Development of an HSV-1 production process involving serum-reduced culturing and bead-to-bead transfer.

Herpes simplex virus type 1 (HSV-1) plays an important role in the field of gene therapy and viral vaccines, especially as an oncolytic virus. However, the mass production of HSV-1 viral vectors remains a challenge in the industry. In this study, a microcarrier-mediated serum-reduced medium culture was used to improve the bioprocess of HSV-1 production and increase HSV-1 yields. The composition of the culture media, which included a basal medium, serum concentration, and glutamine additive, was optimized. The process was successfully conducted in a 1 L bioreactor, and virus production was threefold greater than that of conventional processes with a 10% serum medium. The bead-to-bead transfer process was also developed to further increase scalability. In spinner flasks, the detachment rate increased from 49.4 to 80.6% when combined agitation was performed during digestion; the overall recovery proportion increased from 37.9 to 71.1% after the operational steps were optimized. Specifically, microcarrier loss was reduced during aspiration and transfer, and microcarriers and detached cells were separated with filters. Comparable cell growth was achieved with the baseline process using 2D culture as the inoculum by exchanging the subculture medium. To increase virus production after bead-to-bead transfer, critical parameters, including shear stress during digestion, TrypLE and EDTA concentrations in the subculture, and the CCI, were identified from 47 parameters via correlation analysis and principal component analysis. The optimized bead-to-bead transfer process achieved an average of 90.4% overall recovery and comparable virus production compared to that of the baseline process. This study is the first to report the optimization of HSV-1 production in Vero cells cultured on microcarriers in serum-reduced medium after bead-to-bead transfer. KEY POINTS: • An HSV-1 production process was developed that involves culturing in serum-reduced medium, and this process achieved threefold greater virus production than that of traditional processes. • An indirect bead-to-bead transfer process was developed with over 90% recovery yield in bioreactors. • HSV-1 production after bead-to-bead transfer was optimized and was comparable to that achieved with 2D culture as inoculum.

Research on the dentification of Panax ginseng and Panax quinquefolium using catalysed hairpin assembly technology.

INTRODUCTION: Panax ginseng and Panax quinquefolium are traditional Chinese herb medicines and similar in morphology and some chemical components but differ in drug properties, so they cannot be mixed. However, the processed products of them are often sold in the form of slices, powder, and capsules, which are difficult to identify by traditional morphological methods. Furthermore, an accurate evaluation of P. ginseng, P. quinquefolium and the processed products have not been conducted. OBJECTIVE: This study aimed to establish a catalysed hairpin assembly (CHA) identification method for authenticating products made from P. ginseng and P. quinquefolium based on single nucleotide polymorphism (SNP) differences. METHOD: By analysing the differences of SNP in internal transcribed spacer 2 (ITS2) in P. ginseng and P. quinquefolium to design CHA-specific hairpins. Establish a sensitive and efficient CHA method that can identify P. ginseng and P. quinquefolium, use the sequencing technology to verify the accuracy of this method in identifying Panax products, and compare this method with high-resolution melting (HRM). RESULTS: The reaction conditions of CHA were as follows: the ratio of forward and reverse primers, 20:1; hairpin concentration, 5 ng/µL. Compared with capillary electrophoresis, this method had good specificity and the limit of detection was 0.5 ng/µL. The result of Panax product identification with CHA method were coincidence with that of the sequencing method; the positive rate of CHA reaction was 100%. CONCLUSION: This research presents an effective identification method for authenticating P. ginseng and P. quinquefolium products, which is helpful to improve the quality of Panax products.

Decreased expression of ATP-binding cassette protein G1 promotes abnormal adipogenesis of condylar chondrocytes in temporomandibular joint osteoarthritis.

BACKGROUND: Abnormal lipid metabolism is involved in the development of osteoarthritis (OA). ATP-binding cassette protein G1 (ABCG1) is crucial in mediating the outflow of cholesterol, phosphatidylcholine and sphingomyelin and reducing intracellular lipid accumulation. OBJECTIVE: This study aimed to evaluate whether ABCG1 participates in the abnormal adipogenesis of chondrocytes in osteoarthritic cartilage of temporomandibular joint. METHODS: Eight-week-old female rats were subjected to unilateral anterior crossbite (UAC) to induce OA in the temporomandibular joint (TMJ). Histochemical staining, immunohistochemical (IHC) staining, and qRT-PCR were performed. Primary condylar chondrocytes of rats were transfected with ABCG1 shRNA or overexpression lentivirus and then stimulated with fluid flow shear stress (FFSS). Cells were collected for oil red O staining, immunofluorescence staining, and qRT-PCR analysis. RESULTS: Abnormal adipogenesis, characterized by increased expression of Adiponectin, CCAAT/enhancer-binding protein α (Cebpα), fatty acid binding protein 4 (Fabp4) and Perilipin1, was enhanced in the degenerative cartilage of TMJ OA in rats with UAC, accompanied by decreased expression of ABCG1. After FFSS stimulation, we observed lipid droplets in the cytoplasm of cultured cells with increased expression of Adiponectin, Cebpα, Fabp4 and Perilipin1 and decreased expression of ABCG1. Knockdown of Abcg1 induced abnormal adipogenesis and differentiation of condylar chondrocytes. Overexpression of ABCG1 alleviated the abnormal adipogenesis and differentiation of condylar chondrocytes induced by FFSS. CONCLUSIONS: Abnormal adipogenesis of chondrocytes and decreased ABCG1 expression were observed in degenerative cartilage of TMJ OA. ABCG1 overexpression effectively inhibits the adipogenesis of chondrocytes and thus alleviates TMJ condylar cartilage degeneration.

Selenophene-fused Perylene Diimide-based Cathode Interlayer Enables 19% Efficiency Binary Organic Solar Cells via Stimulative Charge Extraction.

The cathode interlayer is crucial for the development of organic solar cells (OSCs), but the research on simple and efficient interlayer materials is lagging behind. Here, a donor-acceptor (D-A) typed selenophene-fused perylene diimide (PDI) derivative (SePDI3) is developed as cathode interlayer material (CIM) for OSCs, and a non-fused PDI derivative (PDI3) is used as the control CIM for comparison. Compared to PDI3, SePDI3 shows a stronger self-doping effect and better crystallinity, resulting in better charge transport ability. Furthermore, the interaction between SePDI3 and L8-BO can form an efficient extraction channel, leading to superior charge extraction behavior. Finally, benefitting from significantly enhanced charge transport and extraction capacity, the SePDI3-based device displays a champion PCE of 19.04% with an ultrahigh fill factor of 81.65% for binary OSCs based on PM6:L8-BO active layer, which is one of the top efficiencies reported to date in binary OSCs based novel CIMs. Our work prescribes a facile and effective fusion strategy to develop high-efficiency CIMs for OSCs.

Boosting the Reversible, High-Rate Na+ Storage Capability of the Hard Carbon Anode Via the Synergistic Structural Tailoring and Controlled Presodiation.

Hard carbons (HCs) are extensively investigated as the potential anodes for commercialization of sodium-ion batteries (SIBs). However, the practical deployment of HC anode suffers from the retarded Na+ diffusion at the high-rate or low-temperature operation scenarios. Herein, a multiscale modification strategy by tuning HC microstructure on the particle level as well as replenishing extra Na+ reservoir for the electrode through a homogeneous presodiation therapy is presented. Consequently, the coulombic efficiency of HC anode can be precisely controlled till the close-to-unit value. Detailed kinetics analysis observes that the Na+ diffusivity can be drastically enhanced by two orders of magnitude at the low potential region (< 0.1 V vs. Na+ /Na), which accelerates the rate-limiting step. As pairing the presodiated HC anode (≈5.0 ± 0.2 mg cm-2 ) with the NaVPO4 F cathode (≈10.3 mg cm-2 ) in the 200 mAh pouch cell, the optimal balance of the cyclability (83% over 1000 cycles), low-temperature behavior till -40 °C as well as the maximized power output of 1500 W kg-1 can be simultaneously achieved. This synergistic modification strategy opens a new avenue to exploit the reversible, ultrafast Na+ storage kinetics of HC anodes, which thus constitutes a quantum leap forward toward high-rate SIB prototyping.

Development and application of a visualization method for identification of Panax species with LAMP and a DNAzyme.

Panax ginseng and Panax quinquefolium are two valuable Chinese herbal medicines that should not be mixed because they differ in drug properties and efficacy. The traditional identification method is easily affected by subjective factors and cannot effectively distinguish between ginseng products. This study aimed to develop a new chemical analysis method to visually identify P. ginseng and P. quinquefolium. In this method, a large number of sequences containing G-quadruplex were generated by loop-mediated isothermal amplification, and the combination of G-quadruplex and hemin was used to form deoxyribozyme, which catalyzed the color change of H2O2. Artificial simulation of adulteration experiments revealed that this method could detect more than 20% adulterated P. quinquefolium. Compared with the traditional identification methods, this technology was simpler and more efficient, providing a reference for developing rapid visual identification methods and reagents for P. ginseng and P. quinquefolium.

Advances in ligase-based nucleic acid amplification technology for detecting gene mutations: a review.

Gene mutation has been a concern for researchers because it results in genetic variations with base changes in molecular structure. Researchers continue to explore methods to detect gene mutations, which may help in disease diagnosis, medication guidance, and so on. Currently, the detection methods, such as whole-genome sequencing and polymerase chain reaction, have some limitations in terms of cost and sensitivity. Ligase (an enzyme) can recognize base mismatch as a commonly used tool in genetic engineering. Therefore, the ligase-related nucleic acid amplification technology for detecting gene mutations has become a research hotspot. In this study, the main techniques explored for detecting gene mutations included the ligase detection reaction, ligase chain reaction, rolling circle amplification reaction, enzyme-assisted polymerase chain reaction, and loop-mediated isothermal amplification reaction. This review aimed to analyze the aforementioned techniques and mainly present their advantages and disadvantages, sensitivity, specificity, cost, detection time, applications, and so on. The findings may help develop sufficient grounds for further studies on detecting gene mutations.

Bioengineered Platelets Combining Chemotherapy and Immunotherapy for Postsurgical Melanoma Treatment: Internal Core-Loaded Doxorubicin and External Surface-Anchored Anti-PD-L1 Antibody Backpacks.

The pivotal factors affecting the survival rate of patients include metastasis and tumor recurrence after the resection of the primary tumor. Anti-PD-L1 antibody (aPD-L1) has promising efficacy but with some side effects for the off-target binding between aPD-L1 and normal tissues. Here, inspired by the excellent targeting capability of platelets with respect to tumor cells, we propose bioengineered platelets (PDNGs) with inner-loaded doxorubicin (DOX) and outer-anchored aPD-L1-cross-linked nanogels to reduce tumor relapse and metastatic spread postoperation. The cargo does not impair the normal physiological functions of platelets. Free aPD-L1 is cross-linked to form nanogels with a higher drug-loading efficiency and is sustainably released to trigger the T-cell-mediated destruction of tumor cells, reversing the tumor immunosuppressive microenvironment. PDNGs can reduce the postoperative tumor recurrence and metastasis rate, prolonging the survival time of mice. Our findings indicate that bioengineered platelets are promising in postsurgical cancer treatment by the tumor-capturing and in situ microvesicle-secreting capabilities of platelets.

Benzotriazole-Based 3D Four-Arm Small Molecules Enable 19.1 % Efficiency for PM6 : Y6-Based Ternary Organic Solar Cells.

A third component featuring a planar backbone structure similar to the binary host molecule has been the preferred ingredient for improving the photovoltaic performance of ternary organic solar cells (OSCs). In this work, we explored a new avenue that introduces 3D-structured molecules as guest acceptors. Spirobifluorene (SF) is chosen as the core to combine with three different terminal-modified (rhodanine, thiazolidinedione, and dicyano-substituted rhodanine) benzotriazole (BTA) units, affording three four-arm molecules, SF-BTA1, SF-BTA2, and SF-BTA3, respectively. After adding these three materials to the classical system PM6 : Y6, the resulting ternary devices obtained ultra-high power-conversion efficiencies (PCEs) of 19.1 %, 18.7 %, and 18.8 %, respectively, compared with the binary OSCs (PCE=17.4 %). SF-BTA1-3 can work as energy donors to increase charge generation via energy transfer. In addition, the charge transfer between PM6 and SF-BTA1-3 also acts to enhance charge generation. Introducing SF-BTA1-3 could form acceptor alloys to modify the molecular energy level and inhibit the self-aggregation of Y6, thereby reducing energy loss and balancing charge transport. Our success in 3D multi-arm materials as the third component shows good universality and brings a new perspective. The further functional development of multi-arm materials could make OSCs more stable and efficient.

Spatial filtering of Zeeman sub-states in an atomic fountain.

In an atomic fountain, atoms in motion can be spatially separated into discrete Zeeman sub-states by magnetically induced Stern-Gerlach effect. With resonant light pulses acting as a shutter, specific states are selected for subsequent experiments. Such separation-selection process in atomic optics is the analogue of a spatial filter in physical optics which selects and purifies the modes of light. This technique is demonstrated by injecting a pulsed current in a circular coil around a vertical atomic fountain, separating the pre-cooled Rubidium atoms by a distance of centimeters in between, and filtering each single sub-state with block pulses. The filtered atoms after the process is highly purified in the desired sub-state. The apparatus of the atomic spatial filter is adaptable in atomic optics and can be integrated into the high-vacuum chamber of an atomic fountain.

Inhibition of post-surgery tumour recurrence via a sprayable chemo-immunotherapy gel releasing PD-L1 antibody and platelet-derived small EVs.

BACKGROUND: Melanoma is the most serious type of skin cancer, and surgery is an effective method to treat melanoma. Unfortunately, local residual micro-infiltrated tumour cells and systemic circulating tumour cells (CTCs) are significant causes of treatment failure, leading to tumour recurrence and metastasis. METHODS: Small EVs were isolated from platelets by differential centrifugation, and doxorubicin-loaded small EVs (PexD) was prepared by mixing small EVs with doxorubicin (DOX). PexD and an anti-PD-L1 monoclonal antibody (aPD-L1) were co-encapsulated in fibrin gel. The synergistic antitumour efficacy of the gel containing PexD and aPD-L1 was assessed both in vitro and in vivo. RESULTS: Herein, we developed an in situ-formed bioresponsive gel combined with chemoimmunotherapeutic agents as a drug reservoir that could effectively inhibit both local tumour recurrence and tumour metastasis. In comparison with a DOX solution, PexD could better bind to tumour cells, induce more tumour immunogenic cell death (ICD) and promote a stronger antitumour immune response. PexD could enter the blood circulation through damaged blood vessels to track and eliminate CTCs. The concurrent release of aPD-L1 at the tumour site could impair the PD-1/PD-L1 pathway and restore the tumour-killing effect of cytotoxic T cells. This chemoimmunotherapeutic strategy triggered relatively strong T cell immune responses, significantly improving the tumour immune microenvironment. CONCLUSION: Our findings indicated that the immunotherapeutic fibrin gel could "awaken" the host innate immune system to inhibit both local tumour recurrence post-surgery and metastatic potential, thus, it could serve as a promising approach to prevent tumour recurrence.

Singular Configuration Analysis and Singularity Avoidance with Application in an Intelligent Robotic Manipulator.

Recently, robotic sensor systems have gained more attention annually in complex system sense strategies. The robotic sensors sense the information from itself and the environment, and fuse information for the use of perception, decision, planning, and control. As an important supplement to traditional industrial robots, co-bots (short for co-working robots) play an increasingly vital role in helping small and medium-sized enterprises realize intelligent manufacturing. They have high flexibility and safety so that they can assist humans to complete highly repetitive and high-precision work. In order to maintain robot safe operation in the increasing complex working environment and human-computer intelligent interactive control, this paper is concerned with the problem of applicant accuracy analysis and singularity avoidance for co-bots. Based on the dynamic model with load and torque sensors, which is used to detect the external force at the end of the robot, this paper systematically analyzes the causes of singularity phenomenon in the robot motion control. The inverse solution is obtained by analytical method and numerical method, respectively. In order to ensure the smooth and safe operation in the whole workspace, it is necessary for a robot to avoid singularity. Singularity avoidance schemes are utilized for different control tasks, including point-to-point control and continuous path control. Corresponding simulation experiments are designed to verify the effectiveness of different evasion schemes, in which the advantages and disadvantages are compared and analyzed.

Multi-Irradiance: A Method for Simultaneous Measurement of the Temperature and Spectral Emissivity of High-Temperature Targets in SWIR.

The currently used energy methods in spectral emissivity measurement are susceptible to the difference in temperature between the target and the reference blackbody. It is also limited by the state of the observation target and observation. This paper introduces the irradiance condition, while using the correlation between the information of emission energy and reflected energy of the high-temperature target. Based on the principle of radiative transmission and energy conservation, the relationship between the emissivity and bidirectional reflectance factor (BRF) was used to perform the retrieval of emissivity and temperature. An experimental device was designed, and graphite and rock were considered to verify the feasibility of the experimental scheme. The error of emissivity and temperature of both targets were, respectively, less than 5% and 0.5%, due to the Lambertian assumption, and the systematic errors had negligible impact on the retrieval. This verifies that the experimental observation method and scheme is reasonable.

A Truck-Borne System Based on Cold Atom Gravimeter for Measuring the Absolute Gravity in the Field.

The cold atom gravimeter (CAG) has proven to be a powerful quantum sensor for the high-precision measurement of gravity field, which can work stably for a long time in the laboratory. However, most CAGs cannot operate in the field due to their complex structure, large volume and poor environmental adaptability. In this paper, a home-made, miniaturized CAG is developed and a truck-borne system based on it is integrated to measure the absolute gravity in the field. The measurement performance of this system is evaluated by applying it to measurements of the gravity field around the Xianlin reservoir in Hangzhou City of China. The internal and external coincidence accuracies of this measurement system were demonstrated to be 35.4 µGal and 76.7 µGal, respectively. Furthermore, the theoretical values of the measured eight points are calculated by using a forward modeling of a local high-resolution digital elevation model, and the calculated values are found to be in good agreement with the measured values. The results of this paper show that this home-made, truck-borne CAG system is reliable, and it is expected to improve the efficiency of gravity surveying in the field.

Linking microbial community composition to farming pattern in selenium-enriched region: Potential role of microorganisms on Se geochemistry.

Selenium (Se) is an essential micronutrient for lives. Indigenous microbial communities play an important role on Se geochemistry in soils. In this study, the microbial community composition and functions of 53 soil samples were investigated using high-throughput sequencing. Samples were divided into 3 groups with different farming types based on the measured geochemical parameters and microbial functional structures. Results indicated that putative Se related bacteria Bacillus, Dyella, Paenibacillus, Burkholderia and Brevibacillus were dominant in dryland plantation soils which were characterized with higher available Se and low contents of H2O, total organic carbon (TOC), NH4+ and NO2-. In contrast, the putative denitrifier Pseudomonas dominated in flooded paddy soils with higher TOC, NO3- and organic Se, whereas genera Rhizobium, Nitrosospira, and Geobacter preferred woodland soils with higher oxidation-reduction potential (ORP), pH, NH4+ and Fe. Farming patterns resulted in distinct geochemical parameters including moisture, pH, ORP, TOC, and contents of soluble Fe, NO2- and NH4+, shaping the microbial communities, which in turn affected Se forms in soils. This study provides a valuable insight into understanding of Se biogeochemistry in soils and prospective strategy for Se-rich agriculture production.

Heterogeneity and prognosis of programmed cell death-ligand 1 expression in the circulating tumor cells of non-small cell lung cancer.

Due to tumor heterogeneity, the consistency of programmed cell death-ligand 1 (PD-L1) expression between circulating tumor cells (CTCs) and tissue is controversial. This study aimed to establish a method for detecting CTC PD-L1 expression and exploring the impact of the same on the prognosis of lung cancer. In 32 patients with non-small cell lung cancer, lung cancer cells in the blood were enriched using CD326 immunomagnetic beads. Goat anti-mouse polyclonal CD326 antibody stained the epithelial lung cancer cells and anti-PD-L1 antibody was used to detect the expression of CTC PD-L1. The DAKO Link 48 automatic staining device detected the expression in lung cancer tissue. The consistency of PD-L1 expression was analyzed in lung cancer tissue and CTCs. The effect of plasma interferon gamma, tumor necrosis factor alpha, and interleukin-2 on PD-L1 expression and prognosis was analyzed. The number of CTCs detected in patients was 1-36, with a median of 2. There was no significant difference in PD-L1 expression fractions between CTCs and paired tumor tissue (p>0.05). The correlation coefficient was 0.20. Regardless of lung cancer tissue or CTCs, there was no statistically significant difference in the blood cytokine levels between the two groups with positive or negative PD-L1 expression (p>0.05). There was no correlation between CTCs and PD-L1 in 23 untreated patients. The expression of PD-L1 in CTCs and lung cancer tissue is heterogeneous and unaffected by the peripheral cytokines' levels. PD-L1 expression has no correlation between CTCs and tissues and is not related to prognosis.

Diversity and arsenic-metabolizing gene clusters of indigenous arsenate-reducing bacteria in high arsenic groundwater of the Hetao Plain, Inner Mongolia.

Dissimilatory arsenate reduction from arsenic (As)-bearing minerals into highly mobile arsenite is one of the key mechanisms of As release into groundwater. To detect the microbial diversity and As-metabolizing gene clusters of indigenous arsenate-reducing bacteria in high As groundwater in the Hetao Plain of Inner Mongolia, China, three anaerobic arsenate-reducing bacteria were isolated and arrA and arsC gene-based clone libraries of four in situ groundwater samples were constructed. The strains IMARCUG-11(G-11), IMARCUG-C1(G-C1) and IMARCUG-12(G-12) were phylogenetically belonged to genera Paraclostridium, Citrobacter and Klebsiella, respectively. They could reduce >99% of 1 mM arsenate under anoxic conditions with lactate as a carbon source in 60 h, 72 h and 84 h, respectively. As far as we know, this was the first report of arsenate reduction by genus Paraclostridium. Compared with strain G-11 (arsC) and G-C1 (arsRBC), strain G-12 contained two incomplete ars operons (operon1: arsABC, operon2: arsBC), indicating that these strains might present different strategies to resist As toxicity. Phylogenetic analysis illuminating by the arrA genes showed that in situ arsenate-reducing bacterial communities were diverse and mainly composed of Desulfobacterales (53%, dominated by Geobacter), Betaproteobacteria (12%), and unidentified groups (35%). Based on the arsC gene analysis, the indigenous arsenate-reducing bacterial communities were mainly affiliated with Omnitrophica (88%) and Deltaproteobacteria (11%, dominated by Geobacter and Syntrophobacterales). Results of this study expanded our understanding of indigenous arsenic-reducing bacteria in high As groundwater aquifers.

Two new selenite reducing bacterial isolates from paddy soil and the potential Se biofortification of paddy rice.

Selenium (Se) is an essential element for human health. Se-enriched agricultural products can promote people's intake of Se. Microorganisms play an important role in Se cycling. In this study, two new bacterial strains were isolated from paddy soil and were identified as Chitinophaga sp. and Comamonas testosteroni, respectively. More than 44% and 39% of 1.0 mM selenite were reduced in 84 h by them using yeast extract as carbon source, respectively. Scanning electron microscope (SEM) and Energy dispersive X-ray spectrometry (EDS) results indicated that the reduction product of selenite was nanometer Se. These strains could promote the available Se in soil and the content of Se in rice plants in pot experiments. Organic combined Se in soils was increased up to 35%, accompanied by the 92% and 130% increase of Se in rice plants. To our best knowledge, this is the first report of Se reduction by Chitinophaga. This work might provide a prospective strategy for microbial fortification of Se in corps.

The effect of 3D-printed plastic teeth on scores in a tooth morphology course in a Chinese university.

BACKGROUND: The tooth morphology course is an important basic dental course. However, it is difficult to fully reflect the three-dimensional (3D) morphological characteristics of tooth structure in two-dimensional pictures in traditional textbooks. The aim of this study was to assess the effect of 3D-printed plastic model teeth in the teaching of tooth morphology. METHODS: Twenty-two undergraduate students who matriculated at the School of Stomatology, the Fourth Medical University, in 2014 and 23 who matriculated in 2016 participated in the study. Each student who matriculated in 2016 was given a full set of fourteen standard 3D-printed plastic model teeth for use during the learning process, and an anonymous questionnaire was used to evaluate the usefulness of the 3D-printed plastic model teeth from the perspective of the students. RESULTS: There was no significant difference between the two groups in the scores of the theoretical examination or the total score. However, for the score of the sculpted gypsum teeth, the students who used the 3D-printed plastic model teeth in their studies scored significantly higher (P = 0.002). More than 90% of the students thought that the 3D-printed plastic model teeth were of great help or were very helpful for mastering the anatomy of teeth and for carving the gypsum teeth. CONCLUSION: Standard 3D-printed plastic teeth can effectively assist students in learning tooth morphology by transforming two-dimensional pictures and descriptions in the textbook into a 3D conformation, effectively promoting students' learning and mastery of tooth morphology and structure. Additionally, the results suggest that 3D-printed plastic model teeth are of great help to the students in mastering and improving their carving skills.

Dependence of the sensitivity on the orientation for a free-fall atom gravimeter.

The cold atom absolute gravimeters are intrinsically sensitive to its orientation due to the Coriolis effect, which should be understood clearly and compensated for field applications. The sensitivity on the orientation for a free-fall atom gravimeter is investigated in this paper. The apparatus is simplified and improved a lot such that fast adjustment and measurement could be carried out within 20 minutes. From the experimental results, it is found that the orientation angle has a dominant influence on the absolute gravity measurement, especially when the horizontal velocity of atoms is non-negligible. Besides, the magnitude and direction of average horizontal velocity of the detected atoms are obtained in this experiment. In particular, the direction of East-West has been measured by the atom gravimeter itself, such that gravity bias arising from Coriolis effect is estimated precisely.