Efficacy of artemether and artesunate in mice infected with praziquantel non-susceptible isolate of Schistosoma japonicum

Praziquantel is currently the only drug of choice for the treatment of human Schistosoma japonicum infections, and praziquantel-based chemotherapy has been proved to be generally effective to control the morbidity and reduce the prevalence and intensity of S. japonicum infections. However, the potential emergence of praziquantel resistance in S. japonicum seriously threatens the elimination of this neglected tropical disease in China. The purpose of this study was designed, in mouse animals, to evaluate the in vivo efficacy of artemether and artesunate against praziquantel non-susceptible S. japonicum. Mice infected with a praziquantel non-susceptible isolate and a praziquantel-susceptible isolate of S. japonicum were treated with artemether and artesunate at a single oral dose of 300 mg/kg given once on each of days 7–8 and 35–36 post-infection to assess the efficacy against juvenile and adult worms. Administration with artemether and artesunate at a single oral dose of 300 mg/kg on each of days 7–8 post-infection resulted in total worm burden reductions of 72.8 and 73.5 % in mice infected with praziquantel-susceptible S. japonicum, and 77.9 and 74.1 % in mice infected with the non-susceptible isolate (both P values >0.05), while the same treatments given on days 35–36 post-infection reduced total worm burdens by 71.4 and 69.6 % in mice infected with the susceptible isolate, and 75.3 and 69.6 % in mice infected with the non-susceptible parasite (both P values >0.05). It is concluded that there is no evidence for reduced susceptibility of artemether and artesunate in praziquantel non-susceptible S. japonicum.     

Is there a reduced sensitivity of dihydroartemisinin against praziquantel-resistant Schistosoma japonicum?

Praziquantel is currently the only drug of choice for the treatment of human schistosomiases. However, it has been proved that Schistosoma japonicum subjected to drug pressure may develop resistance to praziquantel. To evaluate the efficacy of dihydroartemisinin against praziquantel-resistant S. japonicum, mice infected with a praziquantel-resistant isolate and a praziquantel-susceptible isolate of S. japonicum were treated with dihydroartemisinin at a single oral dose of 300 mg/kg given once on each of 35–36 post-infection days, while infected but untreated mice served as controls. All mice were sacrificed 50 days post-infection, and the worm burden reductions were estimated. Administration of dihydroartemisinin at a single oral dose of 300 mg/kg on each of 35–36 post-infection days reduced total worm burdens of 69.8 % and female worm burdens of 86 % in mice infected with the praziquantel-susceptible isolate, and total worm burdens of 66.1 % and female worm burdens of 85.1 % in mice infected with the praziquantel-resistant isolate (both P values?>?0.05). It is concluded that the sensitivity of artemisinin derivative dihydroartemisinin does not reduce in praziquantel-resistant S. japonicum.     

One-step solution synthesis of a two-dimensional semiconducting covalent organometallic nanosheet via the condensation of boronic acid

In this work, a 2D covalent organometallic nanosheet (COMS) was designed and successfully synthesized through the one-step conjunction of a terpyridine–metal–terpyridine (TMT) sandwich coordinate motif with borate ester covalent heterocyclic (B₃O₃) linkage via the condensation of boronic acid. The obtained 2D COMS with a cobalt coordination center (2D COMS-Co) showed promising p-type semiconducting properties.

A 2D covalent organometallic nanosheet (COMS-Co) was synthesized through the one-step conjunction of sandwich coordinate motif with covalent heterocyclic linkage via the condensation of boronic acid, and it showed promising semiconducting properties.

Two-dimensional (2D) metal–organic frameworks (MOFs) obtained by using the strong bonding effects between metal ions and organic molecule species have aroused great interest;^1–8 these include coordination nanosheets, which are a class of 2D materials featuring metal complex motifs.^9–12 Covalent bonds are considered to be an effective way to fabricate covalent organic frameworks (COFs) such as COF-1, which is mainly constructed by a phenyl ring and borate ester to form covalent heterocyclic (B₃O₃) linkage.^13–15 Based on the synergistic effects of metal coordination and covalent interactions, Jiang and co-workers demonstrated the important role of central metals in controlling π-electronic functions through Mpc-COF.¹⁶ Nevertheless, the coordination bond forms spontaneously within the ring of the porphyrin heterocycle and not as the linkage between organic components. In addition, the connections made between metal ions and ligand motifs cannot facilitate the proper tuning of the physicochemical properties of the structure.¹⁷ Combining the covalent and coordinate features may provide an opportunity to design new 2D materials and thus, the synergetic enhancement in many unique properties can be achieved. As far as we know, the fabrication of 2D semiconducting materials that combine the covalent heterocyclic linkage and coordinate linkage has not been reported. Therefore, it is a pressing need to construct a functional 2D organic framework through a one-step synthesis strategy, which would be a more attractive approach.Herein, we first proposed an efficient one-step strategy to synthesize a 2D material by the synergy of covalent and organometallic interactions; it was named as a covalent organometallic nanosheet (2D COMS-M, M = cobalt (Co)). The as-proposed 2D COMS-Co was constructed by linking the borate ester covalent heterocyclic (B₃O₃) structure and terpyridine (tpy) metal coordination motif (TMT) (Fig. 1).Open in a separate windowFig. 1(a) Synthesis route of the semiconducting 2D COMS. (b) Design principles of COMS via the condensation of boronic acid. (c) The calculated cross-sectional view of 2D COMS-Co.In order to explore the extended construction of 2D COMS, the self-condensation ligand 4-phenylborate-2,2′; 6′,2′′-terpyridine (L¹) integrated with CoCl₂ as the Co²⁺ carrier was employed through an anhydrous and oxygen-free hydrothermal reaction at 120 °C under argon, and the typical synthesis process is depicted in Fig. 1a (for details, please see ESI^†). Starting from the condensation reaction of boronic acid (Fig. 1b), H₂O could be generated and played a key role in dissolving CoCl₂ and further releasing Co²⁺ ions (CoCl₂ is practically insoluble in mesitylene and dioxane). This was followed by coordination between the terpyridine motifs and the released Co²⁺ ions to obtain 2D COMS. This novel strategy could achieve crystalline 2D materials by self-controlling the release of Co²⁺ through the one-step condensation reaction of boronic acid. The calculated cross-sectional view of 2D COMS-Co indicates that the thickness of the monolayer 2D COMS-Co is 0.69 nm (Fig. 1c). The dual synergistic connecting effects of covalence and coordination in 2D COMS-Co provided nanosheet-like morphology with significant improvement in the semiconducting performance. The hole mobility of the 2D COMS-Co-based FET device could reach to 5.7 × 10⁻⁵ cm² V⁻¹ s⁻¹ with an ON–OFF ratio of 221, which demonstrated the potential application of 2D COMS-Co in semiconducting devices.The scanning electron microscopy (SEM) image (Fig. 2a) reveals that 2D COMS-Co has a uniform micron-sized nanosheet-like structure. Furthermore, the transmission electron microscopy (TEM) image indicates that the as-synthesized 2D COMS-Co consists of few multi-layers. Fig. 2c shows an enlarged image of the selected area visualized with high-resolution TEM (HRTEM), where the section enclosed by white lines depicts lattice fringes. Moreover, the selected area electron diffraction (SAED, inset of Fig. 2c) image shows a circular ring pattern that reveals the well-defined crystalline structure of 2D COMS-Co; these results are in agreement with our X-ray diffraction data (Fig. S2, ESI^†). Most interestingly, the atomic force microscopy (AFM) image (Fig. 2d) clearly demonstrates that the selected thickness of 2D COMS-Co is 2.07 nm, and the resultant thickness is three times less than the calculated value of 0.69 nm (Fig. 1c), indicating its uniform three-layer stacked structure. The above results collectively provide strong evidence of typical 2D features for COMS-Co. Moreover, the high-angle annular dark-field (HAADF) image and the scanning transmission electron microscopy (STEM) elemental mapping further revealed that the C (red), B (cyan), N (green), O (blue) and Co (pink) elements are homogeneously distributed on the selected area of 2D COMS-Co (Fig. 2e–k). The electronic structure of 2D COMS-Co was further characterized by four-probe scanning tunnel microscopy (STM) (please see details in ESI^†). The high-resolution STM imaging revealed that the 2D COMS-Co flake has a layered flake structure with uniformly distributed hexagonal hole morphology and the resultant holes have a diameter of 4.72 nm (Fig. 2l); this observation is in accordance with the proposed structure of 2D COMS-Co (Fig. S8, ESI^†).Open in a separate windowFig. 2Morphological characterization of 2D COMS-Co. (a) SEM image of powder. (b) TEM image. (c) HRTEM image (d) AFM image. (e) HAADF image. (f–k) STEM elemental mapping. (l) STM image.Due to the covalence and coordination effects, the absorption peak of 2D COMS-Co obtained from the UV-vis measurements (Fig. 3a) is red-shifted in comparison to that for ligand L¹, and the optical band gap is calculated to be 1.85 eV. Furthermore, density functional theory (DFT) calculations revealed that the highest occupied molecular orbital (HOMO) of 2D COMS-Co was dominated by the π orbital of the B₃O₃ linkage and the phenyl ring, whereas the π* orbital of TMT was responsible for the lowest unoccupied molecular orbital (LUMO). Additionally, the calculated electronic band gap of 2D COMS-Co was 1.89 eV, which was in accordance with the optical band gap, confirming the successful synthesis of 2D COMS-Co. Fig. 3b displays the X-ray photoelectron spectroscopy (XPS) spectrum of 2D COMS-Co, in which the appearance of the binding energy peak at 192.2 eV is significantly different from that for L¹ (191.1 eV), which can be ascribed to the –C–B–O₂ structure.^18,19 Compared to the observation for L¹, the N 1s peak for 2D COMS-Co shifted to a higher binding energy value (399.2 eV for COMS-Co and 397.5 eV for L¹). The skewing of the peaks toward higher binding energy was induced by the contribution of N atoms in terpyridine to the metal center. Therefore, the XPS results clearly provide evidence of the existence of both covalent and coordination effects in the as-prepared 2D COMS-Co. The Fourier transform infrared (FT-IR) spectra in Fig. 3c show that the –B(OH)₂ bands (around 3500 cm⁻¹) of the ligand L¹ are significantly attenuated compared to that observed for 2D COMS-Co. In addition, the B–O stretching vibrations at 1351 cm⁻¹ can be observed for 2D COMS-Co but not for L¹.^13,20–22 Thus, the above results show that the expected B₃O₃ rings for 2D COMS-Co have indeed been formed. Notably, the nitrogen adsorption–desorption isotherms reveal that the Brunauer–Emmett–Teller (BET) specific surface area of 2D COMS-Co is as high as 598 m² g⁻¹ (Fig. 3d); it surpasses those of other layered materials, including the reported graphene oxide paper (10 m² g⁻¹), clays (10 to 100 m² g⁻¹), and pillared clays (50 to 300 m² g⁻¹), and is in the range of the values of the most porous zeolites and many porous carbons.^13,23 This drastic enhancement can be assigned to the uniform porous structure of the as-synthesized 2D COMS-Co.Open in a separate windowFig. 3(a) UV-vis spectra of L¹ and 2D COMS-Co (left), electron distribution on HOMO/LUMO and the orbital energy gap (right). (b) XPS B 1s and N 1s spectra of L¹ and 2D COMS-Co. (c) FT-IR spectra of L¹ and 2D COMS-Co. (d) N₂ adsorption and desorption isotherms of 2D COMS-Co (inset: stacking porous view).The above results show that the 2D COMS-Co units arranged in periodic strips can provide conducting pathways for charge carrier transport through TMT and central cobalt ions. 2D COMS-Co was employed to function as the active semiconducting channel in a field-effect transistor (FET) device. As shown in Fig. 4a, the individual 2D COMS-Co sample is deposited on an Si wafer as the semiconducting layer to construct the FET device. The 2D COMS-Co-based FET device delivered hole mobility of 5.7 × 10⁻⁵ cm² V⁻¹ S⁻¹ and an ON/OFF ratio of 221, which were comparable with those of previously reported 2D MOFs (Table S1^†). Therefore, these results collectively demonstrate the potential application of 2D COMS-Co in semiconducting devices.Open in a separate windowFig. 4(a) Schematic of the FET device employing 2D COMS-Co as the semiconducting layer. (b) Transfer curve of the 2D COMS-Co-based FET device with the inset showing an optical and model diagram of the device; V_G is the gate-source voltage and I_D is the drain current.In summary, a novel two-dimensional covalent organometallic nanosheet (COMS) was designed and successfully synthesized through the strategy of one-step conjunction of a TMT sandwich coordinate motif with B₃O₃ linkage. This facile strategy could achieve crystalline 2D COMS-Co by self-controlling the release of Co²⁺ through a one-step condensation reaction of boronic acid. The systematic characterization demonstrated the successful preparation of porous and crystalline 2D COMS-Co. Particularly, the as-prepared 2D COMS-Co-based FET device presented hole mobility of 5.7 × 10⁻⁵ cm² V⁻¹ S⁻¹ and an ON/OFF ratio of 221, which demonstrated the potential application of 2D COMS-Co in semiconducting devices. Therefore, we envision that this work will open a new avenue for the synthesis of two-dimensional semiconducting covalent organometallic materials by using covalence and coordination dual synergistic connection effects via a one-step facile strategy.     

Syntheses,structures, and magnetic properties of mixed-ligand complexes based on 3,6-bis(benzimidazol-1-yl)pyridazine

Six new metal–organic coordination polymers (CPs) [Ni(L)(2,5-TDC)(H₂O)]_n(1), [Ni(L)(1,3-BDC)(H₂O)]_n (2), [Ni(L)(1,4-BDC)(H₂O)]_n (3), [Mn(L)(2,5-TDC)(H₂O)]_n (4), [Mn(L)(2,6-PYDC)(H₂O)]_n (5) and [Mn(L)(1,4-NDC)]_n (6) were achieved by reactions of the corresponding metal salt with mixed organic ligands (L = 3,6-bis(benzimidazol-1-yl)pyridazine, 2,5-H₂TDC = thiophene-2,5-dicarboxylic acid, 1,3-H₂BDC = isophthalic acid, 1,4-H₂BDC = terephthalic acid, 2,6-H₂PYDC = pyridine-2,6-dicarboxylic acid, 1,4-H₂NDC = naphthalene-1,4-dicarboxylic acid) under solvothermal condition. CPs 1–6 were characterized by single-crystal X-ray diffraction, IR, TG, XRD and elemental analyses. Their structures range from the intricate 3D CPs 1, 3, 4 and 6 to the 2D coordination polymer 2 and the infinite 1D chain 5. The CPs 1–4 and 6 underlying networks were classified from the topological viewpoint, disclosing the distinct sql (in 1), pcu (in 3 and 6), new topology (in 2), and dia (in 4) topological nets. Moreover, analysis of thermal stability shows that they had good thermal stability. Finally, magnetic properties of CPs 1–6 have been studied, the results showed that complex 2 had ferromagnetic coupling and complexes 1, 3–6 were antiferromagnetic.

Six new metal–organic coordination polymers were prepared by reactions of the corresponding metal salt with mixed organic ligands under solvothermal conditions. The compounds were structurally, magnetically and catalytically characterized.     

An ultrasensitive Fano resonance biosensor using two dimensional hexagonal boron nitride nanosheets: theoretical analysis

This study proposed a novel Fano resonance (FR) biosensor with ultrahigh detection sensitivity by integrating two dimensional (2D) hexagonal boron nitride (h-BN) nanosheets with a plasmonic silver film–silicon hybrid nanostructure. Owing to its ultralow-loss in surface plasmon polaritons (SPPs), 2D h-BN nanosheets can act as a planar photon waveguide (PWG) for generating energy level splitting. Notably, both asymmetric FR sharp lines and plasmon induced transparency (PIT) can be produced by modulating the coupling strength between the planar PWG mode provided by h-BN nanosheets and the surface plasmon polariton (SPP) mode in the silver film–silicon hybrid nanostructure. Compared with conventional phase-modulation SPR biosensors, our proposed configuration based on Fano resonance can produce ultrahigh reflectivity of 0.934 and overcome the limitation of quasi-darkness reflectivity which is difficult for further phase extraction. More importantly, our proposed FR configuration can provide a promising phase detection sensitivity as high as 3.13 × 10⁶ degree per RIU (refractive index unit, RIU), which is enhanced by almost 100 times compared with conventional phase-modulation SPR biosensors. In addition, our proposed configuration has also shown the characteristics of multiple-order Fano resonances, largely depending on the partial coupling between the SPP mode and the different-order PWG mode. Our proposed FR biosensor can provide a highly promising candidate for designing a multiple-order FR platform for performing ultrasensitive detection.

This paper proposed an ultrasensitive FR biosensor with multiple-order characteristics using two dimensional hexagonal boron nitride nanosheets in the visible region.     

One-step synthesis of red-emitting carbon dots via a solvothermal method and its application in the detection of methylene blue

The synthesis of carbon dots (CDs) with long wavelengths, particularly the red-emitting ones, has always been the focus of researchers, and a carbon source is critical in this process. In this study, we report the synthesis of red-emitting CDs (CD-tetra) via a one-step solvothermal method with 1,2,4,5-benzenetetramine tetrahydrochloride as a novel carbon source and ethanol as a solvent, and the quantum yield (QY) of CDs is as high as 30.2%. Middle chromatography isolated gel (MCI Gel) column was used to obtain R-CDs, O-CDs and Y-CDs with emission wavelengths at 619, 608 and 554 nm, respectively. It was discovered that these CDs exhibited great differences in their particle sizes and elemental compositions. Moreover, the fluorescence of the CD-tetra could be efficiently quenched using methylene blue (MB). Under optimal conditions, a linear relationship between the decreased fluorescence intensity of the CD-tetra and the concentration of MB was established in the range of 0.05–9.5 μM. The limit of detection (LOD) is 10 nM, suggesting a promising assay for the detection of MB.

Red-emitting CDs was synthesized via a one-step solvothermal method with 1,2,4,5-benzenetetramine tetrahydrochloride as a novel carbon source and ethanol as a solvent. The luminescence mechanism of CDs was studied by MCI gel column chromatography.     

Goldenhar综合征一例报道及文献复习

目的探讨Goldenhar综合征的发病机制、临床表现、诊断及治疗,以提高,临床医生对本病的认识。方法报道一例Goldenhar综合征患儿的临床资料,并复习通过文献数据库检索的相关文献。结果Goldenhar综合征病因尚不清楚,临床表现具有高度多样性,包括眼部畸形、耳部畸形、颜面畸形、脊柱异常、心脏及其它脏器等的发育缺陷;诊断主要依靠特征性的临床表现及头颅、脊柱的影像学检查;治疗以整形外科手术为主,如无合并严重脏器畸形,一般预后良好;产前胎儿超声对产前诊断有一定帮助。结论Goldenhar综合征是一种涉及全身多个器官系统的先天性畸形,详细的体格检查,并进行影像学检查,避免因诊断不全而延误对患者进行及时的诊治非常重要。     

STK11 Domain XI Mutations: Candidate Genetic Drivers Leading to the Development of Dysplastic Polyps in Peutz–Jeghers Syndrome

Peutz–Jeghers syndrome (PJS) is a rare hereditary disorder resulting from mutations in serine/threonine kinase 11 (STK11) and characterized by gastrointestinal (GI) hamartomatous polyps, mucocutaneous pigmentation, and an increased risk for specific cancers. Little is known about the genetic implications of specific STK11 mutations with regard to their role in dysplastic and malignant transformation of GI polyps. Peripheral blood genomic DNA samples from 116 Chinese PJS patients from 52 unrelated families were investigated for STK11 mutations. Genotype–phenotype correlations were investigated. The mutation detection rate was 67.3% (51.9% point mutations, 15.4% large deletions). Fourteen out of the 25 point mutations identified were novel. Nearly one‐third of all mutations, 8/27 (29.6%), were in exon 7, the shortest out of the nine exons. Strikingly, mutations affecting protein kinase domain XI, encoded in part by exon 7, correlated with a 90% (9/10) incidence of GI polyp dysplasia. In contrast, only two out of 17 (11.8%) nondomain XI mutations were linked to polyp dysplasia (P = 0.0001). The extent of the association between dysplasia and the development of GI‐related cancers is currently unknown but our results highlight a novel STK11 genotype–phenotype association as the basis for future genetic counseling and basic research studies.     

老年亚临床甲状腺功能减退对代谢综合征及颅内动脉粥样硬化的影响

目的 探讨老年人亚临床甲状腺功能减退（SCH）对代谢综合征（MS）、颅内动脉粥样硬化的影响。方法 从2013年1月至2014年4月于我科住院的老年患者中随机选取416例,其中甲状腺功能正常者298例,亚临床甲状腺功能减退者118例,比较两组MS相关指标、尿酸、同型半胱氨酸（Hcy）水平的差异。以颅内动脉粥样硬化、MS分别为应变量做Logistic回归分析,并分析促甲状腺激素（TSH）与各观察指标的相关性。结果 与甲状腺功能正常组比较,亚临床甲状腺功能减退组颅内动脉粥样硬化的比例增多,MS患病比例增加,收缩压、总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDLC）、尿酸、Hcy水平明显升高,高密度脂蛋白胆固醇（HDLC）、空腹血糖（FBG）水平显著减少（P<0.05或P<0.01）。经多元逐步Logistic回归分析发现,高TSH、MS、年龄、收缩压、LDLC、Hcy是颅内大动脉粥样硬化独立的危险因素,TSH、尿酸是MS独立的危险因素,且TSH与TG、尿酸、Hcy呈正相关,与HDLC呈负相关（P均<0.05）。结论 高TSH与MS及颅内动脉粥样硬化的发生发展明显相关,亚临床甲状腺功能减退可能通过改变血脂谱,使血尿酸、血Hcy升高等途径参与MS的发生发展,并进一步增加颅内动脉粥样硬化发生的危险。