The Design and Optimization of a Compressive-Type Vector Sensor Utilizing a PMN-28PT Piezoelectric Single-Crystal

Underwater sensors that detect the distance and direction of acoustic sources are critical for surveillance monitoring and target detection in the water. Here, we propose an axial vector sensor that utilizes a small (~1 cm3) compressive-type piezoelectric accelerometer using piezoelectric single crystals. Initially, finite element analysis (FEA) was used to optimize the structure that comprised piezoelectric Pb(Mb1/3Nb2/3)O3-28%PbTiO3 single crystals on a tungsten seismic mass. The receiving voltage sensitivity (RVS) was enhanced through geometric optimization of the thickness and sensing area of the piezoelectric material and the seismic mass. The estimated maximum RVS of the optimized vector sensor was −212 dB. FEA simulations and practical measurements were used to verify the directivity of the vector sensor design, which exhibited a dipole pattern. The dipole beam pattern was used to obtain cardioid patterns using the simulated and measured results for comparison. The results clearly showed the feasibility of using the proposed piezoelectric single-crystal accelerometer for a compressive-type vector sensor. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.1

Development of a high-density piezoelectric micromachined ultrasonic transducer array based on patterned aluminum nitride thin film

This study presents the fabrication and characterization of a piezoelectric micromachined ultrasonic transducer (pMUT; radius: 40 μm) using a patterned aluminum nitride (AlN) thin film as the active piezoelectric material. A 20 x 20 array of pMUTs using a 1 μm thick AlN thin film was designed and fabricated on a 2 x 2 mm2 footprint for a high fill factor. Based on the electrical impedance and phase of the pMUT array, the electromechanical coefficient was ~1.7% at the average resonant frequency of 2.82 MHz in air. Dynamic displacement of the pMUT surface was characterized by scanning laser Doppler vibrometry. The pressure output while immersed in water was 19.79 kPa when calculated based on the peak displacement at the resonant frequency. The proposed AlN pMUT array has potential applications in biomedical sensing for healthcare, medical imaging, and biometrics. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.1

New Remains of Rhinoceros (Rhinocerotidae, Perissodactyla, Mammalia) Associated With Gigantopithecus Blacki From the Early Pleistocene Yanliang Cave, Fusui, South China

Abundant dental fossils of Rhinoceros, associated with Gigantopithecus blacki from the early Early Pleistocene Yanliang Cave deposits in Fusui County, Guangxi Zhuang Autonomous Region of southern China, are described as Rhinoceros fusuiensis sp. nov. (Rhinocerotidae, Perissodactyla, Mammalia). The new species is morphologically more similar to the extant species Rhinoceros sondaicus (Javan rhinoceros) than to other species of the genus, but differs from R.sondaicus in bearing a slightly smaller size, a complete protoloph on P2 after heavily worn, a better developed crochet which is close to the protoloph, and a more curved ectoloph. Rhinoceros fusuiensis sp. nov. is considered as the potential ancestor of the living R.sondaicus and the common element of the Early Pleistocene Gigantopithecus-Sinomastodon fauna in southern China. The Rhinoceros remains from other Early Pleistocene sites (e.g., Longgupo Cave and Mohui Cave in southern China and Irrawaddy sediments in Myanmar) are also assigned into the new species. The discovery of R. fusuiensis sp. nov. provides important information on Quaternary biostratigraphy in southern China, as well as implicating southern China as a significant evolutionary and zoogeographic center for Rhinoceros during the Early Pleistocene

First Mandible and Deciduous Dentition of Juvenile Individuals of Sinomastodon (Proboscidea, Mammalia) From the Early Pleistocene Renzidong Cave of Eastern China

Sinomastodon (Proboscidea, Mammalia) is a unique brevirostrine trilophodont gomphotheriid from Eurasia, which mainly occurs in China during the Plio-Pleistocene. Although much is known about adult individuals, the morphology of juveniles of this taxon is still poorly understood due to the scarcity of pertinent fossils. The present contribution represents the first detailed systematic study of the mandible and deciduous dentition of juvenile individuals of Sinomastodon jiangnanensis from the early Early Pleistocene (2.14-2.15Ma) Renzidong Cave of eastern China. Based on morphological comparisons, the Renzidong juvenile mandible bears, on one hand, the transitional characteristics between the typical long-jawed trilophodont and elephantoid proboscideans, and, on the other hand, more primitive features than adult mandibles of Sinomastodon. This study of juvenile individuals of S.jiangnanensis provides new information to enhance the diagnosis of S.jiangnanensis, and confirms the validity of the species. It also provides evidence to show that the morphological transition of genus Sinomastodon from Neogene to Quaternary is mirrored in adult and juvenile individuals

Pleistocene Lizards (Squamata, Reptilia) From the Karst Caves in Chongzuo, Guangxi, Southern China

Here is provided the first description of Pleistocene lizards recovered from five caves (Baikong, Juyuan, Queque, Sanhe, and Zhiren) in Chongzuo, Zuo River area of Guangxi Zhuang Autonomous Region, southern China. Lizard remains reported here come from faunas that include Gigantopithecus blacki or Homo sapiens dating from the Early to Late Pleistocene with age-range estimates from 2.0Ma to 111ka. The recovery of agamids (Agamidae), skinks (Scincidae), a large species of Gekko, and smaller forms of gekkonids (Gekkonidae) is of interest in that the diversity of lizards for the caves is high given the extremely small sample size from the deposits. The description of cf. Draco reported here is the first indication of the possible occurrence of this genus in the Pleistocene record. Southern China and the adjacent territories in Vietnam and Laos have a diverse lizard fauna today. Cave deposits with established chronologies in the local karst regions such as recovered in Chongzuo, can help record the diversity within the local lizard community through time. Although the fossil lizards reported here appear to represent mammalian prey remains (highly fragmented), caves that contain owl roost pellet deposits might represent a more diverse squamate community with the additional advantage of having specimens that are not as fragmented. Because a Pleistocene-age lizard record does occur in the caves reported here, in all likelihood equivalent deposits should occur in the numerous caves throughout southern China and Southeast Asia

Bifunctional enzyme ATIC promotes propagation of hepatocellular carcinoma by regulating AMPK-mTOR-S6 K1 signaling

Abstract Background Hepatocellular carcinoma (HCC) is one of the cancer types with poor prognosis. To effectively treat HCC, new molecular targets and therapeutic approaches must be identified. 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/inosine monophosphate (IMP) cyclohydrolase (ATIC), a bifunctional protein enzyme, catalyzes the last two steps of the de novo purine biosynthetic pathway. Whether ATIC contributes to cancer development remains unclear. Methods ATIC mRNA levels in different types of human HCC samples or normal tissues were determined from Gene Expression across Normal and Tumor tissue (GENT) database. The expression level of ATIC in human HCC samples or cell lines were examined by RT-PCR and western blot. Overall survival and disease-free survival of HCC patients in the ATIC low and ATIC high groups were determined by Kaplan-Meier analysis. Effects of ATIC knockdown by lentivirus infection were evaluated on cell-proliferation, cell-apoptosis, colony formation and migration. The mechanisms involved in HCC cells growth, apoptosis and migration were analyzed by western blot and Compound C (C-C) rescue assays. Results Here, we first demonstrated that expression of ATIC is aberrantly up-regulated in HCC tissues and high level of ATIC is correlated with poor survival in HCC patients. Knockdown of ATIC expression resulted in a dramatic decrease in proliferation, colony formation and migration of HCC cells. We also identified ATIC as a novel regulator of adenosine monophosphate-activated protein kinase (AMPK) and its downstream signaling mammalian target of rapamycin (mTOR). ATIC suppresses AMPK activation, thus activates mTOR-S6 K1-S6 signaling and supports growth and motility activity of HCC cells. Conclusion Taken together, our results indicate that ATIC acts as an oncogenic gene that promotes survival, proliferation and migration by targeting AMPK-mTOR-S6 K1 signaling

The Design and Optimization of a Compressive-Type Vector Sensor Utilizing a PMN-28PT Piezoelectric Single-Crystal

Underwater sensors that detect the distance and direction of acoustic sources are critical for surveillance monitoring and target detection in the water. Here, we propose an axial vector sensor that utilizes a small (~1 cm3) compressive-type piezoelectric accelerometer using piezoelectric single crystals. Initially, finite element analysis (FEA) was used to optimize the structure that comprised piezoelectric Pb(Mb1/3Nb2/3)O3-28%PbTiO3 single crystals on a tungsten seismic mass. The receiving voltage sensitivity (RVS) was enhanced through geometric optimization of the thickness and sensing area of the piezoelectric material and the seismic mass. The estimated maximum RVS of the optimized vector sensor was −212 dB. FEA simulations and practical measurements were used to verify the directivity of the vector sensor design, which exhibited a dipole pattern. The dipole beam pattern was used to obtain cardioid patterns using the simulated and measured results for comparison. The results clearly showed the feasibility of using the proposed piezoelectric single-crystal accelerometer for a compressive-type vector sensor

The age of human remains and associated fauna from Zhiren Cave in Guangxi, southern China

Zhiren Cave in southern China is an important site for the study of the origin and the environmental background of early modern humans. The combination of Elephas kiangnanensis, Elephas maximus, and Megatapirus augustus, indicates an early representative of the typical Asian elephant fauna. Previous U-series dating of flowstone calcite has pinpointed an upper age limit for the fossils of about 100 ka. In order to achieve a better comprehension of the chronology of the modern human and contemporaneous faunal assemblage, paleomagnetic, stratigraphic, and optically stimulated luminescence (OSL) dating methods have been applied to the cave sediments. Paleomagnetic analyses reveal that there is a reversed polarity excursion below the fossiliferous layer. This excursion can be regarded as the Blake excursion event, given the U-series ages of the overlying flowstone calcite, the OSL measurements, the virtual geomagnetic pole (VGP) path of the excursion, the two reverse polarity zones within this excursion event, and the characteristic of the fauna assemblage. The human remains and mammalian fauna assemblage can be bracketed to 116-106 ka. Application of OSL dating leads to erroneous ages, largely due to the uncertainty associated with the estimation on the dose rates. (C) 2016 Elsevier Ltd and INQUA. All rights reserved