Selectivity-Enhanced Electroreduction of CO2 to CO at Novel Ru-Linked-GO Nanohybrids: the Role of Nanoarchitecture.

Recently, global-scale efforts have been conducted for the electroreduction of CO2 as a potentially beneficial pathway for the conversion of greenhouse gases to useful chemicals and renewable fuels. This study focuses on the development of selective and sustainable electrocatalysts for the reduction of aqueous CO2 to CO. A RuIIcomplex [Ru(tptz)(ACN)Cl2] (RCMP) (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine, ACN = acetonitrile) was prepared as a molecular electrocatalyst for the CO2 reduction reaction in an aqueous solution. Density functional theory-calculated frontier molecular orbitals suggested that the tptz ligand plays a key role in dictating the electrocatalytic reactions. The RCMP electrocatalyst was grafted onto the graphene oxide (GO) surface both noncovalently (GO/RCMP) and covalently (GO-RCMP). The field emission scanning electron microscopy and elemental distribution analyses revealed the homogeneous distribution of the complex onto the GO sheet. The photoluminescence spectra confirmed accelerated charge-transfer in both nanohybrids. Compared to the bare complex, the GO-RCMP and GO/RCMP nanohybrids showed enhanced electrocatalytic activity, achieving >95% and 90% Faradaic efficiencies for CO production at more positive onset potentials, respectively. The GO-RCMP nanohybrid demonstrated outstanding electrocatalytic activity with a current of ∼84 µA. The study offers a perspective on outer- and inner-sphere electron-transfer mechanisms for electrochemical energy conversion systems.

Ni-Ti Layered Double Hydroxide@Graphitic Carbon Nitride Nanosheet: A Novel Nanocomposite with High and Ultrafast Sonophotocatalytic Performance for Degradation of Antibiotics.

Pollution of water resources by antibiotics is a growing environmental concern. In this work, nanocomposites of g-C3N4@Ni-Ti layered double hydroxides (g-C3N4@Ni-Ti LDH NCs) with high surface areas were synthesized through an optimized hydrothermal method, in the presence of NH4F. Application of various characterization techniques unraveled that the prepared nanocomposites are composed of porous Ni-Ti LDH nanoparticles and hierarchical g-C3N4 nanosheets. Further, these NCs were employed for photocatalytic and sonophotocatalytic removal of amoxicillin (AMX), as a model antibiotic, from aqueous solutions. In addition, sonocatalysis was performed. It was found out that the g-C3N4@Ni-Ti LDH NCs outperform their pure g-C3N4 and Ni-Ti LDH components in photocatalytic degradation of AMX under visible light irradiation. Also, the following order was determined for efficiency of the three adopted processes: sonocatalysis < photocatalysis < sonophotocatalysis. Furthermore, variation of the sonophotocatalysis conditions specified 500 W light intensity, 9 s on/1 s off ultrasound pulse modem and 1.25 g/L g-C3N4-20@Ni-Ti LDH as the optimal conditions. In this way, optimization of the highly efficient sonophotocatalytic process resulted in 99.5% AMX degradation within 75 min. Moreover, a TOC analyzer was employed to estimate the rate of AMX degradation over the nanocomposites. In addition, formation of hydroxyl radicals (•OH) on the surface of the g-C3N4-20@Ni-Ti LDH particles was approved using the terephthalic acid probe in photoluminescence (PL) spectroscopy. No significant loss was observed in the sonophotocatalytic activity of the nanocomposites even after five consecutive runs. Also, a plausible mechanism was proposed for the sonophotocatalysis reaction. In general, our findings can be considered as a starting point for synthesis of other g-C3N4-based NCs and application of the resultant nanocomposites to environmental remediation.

Amine-Functionalized Al-MOF#@ yxSm2O3-ZnO: A Visible Light-Driven Nanocomposite with Excellent Photocatalytic Activity for the Photo-Degradation of Amoxicillin.

A visible light-driven amine-functionalized Al-based MOF#@ yxSm2O3-ZnO nanocomposite (NH2-MOF#@ yxSm2O3-ZnO NCP) was synthesized as an effective photocatalyst for AMX degradation in the presence of ultrasound, in which # is MOF synthesis conditions from MOFI to MOFXII and x and y stand for the weight percentages of Sm2O3-to-ZnO and Sm2O3-ZnO-to-MOF, respectively. The ß-lactam antibiotic AMX, which is widely used for treating Gram-positive and Gram-negative bacterial infections in both animals and humans, was employed as a model pollutant. Using different detection techniques, the synthesized materials were characterized. Furthermore, effects of different synthesis methods, ultrasonic time, precursor concentration, sonication amplitude, and modulators on the MOFs photocatalytic behavior were taken into account. Also, catalytic dose and recycling, H2O2 usage, and operating pH effects were investigated. Compared to the pure forms of NH2-MOF-53(Al) and Sm2O3-ZnO, the NCPs having the optimal Sm2O3-ZnO and NH2-MOF-53(Al) contents highly influenced the photocatalytic activity due to the synergetic impacts of the high charge mobility and the red shift in the NH2-MOF@Sm2O3-ZnO NCPs absorption edge compared to the Sm2O3-ZnO nanoflowers. We used a TOC analyzer, UV/vis spectroscopy, and HPLC chromatogram to estimate the rate of AMX elimination in water over NH2-MOFXII@307Sm2O3-ZnO NCPs as our optimal sample. In addition, after the AMX pollutant degradation, the NH2-MOF@Sm2O3-ZnO NCPs were structurally stable and maintained the majority of their photocatalytic properties even after five runs of recycling process The NH2-MOFXII@307Sm2O3-ZnO NCPs as the superior photocatalysts were more examined and a mechanism for the AMX degradation was suggested. As a suggestion, our obtained results can be used as a starting point for the preparation of the other heterogeneous MOF-based NCPs combined with the Sm2O3-ZnO for a variety of applications such as the environmental remediation.

Visible-Light-Induced Graphitic-C3N4@Nickel-Aluminum Layered Double Hydroxide Nanocomposites with Enhanced Photocatalytic Activity for Removal of Dyes in Water.

One of the major challenges in photodegradation of organic dyes is designing a visible light active and highly efficient photocatalyst that can degrade both cationic and anionic dyes. To design such an ideal catalyst, this work synthesized graphitic-C3N4@NiAl layered double hydroxide nanocomposites (g-C3N4@NiAl-LDH NCPs) with various g-C3N4 contents through a convenient and high-yield method. The photocatalytic process was optimized by evaluating the impacts of type of dye (cationic and anionic), photocatalyst dosage, pH, and contact time. According to the results, the photocatalytic performance of g-C3N4@NiAl-LDH NCPs in degradation of cationic and anionic dyes is more noticeable than the photocatalytic activities of its discrete components. The observed improvement in the photocatalytic performance of the g-C3N4@NiAl-LDH NCPs can be attributed to the intimacy of their contact interfaces and a synergistic effect between pristine g-C3N4 and NiAl-LDH, which results in effective mass transfer and separation of photogenerated charge carriers. The impact of some charge scavengers on the process was evaluated to define the role of each active species and propose a possible photodegradation mechanism. The g-C3N4@Ni-Al LDH NCPs could be reused for four cycles without any significant loss in efficiency.

Chitosan Immobilization on Bio-MOF Nanostructures: A Biocompatible pH-Responsive Nanocarrier for Doxorubicin Release on MCF-7 Cell Lines of Human Breast Cancer.

In this work, a bio-metal-organic framework (Bio-MOF) coated with a monodispersed layer of chitosan (CS; CS/Bio-MOF) was synthesized and applied as a pH-responsive and target-selective system for delivery of doxorubicin (DOX) in the treatment of breast cancer. The efficiency of the nanocarrier in loading and releasing DOX was assessed at different pH levels. To monitor the in vitro drug release behavior of the drug-loaded carrier, the carrier was immersed in a phosphate buffered saline solution (PBS, pH 7.4) at 37 °C. According to the observations, the nanocarrier presents a slow and continuous release profile as well as a noticeable drug loading capacity. In addition, the carrier demonstrates a pH-responsive and target-selective behavior by releasing a high amount of DOX at pH 6.8, which is indicative of tumor cells and inflamed tissues and releasing a substantially lower amount of DOX at higher pH values. In addition, the results indicated that pH is effective on DOX uptake by CS/Bio-MOF. A 3.6 mg amount of DOX was loaded into 10 mg of CS/Bio-MOF, resulting in a 21.7% removal at pH 7.4 and 93.0% at pH 6.8. The collapsing and swelling of the CS layers coated on the surface of the Bio-MOFs were found to be responsible for the observed pH dependence of DOX delivery. Moreover, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the trypan blue test were performed on the MCF-7 (breast cancer) cell line in the presence of the CS/Bio-MOF carrier to confirm its biological compatibility. In addition, Annexin V staining was conducted to evaluate the cytotoxicity of the free and loaded DOX molecules. On the basis of the obtained optical microscopy, MTT assay, fluorescence microscopy, and dyeing results, the CS/Bio-MOF carrier greatly enhances cellular uptake of the drug by the MCF-7 cells and, therefore, apoptosis of the cells due to its biocompatibility and pH-responsive behavior.

Understanding the impact of conflict on health services in Iraq: information from 401 Iraqi refugee doctors in Jordan.

OBJECTIVES: This study aims to assess how conflict has affected the function of Iraqi health services and its doctors. METHODS: Interviews were conducted in person or by mobile phone with 401 Iraqi doctors entering Jordan since 2003, using respondent-driven sampling methods. RESULTS: Of the Iraqi doctors interviewed in 2008, 94% came from Baghdad, although 25% had moved within Iraq in the past year. They reported a steady year-by-year decline in Iraqi health services from 2003 through 2006, with perhaps some improvement in 2007. By 2006, 67% of doctors said essential drugs were present less than half of the time (95% confidence interval [CI] 54-81), and 69% (95% CI 56-84) said essential equipment was available or working half the time or less. By 2006, 95% said their facilities lacked skilled health workers, and 90% noted reduced quality of care. Violent death rates among doctors in Baghdad reached 47.6/1000/yr (95% CI 42.0-53.7) in 2006. In the same year, migration rates for Baghdad doctors moving elsewhere in Iraq were 143.8/1000/yr (95% CI 134.0-154.1), and departure from Iraq was 299.5/1000/yr (95% CI 285.3-314.3). CONCLUSIONS: Deterioration of health services quality, staffing levels and violence against doctors continued from 2003 through 2006, although these may have improved slightly in 2007. In 2009 and 2010, reports suggest that assassinations of doctors and out-migration have continued. Few have returned.

A single amino acid change within the R2 domain of the VvMYB5b transcription factor modulates affinity for protein partners and target promoters selectivity.

BACKGROUND: Flavonoid pathway is spatially and temporally controlled during plant development and the transcriptional regulation of the structural genes is mostly orchestrated by a ternary protein complex that involves three classes of transcription factors (R2-R3-MYB, bHLH and WDR). In grapevine (Vitis vinifera L.), several MYB transcription factors have been identified but the interactions with their putative bHLH partners to regulate specific branches of the flavonoid pathway are still poorly understood. RESULTS: In this work, we describe the effects of a single amino acid substitution (R69L) located in the R2 domain of VvMYB5b and predicted to affect the formation of a salt bridge within the protein. The activity of the mutated protein (name VvMYB5b(L), the native protein being referred as VvMYB5b(R)) was assessed in different in vivo systems: yeast, grape cell suspensions, and tobacco. In the first two systems, VvMYB5b(L) exhibited a modified trans-activation capability. Moreover, using yeast two-hybrid assay, we demonstrated that modification of VvMYB5b transcriptional properties impaired its ability to correctly interact with VvMYC1, a grape bHLH protein. These results were further substantiated by overexpression of VvMYB5b(R) and VvMYB5b(L) genes in tobacco. Flowers from 35S::VvMYB5b(L) transgenic plants showed a distinct phenotype in comparison with 35S::VvMYB5b(R) and the control plants. Finally, significant differences in transcript abundance of flavonoid metabolism genes were observed along with variations in pigments accumulation. CONCLUSIONS: Taken together, our findings indicate that VvMYB5b(L) is still able to bind DNA but the structural consequences linked to the mutation affect the capacity of the protein to activate the transcription of some flavonoid genes by modifying the interaction with its co-partner(s). In addition, this study underlines the importance of an internal salt bridge for protein conformation and thus for the establishment of protein-protein interactions between MYB and bHLH transcription factors. Mechanisms underlying these interactions are discussed and a model is proposed to explain the transcriptional activity of VvMYB5(L) observed in the tobacco model.

Sub-level engineering strategy of nitrogen-induced Bi2O3/g-C3N4: a versatile photocatalyst for oxidation and reduction.

Herein, the α-Bi2O3 nanocrystal decorated by nitrogen dopant and its heterojunction nanocomposite with g-C3N4 (N0.1/Bi2O3/g-C3N4) is successfully fabricated for the first time, for photo-oxidation of RhB and photo-reduction of Cr(VI) to Cr(III). The resulting N0.1/Bi2O3/g-C3N4 (3%) nanocomposite showed an optimal Cr(VI) photo-reduction and RhB photo-oxidation rates under visible-light irradiation, being 3-4 times higher than that of pure α-Bi2O3. The results from XPS confirmed the substitution of nitrogen with various oxidation states from N3+ to Nx+ (x < 5), due to the existence of different nitrogen oxides including N-O, O-N=O, and NO3- in the crystal structure. We investigated the reaction mechanism using catalytic tests, impedance spectroscopy, EPR technique, and density functional calculations. The DFT calculations presented the appearance of a new mid-gap hybrid of p states, comprised of N 2p, O 2p, and Bi 6P states, which enhance light absorption capacity and narrow band gap. The theoretical results were in excellent agreement with experimental UV-Vis data. The N0.1/Bi2O3/g-C3N4 nanocomposite exhibited acceptable practical application value and recycling ability for removal of the contaminants. Such improved photocatalytic activity is originated from the modified band positions, new electron evolution pathway, introducing defects in α-Bi2O3 by insertion of N atoms into the Bi sites, and the enhanced charge carrier mobility between N0.1/Bi2O3 and g-C3N4. The strategy to form nitrogen-doped bismuth-based nanocomposites may open a new opportunity to design atomic-level electronic defects by feasible methods to obtain a versatile photocatalyst material with simultaneous photo-reduction and photo-oxidation ability for removal of Cr(VI) and organic dyes from water.

Structural, optical and photocatalytic properties of sol-gel synthesized mesoporous TiO2 film.

TiO2 surfactant-templated nanostructured film was fabricated by supramolecular templating technique using TiCl4 and P-123 as raw material and surfactant, respectively. The film was produced by sol-gel dip coating procedure. Characterization of the product was carried out by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface areas, thermogravimetry (TG), and UV-vis absorption spectroscopy. Detailed characterization reveals that film is transparent and has a wormlike mesostructured with high surface area. It is about 2 microm thick and is composed of closely packed anatase particles. The estimated band gap value of TiO2 thin film in the present work is 3.69 eV which is about 0.3 eV larger than value reported in literature for anatase thin film. It could be due to quantum size effect arising from the small size of TiO2 nanocrystallite in this thin film. The photocatalytic activity of the prepared TiO2 film was evaluated by Crystalviolet dye degradation. The film has excellent photocatalytic efficiencies and more than 70% of dye was decolorized in 60 minutes.

Fabrication and highly sensitive gas sensors based on h-MoO3/SnO2 hollow nanostructures operated at low temperatures.

Simulated by the synthesis of one dimensional hollow nanostructures with significant sensing, electrical, and optical properties, we have successfully synthesized 1D hollow nanostructures of h-MoO3/SnO2 with well-defined multi-side walls. These hollow nanostructured materials synthesized via a hydrothermal method with SnCl2.2H2O as the precursor and h-MoO3 as the template. SnO2 nanoparticles grew on the surface of h-MoO3 with preferential direction [001]. The morphological change was observed with variation of the growth conditions, such as HNO3, and h-MoO3 concentration. 1D hollow nanostructures of h-MoO3/SnO2 were studied and their growth mechanism was discussed. The result revealed that the existence of h-MoO3 caused to increase the sensor response to ethanol gas and downshift the sensor operating temperature at low temperatures.

Rapid synthesis of flower-like ZnO nanostructures.

Flower-like ZnO nanostructures were prepared via microwave assisted heating in the presence and absence of ionic liquid (IL). X-ray diffraction analysis (XRD), Scanning electron microscopy SEM and room temperature photoluminescence (PL) spectra have been employed for characterization of the products. The SEM image illustrates the surface of flower-like ZnO prepared in the presence of IL is not smooth and consists of nanoparticles with grain size of about 48 nm. PL spectra of flower-like ZnO in absence and presence IL reveal similar photoluminescence features: a strong UV, weak blue and green-yellow emissions peak at a bout 393 nm, 448 nm and 583 nm respectively. The strong UV photoluminescence and the weak green emission indicate the good crystallization quality of the flower-like nanostructure. The results show that imidazolium-based IL can be used as template for achieving very high level control over the size and shape of nanostructures. The approach developed in this work can potentially be used as a viable method for making various other uniform nanostructures in the presence of IL. This method is simple, fast, low-cost and suitable for large-scale production of ZnO nanostructures.

Highly sensitive tin oxide hollow microspheres and nanosheets to ethanol gas prepared by hydrothermal method.

In this study, we synthesized tetragonal-phase SnO2 with a variety of well-crystallized morphologies as solid microspheres, hollow microspheres and mixture of hollow microspheres and nanosheets via the hydrothermal method. The synthesized samples were characterized with XRD, SEM, and BET. SnO2 hollow microsphere structures have been hydrothermally synthesized by using urea and SnCl2 as raw materials. With the addition of cetyltrimethylammonium bromide (CTAB), nanostructures with morphologies of hollow microspheres and nanosheets were obtained. Also, when CTAB was added in the reaction solution without urea, SnO2 microsphere with a solid interior composed of nanoparticles were obtained. A possible formation mechanism of these samples was briefly discussed. The gas sensing properties of sensors based on these samples were investigated. The result revealed that sample with morphology of hollow microsphere and nanosheet calcined at 600 degrees C showed the highest sensitivity to ethanol due to the special morphology and absence of SnO phase.

Novel Biocompatible Amino Acids-Functionalized Three-dimensional Graphene Foams: As the Attractive and Promising Cisplatin Carriers for Sustained Release Goals.

Application of amino acids-immobilized porous materials for drug delivery studies has been attracted a lot of attention in the recent years. In this study, amino acids-grafted graphene foams were prepared by anchoring of Alanine (Ala), Cysteine (Cys) and Glycine (Gly) amino acids on the surface of graphene oxide (GO) nanostructures and used as the novel biocompatible carriers to control releasing of the cisplatin as the cytotoxic anticancer drug. The characterization of prepared compounds was done by the FT-IR, Raman, TGA, N2 adsorption-desorption isotherms, SEM, and TEM techniques. Adsorption and in vitro release behavior of amino acids-functionalized foams were studied using ICP standard method. The results show that the drug loading amount and the drug releasing rate are significantly enhanced upon functionalization process. The Ala-Foam sample with the larger surface area and pore volume showed a higher loading content (4.53%) than other samples. In addition, the MTT test on the two MCF-7 and HepG2 human cancer cell lines exhibited an acceptable biocompatibility and sustainable drug releasing from the carriers up to 48 h, leading to the dosage frequency decrease and the patient compliance improvement.

A new Ru(ii) polypyridyl complex as an efficient photosensitizer for enhancing the visible-light-driven photocatalytic activity of a TiO2/reduced graphene oxide nanocomposite for the degradation of atrazine: DFT and mechanism insights.

TiO2 is one of the most widely used semiconductors for photocatalytic reactions. However, its wide bandgap energy and fast charge recombination limit its catalytic activity. Thus, herein, a new Ru(ii) polypyridyl complex, [Ruii(tptz)(CH3CN)Cl2] (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine), was synthesized and used as a visible-light photosensitizer dye for improving the light harvesting and quantum efficiency of TiO2. Accordingly, a well-designed nanostructured photocatalyst was proposed using mesoporous TiO2 nanocrystals coupled with reduced graphene oxide (rGO) and the polypyridyl Ru(ii) complex, which was tested for the photocatalytic degradation of atrazine (ATZ) as a model of emerging water contaminants. Specifically, the Ru complex (Ru-CMP) served as an electron donor, while rGO acted as an electron acceptor, and the synergistic effect between them promoted the separation of electron-hole pairs and suppressed the charge recombination in the hybridized species. Structural analysis indicated that the TiO2 nanoparticles with an anatase crystal structure had a mesoporous texture and were homogeneously coated on the rGO sheets. The detailed FT-IR, Raman, XPS and UV-vis absorption spectroscopic analyses combined with EDS mapping clearly confirmed the successful loading of the Ru complex onto the catalyst. The PL and EIS results revealed that the addition of the Ru-CMP photosensitizer enhanced the charge separation and transport. The gas-phase geometry and energies of the molecular orbitals of the Ru complex were evaluated via DFT calculations. The results from the DFT calculations were consistent with the experimental results. Compared to pure TiO2, the as-synthesized Ru-CMP-TiO2/rGO hybrid exhibited significantly enhanced photocatalytic activity for the degradation of ATZ. The rate of ATZ degradation in the developed photocatalytic process with the Ru-CMP-TiO2/rGO hybrid was 9 times that with commercial TiO2. The enhanced photocatalytic activity of the prepared catalyst can be attributed to its better light harvesting and efficient electron transportation due to its more suitable LUMO position than the conduction band of TiO2. Moreover, the excellent conductivity and adsorption capacity of graphene contributed to the increase in photocatalytic activity. Thus, these features make the Ru-CMP-TiO2/rGO hybrid nanomaterial an excellent candidate for the photocatalytic purification of contaminated water.

2,2'-Diamino-5,5'-dimethyl-4,4'-bi-1,3-thia-zolium tetra-chlorido-zincate(II).

In the dianion of the title compound, (C(8)H(12)N(4)S(2))[ZnCl(4)], the Zn(II) ion is in a slightly distorted tetra-hedral environment. In the cation, the mean planes of the thia-zole rings form a dihedral angle of 67.81 (6) Å. In the crystal structure, anions and cations are linked into a three-dimensional network via inter-molecular N-H⋯Cl hydrogen bonds.

Preparation of amine functionalized g-C3N4@H/SMOF NCs with visible light photocatalytic characteristic for 4-nitrophenol degradation from aqueous solution.

At ambience temperature, a facile and large-scale sonochemical synthesis route was used to synthesize graphitic carbon nitride@[Ti4C24H39N3O29] metal-organic framework nanocomposites (g-C3N4-X@YTi-MIL125-NH2 NCs, where X and Y stood for the weight percentages of g - C3N4 and the synthesis method of Ti-MIL125-NH2, respectively) having 2-Amino-1,4-benzenedicarboxylic acid (2-ATA) ligand with amine functional free groups. The obtained NCs were characterized by FT-IR, PXRD, FE-SEM, BET, UV-DRS, PL, EIS, and zeta potential. Moreover, g-C3N4-X@YTi-MIL125-NH2 capability to eliminate 4-nitrophenol (4-NP) contaminant from water via visible light illumination was explored. Our synthesized NCs under a facile, green ultrasonic technique (i.e. g-C3N4-30@STi-MIL125-NH2) had a higher percentage of degradation than those from hydrothermal technique (i.e. g-C3N4-30@HTi-MIL125-NH2) with degradation percentages of 75% and 57%, respectively, which resulted in effective mass transfer and separation of photo - generated charge carriers. Additionally, this higher percentage of degradation could be attributed to the larger surface area and unique morphology of the ultrasonically synthesized particles with higher homogeneity and better and non-agglomerated distribution. Furthermore, excellent reusability and stability were observed for g-C3N4-30@STi-MIL125-NH2. We also explored the role of some scavengers in the degradation procedures to investigate the effect of active species. The experimental results were used to describe the suggested mechanism capability for improved photocatalysis.

Synthesis of a nanostructured pillar MOF with high adsorption capacity towards antibiotics pollutants from aqueous solution.

In this study, various sonochemical conditions were applied to prepare the microsheets, nanosheets and nanoflowers of a metal-organic framework (MOF; [Zn6(IDC)4(OH)2(Hprz)2]n) that is composed of Zn(II) cations coordinated with the linear N-donor piperazine (prz) and rigid planar imidazole-4,5-dicarboxylate (H3IDC) ligands. The PXRD patterns approved purity of the samples and the FT-IR spectra related the detected bonds and functional groups to [Zn6(IDC)4(OH)2(Hprz)2]n crystals. The morphological results indicated that any changes in the synthesis conditions can affect nucleation and morphology of the nanostructures. The prepared MOF nanosheets and nanoflowers (with particle size average of 95 and 116 nm, respectively) were employed to adsorb the ampicillin, amoxicillin and cloxacillin antibiotics. Then, the MOFs were calcined at 550 ℃ and atmospheric pressure to produce ZnO nanoparticles and the resultant nanoparticles were adopted to photodegrade the antibiotics. These nanoparticles can photodegrade 37% of the amoxicillin compounds within 180 min. Among the examined samples, the nanoflowers demonstrated the highest adsorption capacity by eliminating 92.5%, 88% and 89% of the antibiotic molecules from the 60-ppm amoxicillin, ampicillin and cloxacillin solutions, respectively. Also, these nanoflowers are thermally stable up to 365 ℃. The associated adsorption process was found to follow pseudo-first-order kinetics, in the case of amoxicillin.

Amino Acid-functionalized hollow mesoporous silica nanospheres as efficient biocompatible drug carriers for anticancer applications.

Herein, a series of new amino acid-functionalized hollow mesoporous silica nanospheres (HMSNs) by post-grafting methods were prepared. These new materials were characterized by different techniques and were studied as matrices for the antineoplastic drug (cisplatin) transport and delivery. The results demonstrate that the surface functionalization of the carriers has a remarkable positive influence on the loading efficiency and release rate of cisplatin. The highest drug entrapment efficiency and the most optimal release properties were observed when the (2-(butylamino) ethyl) glycine groups are grafted on the HMSNs surface (AFS-2-HMSNs sample). Moreover, the in vitro cytotoxic effect of both empty and cisplatin-loaded AFS-2-HMSNs sample (CDDP@AFS-2-HMSNs) on MCF-7 cells (human breast adenocarcinoma cell line) and HepG2 cells (human liver carcinoma cell line) were evaluated by MTT assay. The most important outcome is that the empty carrier revealed no cytotoxicity to cancer cells. However, CDDP@AFS-2-HMSNs caused a notable inhibition of cell viability which was affected from the dose and time. Our results demonstrate that the synthesized materials could be used as carriers for drug delivery with controlled release applications.

Ultrasound-assisted synthesis of Zinc(II)-based metal organic framework nanoparticles in the presence of modulator for adsorption enhancement of 2,4-dichlorophenol and amoxicillin.

In this study, under a sonochemical method, a 3D, porous Zn(II)-based metal-organic framework [Zn(TDC)(4-BPMH)]n·n(H2O) is produced, which is called compound 1. To this end, the dicarboxylate linker of TDC, (2,5-thiophene dicarboxylic acid) and the pillar spacer of 4-BPMH, (N,N-bis-pyridin-4-ylmethylene-hydrazine) were employed. Moreover, variations in the morphology and growth of the micro/nanoparticles of compound 1 were investigated in terms of the effect of temperature, ultrasound irradiation power, sonication time, initial reagent concentrations, and pyridine concentration as a modulator. DFT model was used to examine the sonication effect on the distribution of the pore sizes. Moreover, the preparation method effect on the porosity and removal of two sample pollutants (i.e., 2,4-dichlorophenol (24-DCP) and amoxicillin (AMX)) from wastewater was studied.

Sonochemical synthesis of amide-functionalized metal-organic framework/graphene oxide nanocomposite for the adsorption of methylene blue from aqueous solution.

Graphene oxide-[Zn2(oba)2(bpfb)]·(DMF)5 metal-organic framework nanocomposite (GO-TMU-23; H2oba=4,4'-oxybisbenzoic acid, bpfb=N,N'-bis-(4-pyridylformamide)-1,4-benzenediamine, DMF=N,N-dimethylformamide) is prepared through a simple and large-scale sonochemical preparation method at room temperature. The obtained nanocomposite is characterized by Field Emission Scanning Electron Microscopy (FE-SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. Additionally, the absorption ability of GO-TMU-23 nanocomposite toward cationic dye methylene blue was also performed. Significantly, GO-TMU-23 nanocomposite exhibits remarkably accelerated adsorption kinetics for methylene blue in comparison with the parent materials. The adsorption process shows that 90% of the dye has been removed and the equilibrium status has been reached in 2min by using the nanocomposites as the adsorbent.