Active ballistic orbital transport in Ni/Pt heterostructure.

Orbital current, defined as the orbital character of Bloch states in solids, can travel with larger coherence length through a broader range of materials than its spin counterpart, facilitating a robust, higher density and energy efficient information transmission. Hence, active control of orbital transport plays a pivotal role in the progress of the evolving field of quantum information technology. Unlike spin angular momentum, orbital angular momentum couples to phonon angular momentum efficiently via orbital-crystal momentum (L-k) coupling, allowing us to control orbital transport through crystal field potential mediated angular momentum transfer. Here, leveraging the orbital dependant efficient L-k coupling, we have experimentally demonstrated the active control of orbital current velocity in Ni/Pt heterostructure. We observe terahertz emission from Ni/Pt heterostructure via long-range ballistic orbital transport, as evidenced by the delay, and chirping in the emitted THz pulse correlating with increased Pt thickness. Additionally, we also have identified a critical energy density required to overcome collisions in orbital transport, enabling a swifter flow of orbital current. Femtosecond light driven active control of the ballistic orbital transport lays the foundation for the development of dynamic optorbitronics for transmitting information over extended distance.

Extended Conjugation Strategy Enabling Red-Shifted and Efficient Emission of Orange-Red Thermally Activated Delayed Fluorescence Materials.

In account of the energy gap law, the development of efficient narrow-band gap thermally activated delayed fluorescence (TADF) materials remains a major challenge for the application of organic light-emitting diodes (OLEDs). The orange-red TADF materials are commonly designed with either large π-conjugated systems or strong intramolecular donor-acceptor (D-A) interactions for red-shift emission and small singlet-triplet energy gap (ΔEST). There are rare reports on the simultaneous incorporation of these two strategies on the same material systems. Herein, two orange-red emitters named 1P2D-BP and 2P2D-DQ have been designed by extending the conjugation degree of the center acceptor DQ and increasing the number distribution of the peripheral donor PXZ units, respectively. The emission peak of 1P2D-BP is red-shifted to 615 nm compared to 580 nm for 2P2D-DQ, revealing the pronounced effect of the conjugation extension on the emission band gap. In addition, the distorted molecular structure yields a small ΔEST of 0.02 eV, favoring the acquisition of a high exciton utilization through an efficient reverse intersystem crossing process. As a result, orange-red OLEDs with both 1P2D-BP and 2P2D-DQ have achieved an external quantum efficiency (EQE) of more than 17%. In addition, the efficient white OLED based on 1P2D-BP is realized through precise exciton assignment and energy transport modulation, showing an EQE of 23.6% and a color rendering index of 82. The present work provides an important reference for the design of high-efficiency narrow-band gap materials in the field of solid-state lighting.

Dynamics of rhizosphere microbial structure and function associated with the biennial bearing of moso bamboo.

Moso bamboo (Phyllostachys edulis) is a valuable nontimber forestry product with a biennial cycle, producing abundant bamboo shoots within one year (on-year) and few shoots within the following year (off-year). Moso bamboo plants undergo clonal reproduction, resulting in similar genetic backgrounds. However, the number of moso bamboo shoots produced each year varies. Despite this variation, the impact of soil nutrients and the root microbiome on the biennial bearing of moso bamboo is poorly understood. We collected 139 soil samples and determined 14 major physicochemical properties of the rhizosphere, rhizoplane, and bulk soil in different seasons (i.e., the growing and deciduous seasons) and different years (i.e., on- and off-years). Based on 16S rRNA and metagenomic sequencing, major variations were found in the rhizospheric microbial composition during different seasons and years in the moso bamboo forest. Environmental driver analysis revealed that essential nutrients (i.e., SOC, TOC, TN, P, and NH4+) were the main drivers of the soil microbial community composition and were correlated with the on- and off-year cycles. Moreover, 19 MAGs were identified as important biomarkers that could distinguish on- and off-years. We found that both season and year influenced both the microbial community structure and functional pathways through the biosynthesis of nutrients that potentially interact with the moso bamboo growth rhythm, especially the on-year root-associated microbiome, which had a greater abundance of specific nutrients such as gibberellins and vitamin B6. This work provides a dynamic perspective of the differential responses of various on- and off-year microbial communities and enhances our understanding of bamboo soil microbiome biodiversity and stability.

Chiral Interlayer Exchange Coupling for Asymmetric Domain Wall Propagation in Field-Free Magnetization Switching.

The discovery of chiral spin texture has unveiled many unusual yet extraordinary physical phenomena, such as the Néel type domain walls and magnetic skyrmions. A recent theoretical study suggests that a chiral exchange interaction is not limited to a single ferromagnetic layer; instead, three-dimensional spin textures can arise from an interlayer Dzyaloshinskii-Moriya interaction. However, the influence of chiral interlayer exchange coupling on the electrical manipulation of magnetization has rarely been addressed. Here, the coexistence of both symmetric and chiral interlayer exchange coupling between two orthogonally magnetized CoFeB layers in PtMn/CoFeB/W/CoFeB/MgO is demonstrated. Images from polar magneto-optical Kerr effect microscopy indicate that the two types of coupling act concurrently to induce asymmetric domain wall propagation, where the velocities of domain walls with opposite chiralities are substantially different. Based on this microscopic mechanism, field-free switching of the perpendicularly magnetized CoFeB is achieved with a wide range of W thicknesses of 0.6-4.5 nm. This work enriches the understanding of interlayer exchange coupling for spintronic applications.

Three-Dimensional Printing to Guide Fenestrated/Branched TEVAR in Triple Aortic Arch Branch Reconstruction With a Curative Effect Analysis.

PURPOSE: To summarize experience with and the efficacy of fenestrated/branched thoracic endovascular repair (F/B-TEVAR) using physician-modified stent-grafts (PMSGs) under 3D printing guidance in triple aortic arch branch reconstruction. MATERIALS AND METHODS: From February 2018 to April 2022, 14 cases of aortic arch aneurysms and 30 cases of aortic arch dissection (22 acute aortic arch dissection and 8 long-term aortic arch dissection)were treated by F/B-TEVAR in our department, including 34 males and 10 females, with an average age of 59.84 ± 11.72 years. Three aortic arch branches were affected in all patients. A 3D-printed model was made according to computed tomography angiography images and used to guide the fabrication of PMSGs. All patients were followed up. RESULTS: A total of 132 branches were successfully reconstructed with no case of conversion to open surgery. The average operation time was 4.97 ± 1.40 hours, including a mean 44.05 ± 7.72 minutes for stent-graft customization, the mean postoperative hospitalization duration was 9.91 ± 4.47 days, the average intraoperative blood loss was 480.91 mL (100-2810 mL), and the mean postoperative intensive care unit monitoring duration was 1.02 days (0-5 days). No deaths occurred within 30 days of surgery. Postoperative neurological complications occurred in 1 case (2.3%), and retrograde type A dissection occurred in 1 case (2.3%). CONCLUSION: Compared with conventional surgery, triple aortic arch branch reconstruction under the guidance of 3D printing is a minimally invasive treatment method with the advantages of accurate positioning, rapid postoperative recovery, few complications, and reliable short- to mid-term effects. CLINICAL IMPACT: At present the PMSG usually depend on imaging data and software calculation. With the guidance of 3D printing technology, image data could be transformed into 3D model, which has improved the accuracy of the positioning of the fenestrations. The diameter reduction technique and the internal mini cuff technique have made a complement to the slimed-down fenestration selection process and the low rate of endoleak. As reproducible study, our results may provide reference for TEVAR in different cases.

Ecological strategy of Phyllostachys heteroclada oliver in the riparian zone based on ecological stoichiometry.

The abnormality of seasonal water level fluctuation in the riparian zone causes various ecological and environmental problems, such as vegetation degradation, biodiversity reduction, soil erosion, and landscape transformation, thereby critically modifying the ecosystem structure and functions. This necessitates the development of a dominant vegetation zone with competitive potential. In this study, we investigated the content and distribution pattern of nutrient elements in each organ of the dominant bamboo species, Phyllostachys heteroclada, in the riparian zone. We also analyzed the morphological characteristics, root aeration tissue structure, root oxygen exchange capacity, ATP supply situation, and leaf PSII photosynthetic mechanism of two bamboo species (P. heteroclada and P. nigra) in the riparian zone. Compared with P. nigra, the roots of P. heteroclada formed well-developed oxygen storage and transport structure, i.e., aeration tissue, and exhibited root oxygen secretion in the waterlogging environment of the riparian zone, whereas the roots maintained a high ATP content through energy metabolism, thus benefiting mineral absorption and transport. Moreover, the accumulation of N, P, Ca, Mg, and Fe in the leaves of P. heteroclada was greater under waterlogging conditions than under non-waterlogging conditions, which is the basis for the efficient operation of the photosynthetic mechanism of the leaves. Compared with waterlogged P. nigra, the PSII electron acceptor QA of P. heteroclada leaves had a vigorous reducing ability and showed higher efficiency of light uptake energy as well as higher quantum yield indexes ϕ(Eo) and ϕ(Po). This study demonstrates that the ecological adaptive regulation strategies of P. heteroclada in the riparian zone are intrinsic driving factors affecting their stoichiometric characteristics, including changes in the absorption and transport of minerals caused by root aeration structure and energy metabolism. Moreover, carbon production and allocation may be caused by the stable photosynthetic mechanism and source-sink relationship of leaves. Through the synergistic regulation of different organs realizing their roles and functions, P. heteroclada developed ecological stoichiometry characteristics adapted to the riparian zone.

[Application of pueumatic tourniquet in the operation of lower tibiofibular fracture].

OBJECTIVE: To investigate the complications of tourniquet in the clinical application of lower tibiofibular fracture. METHODS: From June 2018 to September 2019, 33 cases of closed lower tibiofibular fractures (AO type 43A) were treated with plates and screws and were divided into two groups according to whether pueumatic tourniquet was used:16 cases in the observation group, 13 males and 3 females, aged 18 to 69 (38.8±17.0) years, the operation time after injury was (6.9±1.7) days, and tourniquet was not used during operation. There were 17 cases in the control group, 13 males and 4 females, aged from 21 to 71 (43.8±12.4) years, the operation time after injury was (6.5±1.0) days, automatic pneumatic tourniquetwas routinely used in the operation. The operation time, blood loss, postoperative swelling, pain and other complications were compared between two groups. RESULTS: Total of 33 patients were followed up for an average of 15 months. There was no significant difference in operation time and blood loss between two groups (P>0.05). The VAS scores of limb pain in the observation group were 5.13±1.70 and 2.25±1.60 respectively 1 and 3 days after operation, which were significantly lower than those in the control group 7.35±1.30 and 4.18±1.60;the swelling was (3.67±0.70) cm and (2.02±0.90) cm respectively, which was significantly lower than(4.54±0.40) cm and(3.54±0.40) cm in the control group (P<0.05);there were 1 case of tourniquet pain, 1 case of numbness, 1 case of blister and 1 case of poor wound healing in the control group, there were no such complications in the observation group (P<0.05). CONCLUSION: The fracture of lower tibiofibular segment is superficial and easy to be exposed and fixed during operation. In order to avoid tourniquet complications, it is not recommended to use air bag tourniquet routinely or minimize the application time of tourniquet.

Screening and identifying hepatobiliary diseases through deep learning using ocular images: a prospective, multicentre study.

BACKGROUND: Ocular changes are traditionally associated with only a few hepatobiliary diseases. These changes are non-specific and have a low detection rate, limiting their potential use as clinically independent diagnostic features. Therefore, we aimed to engineer deep learning models to establish associations between ocular features and major hepatobiliary diseases and to advance automated screening and identification of hepatobiliary diseases from ocular images. METHODS: We did a multicentre, prospective study to develop models using slit-lamp or retinal fundus images from participants in three hepatobiliary departments and two medical examination centres. Included participants were older than 18 years and had complete clinical information; participants diagnosed with acute hepatobiliary diseases were excluded. We trained seven slit-lamp models and seven fundus models (with or without hepatobiliary disease [screening model] or one specific disease type within six categories [identifying model]) using a development dataset, and we tested the models with an external test dataset. Additionally, we did a visual explanation and occlusion test. Model performances were evaluated using the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, and F1* score. FINDINGS: Between Dec 16, 2018, and July 31, 2019, we collected data from 1252 participants (from the Department of Hepatobiliary Surgery of the Third Affiliated Hospital of Sun Yat-sen University, the Department of Infectious Diseases of the Affiliated Huadu Hospital of Southern Medical University, and the Nantian Medical Centre of Aikang Health Care [Guangzhou, China]) for the development dataset; between Aug 14, 2019, and Jan 31, 2020, we collected data from 537 participants (from the Department of Infectious Diseases of the Third Affiliated Hospital of Sun Yat-sen University and the Huanshidong Medical Centre of Aikang Health Care [Guangzhou, China]) for the test dataset. The AUROC for screening for hepatobiliary diseases of the slit-lamp model was 0·74 (95% CI 0·71-0·76), whereas that of the fundus model was 0·68 (0·65-0·71). For the identification of hepatobiliary diseases, the AUROCs were 0·93 (0·91-0·94; slit-lamp) and 0·84 (0·81-0·86; fundus) for liver cancer, 0·90 (0·88-0·91; slit-lamp) and 0·83 (0·81-0·86; fundus) for liver cirrhosis, and ranged 0·58-0·69 (0·55-0·71; slit-lamp) and 0·62-0·70 (0·58-0·73; fundus) for other hepatobiliary diseases, including chronic viral hepatitis, non-alcoholic fatty liver disease, cholelithiasis, and hepatic cyst. In addition to the conjunctiva and sclera, our deep learning model revealed that the structures of the iris and fundus also contributed to the classification. INTERPRETATION: Our study established qualitative associations between ocular features and major hepatobiliary diseases, providing a non-invasive, convenient, and complementary method for hepatobiliary disease screening and identification, which could be applied as an opportunistic screening tool. FUNDING: Science and Technology Planning Projects of Guangdong Province; National Key R&D Program of China; Guangzhou Key Laboratory Project; National Natural Science Foundation of China.

Shift in HIV/AIDS Epidemic and Factors Associated with False Positives for HIV Testing: A Retrospective Study from 2013 to 2018 in Xi'an, China.

BACKGROUND: In China, although quite a few bold programmes have been made for HIV/AIDS, the epidemic has still shown an increasing trend. OBJECTIVES: The study was aimed to investigate the characteristics of new HIV/AIDS and the major factors of false positives (FP) for HIV testing. METHODS: A retrospective review was performed in a teaching hospital in Xi'an between 2013 and 2018. The overall characteristics and trends of new HIV/AIDS were described. Moreover, the major factors of FP were determined by the Pareto analysis. RESULTS: A total of 469 new HIV/AIDS were diagnosed, with an increasing prevalence of the new HIV/AIDS from 0.0626% (41/65503) in 2013 to 0.0827% (115/139046) in 2018. Of them, the majority occurred in the males (88.50%), people aged 21-50 years (76.97%), migrants (60.98%), and sexual contact route (88.70%). There was a rapid increase in the annual number of new HIV/AIDS and increasing trends in groups of young individuals, students, and homosexual mode; however, a downward trend in the percentage of injecting drug use was also observed. Over 50 years old and patients from oncology, obstetrics, hepatobiliary surgery, nephrology, cardiology, and infectious disease constituted the major factors of FP. CONCLUSION: The HIV/AIDS epidemic in Xi'an is still evolving, therefore, effective strategies, appropriate education and scaling up HIV testing should be developed. In addition, old adults and specific departments were associated with FP.

Effects of Rhizome Integration on the Water Physiology of Phyllostachys edulis Clones Under Heterogeneous Water Stress.

Water is crucial to plant growth and development. Under heterogeneous environmental water deficiency, physiological integration of the rhizomatous clonal plant triggers a series of physiological cascades, which induces both signaling and physiological responses. It is known that the rhizome of Phyllostachys edulis, which connects associated clonal ramets, has important significance in this physiological integration. This significance is attributed to the sharing of water and nutrients in the vascular bundle of clonal ramets under heterogeneous water conditions. However, the physiological characteristics of physiological integration under heterogeneous water stress remain unclear. To investigate these physiological characteristics, particularly second messenger Ca2+ signaling characteristics, long-distance hormone signaling molecules, antioxidant enzyme activity, osmotic adjustment substance, and nitrogen metabolism, ramets with a connected (where integration was allowed to take place) and severed rhizome (with no integration) were compared in this study. The vascular bundle structure of the rhizome was also observed using laser confocal microscopy. Overall, the results suggest that interconnected rhizome of P. edulis can enhance its physiological function in response to drought-induced stress under heterogeneous water deficiency. These measured changes in physiological indices serve to improve the clonal ramets' drought adaptivity through the interconnected rhizome.

TORCH screening used appropriately in China?─three years results from a teaching hospital in northwest China.

OBJECTIVES: TORCH infections caused by Toxoplasma gondii (TOX), rubella virus (RV), cytomegalovirus (CMV) and herpes simplex virus 1,2 (HSV-1,2) are associated with congenital anomalies. The study aimed to analyze the characteristics of TORCH screening in reproductive age women. METHODS: A total of 18,104 women (2015-2017) from a teaching hospital in Xi'an, China, were enrolled in the study. The characteristics of TORCH screening, i.e., the application of TORCH test, the seroprevalence, the impact of age, periods of gestation and woman with bad obstetric history (BOH) on the serological data were investigated. RESULTS: In the study, 319 women (1.76%) performed dynamic TORCH test. 51.66, 20.44 and 3.83% of the population did the test in the pre-gestation period, the first and third trimester, respectively. Quite a few pre-gestation women (29.74%) ignored screening of IgG antibodies. The overall IgG/IgM seropositvity of TOX, RV, CMV, HSV-1 and HSV-2 was 4.35%/0.35, 90%/0.63, 96.79%/0.97, 81.11%/0.14 and 6.1%/0.19%, respectively. The age-specific distributions and periods of gestation had no significant effect on the seroprevalence of TORCH agents, p>0.05. However, BOH was significantly associated with higher seropositvity of IgM (RV, CMV, HSV-1 and HSV-2) and IgG (CMV and HSV-1) antibodies, p < 0.05. CONCLUSION: In Xi'an region, more attentions should be paid to TOX, CMV, HSV-2 and the women with BOH for TORCH screening. Meanwhile, a greater emphasis needs to be placed on TORCH test used inappropriately in China.

Angled tooth segmentation from computerized tomography images.

Tooth contour segmentation from dental computerized tomography (CT) images is one of the fundamental steps in reconstructing the three-dimensional models of teeth. However, existing methods depend on the tooth shape similarity between adjacent slices, and have difficulty to segment these angled teeth whose contour shapes from adjacent slices may differ a lot. This study proposes a new method for contour segmentation of angled teeth from CT images. The volume of interest (VOI) of target tooth and corresponding tooth axis are first extracted from volumetric CT images. Local images within the VOI of target tooth are then rotated such that the tooth axis in the rotated images is perpendicular to the transverse section. Tooth contours are finally segmented from the rotated images using a hybrid level set model slice-by-slice. Experimental results verified that the proposed method was effective to segment contours of angled teeth from CT images.

Behavioral intervention reduces unhealthy eating behaviors in preschool children via a behavior card approach.

Many eating behaviors form in childhood, and some unhealthy behaviors may persist into adulthood and have potential impacts on people's health. This study evaluated the effectiveness of behavioral intervention in reducing consumption of Western fast food, sweetened beverages, fried food in preschool children, and changing parents' rewarding behaviors that encourage the consumption of the unhealthy foods. The research was a cluster randomized trial of seven kindergartens, involving 1138 children aged 3-6 years and their parents in Beijing, China. Parents and children allocated to the intervention group received two lectures and printed resources, including behavior cards, educational sheets. Children's behavior cards, applied with behavior-changing techniques, were used to intervene, and monitor behavior changes over time. Children in the control group just followed their usual health education curriculum in kindergartens. Intervention effects on food consumption behaviors were assessed by examining pre- and post-questionnaires. Of the 1138 children screened at baseline, 880 (77.3%) were measured at the end of the intervention period. The intervention lasted from March to June in 2010. The results showed that consumption of Western fast food, sweetened beverages, and fried food was decreased among the intervention group (P<0.001). Proportions of parents using Western fast food as rewards for their children were decreased (P=0.002). From March to June 2010, the frequency of each target behavior in children tended to decrease over the intervention period (P<0.001). Most parents favored regularly-delivered behavior cards or materials for behavioral intervention. In conclusion, the behavioral intervention encourages the healthier eating behaviors of children and reduces the parents' practice of using unhealthy foods as reward.

[Application of a self-made steel wire guide in the treatment of avulsion fractures of tibial posterior cruciate ligament].

OBJECTIVE: To explore the effect of a self-made guiding needle of steel wire in guiding the wire through the tibial tunnel for the treatment of avulsion fractures of tibial posterior cruciate ligament with open reduction and wire fixation. METHODS: From February 2011 to June 2014, a total of 22 patients with avulsion fractures of tibial posterior cruciate ligament underwent surgical treatments were analyzed, including 14 males and 8 females with an average age of 35.6 years old (ranged, 17 to 63 years old). According to Meyers classification, 9 patients were classified as type II, 13 patients were classified as type III. All the patients underwent open reduction and wire fixation with medial knee "L" shape approach. A wire guiding needle was used to guide the wire through the tibial tunnel during operation. RESULTS: With the assistance of wire guidance needles, wires passed through the tibial tunnel rapidly during the operation in all the 22 patients. All the patients were followed up, X-ray imagings 6 months after operation showed the fractures healed well. The average follow-up time in all patients was 6 months (ranged, 6 to 12 months). The averaged Lysholm knee score in 22 knee was 92.7 +/- 3.4. All patients' posterior drawer test were negative. CONCLUSION: Self-made wire guiding needle can simplify the operation procedures in which the wires pass through the tibial tunnel, shorten the operation time, reduce the surgical trauma and complications, and be worthy of clinical application.

[Air Microbial Pollution and Health Risk of Urban Black Odorous Water].

Aiming at the possihle air microbial pollution of urban black odorous water the contamination characteristics of bacteria, fungi and total microbe as well as health risks of different types of population within certain distance from the urban black odorous water were studied. The results showed that hbcteria and fungi pollution was primary within offshore 200 m; under near calm condition, there was an aggregation phenomenon of microorganisms within offshore 20 m; the concentrations of bacteria, fungi and total microbe were the highest in the morning, the middle at noon, and the lowest in the afternoon; within offshore 200 m, the width of black odorous water was significantly correlated with the concentrations of bacteria, fungi and total microorganisms; the microbial health risk of residents mainly existed in the offshore 100 m range; at the same offshore distance, the short-term exposure health risk to children was the greatest, followed by women, men to a minimum.

Feeding methods, sleep arrangement, and infant sleep patterns: a Chinese population-based study.

BACKGROUND: Findings from prior research into the effect of feeding methods on infant sleep are inconsistent. The objectives of this study were to examine infants' sleep patterns by feeding methods and sleep arrangement from birth to eight months old. METHODS: This longitudinal cohort study enrolled 524 pregnant women at 34-41 weeks of gestation and their infants after delivery in 2006 and followed up until eight months postpartum. The study subjects were recruited from nine women and children hospitals in nine cities in China (Beijing, Chongqing, Wuhan, Changsha, Nanning, Xiamen, Xi'an, Jinan, and Hailin). Participating infants were followed up weekly during the first month and monthly from the second to the eighth month after birth. Twenty-four hour sleep diaries recording infants' sleeping and feeding methods were administered based on caregiver's self-report. Multivariable mixed growth curve models were fitted to estimate the effects of feeding methods and sleep arrangement on infants' sleep patterns over time, controlling for maternal and paternal age, maternal and paternal education level, household income, supplementation of complementary food, and infant birth weight and length. RESULTS: Exclusively formula fed infants had the greatest sleep percentage/24 h, followed by exclusively breast milk fed infants and partially breast milk fed infants (P<0.01). Night waking followed a similar pattern. However, the differences in sleep percentage and night waking frequency between exclusively formula and exclusively breast milk fed infants weakened over time as infants developed. In addition, compared to infants with bed-sharing sleep arrangement, those with room sharing sleep arrangement had greater daytime and 24-hour infant sleep percentage, whereas those with sleeping alone sleep arrangement had greater nighttime sleep percentage. CONCLUSIONS: Our data based on caregiver's self-report suggested that partial breastfeeding and bed-sharing may be associated with less sleep in infants. Health care professionals need to work with parents of newborns to develop coping strategies that will help prevent early weaning of breastfeeding.

Molar axis estimation from computed tomography images.

Estimation of tooth axis is needed for some clinical dental treatment. Existing methods require to segment the tooth volume from Computed Tomography (CT) images, and then estimate the axis from the tooth volume. However, they may fail during estimating molar axis due to that the tooth segmentation from CT images is challenging and current segmentation methods may get poor segmentation results especially for these molars with angle which will result in the failure of axis estimation. To resolve this problem, this paper proposes a new method for molar axis estimation from CT images. The key innovation point is that: instead of estimating the 3D axis of each molar from the segmented volume, the method estimates the 3D axis from two projection images. The method includes three steps. (1) The 3D images of each molar are projected to two 2D image planes. (2) The molar contour are segmented and the contour's 2D axis are extracted in each 2D projection image. Principal Component Analysis (PCA) and a modified symmetry axis detection algorithm are employed to extract the 2D axis from the segmented molar contour. (3) A 3D molar axis is obtained by combining the two 2D axes. Experimental results verified that the proposed method was effective to estimate the axis of molar from CT images.

Human-robot collaborated path planning for bevel-tip needle steering in simulated human environment.

Clinical Application of linear percutaneous needle insertion is restricted due to issues such as limited path and deflection. Thus steering of flexible needle is critical demanded in the clinic. Previous studies tended to use autonomous methods to conduct path planning for needle steering. However, these methods had very limited adaptabilities, and they also decreased the human operator's domination of the operation, as clinically required. In this case, teleoperation has been an option, while in complicated environments sole teleoperation is not sufficient for a human operator to generate multi-curved insertion path. Therefore, in this paper, we propose a semiautonomous human-robot collaborated path planning method for teleoperated bevel-tip needle steering. The key module of this method is a human-robot collaboration mechanism which consists of the operator input, environment constraints, and path constraints. The proposed method were tested semi-physically in a simulated human environment and the results validated that the proposed method were able to efficiently assist the operator to generate multi-curved paths under human operator's domination.

Orthodontic force simulation of Tooth-PDL-Bone Complex under archwire loading.

Orthodontic force simulation is very important for the guidance of clinical orthodontic treatment. Previous works were mainly conducted by directly loading the force on a single or a few teeth. However, in clinic, the orthodontic force is provided by loading orthodontic appliances, and there currently is no appropriate way to measure the force on the teeth provided by the loaded appliances. This study presents a method to simulate the orthodontic force of a whole Tooth-Periodontal Ligament-Bone Complex (TPBC) by directly loading the archwire to the dentition applying the finite element method. A 3D TPBC model was reconstructed from CT images, and models of brackets and the archwire were also built. The loading procedure of the archwire was implemented by simulating the deformation and displacement of the archwire before and after the loading, and the stress of the archwire induced by the deformation and displacement was obtained. Then, the stress was applied to the brackets, and the corresponding orthodontic force of the TPBC was simulated. By applying the method, archwire designed according to the planned dentition shape was loaded successfully to the original dentition, and the orthodontic force of the TPBC was obtained.

A new bifunctional electrochemical sensor for hydrogen peroxide and nitrite based on a bimetallic metalloporphyrinic framework.

Metalloporphyrinic frameworks have been studied in many fields. However, their electrochemical properties were seldom reported. This work reports the synthesis and the electrochemical application of a new bimetallic metalloporphyrinic framework, [Cu2-Co[5,10,15,20-(4-carboxyphenyl)porphyrin](H2O)2]·0.5DMF·5H2O (Cu-CoTCPP) in which [5,10,15,20-(4-carboxyphenyl)porphyrin]Co(ii) (CoTCPP) struts are bound by Cu(ii)-carboxylate clusters (Cu2(COO)4). Cu-CoTCPP was synthesized by the solvothermal method and characterized by various techniques, including XRD, IR, UV-vis, elemental analysis, TG, and TEM. Cu-CoTCPP showed novel bifunctional electrocatalytic ability toward the reduction/oxidation of H2O2 and the oxidation of NaNO2, which might be due to Cu and Co central ions, respectively. With the assistance of multi-walled carbon nanotubes (MWCNTs), Cu-CoTCPP showed further improved sensing performance toward H2O2. The linear detection ranges of the Cu-CoTCPP/MWCNTs/GCE for H2O2 and NaNO2 are 5.0 × 10-7 to 1.8 × 10-4 M and 2.5 × 10-6 to 1.1 × 10-3 M, respectively, with the detection limits of 2.4 × 10-7 M and 1.7 × 10-7 M, and the sensitivity of 168 and 439 mA mol-1 L cm-2. The bifunctional electrocatalytic ability and the excellent performance imply that the metalloporphyrinic frameworks are promising candidates for fabricating electrochemical sensors.