An umbrella-inspired snap-on robotic 3D photoacoustic endoscopic probe for augmented intragastric sensing: Proof of concept study.

In this paper, we present a novel on-demand modular robotic photoacoustic tomography (PAT) probe integrated into an endoscopic device, potentially for deep intragastric sensing. The proposed solution offers a plug-and-play approach through the use of meso-scale steerable endoscopy and a new 'snap-on' 3D robotic PAT probe that can reconfigure the geometry of the intracorporeal light delivery, inspired by an umbrella structure. Specifically, using the limited esophageal access, steerable endoscopy allows navigation and advancement of a distally mounted robotic add-on for PAT that is folded until it reaches the deep-seated gastric lesion. Once the tip is positioned near the lesion site in the gastric cavity, there is ample working space for the robotic probe to adjust its umbrella-like unfolded shape. This allows fine-tuning of the laser delivery orientation of the fiber bundles to achieve the lesion-specific light delivery scheme. This design allows volumetric imaging of the intragastric PAT with enhanced sensitivity. To evaluate the performance of the modular robotic PAT probe, we performed a simulation analysis of the light intensity and ultrasound field distribution. The simulation results show that the robotic probe is feasible for intracorporeal PAT imaging. In addition, we printed a 3D model of a human stomach containing a simulated gastric tumour. Both the phantom and ex vivo experimental results validate the feasibility of the proposed robotic PAT probe.

Nitrogen and fluoride co-doped graphdiyne with metal-organic framework (MOF)-derived NiCo2O4-Co3O4 nanocages as sensing layers for ultra-sensitive pesticide detection.

Heteroatom doped graphdiyne (GDY) has been demonstrated to be an effective strategy for achieving outstanding electrochemical properties, including improved electrocatalytic activity, tunable electronic properties and high electronic conductivity, by producing numerous heteroatomic defects as well as active sites. Extensive efforts have been devoted to the issue of single element doping of GDY. Introducing two or more kinds of heteroatoms into GDY materials may create a synergic effect between the co-dopants, thus generating superior electrochemical performance. Nevertheless, little research on multiple elements co-doped GDY, especially in the application of constructing electrochemical biosensor. Herein, nitrogen and fluoride co-doped GDY (N-F-GDY) has been synthesized and employed to combine with NiCo2O4-Co3O4 hollow multishelled nanocages to establish an ultrasensitive electrochemical biosensor for the assay of pesticide residue. The as-prepared electrochemical biosensor possesses a wide linear range of 0.448 pM-44.8 nM for monocrotophos detection and a low detection limit of 0.0166 fM (S/N = 3).

Oriented Design of Transition-Metal-Oxide Hollow Multishelled Micropolyhedron Derived from Bimetal-Organic Frameworks for the Electrochemical Detection of Multipesticide Residues.

Transition-metal oxides (TMOs) with a hollow multishelled structure have emerged as highly potential materials for high-performance electrochemical sensing, benefiting from their superior electronic conductivity, exceptionally large specific surface area, excellent stability, and electrochemistry properties. In particular, binary TMOs are expected to outperform unitary TMOs due to the synergistic effect of the different metals. Herein, MnCo2O4.5 hollow quadruple-shelled porous micropolyhedrons (MnCo2O4.5 HoQS-MPs) were prepared and employed to construct an ultrasensitive sensing platform for a multipesticide assay. Profiting from complex hollow interior structures and abundant active sites, the MnCo2O4.5 HoQS-MPs manifest outstanding electrochemical properties as electrode materials for the pesticide assay. The MnCo2O4.5 HoQS-MP-based biosensor demonstrated remarkable performance for monocrotophos, methamidophos, and carbaryl detection, with wide linear ranges, as well as low detection limits. This work unveils a new pathway for the ultrasensitive detection of pesticides and demonstrates tremendous potential for detecting other environmentally deleterious chemicals.

RGAIA: a reconfigurable AWGR based optical data center network.

Benefitting from the cost-effective and flexible interconnection between computing nodes and storing infrastructures, various applications and services are deployed in data centers (DCs). These traffic-boosting applications put tremendous pressures on current electrically switched DC networks (DCNs) which suffer the bandwidth bottleneck. Benefitting from the data-rate and format transparency, the optically switched DCN with intrinsic high-bandwidth characteristics is a promising solution to update the hierarchical electrical DCNs with bandwidth limitations. Moreover, the applications deployed in DCNs with mixed traffic characteristics require dynamic quality of service (QoS) provisioning. Optical DCNs thus need to be designed in a flexible topology with the capability of bandwidth reconfigurability to adapt the variety of the traffic. In this paper, we propose and experimentally investigate a reconfigurable optical packet switching DCN named RGAIA, based on flexible top of racks (ToRs) and fast optical switch, where the optical switch is implemented by tunable transceiver combing with arrayed waveguide grating router (AWGR). Under the management of the designed software defined network (SDN) control plane, RGAIA can dynamically distribute the wavelength resource and then reconfigure the bandwidth in real-time based on the monitored traffic characteristics. Experimental assessments validate RGAIA improving performance of 37% and 66% in latency and packet loss, respectively, compared with the network with rigid interconnections at the traffic load of 0.8.

Ternary heterostructures of 1D/2D/2D CuCo2S4/CuS/Ti3C2 MXene: Boosted amperometric sensing for chlorpyrifos.

Multicomponent heterogeneous Ti3C2 transition metal carbide (MXene)-based materials are receiving extensive research attention due to their interesting synergistic interactions and catalytic properties. However, the morphology-controllable synthesis of heterostructures as structural stabilizers for Ti3C2 MXene remains a challenge owing the complicated synthesis procedure. In this work, a kind of ternary heterogeneous nanomaterials CuCo2S4/CuS/Ti3C2 MXene with a nanorod/nanoplate/nanosheet hybrid architecture is constructed through a one-step low-temperature solvothermal method. The well-designed ternary one-dimensional (1D)/two-dimensional (2D)/2D CuCo2S4/CuS/Ti3C2 MXene heteromaterials exhibit synergistic improvements in substrate-catalyzed reactions for electrochemical acetylcholinesterase (AChE) biosensor. The Michaelis-Menten constant for the Nafion/AChE/CuCo2S4/CuS/Ti3C2 MXene/GCE biosensor is 228 µM, which is smaller than ones reported in previous literatures, indicating a higher affinity of the fabricated enzyme biosensor to acetylthiocholine chloride. The biosensor exhibits a well linear relationship with chlorpyrifos concentration ranging from 2.852 × 10-12 M to 2.852 × 10-6 M. The multicomponent 1D/2D/2D CuCo2S4/CuS/Ti3C2 MXene heteromaterial may shine a light in more electrochemical applications.

One-dimensional bimetallic PdRh alloy mesoporous nanotubes constructed for ultra-sensitive detection of carbamate pesticide.

Bimetallic nanomaterials with various dimensions have been successfully explored in electrochemical biosensor to detect the carbamate pesticide. One-dimensional bimetallic nanomaterials with mesoporous, which possess bigger electrochemical active area, more catalytic active sites and faster electron transmission efficiency, may have excellent performance in electrochemical biosensor, but have been rarely reported. In order to confirm this hypothesis, one-dimensional PdRh alloy mesoporous nanotubes were prepared and applied as a platform for carbamate pesticide electrochemical detection. Upon optimum conditions, the constructed AChE sensor showed an ultrahigh sensitivity (0.279 µA/nM), a wide linear range (9.44 × 10-8 - 0.944 mg/L) and a low detection limit (9.44 × 10-8 mg/L) for carbaryl. And the biosensor exhibited outstanding anti-interference ability, precision and stability. Moreover, the actual sample detection of the biosensor has been demonstrated with a satisfactory recovery (94.01%-102.80%). The remarkable property may attribute to the integrated advantages of one-dimensional mesoporous structure and bimetallic alloy.

A stable enzyme sensor via embedding enzymes into zeolitic imidazolate frameworks for pesticide determination.

The stability of biosensors is of significant importance for practical applications, and the natural biomineralization processes in living organisms have inspired us from a new perspective. In this work, acetylcholinesterase (AChE) was embedded into zeolitic imidazolate framework-8 carriers (with negligible cytotoxicity) via biomimetic mineralization, being demonstrated to be a stable strategy for enzyme immobilization. When further coupled with the conductive and catalytic Au nanoparticles, the biocomposites were explored as electrochemical pesticide detection biosensor, which showed favorable analytical performance, and improved stability comparing with other biosensors. This work provides a new strategy for the reasonable design of stable biosensors for different analytes monitoring.

Electrochemical biosensor based on CuPt alloy NTs-AOE for the ultrasensitive detection of organophosphate pesticides.

The electrode material is vital for the performance of the electrochemical biosensor. Lately, many nanomaterials have been developed to improve the sensitivity and detection efficiency of the biosensors. In this work, a kind of one-dimensional nanomaterials, the CuPt alloy nanotubes with an open end (CuPt alloy NTs-AOE), was explored. The nanotubes with an open end can provide a larger electrochemical active surface area and more active sites for the immobilization of enzyme. The CuPt alloy displays excellent conductivity and catalytic activity. In addition, the Cu shows the great affinity to thio-compounds, which can greatly enhance the detection efficiency and sensitivity. As a result, the prepared biosensor demonstrates the wider linear range of 9.98 × 10-10-9.98 × 10-5g l-1for fenitrothion and 9.94 × 10-11-9.94 × 10-4g l-1for dichlorvos (as model OPs ) and with the lower detection limit of 1.84 × 10-10g l-1and 6.31 × 10-12g l-1(S/N = 3), respectively. Besides, the biosensor has been used to detect the real samples and obtains satisfactory recoveries (95.58%-100.56%).

A highly sensitive acetylcholinesterase electrochemical biosensor based on Au-Tb alloy nanospheres for determining organophosphate pesticides.

Accurately detect the residues of organophosphate pesticides (OPs) in food and environment is critical to our daily lives. In this study, we developed a novel acetylcholinesterase (AChE) biosensor based on Au-Tb alloy nanospheres (NSs) for rapid and sensitive detection of OPs for the first time. Au-Tb alloy NSs that with good conductivity and biocompatibility were produced with a mild hydrothermal. Under optimal conditions, the AChE biosensor was obtained by a simple assembly process, with a big linear range (10-13-10-7M) and the limit of detection was 2.51 × 10-14M for the determination of methyl parathion. Moreover, the determination of methyl parathion with the prepared biosensor presented a high sensitivity, outstanding repeatability and superior stability compared with other reported biosensors. Through the determination of tap water and Yanming lake samples, it was proved that the modified biosensor with satisfactory recoveries (96.76%-108.6%), and are realizable in the determination of OPs in real samples.

Dianchi Lake watershed impervious surface area dynamics and their impact on lake water quality from 1988 to 2017.

The relationships between impervious surface area (ISA) patterns and characteristics have long been studied to examine the impacts of hydrological cycles, water management, surface energy balances, and biodiversity. This study assessed the Dianchi Lake watershed as a case study area to illustrate ISA change characteristics and their impacts on Dianchi Lake water quality. More than 200 Landsat images (from 1988 to 2017) were first downloaded through the US Geological Survey (USGS) online portal. Then, a series of ISA maps of the Dianchi Lake watershed at an annual resolution were built using a robust method we proposed. Then, the change characteristics of main water quality parameters were analyzed from spatial-temporal viewpoints. Finally, correlations between ISA and Lake water quality were made. The research results indicated that the ISA proportion of the Dianchi Lake watershed rapidly increased (from 1.84% in 1988 to 34.32% in 2017), the annual ISA total growth rate exceeded 21 km2/year, and the urban area encircled Dianchi Lake. The Dianchi Lake watershed has begun to adopt the "Rashly Advancing" and "Great Leap Forward" strategies of urbanization. Chlorophyll a (Chla), dissolved oxygen (DO), and transparency (Trans) showed significantly changing tendencies, whereas the values of pH, total nitrogen, and total phosphorus stayed relatively constant. The polynomial regression models and corresponding R2 values indicated strong correlations between ISA and three water quality parameters (Chla, DO, and Trans). The development of better strategies for the control and reduction of water pollution without optimizing ISA spatial distribution is essential for Kunming's continued urbanization.

[p38 signal pathway regulates osteogenic differentiation of maxillary primordium mesenchymal cells].

PURPOSE: To explore whether p38 signal pathway regulates osteogenic differentiation of maxillary primordium mesenchymal cells. METHODS: The first passage of maxillary primordium mesenchymal cells (MPMCs) from E12.5 embryos were cultured in the osteogenic medium, and 10 nM SB203580 (an inhibitor of phosphorylation of p38) was added in the medium in the experimental group for 1 week. Then immunofluorescence staining was applied to detect the phosphorylation of p38 in MPMCs. Brdu label and immunofluorescence staining were used to detect the proliferation of MPMCs. ALP staining and qPCR were used to detect the mRNA expression of ALP, Runx2, OCN and OPN in MPMCs. ALP staining and PCR were used to evaluate the osteogenic capability of MPMCs. SPSS 18.0 software package was used to analyze the data. RESULTS: Osteogenic induction could promote phosphorylation of p38, inhibit phosphorylation of p38 and proliferation of MPMCs, down-regulate the expression of ALP, Runx2, OCN and OPN, thus weaken the ALP staining in MPMCs. CONCLUSIONS: p38 signal pathway regulates osteogenic differentiation of MPMCs in vitro.

Two new resorcinol derivatives with strong cytotoxicity from the roots of Ardisia brevicaulis Diels.

Two new resorcinol derivatives, 4-hydroxy-2-methoxy-6-[(8Z)-pentadec-8-en-1-yl]phenyl acetate (1) and 4-hydroxy-2-methoxy-6-pentadecylphenyl acetate (2), together with known compounds ardisiphenol D (3), 5-tridecylresorcinol (4), 5-pentadecylresorcinol (5), 5-[(8Z)-pentadec-8-en-1-yl]resorcinol (6), belamcandaquinones C and D (7 and 8, resp.), ardisicrenoside A, ardisiacrispin B, (22E)-24-ethyl-5α-cholesta-7,22-dien-3-one, and (22E)-24-ethyl-5α-cholesta-7,22-dien-3ß-ol were isolated from the MeOH extract of the roots of Ardisia brevicaulis Diels. Their structures were determined by spectroscopic analysis including ESI- and EI-MS, and NMR data. Cytotoxicities of 1-4 against cell lines A549, MCF-7, and PANC-1 were tested in vitro by the MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. Compounds 1-4 showed cytotoxic activity against all cell lines stronger than that of cisplatin against A549.

Dimeric 1,4-benzoquinone derivatives and a resorcinol derivative from Ardisia gigantifolia.

Naturally occurring dimeric 1,4-benzoquinone derivatives, belamcandaquinones F, G, H, and I, as well as one resorcinol derivative and four known compounds, were isolated from rhizomes of Ardisia gigantifolia. Their structures were established by means of spectroscopic analyses. All compounds were tested against cell lines PC-3, EMT6, A549, Hela, RM-1, and SGC7901 for cytotoxicity in vitro. In comparison with cisplatin, compounds 5 and 6 showed a strong cytotoxicity with IC(50) values less than 30 microM for most cell lines tested.

Study of correlation between expression of bradykinin B2 receptor and pathological grade in human gliomas.

In clinical practice there is a difference in response of the blood-tumour barrier (BTB) permeability induced by bradykinin in brain tumours with the same pathology. The variability in response of tumours to bradykinin is likely to be related to the expression level of bradykinin B(2) receptor. This study used fresh human glioma samples to determine the expression level of bradykinin B(2) receptor on gliomas with different pathological grades. The grade of tumour was classified using the WHO classification. To determine the bradykinin B(2) receptor expression level in gliomas, Immunohistochemistry and Western blot methods were used. In 24 cases of gliomas there were eight cases of WHO I glioma, eight cases of WHO II glioma and eight cases of WHO III glioma. Both Western blot and immunohistochemistry showed bradykinin B(2) receptors localized on tumour cells, whilst brain cells at the edge of the glioma hardly expressed B(2) receptor. There were significant differences of bradykinin B(2) receptor expression level among different pathological grades of glioma. The expression of B(2) receptor in the three grades of glioma was in the order of WHO I < WHO II < WHO III. Determination of bradykinin B(2) receptor expression level in human glioma may be useful in screening glioma patients to predict whether they will be suitable for opening of the blood - tumour barrier with bradykinin or its analogue.

[Relationship between gastric cancer and gene amplification of p14 and mdm2].

BACKGROUND & OBJECTIVE: Some genes are related to the occurrence of tumor. p53 is one of these kinds of gene. Mdm2 and p14 can modulate the function of p53. However, the reports about the function of mdm2 and p14 in gastric tumor are rare. The aim of this study was to observe the change of oncogene mdm2 and suppressor cancer gene p14 in gastric cancer cell and to investigate the relationship of mdm2, p14 with gastric cancer. METHODS: A total of 55 gastric mucosal biopsy specimens were enrolled, including 10 of normal gastric mucosa and 45 gastric tumor, which were proved pathologically as adenoma, including 15 poorly, moderately, and well differentiated specimens, respectively. The mRNA expression of mdm2 and p14 in gastric cancer were identified by reverse transcription polymerase chain reaction (RT-PCR), and the relationship of mdm2, p14 with gastric cancer was analyzed. RESULTS: (1) There was significant difference of the expression positive ratio of mdm2 mRNA between gastric tumor and normal gastric tissues (73.3% vs. 40%) (P< 0.05) [93.3% for the well differentiated specimens, 80.0% for the moderately differentiated specimens, and 46.6% for the poorly differentiated specimens]. There was significant difference between any two groups of the three specimens (P< 0.05). (2) There was no significant difference of the expression positive ratio of p14 mRNA between gastric tumor and normal gastric tissues (60.0% vs. 50.0%) (P >0.05) [60.0% for the well differentiated specimens, 66.6% for the moderately differentiated specimens, and 53.5% for the poorly differentiated specimens]. There was no significant difference between any two groups of the three specimens (P >0.05). CONCLUSION: The mRNA expression of mdm2 is closely correlated with the progression of gastric cancer. The relationship between p14 and gastric tumor has not been tested in this study and further study will be needed.