The efficient extraction of targets from complex surfaces is vital for technological applications ranging from environmental pollutant monitoring to analysis of explosive traces and pesticide residues. In our present study, we proposed a proof-of-concept surface enhance Raman scattering (SERS) active substrate serving directly to the rapid extraction and detection of target molecules. The novel substrate was constructed by decorating the commercial tape with colloidal gold nanoparticles (Au NPs), which simultaneously provides SERS activity and "sticky" of adhesive. The utility of SERS tape was demonstrated by directly extracting pesticide residues in fruits and vegetables via a simple and viable "paste and peel off" approach. The obtained strong and easily distinguishable SERS signals allow us to detect various pesticide residues such as parathion-methyl, thiram, and chlorpyrifos in the real samples with complex surfaces including green vegetable, cucumber, orange, and apple.

Development of new porous materials as hosts to suppress the dissolution and shuttle of lithium polysulfides is beneficial for constructing highly efficient lithium–sulfur batteries (LSBs). Although 2D covalent organic frameworks (COFs) as host materials exhibit promising potential for LSBs, their performance is still not satisfactory. Herein, we develop polyimide COFs (PI-COF) with a well-defined lamellar structure, which can be exfoliated into ultrathin (∼1.2 nm) 2D polyimide nanosheets (PI-CONs) with a large size (∼6 μm) and large quantity (40 mg/batch). Explored as new sulfur host materials for LSBs, PI-COF and PI-CONs deliver high capacities (1330 and 1205 mA h g–1 at 0.1 C, respectively), excellent rate capabilities (620 and 503 mA h g–1 at 4 C, respectively), and superior cycling stability (96% capacity retention at 0.2 C for PI-CONs) by virtue of the synergy of robust conjugated porous frameworks and strong oxygen–lithium interactions, surpassing the vast majority of organic/polymeric lithium–sulfur battery cathodes ever reported. Our finding demonstrates that ultrathin 2D COF nanosheets with carbonyl groups could be promising host materials for LSBs with excellent electrochemical performance.

The synthesis and characterization of multi-sensitive polymers for use as injectable hydrogels for controlled protein/drug delivery is reported. A series of biodegradable multi-sensitive poly(ether-urethane)s were prepared through a simple one-pot condensation of poly(ethylene glycol), 2,2'-dithiodiethanol, N-methyldiethanolamine, and hexamethylene diisocyanate. The sol-gel phase transition behaviors of the obtained copolymers were investigated. Experimental results showed that the aqueous medium comprising the multi-segment copolymers underwent a sol-to-gel phase transition with increasing temperature and pH. At a certain concentration, the copolymer solution could immediately change to a gel under physiological conditions (37 °C and pH 7.4), indicating their suitability as in situ injectable hydrogels in vivo. Insulin was used as a model protein drug for evaluation of the injectable hydrogels as a site-specific drug delivery system. The controlled release of insulin from the hydrogel devices was demonstrated by degradation of the copolymer, which is modulated via the 2,2'-dithiodiethanol content in the poly(ether-urethane)s. These hydrogels having multi-responsive properties may prove to be promising candidates for injectable and controllable protein drug delivery devices.

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Background: We aimed to investigate whether pre-therapeutic radiomic features based on magnetic resonance imaging (MRI) can predict the clinical response to neoadjuvant chemotherapy (NACT) in patients with locally advanced cervical cancer (LACC). Methods: A total of 275 patients with LACC receiving NACT were enrolled in this study from eight hospitals, and allocated to training and testing sets (2:1 ratio). Three radiomic feature sets were extracted from the intratumoural region of T1-weighted images, intratumoural region of T2-weighted images, and peritumoural region of T2-weighted images before NACT for each patient. With a feature selection strategy, three single sequence radiomic models were constructed, and three additional combined models were constructed by combining the features of different regions or sequences. The performance of all models was assessed using receiver operating characteristic curve. Findings: The combined model of the intratumoural zone of T1-weighted images, intratumoural zone of T2-weighted images,and peritumoural zone of T2-weighted images achieved an AUC of 0.998 in training set and 0.999 in testing set, which was significantly better (p b .05) than the other radiomic models. Moreover, no significant variation in performance was found if different training sets were used. Interpretation: This study demonstrated that MRI-based radiomic features hold potential in the pretreatment prediction of response to NACT in LACC, which could be used to identify rightful patients for receiving NACT avoiding unnecessary treatment.

The retina, the most crucial unit of the human visual perception system, combines sensing with wavelength selectivity and signal preprocessing. Incorporating energy conversion into these superior neurobiological features to generate core visual signals directly from incoming light under various conditions is essential for artificial optoelectronic synapses to emulate biological processing in the real retina. Herein, self-powered optoelectronic synapses that can selectively detect and preprocess the ultraviolet (UV) light are presented, which benefit from high-quality organic asymmetric heterojunctions with ultrathin molecular semiconducting crystalline films, intrinsic heterogeneous interfaces, and typical photovoltaic properties. These devices exhibit diverse synaptic behaviors, such as excitatory postsynaptic current, paired-pulse facilitation, and high-pass filtering characteristics, which successfully reproduce the unique connectivity among sensory neurons. These zero-power optical-sensing synaptic operations further facilitate a demonstration of image sharpening. Additionally, the charge transfer at the heterojunction interface can be modulated by tuning the gate voltage to achieve multispectral sensing ranging from the UV to near-infrared region. Therefore, this work sheds new light on more advanced retinomorphic visual systems in the post-Moore era.

BackgroundCold tolerance is a key determinant of the geographical distribution range of a plant species and crop production. Cold acclimation can enhance freezing-tolerance of plant species through a period of exposure to low nonfreezing temperatures. As a subtropical evergreen broadleaf plant, oil-tea camellia demonstrates a relatively strong tolerance to freezing temperatures. Moreover, wild oil-tea camellia is an essential genetic resource for the breeding of cultivated oil-tea camellia, one of the four major woody oil crops in the world. The aims of our study are to identify variations in transcriptomes of wild oil-tea camellia from different latitudes and elevations, and discover candidate genes for cold acclimation.ResultsLeaf transcriptomes were obtained of wild oil-tea camellia from different elevations in Lu and Jinggang Mountains, China. Huge amounts of simple sequence repeats (SSRs), single-nucleotide polymorphisms (SNPs) and insertion/deletions (InDels) were identified. Based on SNPs, phylogenetic analysis was performed to detect genetic structure. Wild oil-tea camellia samples were genetically differentiated mainly between latitudes (between Lu and Jinggang Mountains) and then among elevations (within Lu or Jinggang Mountain). Gene expression patterns of wild oil-tea camellia samples were compared among different air temperatures, and differentially expressed genes (DEGs) were discovered. When air temperatures were below 10 °C, gene expression patterns changed dramatically and majority of the DEGs were up-regulated at low temperatures. More DEGs concerned with cold acclimation were detected at 2 °C than at 5 °C, and a putative C-repeat binding factor (CBF) gene was significantly up-regulated only at 2 °C, suggesting a stronger cold stress at 2 °C. We developed a new method for identifying significant functional groups of DEGs. Among the DEGs, transmembrane transporter genes were found to be predominant and many of them encoded transmembrane sugar transporters.ConclusionsOur study provides one of the largest transcriptome dataset in the genus Camellia. Wild oil-tea camellia populations were genetically differentiated between latitudes. It may undergo cold acclimation when air temperatures are below 10 °C. Candidate genes for cold acclimation may be predominantly involved in transmembrane transporter activities.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3570-4) contains supplementary material, which is available to authorized users.

While studying the bile acid synthetic pathway of hamsters, we discovered an NADP ؉ -dependent liver microsomal 7␣-hydroxycholesterol dehydrogenase (7␣-HCD) activity that was not observed in rat liver microsomal fractions. The hamster liver microsomal 7␣-HCD was purified to homogeneity using 2,5-ADP and cholic acidagarose affinity chromatography. 7␣-HCD displayed a molecular weight of approximately 34,000 on SDS-polyacrylamide gel electrophoresis; it is an intrinsic membrane protein of the hamster liver endoplasmic reticulum and exists as a multimeric aggregate in pure form. Partial N-terminal amino acid sequence analysis showed that 7␣-HCD had high sequence similarity to human 11␤-hydroxysteroid dehydrogenase (11␤-HSD; 24/30 amino acid identity). The K m values for corticosterone and 7␣-hydroxycholesterol were 1.2 and 1.9 M, respectively, for purified 7␣-HCD; both reactions displayed identical V max values (approximately 170 nmol/ min/mg of protein). The IC 50 of carbenoxolone, a competitive inhibitor of 11␤-HSD, was 75 nM for 7␣-hydroxycholesterol dehydrogenation and 210 nM for corticosterone dehydrogenation. The tissue-specific expression in hamster was as follows: adrenal > liver > kidney > testis > > brain > lung.Microsomal 7␣-HCD is uniquely expressed in hamster liver and to some extent in human liver but not in rat liver. Western blot analysis with two antibodies elicited against an N-terminal peptide of the human 11␤-HSD and purified hamster liver 7␣-HCD, respectively, suggested the presence of multiple forms of 7␣-HCD in hamster liver, most likely due to the existence of a family of 11␤-HSD proteins. Since 7-oxocholesterol is a potent inhibitor of cholesterol 7␣-hydroxylase, alternative mechanisms for regulation of bile acid synthesis may exist in human and hamster liver due to production of this metabolite and its potential as an oxysterol.The first regulated step in bile acid synthesis is hydroxylation of cholesterol to 7␣-hydroxycholesterol by cholesterol 7␣-hydroxylase, the apparent rate limiting reaction in this pathway (1). Oxidation of the 3␤-ol group to an oxo group and rearrangement of the unsaturated bond at ⌬ 5 -position to ⌬ 4 followed by hydroxylation at either the C-12 or C-27 position converts the sterol to its active form essential for digestion of fatty nutrients. Recently, an alternate pathway to bile acids has been elucidated involving first 27-hydroxylation of cholesterol and subsequent oxidation at position C-3 and hydroxylation at position C-7 eventually leading to chenodeoxycholic acid (2). A unique hamster liver microsomal 7␣-hydroxycholesterol dehydrogenase (7␣-HCD) 1 was discovered in our laboratory during the development of an HPLC method for assay of cholesterol 7␣-hydroxylase activity (3, 4). The oxidized metabolite produced by 7␣-HCD, 7-oxocholesterol, is a bioactive sterol and potent competitive inhibitor of cholesterol 7␣-hydroxylase activity (approximately K i for 7-oxocholesterol of 7 M versus approximately K m for exogenous cholesterol of 100 M; Ref. 5). Although oxych...