A ferroelectric fin diode for robust non-volatile memory

Among today's nonvolatile memories, ferroelectric-based capacitors, tunnel junctions and field-effect transistors (FET) are already industrially integrated and/or intensively investigated to improve their performances. Concurrently, because of the tremendous development of artificial intelligence and big-data issues, there is an urgent need to realize high-density crossbar arrays, a prerequisite for the future of memories and emerging computing algorithms. Here, a two-terminal ferroelectric fin diode (FFD) in which a ferroelectric capacitor and a fin-like semiconductor channel are combined to share both top and bottom electrodes is designed. Such a device not only shows both digital and analog memory functionalities but is also robust and universal as it works using two very different ferroelectric materials. When compared to all current nonvolatile memories, it cumulatively demonstrates an endurance up to 1010 cycles, an ON/OFF ratio of ~102, a feature size of 30 nm, an operating energy of ~20 fJ and an operation speed of 100 ns. Beyond these superior performances, the simple two-terminal structure and their self-rectifying ratio of ~ 104 permit to consider them as new electronic building blocks for designing passive crossbar arrays which are crucial for the future in-memory computing.

Highly Reliable Van Der Waals Memory Boosted by a Single 2D Charge Trap Medium

Charge trap materials that can store carriers efficiently and controllably are desired for memory applications. 2D materials are promising for highly compacted and reliable memory mainly due to their ease of constructing atomically uniform interfaces, however, remain unexplored as being charge trap media. Here it is discovered that 2D semiconducting PbI2 is an excellent charge trap material for nonvolatile memory and artificial synapses. It is simple to construct PbI2 -based charge trap devices since no complicated synthesis or additional defect manufacturing are required. As a demonstration, MoS2 /PbI2 device exhibits a large memory window of 120 V, fast write speed of 5 µs, high on-off ratio around 106 , multilevel memory of over 8 distinct states, high reliability with endurance up to 104 cycles and retention over 1.2 × 104 s. It is envisioned that PbI2 with ionic activity caused by the natively formed iodine vacancies is unique to combine with unlimited 2D materials for versatile van der Waals devices with high-integration and multifunctionality.

Ferroelectric-defined reconfigurable homojunctions for in-memory sensing and computing

Recently, the increasing demand for data-centric applications is driving the elimination of image sensing, memory and computing unit interface, thus promising for latency- and energy-strict applications. Although dedicated electronic hardware has inspired the development of in-memory computing and in-sensor computing, folding the entire signal chain into one device remains challenging. Here an in-memory sensing and computing architecture is demonstrated using ferroelectric-defined reconfigurable two-dimensional photodiode arrays. High-level cognitive computing is realized based on the multiplications of light power and photoresponsivity through the photocurrent generation process and Kirchhoff's law. The weight is stored and programmed locally by the ferroelectric domains, enabling 51 (>5 bit) distinguishable weight states with linear, symmetric and reversible manipulation characteristics. Image recognition can be performed without any external memory and computing units. The three-in-one paradigm, integrating high-level computing, weight memorization and high-performance sensing, paves the way for a computing architecture with low energy consumption, low latency and reduced hardware overhead.

[Influencing factors of visual prognosis in patients with persistent submacular fluid after successful scleral buckle surgery for macula-off retinal detachment]

Objective: To investigate the factors influencing visual outcomes in patients with rhegmatogenous retinal detachment (RRD) who developed persistent submacular fluid (PSF) after scleral buckling surgery. Methods: A retrospective case series analysis was conducted. Clinical data were collected from patients who underwent successful scleral buckling surgery for RRD at Beijing Tongren Hospital from June 2020 to December 2022 and were followed up. Patients with RRD involving the macular area preoperatively and graded as C1 or below in proliferative vitreoretinopathy (PVR) were included. Surgical procedures followed a minimally invasive scleral buckling approach. PSF was defined as subretinal fluid persisting for more than 1 month postoperatively. Regular follow-up visits were scheduled at postoperative days 1, 3, 7, 2 weeks, and 1 month, followed by monthly visits until complete PSF absorption. Best-corrected visual acuity (BCVA), intraocular pressure, refractive error, slit-lamp biomicroscopy, binocular indirect ophthalmoscopy, and optical coherence tomography (OCT) were performed at each follow-up time point. Eyes were divided into two groups based on whether the final follow-up BCVA was≥0.5 and whether the absorption time of PSF was>6 months, and statistical analysis was performed using the Wilcoxon signed-rank test, chi-squared test, and Mann-Whitney U test. Results: A total of 46 patients (46 eyes) were included in this study, comprising 25 males and 21 females, with a median age of 32.5 (21.0, 57.3) years. The preoperative equivalent spherical refractive error was (-5.27±4.05) D, and the preoperative duration of illness was 30 (14, 92) days. The preoperative BCVA (logarithm of the minimum angle of resolution,logMAR) was 2.00 (1.00, 2.50). Scleral buckle surgery was performed in 28 eyes (60.9%), and 18 eyes (39.1%) underwent scleral buckle surgery combined with encircling. External drainage was performed in 15 eyes (32.6%), while 31 eyes (67.4%) had no external drainage. BCVA (logMAR) at 1 month, 3 months, and the final follow-up postoperatively was 0.60 (0.50, 1.00), 0.40 (0.28, 0.53), and 0.15 (0.00, 0.50), respectively. In the final follow-up, 31 eyes (67.4%) achieved BCVA≥0.5, and 26 eyes (56.5%) had continuous ellipsoid zone on OCT. The differences in BCVA (logMAR) between preoperative, 1 month, 3 months, and the final follow-up were statistically significant (Z=-5.85, -5.63, -4.73;all P<0.001). The absorption time of PSF postoperatively was 6.50 (3.00, 9.00) months, ranging from 2 to 19 months. The eyes with PSF duration<3 months, 3-6 months, and>6 months were 12 eyes (26.1%), 11 eyes (23.9%), and 23 eyes (50.0%), respectively. There were statistically significant differences between the two groups in preoperative BCVA≥0.05, preoperative duration of illness within 1 month, PVR grading, surgical method, and continuous ellipsoid zone on OCT (all P<0.05), while there were no statistically significant differences between the two groups in PSF absorption time, different types of PSF, and intraoperative drainage (all P>0.05). The PSF absorption time in the two groups was 7 (3, 10) months and 6 (4, 8) months, with no statistically significant difference (P>0.05). Conclusions: Preoperative visual acuity, duration of illness, and PVR grading are factors influencing visual outcomes in patients with RRD who have undergone scleral buckling surgery and develop PSF. In contrast, intraoperative drainage, PSF absorption time, and different PSF types are not factors affecting visual prognosis. Although PSF may persist for a long time after scleral buckling surgery, it does not significantly impact long-term visual outcomes.

[Developing traditional medical heritage for further achievements in medical history and literature research-Commemorating the establishment of China Institute for History of Medicine and Medical Literature in the China Academy of Traditional Chinese Medicine]

The Institute of Chinese Medical History and Literature in the China Academy of Traditional Chinese Medicine was officially established on May 28, 1982. Its predecessor was the Medical History Research Office in the Chinese Medicine Institute of the Central Institute of Health, the Editorial Office of the China Academy of Traditional Chinese Medicine, and the Theory and Literature Research Office of the Institute of Acupuncture and Moxibustion. Before that, the Research Office of Chinese Medical History and Literature in the China Academy of Traditional Chinese Medicine was established in 1971. It made remarkable achievements in scientific research, personnel training and discipline construction in terms of medical history and literature. It was upgraded to the Institute with the approval of the Ministry of Health in 1980. After its establishment, the institute has benefited from great achievements.

[Medical figures in Wang Ao Ji]

Wang Ao was a famous politician and litterateur in the middle of Ming Dynasty. Wang Ao Ji comprehensively sorts out Wang's works for the first time, and collects all the poems and notes written by himself. A total of 38 physicians were recorded in Wang Ao Ji, among them, Wang Ao had close contacts with many physicians such as Zhou Geng, Zhou Xu'an, Sheng Rubi, Zhang Yangzheng and Chen Chong. Wang Ao and Zhou Geng are both core members of the literary society of Wuzhong, in the capital of Beijing. Wang Ao once wrote an epitaph for Zhou Xu'an, a tablet inscription for Sheng Rubi and a biography for Zhang Yangzheng. And Chen Chong once cured Wang's nephew's diarrhea caused by acne rash.The biographical records of physicians in Wang Ao Ji are highly reliable, and some medical information is the main source of official history and medical history works, which contains important historical value. Relevant contents about medical figures recorded in class of works, local chronicles, genealogy, anthology, notes and other ancient books, to a great extent, enrich biographical data of physicians, which is worth further research.

[Quantitative study of supraspinatus tendon injury grading based on synthetic magnetic resonance imaging]

Objective: To investigate the diagnostic value of quantitative parameters of synthetic magnetic resonance imaging (SyMRI) in the grade of supraspinatus tendon injury. Methods: Ninety-seven patients with clinical definite of supraspinatus tendon injury from July 2021 to July 2022 in General Hospital of Ningxia Medical University were prospectively collected (case group), including 54 males and 43 females, with an age of 29 to 56 (37.4±9.6) years. According to the results of shoulder arthroscopy, the case group were divided into three subgroups included tendinopathy group (37 cases, grade Ⅱ), partial tear group (34 cases, grade Ⅲ) and complete tear group (26 cases, grade Ⅳ). During the same period, 28 normal rotator cuff volunteers without supraspinatus tendon injury were recruited (control group), including 16 males and 12 females, aged 23 to 49 (36.1±7.2) years, and marked as grade Ⅰ. All the subjects underwent MRI scan of articulatio humeri included T₁-weighted imaging(T₁WI) fast spin echo(FSE) sequences in axial view, T₂-weighted imaging(T₂WI) fat suppression(FS) sequences in axial view, T₂WI FS sequences in oblique coronal view, proton density-weighted (PDW) imaging in oblique sagittal view and SyMRI in oblique coronal view. The supraspinatus tendon was divided into lateral, medial and middle subregions according to its shape in oblique coronal T₂WI view, two radiologists measured the T₁, T₂ and PD values of the supraspinatus tendon. The interclass correlation coefficient (ICC) were used to compare the consistency between and within observers. One-way analysis of variance or Kruskal-Wallis H test were used to compare the differences of quantitative parameters in different grades, the multivariate logistic regression model was used to analyze the risk factors of supraspinatus tendon injury grade, and the receiver operating characteristic (ROC) curves and area under curve (AUC) was drawn and calculated to evaluate the diagnostic efficacy. The Spearman correlation was used to analyze the correlation between the quantitative values and grades of supraspinatus tendon injury. Results: The ICC values of T₁, T₂ and PD values for the three subregions of the supraspinatus tendon were greater than 0. 700. The differences of T₁ values in the lateral subregion, T₂ values in the lateral and middle subregions were statistically significant in the overall comparison across different grades (all P<0. 001).The differences of T₁ values in the middle and medial subregions, T₂ values in the medial subregion and PD values in the lateral, middle and medial subregions were not statistically significant in the overall comparison of different grades (all P>0. 05). Multiple logistic regression model analysis showed that T₂ values in the lateral and middle subregions were related factors for the grade of supraspinatus tendon injury[ OR (95%CI):1.123 (1.037-1.216), 0.122 (1.151-1.197);all P<0.001 ]. The AUC of the T₂ values in lateral subregion diagnosing grade Ⅰ vs grade Ⅳ, grade Ⅱ vs grade Ⅳ and grade Ⅲ vs grade Ⅳ were 0.891(95%CI: 0.801-0.981), 0.797(95%CI: 0.680-0.914), 0.723(95%CI: 0.594-0.853) (all P<0.001), and the AUC of the T₂ values in middle subregion diagnosing grade Ⅰ vs Ⅳ, grade Ⅱ vs Ⅳ, grade Ⅱ vs Ⅲ, and grade Ⅰ vs Ⅲ were 0.946 (95%CI: 0.849-0.989), 0.886 (95%CI: 0.809-0.962), 0.746 (95%CI: 0.631-0.861), 0.843 (95%CI: 0.745-0.941)(all P<0.001). The T₂ values in the lateral and middle subregions were positively correlated with the grade of supraspinatus tendon injury (r=0.542, 0.615; both P<0.001), while T₁ values and T₂ values in the medial subregions were not significantly correlated with the grade of supraspinatus tendon injury (both P>0.05). Conclusion: SyMRI has high clinical application value in the grading of supraspinatus tendon injury, especially T₂ value can be used as an effective quantitative parameter for the grading of supraspinatus tendon injury.

Ultralow-power in-memory computing based on ferroelectric memcapacitor network

Analog storage through synaptic weights using conductance in resistive neuromorphic systems and devices inevitably generates harmful heat dissipation. This thermal issue not only limits the energy efficiency but also hampers the very-large-scale and highly complicated hardware integration as in the human brain. Here we demonstrate that the synaptic weights can be simulated by reconfigurable non-volatile capacitances of a ferroelectric-based memcapacitor with ultralow-power consumption. The as-designed metal/ferroelectric/metal/insulator/semiconductor memcapacitor shows distinct 3-bit capacitance states controlled by the ferroelectric domain dynamics. These robust memcapacitive states exhibit uniform maintenance of more than 104 s and well endurance of 109 cycles. In a wired memcapacitor crossbar network hardware, analog vector-matrix multiplication is successfully implemented to classify 9-pixel images by collecting the sum of displacement currents (I = C × dV/dt) in each column, which intrinsically consumes zero energy in memcapacitors themselves. Our work sheds light on an ultralow-power neural hardware based on ferroelectric memcapacitors.

Porous Metal-Organic Framework/ReS2 Heterojunction Phototransistor for Polarization-Sensitive Visual Adaptation Emulation

Visual adaptation allows organisms to accurately perceive the external world even in dramatically changing environments, from dim starlight to bright sunlight. In particular, polarization-sensitive visual adaptation can effectively process the polarized visual information that is ubiquitous in nature. However, such an intriguing characteristic still remains a great challenge in semiconductor devices. Herein, a novel porous metal-organic-framework phototransistor with anisotropic-ReS₂ -based heterojunction is demonstrated for polarization-sensitive visual adaptation emulation. The device exhibits intriguing polarized sensitivity and an adaptive ability due to its strong anisotropic and trapping-detrapping characteristics, respectively. A series of polarization-sensitive neuromorphic behaviors like polarization-perceptual excitatory postsynaptic current, multimode adjustable dichroic ratio and reconfigurable sensory adaption, are experimentally demonstrated through this porous heterojunction phototransistor. More importantly, with the polarization-electricity cooperation strategy, advanced polarization-sensitive visual adaptation with strong bottom-gate control and environment dependence is successfully realized. These results represent a significant step toward the new generation of intelligent visual perception systems in autonomous navigation and human-machine interaction, etc.

Large-Area Flexible Memory Arrays of Oriented Molecular Ferroelectric Single Crystals with Nearly Saturated Polarization

Molecular ferroelectrics (MFs) have been proven to demonstrate excellent properties even comparable to those of inorganic counterparts usually with heavy metals. However, the validation of their device applications is still at the infant stage. The polycrystalline feature of conventionally obtained MF films, the patterning challenges for microelectronics and the brittleness of crystalline films significantly hinder their development for organic integrated circuits, as well as emerging flexible electronics. Here, a large-area flexible memory array is demonstrated of oriented molecular ferroelectric single crystals (MFSCs) with nearly saturated polarization. Highly-uniform MFSC arrays are  prepared on large-scale substrates including Si wafers and flexible substrates using an asymmetric-wetting and microgroove-assisted coating (AWMAC) strategy. Resultant flexible memory arrays exhibit excellent nonvolatile memory properties with a low-operating voltage of <5 V, i.e., nearly saturated ferroelectric polarization (6.5 µC cm^-2 ), and long bending endurance (>10³ ) under various bending radii. These results may open an avenue for scalable flexible MF electronics with high performance.

Ultralow-Power Machine Vision with Self-Powered Sensor Reservoir

A neuromorphic visual system integrating optoelectronic synapses to perform the in-sensor computing is triggering a revolution due to the reduction of latency and energy consumption. Here it is demonstrated that the dwell time of photon-generated carriers in the space-charge region can be effectively extended by embedding a potential well on the shoulder of Schottky energy barrier. It permits the nonlinear interaction of photocurrents stimulated by spatiotemporal optical signals, which is necessary for in-sensor reservoir computing (RC). The machine vision with the sensor reservoir constituted by designed self-powered Au/P(VDF-TrFE)/Cs2 AgBiBr6 /ITO devices is competent for both static and dynamic vision tasks. It shows an accuracy of 99.97% for face classification and 100% for dynamic vehicle flow recognition. The in-sensor RC system takes advantage of near-zero energy consumption in the reservoir, resulting in decades-time lower training costs than a conventional neural network. This work paves the way for ultralow-power machine vision using photonic devices.

[Safety and efficacy of left atrial appendage closure combined with patent foramen ovale closure for atrial fibrillation patients with patent foramen ovale]

Objective: To analyze the safety and efficacy of combined left atrial appendage (LAA) and patent foramen ovale (PFO) closure in adult atrial fibrillation (AF) patients complicating with PFO. Methods: This study is a retrospective and cross-sectional study. Seven patients with AF complicated with PFO diagnosed by transesophageal echocardiography (TEE) in Zhoupu Hospital Affiliated to Shanghai University of Medicine & Health Sciences from June 2017 to October 2020 were selected. Basic data such as age, gender and medical history were collected. The atrial septal defect or PFO occluder and LAA occluder were selected according to the size of PFO, the ostia width and depth of LAA. Four patients underwent left atrial appendage closure(LAAC) and PFO closure at the same time. PFO closure was performed during a one-stop procedure of cryoablation combined with LAAC in 2 patients. One patient underwent PFO closure at 10 weeks after one-stop procedure because of recurrent transient ischemic attack (TIA). All patients continued to take oral anticoagulants. TEE was repeated 8-12 weeks after intervention. In case of device related thrombus(DRT), TEE shall be rechecked 6 months after adjusting anticoagulant and antiplatelet drug treatment. Patients were follow-up at 1, 3, 6, 12, 24 months by telephone call, and the occurrence of cardio-cerebrovascular events was recorded. Results: Among the 7 patients with AF, 2 were male, aged (68.0±9.4) years, and 3 had a history of recurrent cerebral infarction and TIA. Average PFO diameter was (3.5±0.8)mm. Three patients were implanted with Watchman LAA occluder (30, 30, 33 mm) and atrial septal defect occluder (8, 9, 16 mm). 2 patients were implanted with LAmbre LAA occluder (34/38, 18/32 mm) and PFO occluder (PF1825, PF2525). 2 patients were implanted with LACbes LAA occluder (24, 28 mm) and PFO occluder (PF2525, PF1825) respectively. The patients were followed up for 12 (11, 24) months after operation. TEE reexamination showed that the position of LAA occluder and atrial septal defect occluder or PFO occluder was normal in all patients. DRT was detected in 1 patient, and anticoagulant therapy was adjusted in this patient. 6 months later, TEE showed that DRT disappeared. No cardiovascular and cerebrovascular events occurred in all patients with AF during follow-up. Conclusions: In AF patients complicated with PFO, LAAC combined with PFO closure may have good safety and effectiveness.

[Reanalysis on the Preface of Medical Classics and Classical Prescriptions in Hanshu Yiwenzhi]

Hanshu Yiwenzhi is the earliest comprehensive catalogue of medical books in China, in which FangJi Lue was divided into four categories: "Medical Classics", "Classical Prescriptions", "Fangzhong" and "Shenxian". This paper reanalysed the preface contents of "Medical Classics" and "Classical Prescriptions", and found that the differences between the two sections focused on the definitions of disease treatment and standpoints. "Medical Classics" refers to people who suffered from diseases, but "Classical Prescriptions" refers to the disease which people suffered. This means "Medical Classics" focuses on the human body, but "Classical Prescriptions" centres on diseases.

[Artificial intelligence based on images in ophthalmology]

The application of artificial intelligence (AI) in ophthalmology will greatly reduce the workload of ophthalmologists. Machine learning is an important branch of AI, and deep learning is the most important algorithm in machine learning. At present, AI is well applied in the ophthalmic field. This article summarizes the use of AI in ophthalmology and discusses its inadequacy and future to provide reference for clinical practice. (Chin J Ophthalmol, 2021, 57: 465-469).

Research progress on solutions to the sneak path issue in memristor crossbar arrays

Since the emergence of memristors (or memristive devices), how to integrate them into arrays has been widely investigated. After years of research, memristor crossbar arrays have been proposed and realized with potential applications in nonvolatile memory, logic and neuromorphic computing systems. Despite the promising prospects of memristor crossbar arrays, one of the main obstacles for their development is the so-called sneak-path current causing cross-talk interference between adjacent memory cells and thus may result in misinterpretation which greatly influences the operation of memristor crossbar arrays. Solving the sneak-path current issue, the power consumption of the array will immensely decrease, and the reliability and stability will simultaneously increase. In order to suppress the sneak-path current, various solutions have been provided. So far, some reviews have considered some of these solutions and established a sophisticated classification, including 1D1M, 1T1M, 1S1M (D: diode, M: memristor, T: transistor, S: selector), self-selective and self-rectifying memristors. Recently, a mass of studies have been additionally reported. This review thus attempts to provide a survey on these new findings, by highlighting the latest research progress realized for relieving the sneak-path issue. Here, we first present the concept of the sneak-path current issue and solutions proposed to solve it. Consequently, we select some typical and promising devices, and present their structures and properties in detail. Then, the latest research activities focusing on single-device structures are introduced taking into account the mechanisms underlying these devices. Finally, we summarize the properties and perspectives of these solutions.

Characterization and Application of PVDF and Its Copolymer Films Prepared by Spin-Coating and Langmuir-Blodgett Method

Poly(vinylidene fluoride) (PVDF) and its copolymers are key polymers, displaying properties such as flexibility and electroactive responses, including piezoelectricity, pyroelectricity, and ferroelectricity. In the past several years, they have been applied in numerous applications, such as memory, transducers, actuators, and energy harvesting and have shown thriving prospects in the ongoing research and commercialization process. The crystalline polymorphs of PVDF can present nonpolar α, ε phase and polar β, γ, and δ phases with different processing methods. The copolymers, such as poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), can crystallize directly into a phase analogous to the β phase of PVDF. Since the β phase shows the highest dipole moment among polar phases, many reproducible and efficient methods producing β-phase PVDF and its copolymer have been proposed. In this review, PVDF and its copolymer films prepared by spin-coating and Langmuir-Blodgett (LB) method are introduced, and relevant characterization techniques are highlighted. Finally, the development of memory, artificial synapses, and medical applications based on PVDF and its copolymers is elaborated.

Emergence and complete genome of Senecavirus A in pigs of Henan Province in China, 2017

Senecavirus A (SVA) the only member of the Senecavirus genus within the Picornaviridae family, is an emerging pathogen causing swine idiopathic vesicular disease and epidemic transient neonatal losses. Here, SVA strain (CH-HNKZ-2017) was isolated from a swine farm exhibiting vesicular disease in Henan Province of Central China. A phylogenetic analysis based on complete genome sequence indicated that CH-HNKZ-2017 was closely related to US-15-40381IA, indica- ting that a new SVA isolate had emerged in China.

Surveillance of Unruptured Intracranial Saccular Aneurysms Using Noncontrast 3D-Black-Blood MRI: Comparison of 3D-TOF and Contrast-Enhanced MRA with 3D-DSA

BACKGROUND AND PURPOSE

Patients with unruptured intracranial aneurysms routinely undergo surveillance imaging to monitor growth. Angiography is the criterion standard for aneurysm diagnosis, but it is invasive. This study aimed to evaluate the accuracy and reproducibility of a 3D noncontrast black-blood MR imaging technique for unruptured intracranial aneurysm measurement in comparison with 3D-TOF and contrast-enhanced MRA, using 3D rotational angiography as a reference standard.

MATERIALS AND METHODS

Sixty-four patients (57.3 ± 10.9 years of age, 41 women) with 68 saccular unruptured intracranial aneurysms were recruited. Patients underwent 3T MR imaging with 3D-TOF-MRA, 3D black-blood MR imaging, and contrast-enhanced MRA, and they underwent 3D rotational angiography within 2 weeks. The neck, width, and height of the unruptured intracranial aneurysms were measured by 2 radiologists independently on 3D rotational angiography and 3 MR imaging sequences. The accuracy and reproducibility were evaluated by Bland-Altman plots, the coefficient of variance, and the intraclass correlation coefficient.

RESULTS

3D black-blood MR imaging demonstrates the best agreement with DSA, with the smallest limits of agreement and measurement error (coefficients of variance range, 5.87%-7.04%). 3D-TOF-MRA had the largest limits of agreement and measurement error (coefficients of variance range, 12.73%-15.78%). The average coefficient of variance was 6.26% for 3D black-blood MR imaging, 7.03% for contrast-enhanced MRA, and 15.54% for TOF-MRA. No bias was found among 3 MR imaging sequences compared with 3D rotational angiography. All 3 MR imaging sequences had excellent interreader agreement (intraclass correlation coefficient, >0.95). 3D black-blood MR imaging performed the best for patients with intraluminal thrombus (n = 10).

CONCLUSIONS

3D black-blood MR imaging achieves better accuracy for aneurysm size measurements compared with 3D-TOF, using 3D rotational angiography as a criterion standard. This noncontrast technique is promising for surveillance of unruptured intracranial aneurysms.

[Evaluation of the efficacy and safety of a foldable capsular vitreous body in the treatment of severe retinal detachment]

Objective: To determine the efficacy and safety of vitrectomy combined with implantation of a foldable capsular vitreous body in the treatment of severe retinal detachment with early ocular atrophy in human eyes. Methods: This study was a prospective, multicenter, and one-arm phase Ⅱ clinical trial. Patients with severe retinal detachment and early eyeball atrophy attending Beijing Tongren Eye Center from April 2011 to July 2012 were included. A standard three-port pars plana vitrectomy was performed, and a foldable capsular vitreous body was folded and sent into the vitreous cavity; silicone oil was injected into the capsule. Measurement of visual acuity and intraocular pressure, corneal endothelium count, color fundus photography, optical coherence tomography, and ocular ultrasonography were performed to observe retinal reattachment and adverse reactions after surgery. Wilcoxon signed rank test was performed to compare the baseline and postoperative visual acuity, intraocular pressure and corneal endothelium count. Results: A total of 26 patients were enrolled, including 23 males and 3 females. The age was (37.5±11.5) years, with an average follow-up of 33 months. For each patient, only the left or right eye was included (13 left eyes and 13 right eyes). Retinal reattachment was found in all 24 eyes, and the eyeball atrophy was controlled in all patients. Visual acuity was improved in 4 patients (15.4%) and unchanged in 5 patients (19.2%). The mean intraocular pressure [(14.4±3.9) mmHg(1 mmHg=0.133 kPa)] at the last follow-up was higher than the baseline intraocular pressure [(12.0±6.5) mmHg], but the difference was not statistically significant (Z=-1.859, P=0.063). For the 16 patients with ocular atrophy at baseline, the last follow-up intraocular pressure [(14.6±3.9) mmHg] was significantly higher than the preoperative intraocular pressure [(8.5±2.4) mmHg] (t=-5.326, P<0.001). No obvious adverse reactions were observed. Conclusions: Implantation of a foldable capsular vitreous body is an effective way to treat severe retinal detachment with early eyeball atrophy. It can help to reattach the retina, control eyeball atrophy, maintain the eye shape and intraocular pressure, while visual acuity improvement is limited. (Chin J Ophthalmol, 2019, 55: 259-266).

[Survey of current status of prevention of venous thromboembolism after thoracic surgery in China]

Objective: To investigate the current status of prevention and treatment of venous thromboembolism (VTE) after thoracic surgery in China. Method: Chinese thoracic surgeons were investigated by the online questionnaire which was based on the Chinese version of International VTE questionnaire added with 6 extra questions with Chinese characteristics. Results: A total of 1 150 valid questionnaires were retrieved, accounting for about 20% of all the Chinese thoracic surgeons. The surgeons participating in this survey came from all over the country, most of whom were experienced professionals with high academic titles.For lung cancer patients, 66.96% (770/1 150) of the surgeons suggested that VTE prophylaxis should start 1 day after lung cancer resection, and 64.61% (743/1 150) of the surgeons suggested extending after discharge. For esophagestomy patients, and 48.35% (514/1 063) of the surgeons suggested that there was no need for patients to extend VTE prophylaxis after discharge. More than half of the surgeons participating in this survey made decision of the method and duration of VTE prophylaxis after lung cancer resection (53.91% (620/1 150)) or esophagectomy (52.49% (558/1 063)) depending on the clinical experience.Low molecular weight heparin was the common choice of most surgeons in VTE prophylaxis. More than half of the surgeons thought that previous history of VTE, advanced age, complicated with thrombophilia, obesity (body mass index>30 kg/m²), duration of surgery longer than 6 hours and family history of VTE were key risk factors of the occurrence of postoperative VTE. Conclusions: The results of this survey are highly credible and are a good reflection of the current status of VTE prevention and treatment after thoracic surgery in China. This survey will play an important role in promoting VTE prevention and treatment in Chinese thoracic surgery department, it will also provide data support for government setting new policies, hospital construction of VTE prevention and control as well as raising physicians' awareness.

Graphene Dirac point tuned by ferroelectric polarization field

Graphene has received numerous attention for future nanoelectronics and optoelectronics. The Dirac point is a key parameter of graphene that provides information about its carrier properties. There are lots of methods to tune the Dirac point of graphene, such as chemical doping, impurities, defects, and disorder. In this study, we report a different approach to tune the Dirac point of graphene using a ferroelectric polarization field. The Dirac point can be adjusted to near the ferroelectric coercive voltage regardless its original position. We have ensured this phenomenon by temperature-dependent experiments, and analyzed its mechanism with the theory of impurity correlation in graphene. Additionally, with the modulation of ferroelectric polymer, the current on/off ratio and mobility of graphene transistor both have been improved. This work provides an effective method to tune the Dirac point of graphene, which can be readily used to configure functional devices such as p-n junctions and inverters.

Solid-State Synapse Based on Magnetoelectrically Coupled Memristor

Brain-inspired computing architectures attempt to emulate the computations performed in the neurons and the synapses in the human brain. Memristors with continuously tunable resistances are ideal building blocks for artificial synapses. Through investigating the memristor behaviors in a La_0.7Sr_0.3MnO₃/BaTiO₃/La_0.7Sr_0.3MnO₃ multiferroic tunnel junction, it was found that the ferroelectric domain dynamics characteristics are influenced by the relative magnetization alignment of the electrodes, and the interfacial spin polarization is manipulated continuously by ferroelectric domain reversal, enriching our understanding of the magnetoelectric coupling fundamentally. This creates a functionality that not only the resistance of the memristor but also the synaptic plasticity form can be further manipulated, as demonstrated by the spike-timing-dependent plasticity investigations. Density functional theory calculations are carried out to describe the obtained magnetoelectric coupling, which is probably related to the Mn-Ti intermixing at the interfaces. The multiple and controllable plasticity characteristic in a single artificial synapse, to resemble the synaptic morphological alteration property in a biological synapse, will be conducive to the development of artificial intelligence.

A MEMS SOI-based piezoresistive fluid flow sensor

In this paper, a SOI (silicon-on-insulator)-based piezoresistive fluid flow sensor is presented; the presented flow sensor mainly consists of a nylon sensing head, stainless steel cantilever beam, SOI sensor chip, printed circuit board, half-cylinder gasket, and stainless steel shell. The working principle of the sensor and some detailed contrastive analysis about the sensor structure were introduced since the nylon sensing head and stainless steel cantilever beam have distinct influence on the sensor performance; the structure of nylon sensing head and stainless steel cantilever beam is also discussed. The SOI sensor chip was fabricated using micro-electromechanical systems technologies, such as reactive ion etching and low pressure chemical vapor deposition. The designed fluid sensor was packaged and tested; a calibration installation system was purposely designed for the sensor experiment. The testing results indicated that the output voltage of the sensor is proportional to the square of the fluid flow velocity, which is coincident with the theoretical derivation. The tested sensitivity of the sensor is 3.91 × 10^-4 V ms²/kg.

The Influence of Fatty Acids on Cold Hardiness of Eogystia hippophaecolus Larvae

BACKGROUND: Larvae of the Cossidae family moth Eogystia hippophaecolus bore into and overwinter in the roots of sea buckthorn, which damages this plant in China.

OBJECTIVE

The primary aims of the current study were to investigate the effects of fatty acids on cold hardness in overwintering larvae.

MATERIALS AND METHODS

The supercooling point (SCP), low temperature mortality and fatty acid composition of different overwintering larvae were assessed.

RESULTS

E. hippophaecolus larvae could survive for a long time at temperatures far below the SCP. Saturated fatty acids became less abundant as overwintering proceeded, while unsaturated fatty acids did the opposite. C10:0, C16:1, C16:0, C18:0, C20:0, C20:5, C22:0 and C24:0 fatty acids showed significant seasonal variation during the overwintering period.

CONCLUSION

E. hippophaecolus is "freezing-tolerant" and cold hardiness is enhanced by increasing fatty acid unsaturation and degrading medium- and long-chain fatty acids and eicosapentaenoic acid.

Identification of potential pathogenic genes associated with osteoporosis

OBJECTIVES

Osteoporosis is a chronic disease. The aim of this study was to identify key genes in osteoporosis.

METHODS

Microarray data sets GSE56815 and GSE56814, comprising 67 osteoporosis blood samples and 62 control blood samples, were obtained from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified in osteoporosis using Limma package (3.2.1) and Meta-MA packages. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to identify biological functions. Furthermore, the transcriptional regulatory network was established between the top 20 DEGs and transcriptional factors using the UCSC ENCODE Genome Browser. Receiver operating characteristic (ROC) analysis was applied to investigate the diagnostic value of several DEGs.

RESULTS

A total of 1320 DEGs were obtained, of which 855 were up-regulated and 465 were down-regulated. These differentially expressed genes were enriched in Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, mainly associated with gene expression and osteoclast differentiation. In the transcriptional regulatory network, there were 6038 interactions pairs involving 88 transcriptional factors. In addition, the quantitative reverse transcriptase-polymerase chain reaction result validated the expression of several genes (VPS35, FCGR2A, TBCA, HIRA, TYROBP, and JUND). Finally, ROC analyses showed that VPS35, HIRA, PHF20 and NFKB2 had a significant diagnostic value for osteoporosis.

CONCLUSION

Genes such as VPS35, FCGR2A, TBCA, HIRA, TYROBP, JUND, PHF20, NFKB2, RPL35A and BICD2 may be considered to be potential pathogenic genes of osteoporosis and may be useful for further study of the mechanisms underlying osteoporosis.Cite this article: B. Xia, Y. Li, J. Zhou, B. Tian, L. Feng. Identification of potential pathogenic genes associated with osteoporosis. Bone Joint Res 2017;6:640-648. DOI: 10.1302/2046-3758.612.BJR-2017-0102.R1.

Identification and Quantitative Assessment of Different Components of Intracranial Atherosclerotic Plaque by Ex Vivo 3T High-Resolution Multicontrast MRI

BACKGROUND AND PURPOSE

High-resolution 3T MR imaging can visualize intracranial atherosclerotic plaque. However, histologic validation is still lacking. This study aimed to evaluate the ability of 3T MR imaging to identify and quantitatively assess intracranial atherosclerotic plaque components ex vivo with histologic validation.

MATERIALS AND METHODS

Fifty-three intracranial arterial specimens with atherosclerotic plaques from 20 cadavers were imaged by 3T MR imaging with T1, T2, and proton-density-weighted FSE and STIR sequences. The signal characteristics and areas of fibrous cap, lipid core, calcification, fibrous tissue, and healthy vessel wall were recorded on MR images and compared with histology. Fibrous cap thickness and maximum wall thickness were also quantified. The percentage of areas of the main plaque components, the ratio of fibrous cap thickness to maximum wall thickness, and plaque burden were calculated and compared.

RESULTS

The signal intensity of the lipid core was significantly lower than that of the fibrous cap on T2-weighted, proton-density, and STIR sequences (P < .01) and was comparable on T1-weighted sequences (P = 1.00). Optimal contrast between the lipid core and fibrous cap was found on T2-weighted images. Plaque component mean percentages were comparable between MR imaging and histology: fibrous component (81.86% ± 10.59% versus 81.87% ± 11.59%, P = .999), lipid core (19.51% ± 10.76% versus 19.86% ± 11.56%, P = .863), and fibrous cap (31.10% ± 11.28% versus 30.83% ± 8.51%, P = .463). However, MR imaging overestimated mean calcification (9.68% ± 5.21% versus 8.83% ± 5.67%, P = .030) and plaque burden (65.18% ± 9.01% versus 52.71% ± 14.58%, P < .001).

CONCLUSIONS

Ex vivo 3T MR imaging can accurately identify and quantitatively assess intracranial atherosclerotic plaque components, providing a direct reference for in vivo intracranial plaque imaging.

Interfacial memristors in Al–LaNiO3heterostructures

Self-assembled interfacial memristive systems in Al–LaNiO₃heterostructures.

Epidemiology, diagnosis, surgical treatment and prognosis of the pancreatic neuroendocrine tumors: Report of 125 patients from one single center

OBJECTIVE

The objective of the following study is to summarize the epidemiology of pancreatic neuroendocrine tumors (p-NETs) in our single institution, analyze the diagnostic characteristics, share the experience of surgical treatments and discuss the prognostic factors.

METHODS

A retrospective collection and analysis of clinical data of 125 patients with p-NETs which were pathologically confirmed in our hospital from January 2002 to December 2012.

RESULTS

A total of 125 patients of which 52 were males and 73 were females. Totally 92 patients had functional p-NETs, while non-functional p-NETs were diagnosed in 33 patients. The most common operative procedures performed were local resection of pancreatic tumor (47.2%), followed by distal pancreatectomy (29.6%). Thirty patients (28%) had post-operative complications, the most common of which was pancreatic fistula (22.4%). The overall survival rate at 5 years was 68.4%. The 5-year survival rate for patients with functional tumors was 75.1%, compared with 50.0% for those with non-functional tumors (P = 0.021). The survival time of patients with R0 resection was statistically longer than that of patients with Not R0 resection (P < 0.005). In univariate analysis, the most powerful predictors of poor outcome were gender, age, tumor size, functional status, surgical margins, lymph node invasion and distant metastasis. However only surgical margin and distant metastasis were significant predictors in multivariate analysis (P = 0.001, 0.047, respectively).

CONCLUSION

p-NETs are an uncommon and heterogeneous group of tumors, with a rising incidence. Surgery is the most effective treatment. Surgical margin and distant metastasis were the most significant prognostic factors. Radical resection should be taken more into considerations.

Optoelectronic Properties of Few-Layer MoS2 FET Gated by Ferroelectric Relaxor Polymer

Recently, new devices combining two-dimensional (2D) materials with ferroelectrics, have been a new hotspot for promising applications in electronics and optoelectronics. Here, we design a new type of FET using the 2D MoS₂ and poly(vinylidene fluoride-trifluoroethylene-chlorofloroethylene) terpolymer ferroelectric relaxor. The devices exhibit excellent performance including a large on/off ratio) and an insignificant leakage current. Moreover, the hysteresis characteristics are effectively modulated for its ferroelectric properties at low temperature. Additionally, a broad range photoresponse (visible to 1.55 μm) and a high sensitivity (>300 A/W, λ = 450 nm) are achieved. These results indicate that ferroelectric relaxor can be applied into the high-performance 2D optoelectronic devices.

Discovery of a BTK/MNK dual inhibitor for lymphoma and leukemia

Bruton's tyrosine kinase (BTK) kinase is a member of the TEC kinase family and is a key regulator of the B-cell receptor (BCR)-mediated signaling pathway. It is important for B-cell maturation, proliferation, survival and metastasis. Pharmacological inhibition of BTK is clinically effective against a variety of B-cell malignances, such as mantle cell lymphoma, chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML) and activated B-cell-diffuse large B-cell lymphoma. MNK kinase is one of the key downstream regulators in the RAF-MEK-ERK signaling pathway and controls protein synthesis via regulating the activity of eIF4E. Inhibition of MNK activity has been observed to moderately inhibit the proliferation of AML cells. Through a structure-based drug-design approach, we have discovered a selective and potent BTK/MNK dual kinase inhibitor (QL-X-138), which exhibits covalent binding to BTK and noncovalent binding to MNK. Compared with the BTK kinase inhibitor (PCI-32765) and the MNK kinase inhibitor (cercosporamide), QL-X-138 enhanced the antiproliferative efficacies in vitro against a variety of B-cell cancer cell lines, as well as AML and CLL primary patient cells, which respond moderately to BTK inhibitor in vitro. The agent can effectively arrest the growth of lymphoma and leukemia cells at the G0-G1 stage and can induce strong apoptotic cell death. These primary results demonstrate that simultaneous inhibition of BTK and MNK kinase activity might be a new therapeutic strategy for B-cell malignances.

A beam-membrane structure micromachined differential pressure flow sensor

A beam-membrane structure micromachined flow sensor is designed, depending on the principle of differential pressure caused by the mass flow, which is directly proportional to the square flow rate. The FSI (fluid structure interaction) characteristics of the differential pressure flow sensor are investigated via numerical analysis and analog simulation. The working mechanism of the flow sensor is analyzed depending on the FSI results. Then, the flow sensor is fabricated and calibrated. The calibration results show that the beam-membrane structure differential pressure flow sensor achieves ideal static characteristics and works well in the practical applications.

The endoplasmic reticulum stress response is associated with insulin resistance-mediated drug resistance in HepG2 cells

Insulin resistance has a close relationship with tumorigenesis, tumor progression, and cancer prognosis. Importantly, the liver is the main target tissue of insulin, and the resistance to chemotherapeutic agents has been reported in hepatocarcinoma. However, little is known about the relationship between drug resistance and insulin resistance in hepatocarcinoma. Therefore, we treated HepG2 cells (a human hepatoma cell line) with high concentrations of insulin to establish a cell-based model of insulin resistance (HepG2/IR cells) to define the relationship between insulin resistance and the resistance to chemotherapy. We identified that HepG2/IR cells exhibited stable insulin resistance, with decreased glucose consumption, reduced glycogen synthesis, and decreased expression of the insulin receptor gene. HepG2/IR cells also exhibited endoplasmic reticulum (ER) dilatation and degranulation. Molecular markers of endoplasmic reticulum stress, including glucose-regulated protein78 (GRP78) and phosphorylated protein kinase R-like ER kinase (p-PERK), increased significantly, which was accompanied by increased reactive oxygen metabolism and decreased mitochondrial membrane potential. In addition, HepG2/IR cells were resistant to the chemotherapy agent Adriamycin, which was accompanied by the upregulation of multidrug resistance gene 1/ P-glycoprotein (P-gp; an endoplasmic reticulum chaperone that plays a role in ER stress), and enhanced drug efflux. These data suggest that the endoplasmic reticulum (ER) stress response was active in HepG2/IR cells, and that insulin resistance was related to drug resistance in HepG2 cells. Interestingly, the ER stress and chemotherapy resistance observed in HepG2/IR cells could be reversed by treatment with the insulin sensitizer pioglitazone. Therefore, our study suggests that there is a close relationship between the resistance to chemotherapy and insulin resistance in HepG2 cells, and that the ER stress response play a role in insulin resistance-mediated drug resistance in hepatocarcinoma cells.

KEYWORDS

Insulin resistance, drug resistance, P-gp, endoplasmic reticulum stress, HepG2 cells.

Andrographolide suppresses RANKL-induced osteoclastogenesis in vitro and prevents inflammatory bone loss in vivo

BACKGROUND AND PURPOSE

Osteoclasts play a pivotal role in diseases such as osteoporosis, rheumatoid arthritis and tumour bone metastasis. Thus, searching for natural compounds that may suppress osteoclast formation and/or function is promising for the treatment of osteoclast-related diseases. Here, we examined changes in osteoclastogenesis and LPS-induced osteolysis in response to andrographolide (AP), a diterpenoid lactone isolated from the traditional Chinese and Indian medicinal plant Andrographis paniculata.

EXPERIMENTAL APPROACH

Effects of AP on osteoclast differentiation and bone resorption were measured in vitro. Western blots and RT-PCR techniques were used to examine the underlying molecular mechanisms. The bone protective activity of AP in vivo was assessed in a mouse model of osteolysis.

KEY RESULTS

AP concentration-dependently suppressed RANKL-mediated osteoclast differentiation and bone resorption in vitro and reduced the expression of osteoclast-specific markers, including tartrate-resistant acid phosphatase, calcitonin receptors and cathepsin K. Further molecular analysis revealed that AP impaired RANKL-induced NF-κB signalling by inhibiting the phosphorylation of TGF-β-activated kinase 1, suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the nuclear translocation of the NF-κB p65 subunit. AP also inhibited the ERK/MAPK signalling pathway without affecting p38 or JNK signalling.

CONCLUSIONS AND IMPLICATIONS

AP suppressed RANKL-induced osteoclastogenesis through attenuating NF-κB and ERK/MAPK signalling pathways in vitro, thus preventing bone loss in vivo. These data indicated that AP is a promising natural compound for the treatment of osteoclast-related bone diseases.

Mapping quantitative trait loci with additive effects and additive x additive epistatic interactions for biomass yield, grain yield, and straw yield using a doubled haploid population of wheat (Triticum aestivum L.)

Biomass yield is one of the most important traits for wheat (Triticum aestivum L.)-breeding programs. Increasing the yield of the aerial parts of wheat varieties will be an integral component of future wheat improvement; however, little is known regarding the genetic control of aerial part yield. A doubled haploid population, comprising 168 lines derived from a cross between two winter wheat cultivars, 'Huapei 3' (HP3) and 'Yumai 57' (YM57), was investigated. Quantitative trait loci (QTL) for total biomass yield, grain yield, and straw yield were determined for additive effects and additive x additive epistatic interactions using the QTLNetwork 2.0 software based on the mixed-linear model. Thirteen QTL were determined to have significant additive effects for the three yield traits, of which six also exhibited epistatic effects. Eleven significant additive x additive interactions were detected, of which seven occurred between QTL showing epistatic effects only, two occurred between QTL showing epistatic effects and additive effects, and two occurred between QTL with additive effects. These QTL explained 1.20 to 10.87% of the total phenotypic variation. The QTL with an allele originating from YM57 on chromosome 4B and another QTL contributed by HP3 alleles on chromosome 4D were simultaneously detected on the same or adjacent chromosome intervals for the three traits in two environments. Most of the repeatedly detected QTL across environments were not significant (P > 0.05). These results have implications for selection strategies in wheat biomass yield and for increasing the yield of the aerial part of wheat.

Identification and characterization of the geranylgeranyl diphosphate synthase in Deinococcus radiodurans

Deinococcus radiodurans strain R1 utilizes multiple antioxidants including a unique carotenoid, deinoxanthin, to fight again oxidative stress. Most of the enzymes involved in the deinoxanthin biosynthetic pathway have been identified. However, the enzyme catalysing the synthesis of geranylgeranyl diphosphate (GGPP), which is a precursor of carotenoid biosynthesis, has yet to be identified. Two putative isoprenyl diphosphate synthases (IPPS) homologues (DR1395 and DR932) were screened out by analysis of conserved amino acid regions, and their biochemical functions were investigated. Gene mutation, gene expression in Escherichia coli and analysis of carotenoid products were used to investigate the functions of these candidates. The results suggested that DR1395 encodes the protein for GGPP synthesis. Site-directed mutant analysis indicated that the amino acid composition of and around the first aspartate-rich motif is vital for GGPP synthase function.

SIGNIFICANCE AND IMPACT OF THE STUDY

Deinococcus radiodurans strain R1 produces a unique carotenoid product, deinoxanthin, as an antioxidant. In this study, DR1395 was identified as the gene encoding geranylgeranyl diphosphate synthase (GGPPS) for entrance to deinoxanthin biosynthesis in D. radiodurans. Moreover, site-directed mutagenesis studies on DR1395 identified the effect of amino acid composition of the aspartate-rich motif on the production of this carotenoid. This study demonstrated the entrance step in the deinoxanthin biosynthetic pathway. These results can be useful in genetic engineering strategies for deinoxanthin production including enhancement of GGPPS gene expression in D. radiodurans.

Molecular analysis and frequency of Staphylococcus aureus virulence genes isolated from bloodstream infections in a teaching hospital in Tianjin, China

Staphylococcus aureus is an important cause of bloodstream infections worldwide. We examined the prevalence of genes that encode erythromycin ribosome methylase and bacterial toxins in S. aureus collected from bloodstream infections. Sixty different S. aureus isolates were obtained from blood cultures of patients who were admitted to a Teaching Hospital in Tianjin from January 2006 to August 2011. The susceptibility of the isolates to 16 antibiotics was tested. Methicillin-resistant S. aureus (MRSA) was identified using the disk diffusion method with cefoxitin. PCR was used to detect genes that encode the staphylococcal enterotoxins, Panton-Valentine leukocidin, toxic shock syndrome toxin 1 and erythromycin ribosome methylase. Molecular analysis of the MRSA strains was done using pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing. The positivity rates of mecA, ermA, ermB, and ermC in the isolates were 13/60, 10/60, 18/60, and 18/60, respectively. Among the 60 isolates, 30 harbored enterotoxin genes, with sea as the most frequent toxin gene (33%), followed by sec (15%), sed (12%), and seb (5%). The see and tst genes were not found in any of the isolates. The pvl gene was detected in four strains. Eleven MRSA isolates were of the SCCmec type III; two MRSA isolates could not be determined through SCCmec typing. PFGE analysis of the 13 MRSA isolates produced 8 distinct pulsotypes. Virulence genes and erythromycin ribosome methylase genes were highly prevalent in these isolates. The PFGE results demonstrated that the MRSA spread through cloning, mainly involving SCCmec type III.

Acquisition and Transmissibility of U.S. Soybean dwarf virus Isolates by the Soybean Aphid, Aphis glycines

Soybean dwarf virus (SbDV) exists as several distinct strains based on symptomatology, vector specificity, and host range. Originally characterized Japanese isolates of SbDV were specifically transmitted by Aulacorthum solani. More recently, additional Japanese isolates and endemic U.S. isolates have been shown to be transmitted by several different aphid species. The soybean aphid, Aphis glycines, the only aphid that colonizes soybean, has been shown to be a very inefficient vector of some SbDV isolates from Japan and the United States. Transmission experiments have shown that the soybean aphid can transmit certain isolates of SbDV from soybean to soybean and clover species and from clover to clover and soybean with long acquisition and inoculation access periods. Although transmission of SbDV by the soybean aphid is very inefficient, the large soybean aphid populations that develop on soybean may have epidemiological potential to produce serious SbDV-induced yield losses.

Macaca fascicularis are highly susceptible to an RT-SHIV following intravaginal inoculation: a new model for microbicide evaluation

BACKGROUND

Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) is a major target for antiretroviral strategy to block or curtail HIV infection. A suitable RT-SHIV/macaque model is urgently needed for the evaluation of HIV/AIDS therapies and microbicides specifically targeting HIV-1 RT.

METHODS

Fifteen cynomolgus macaques (Macaca fascicularis) were divided into three groups (n = 5) and intravaginally inoculated with 4800, 1200, or 300 TCID(50) of RT-SHIVtc. Systemic infections of RT-SHIVtc exposed macaques were determined by both virological and immunologic parameters during 24 weeks post-challenge.

RESULTS

Within 2 weeks post-inoculation, 13 of 15 macaques became infected as confirmed by virus isolation, plasma viral RNA, proviral DNA, declined CD4(+)T cell counts in peripheral blood and seroconversion.

CONCLUSIONS

Results serve to validate the infectivity and pathogenicity of RT-SHIVtc following vaginal exposure in M. fascicularis. This RT-SHIVtc/macaque model could be suitable for the pre-clinical evaluation of non-nucleoside RT inhibitor-based anti-HIV microbicides.

Effects of carotenoids from Deinococcus radiodurans on protein oxidation

AIMS

To evaluate the antioxidant effect of carotenoids from Deinococcus radiodurans on protein.

METHODS AND RESULTS

Deinococcus radiodurans strain R1 (ATCC 13939) and its mutant strain R1DeltacrtB were used for this study. The total carotenoids (R1ex) from D. radiodurans were obtained by extraction with acetone/methanol (7 : 2, by vol), and their antioxidant activity was measured using the DPPH (2,2-diphenyl-1-picrylhydrazyl) system. The protein oxidation level, in vitro and in the cell, was measured using the DNPH (2,4-dinitrophenyl hydrazine) method. The carotenoid extract R1ex scavenged 40.2% DPPH radicals compared to beta-carotene (31.7%) at a concentration of 0.5 mg ml(-1). The intracellular level of protein oxidation in mutant R1DeltacrtB, which does not contain carotenoid, was 0.0212 mmol mg(-1) protein which is significantly greater than that in the wild type (0.0169 mmol mg(-1) protein) following the treatment with H(2)O(2). The purified major carotenoid product (deinoxanthin) from the wild type showed a greater inhibition of oxidative damage in bovine serum albumin than lycopene or lutein.

CONCLUSIONS

Carotenoids prevent protein oxidation and contribute to the resistance to cell damage in D. radiodurans.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results provide the evidence that carotenoids can protect proteins in D. radiodurans against oxidative stress.