Polyethyleneimine in designed nanocomposite based magnetic halloysite nanotubes for extraction and determination of gallic acid in green tea.

An innovative and simple nanocomposite denoted as MHNTs@PEI was synthesized for gallic acid (GA) analytical sample pretreatment. Polyethyleneimine (PEI) functionalized was binded onto magnetic halloysite nanotubes (MHNTs) to inhence adsorption capacity. MHNTs@PEI was obtained only through two steps modification (amination and PEI modification). Characterizations showed that there are layers of synthetic PEI on the tubular structure of the material and magnetic spheres on its surface, both indicating successful synthesis of the nanocomposite. Furthermore, the adsorption isotherms and kinetic modeling showed that the Langmuir model and pseudo-first-order model fit the adsorption data, respectively. MHNTs@PEI achieved an adsorption capacity of 158 mg·g-1. Overall, the abundant adsorption sites significantly improved the adsorption performance of the MHNTs@PEI. Regeneration tests demonstrated that the MHNTs@PEI exhibits effective adsorption, even after undergoing five consecutive cycles. Optimization of key parameters (ratio, volume of elution, elution time and frequency) in the process of adsorption and desorption was also conducted. The limit of detection (LOD) and that of the quantification (LOQ) were 0.19 and 0.63 µg·mL-1, respectively, and the recoveries were 95.67-99.43 %. Finally, the excellent magnetism (43.5 emu·g-1) and the adsorption feature of MHNTs@PEI enabled its successful utilization in analytical sample pretreatment through the extraction of GA from green tea.

Imaging, pathology, and diagnosis of solitary fibrous tumor of the pancreas: A case report and review of literature.

BACKGROUND: A solitary fibrous tumor (SFT) is often located in the pleura, while SFT of the pancreas is extremely rare. Here, we report a case of SFT of the pancreas and discuss imaging, histopathology, and immunohistochemistry for accurate diagnosis and treatment. CASE SUMMARY: A 54-year-old man presented to our hospital with pancreatic occupancy for over a month. There were no previous complaints of discomfort. His blood pressure was normal. Blood glucose, tumor markers, and enhanced computed tomography (CT) suggested a malignant tumor. Because the CT appearance of pancreatic cancer varies, we could not confirm the diagnosis; therefore, we performed endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB). Pathology and immunohistochemistry were consistent with SFT of the pancreas. The postoperative pathology and immunohistochemistry were consistent with the puncture results. The patient presented for a follow-up examination one month after discharge with no adverse effects. CONCLUSION: Other diseases must be excluded in patients with a pancreatic mass that cannot be diagnosed. CT and pathological histology have diagnostic value for pancreatic tumors. Endoscopic puncture biopsy under ultrasound can help diagnose pancreatic masses that cannot be diagnosed preoperatively. Surgery is an effective treatment for SFT of the pancreas; however, long-term follow-up is strongly recommended because of the possibility of malignant transformation of the tumor.

Efficient and Selective Adsorption of cis-Diols via the Suzuki-Miyaura Cross-Coupling-Modified Phenylboronic-Acid Functionalized Covalent Organic Framework.

In this work, a functional group (boronic acid) was modified onto a covalent organic framework (COF) using the Suzuki-Miyaura cross-coupling reaction to obtain a phenylboronic acid-functionalized covalent organic framework (BrCOF-PBA). This product was used as a selective adsorbent and largely as an efficient solid-phase extractant of flavonoids containing cis-diol structures like quercetin (QUE). Five or six-membered cyclic esters generated from the COF were characterized, and some physicochemical studies were performed, resulting in excellent chemical stability and crystallinity, high specific surface area, stable pore structure, and regular pore size. Unique selectivity of BrCOF-PBA was observed toward QUE and exhibited a huge adsorption capacity (213.96 mg g-1) in a relatively short time (90 min). In contrast, the adsorption properties of morin (MOR) and kaempferol (KAE) with a certain degree of chemical similarity to QUE were only 27.62 and 21.76 mg g-1, respectively. BrCOF-PBA also demonstrated good reusability and robustness, making it an attractive composite material for further analytical applicability.

Research progress of sensors based on molecularly imprinted polymers in analytical and biomedical analysis.

Molecularly imprinted polymers (MIPs) have had tremendous impact on biomimetic recognition due to their precise specificity and high affinity comparable to that of antibodies, which has shown the great advantages of easy preparation, good stability and low cost. The combination of MIPs with other analytical technologies can not only achieve rapid extraction and sensitive detection of target compounds, improving the level of analysis, but also achieve precise targeted delivery, in-vivo imaging and other applications. Among them, the recognition mechanism plays a vital role in chemical and biological sensing, while the improvement of the recognition element, such as the addition of new nanomaterials, can greatly improve the analytical performance of the sensor, especially in terms of selectivity. Currently, due to the need for rapid diagnosis and improved sensing properties (such as selectivity, stability, and cost-effectiveness), researchers are investigating new recognition elements and their combinations to improve the recognition capabilities of chemical sensing and bio-sensing. Therefore, this review mainly discusses the design strategies of optical sensors, electrochemical sensors and photoelectric sensors with molecular imprinting technology and their applications in environmental systems, food fields, drug detection and biology including bacteria and viruses.

Preparation and Application of Nanozymes with Uricase-Like Activity Based on Molecularly Imprinted Polymers.

Nanozymes have advantages over natural enzymes in terms of efficiency, stability, and economy. MVSM (Mixed Valence State MOF) is a nano-oxidase with uricase-like activity that may catalyze uric acid (UA) in the body into allantoin and H2 O2 to treat gout and hyperuricemia by substituting natural uricase. However, it cannot specifically identify and choose UA. To increase the selectivity and affinity of MVSM for UA, the composite material MVSM@MIP is innovatively synthesized using a new synthetic approach termed the "two-step synthesis method," which may prevent UA from being oxidized by MVSM during manufacture in this study. At the same time, this study also provides experimental proof of the effective creation of the material, the advantages of the "two-step synthesis approach," and the high selectivity and affinity of MVSM@MIP for UA. Based on these findings, the suggested technique may be used to effectively catalyze uric acid in human urine with high activity.

Numerical optimization of pacing strategy in cross-country skiing based on Gauss pseudo-spectral method.

In cross-country skiing competitions, the choice of pacing strategy is of decisive significance to athletes' performance. A reasonable pacing strategy is essential for athletes to improve their performance. In this paper, the mathematical models of cross-country skiing simulation and pacing optimization are established, including motion model, athlete power output model, and optimization model. The actual competition data of a Chinese athlete in Guyangshu 1.5 km track was compared with the model simulation results. The whole process time error is less than 3%, which verifies the accuracy of the motion and power output model. Gauss pseudo-spectral method is applied to the optimization model. By changing the distribution of athletes' power output, the racing time is minimized under the condition that the total energy output remains unchanged. Compared with the pacing strategy before optimization, the optimized racing time was shortened by 12.6 s, which verifies the effectiveness of the optimization model. Optimized results show that in the first significant uphill section, a recommendation is to use a more conservative strategy, while in the latter half of uphill sections the power output should be increased.

ACLP promotes activation of cancer-associated fibroblasts and tumor metastasis via ACLP-PPARγ-ACLP feedback loop in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with poor prognosis. Its fibrotic tumor microenvironment (TME) plays a crucial role in promoting tumor invasion and metastasis, which eventually leads to a dismal 5-year survival rate in PDAC patients. Aortic carboxypeptidase-like protein (ACLP) promotes tissue fibrosis in benign diseases. However, its role in cancer-associated fibrosis remains unelucidated. Here, we show that ACLP was mainly expressed in cancer-associated fibroblasts (CAFs) but not in cancer cells and highly expressed in PDAC tissues. High ACLP expression was correlated with poor overall survival. Moreover, ACLP expression in PDAC patients with liver metastases was higher than that in PDAC patients without liver metastases. By detecting activation marker expression and CAF contractility and motility, we found that ACLP promoted CAF activation in PDAC, leading to TME fibrosis. Furthermore, ACLP-activated CAFs could promote cancer cell invasion in vitro and tumor metastasis in vivo. Mechanistically, ACLP promotes the expressions of MMP1 and MMP3 in CAFs, thus promoting PDAC invasion and metastasis. Intriguingly, we identified an ACLP-PPARγ-ACLP feedback loop in PDAC CAFs. Abatement of this feedback loop might be a promising approach in CAF-targeting PDAC treatment.

Analgesia with 5' extracellular nucleotidase-mediated electroacupuncture for neuropathic pain.

BACKGROUND: Acupuncture is a treatment for neuropathic pain, but its mechanism remains unclear. Previous studies showed that analgesia was induced in rats with neuropathic pain when their spinal cord adenosine content increased after electroacupuncture (EA); however, the mechanism behind this electroacupuncture-induced increase has not been clarified. OBJECTIVE: This study aimed to determine the role that ecto-5'-nucleotidase plays in EA-induced analgesia for neuropathic pain. METHODS: We performed electroacupuncture at the Zusanli acupoint on the seventh day after establishing a rat model of neuropathic pain induced through chronic constriction injuries. We observed the mechanical withdrawal threshold and thermal pain threshold and detected the expression of ecto-5'-nucleotidase in the spinal cord using Western blot. Chronic constriction injury rat models were intraperitoneally injected with α,ß-methyleneadenosine 5'-diphosphate, an ecto-5'-nucleotidase inhibitor, 30 min before electroacupuncture. The adenosine content of the spinal cord was detected using high-performance liquid chromatography. Lastly, the adenosine A1 receptor agonist N6-cyclopentyladenosine was intrathecally injected into the lumbar swelling of the rats, and the mechanical withdrawal and thermal pain thresholds were reevaluated. RESULTS: Analgesia and increased ecto-5'-nucleotidase expression and adenosine content in the spinal cord were observed 1 h after electroacupuncture. α,ß-methyleneadenosine 5'-diphosphate was able to inhibit upregulation of adenosine content and electroacupuncture-induced analgesia. After administration of N6-cyclopentyladenosine, electroacupuncture-induced analgesia was restored. CONCLUSIONS: Our results suggest that electroacupuncture at Zusanli can produce analgesia in chronic constriction injury rat models, possibly via the increased ecto-5'-nucleotidase expression induced through electroacupuncture, thus leading to increased adenosine expression in the spinal cord.

Novel composite nanomaterials based on magnetic molecularly imprinted polymers for selective extraction and determination of rutin in fruit juice.

In this work, with the attempt to further improve the selectivity, magnetism and loading proportion of existing adsorbents, a novel composite (MGO/MHNTs@MIPs) was synthesized by electrostatically combining molecularly imprinted polymer based on the surface of magnetic halloysite nanotubes (MHNTs@MIPs) with magnetic graphene oxide (MGO). Then some characterizations were done to prove its successful synthesis. Besides, the bonding experiment showed that it possessed a loading capacity of up to 132 mg·g-1, and the adsorption behavior of MGO/MHNTs@MIPs was elucidated by Langmuir isotherm model and Pseudo-second order model. By comparing its adsorption capacity to analogues, we concluded that the MGO/MHNTs@MIPs with the MHNTs@MIPs as basic elements exhibited higher selectivity (imprinting factor = 2.25) than that of MGO/MHNTs@NIPs based on MHNTs@NIPs for template rutin. Furthermore, a series of solid phase extraction conditions were optimized, and then the materials were used for the extraction and detection of rutin in fruit juice under the optimal conditions.

Targeted gene disruption by CRISPR/xCas9 system in Drosophila melanogaster.

Although the Cas9 protein from Streptococcus pyogenes (SpCas9) is the most widely used clustered regularly interspaced short palindromic repeats (CRISPR) variant in genome engineering experiments, it does have certain limitations. First, the stringent requirement for the protospacer adjacent motif (PAM) sequence limits the target DNA that can be manipulated using this method in insects. Second, its complementarity specifications are not very stringent, meaning that it can sometimes cause off-target effects at the target site. A recent study reported that an evolved SpCas9 variant, xCas9(3.7), with preference for various 5'-NG-3' PAM sequences not only has the broadest PAM compatibility but also has much greater DNA specificity and lower genome-wide off-target activity than SpCas9 in mammalian cells. Here we applied the CRISPR/xCas9 system to target the white gene in Drosophila melanogaster, testing the genome-editing efficiency of xCas9 at different PAM sites. On the GGG PAM site, xCas9 showed less activity than SpCas9. For the non-NGG PAM site TGA, xCas9 could produce DNA cleavage and indel-mediated disruption on the target gene. However, for other non-NGG PAM sites, xCas9 showed no activity. These findings show that the evolved Cas9 variant with broad PAM compatibility is functional in Drosophila to induce heritable gene alterations, increasing the targeting range for the applications of genome editing in insects.

Expert consensus on image-guided radiofrequency ablation of pulmonary tumors: 2018 edition.

Lung cancer ranks first in incidence and mortality in China. Surgery is the primary method to cure cancer, but only 20-30% of patients are eligible for curative resection. In recent years, in addition to surgery, other local therapies have been developed for patients with numerous localized primary and metastatic pulmonary tumors, including stereotactic body radiation therapy and thermal ablative therapies through percutaneously inserted applicators. Percutaneous thermal ablation of pulmonary tumors is minimally invasive, conformal, repeatable, feasible, cheap, has a shorter recovery time, and offers reduced morbidity and mortality. Radiofrequency ablation (RFA), the most commonly used thermal ablation technique, has a reported 80-90% rate of complete ablation, with the best results obtained in tumors < 3 cm in diameter. Because the clinical efficacy of RFA of pulmonary tumors has not yet been determined, this clinical guideline describes the techniques used in the treatment of localized primary and metastatic pulmonary tumors in nonsurgical candidates, including mechanism of action, devices, indications, techniques, potential complications, clinical outcomes, post-ablation surveillance, and use in combination with other therapies. In the future, the role of RFA in the treatment of localized pulmonary tumors should ultimately be determined by evidence from prospective randomized controlled trials comparing sublobar resection or stereotactic body radiation therapy.

Characterization of three serotonin receptors from the small white butterfly, Pieris rapae.

Serotonin (5-hydroxytryptamine, 5-HT) plays a key role in modulating diverse physiological processes and behaviors in both protostomes and deuterostomes. These functions are mediated through the binding of serotonin to its receptors, which are recognized as potential insecticide targets. We investigated the sequence, pharmacology and tissue distribution of three 5-HT receptors (Piera5-HT1A, Piera5-HT1B, Piera5-HT7) from the small white butterfly Pieris rapae, an important pest of cultivated cabbages and other mustard family crops. Activation of Piera5-HT1A or Piera5-HT1B by 5-HT inhibited the production of cAMP in a dose-dependent manner. Stimulation of Piera5-HT7 with 5-HT increased cAMP level significantly. Surprisingly, with the exception of 5-methoxytryptamine, agonists including α-methylserotonin, 8-Hydroxy-DPAT and 5-carboxamidotryptamine activated these receptors poorly. The results are consistent with previous findings in Manduca sexta. All three receptors were blocked by methiothepin, but ketanserin and yohimbine were not effective. The selective mammalian 5-HT receptor antagonists SB 216641 and SB 269970 displayed potent inhibition effects on Piera5-HT1B and Piera5-HT7 respectively. The results we achieved here indicate that the pharmacological properties of Lepidoptera 5-HT receptors are quite different from those in other insects and vertebrates and may contribute to development of new selective pesticides. This study offers important information on three 5-HT receptors from P. rapae that will facilitate further analysis of the functions of 5-HT receptors in insects.

Surface phononic graphene.

Strategic manipulation of wave and particle transport in various media is the key driving force for modern information processing and communication. In a strongly scattering medium, waves and particles exhibit versatile transport characteristics such as localization, tunnelling with exponential decay, ballistic, and diffusion behaviours due to dynamical multiple scattering from strong scatters or impurities. Recent investigations of graphene have offered a unique approach, from a quantum point of view, to design the dispersion of electrons on demand, enabling relativistic massless Dirac quasiparticles, and thus inducing low-loss transport either ballistically or diffusively. Here, we report an experimental demonstration of an artificial phononic graphene tailored for surface phonons on a LiNbO3 integrated platform. The system exhibits Dirac quasiparticle-like transport, that is, pseudo-diffusion at the Dirac point, which gives rise to a thickness-independent temporal beating for transmitted pulses, an analogue of Zitterbewegung effects. The demonstrated fully integrated artificial phononic graphene platform here constitutes a step towards on-chip quantum simulators of graphene and unique monolithic electro-acoustic integrated circuits.

Acoustic asymmetric transmission based on time-dependent dynamical scattering.

An acoustic asymmetric transmission device exhibiting unidirectional transmission property for acoustic waves is extremely desirable in many practical scenarios. Such a unique property may be realized in various configurations utilizing acoustic Zeeman effects in moving media as well as frequency-conversion in passive nonlinear acoustic systems and in active acoustic systems. Here we demonstrate a new acoustic frequency conversion process in a time-varying system, consisting of a rotating blade and the surrounding air. The scattered acoustic waves from this time-varying system experience frequency shifts, which are linearly dependent on the blade's rotating frequency. Such scattering mechanism can be well described theoretically by an acoustic linear time-varying perturbation theory. Combining such time-varying scattering effects with highly efficient acoustic filtering, we successfully develop a tunable acoustic unidirectional device with 20 dB power transmission contrast ratio between two counter propagation directions at audible frequencies.

Different effects of etomidate and propofol on memory in immature rats.

This study is to investigate the effects of etomidate and propofol on memory and possible involved mechanisms using immature rats. Forty-eight rats randomly received intraperitoneal injection of 5 mg/kg etomidate (n = 16), 50 mg/kg propofol (n = 16) or normal saline (control, n = 16). Three hours after awakening, memory was assessed by Y-maze test using 10 rats in each drug group. Gamma-aminobutyric acid (GABA) content in hippocampal tissue was measured using six rats in each group. Etomidate group had more total reaction time (TRT) compared with the control group in Y-maze test ( p < 0.05). No other difference between these two groups was observed. Propofol group had less number of correct response ( p < 0.01) and more TRT ( p < 0.05) in Y-maze test, as well as more GABA concentration detected in hippocampal tissue ( p < 0.01) than the control group. Propofol group also showed less number of correct response ( p < 0.05) and more hippocampal GABA concentration ( p < 0.01) compared with etomidate group. Etomidate does not show significant effects on memory in rat and further investigation is required. Propofol can affect memory in rat possibly via increasing the synthesis and/or secretion of GABA as one of the factors.

Acoustic rainbow trapping by coiling up space.

We numerically realize the acoustic rainbow trapping effect by tapping an air waveguide with space-coiling metamaterials. Due to the high refractive-index of the space-coiling metamaterials, our device is more compact compared to the reported trapped-rainbow devices. A numerical model utilizing effective parameters is also calculated, whose results are consistent well with the direct numerical simulation of space-coiling structure. Moreover, such device with the capability of dropping different frequency components of a broadband incident temporal acoustic signal into different channels can function as an acoustic wavelength division de-multiplexer. These results may have potential applications in acoustic device design such as an acoustic filter and an artificial cochlea.

Accidental degeneracy of double Dirac cones in a phononic crystal.

Artificial honeycomb lattices with Dirac cone dispersion provide a macroscopic platform to study the massless Dirac quasiparticles and their novel geometric phases. In this paper, a quadruple-degenerate state is achieved at the center of the Brillouin zone in a two-dimensional honeycomb lattice phononic crystal, which is a result of accidental degeneracy of two double-degenerate states. In the vicinity of the quadruple-degenerate state, the dispersion relation is linear. Such quadruple degeneracy is analyzed by rigorous representation theory of groups. Using k·p method, a reduced Hamiltonian is obtained to describe the linear Dirac dispersion relations of this quadruple-degenerate state, which is well consistent with the simulation results. Near such accidental degeneracy, we observe some unique properties in wave propagating, such as defect-insensitive propagating character and the Talbot effect.

Tunable unidirectional sound propagation through a sonic-crystal-based acoustic diode.

Nonreciprocal wave propagation typically requires strong nonlinear materials to break time reversal symmetry. Here, we utilized a sonic-crystal-based acoustic diode that had broken spatial inversion symmetry and experimentally realized sound unidirectional transmission in this acoustic diode. These novel phenomena are attributed to different mode transitions as well as their associated different energy conversion efficiencies among different diffraction orders at two sides of the diode. This nonreciprocal sound transmission could be systematically controlled by simply mechanically rotating the square rods of the sonic crystal. Different from nonreciprocity due to the nonlinear acoustic effect and broken time reversal symmetry, this new model leads to a one-way effect with higher efficiency, broader bandwidth, and much less power consumption, showing promising applications in various sound devices.

Acoustic surface evanescent wave and its dominant contribution to extraordinary acoustic transmission and collimation of sound.

We demonstrate both theoretically and experimentally the physical mechanism that underlies extraordinary acoustic transmission and collimation of sound through a one-dimensional decorated plate. A microscopic theory considers the total field as the sum of the scattered waves by every periodically aligned groove on the plate, which divides the total field into far-field radiative cylindrical waves and acoustic surface evanescent waves (ASEWs). Different from the well-known acoustic surface waves like Rayleigh waves and Lamb waves, ASEW is closely analogous to a surface plasmon polariton in the optical case. By mapping the total field, the experiments well confirm the theoretical calculations with ASEWs excited. The establishment of the concept of ASEW provides a new route for the integration of subwavelength acoustic devices with a structured solid surface.