitumor sensitivity test in vitro was devised with MTT assay. RESULTS: The microcapsules of ADM and CBP were spherical in shape with diameters of 196 +/- 64 micro m and 214 +/- 48 micro m respectively. The contents of one-layer and two-layer CBP and ADM microcapsules were 51.4%, 35.7% and 39.8% respectively, with the release rates in vitro of 62.4%/day, 54.8%/day and 48.2%/8 h. The results of drug sensitivity test in vitro demonstrated that the current preparation has never affected the stability and antitumor activity of CBP and ADM. CONCLUSION: Microcapsules with different drugs and different thickness of material have different release rate. Combined arterial chemoembolization with different microcapsules could approach the sequential release and promote the effect of chemotherapy.

Haversian remodeling in guided bone regeneration with calcium alginate film in circular bone defect model of rabbit.

The objective of this study is to investigate the effect of bioabsorbable Calcium alginate film in guided bone regeneration by the study of Haversian remodeling. Circular bone defects of 5 mm diameter were created in the corners of mandibles in 35 rabbits. The defects were covered with calcium alginate film (CAF) served as the experimental group, or collagen membrane (CM) as the control group, respectively. Healing condition was analyzed with gross, histological and immunohistochemical studies after 1, 2, 4, 6 and 8 weeks. The experimental group appeared more and earlier Haversian remodeling and osteoinductive factors leading to better bone regeneration. The control group showed more macrophages, less and later Haversian remodeling, absorbed slowly, while collected fewer osteoinductive factors in the early stage. Calcium alginate film, which is a relatively cheaper material, provides better effect than the collagen membrane in bone regeneration, Haversian remodeling and quantity of osteoinductive factors.

Anatomical and clinical study of lingual arterial chemoembolization for tongue carcinoma.

OBJECTIVE: The aim of this study was to develop an alternative treatment approach using lingual artery chemoembolization for certain tongue carcinomas. STUDY DESIGN: Fifty-three lingual artery, postmortem, cast human specimens were studied. Seventy-eight patients with tongue carcinoma were chemoembolized with Car-platinum microcapsules. RESULTS: The deposition of the microcapsule embolism was approximately at the fifth- to the sixth-branch level of the deep lingual artery. The results complied with the anatomy, and the clinical outcomes were effective. CONCLUSIONS: Lingual artery chemoembolization showed efficacy for curing carcinoma in the midmargin and midbody areas of the tongue, within the limitations of this study.