Aptasensor based on high surface area covalent organic framework for simple and ultrasensitive detection of sarcosine in the diagnosis of prostate cancer.

In this study, an electrochemical aptasensor was developed for the specific detection of sarcosine using a covalent organic framework (COF). The imine-based two-dimensional COF was synthesized through a solvothermal process using terephthaldehyde and melamine. This resulted in the formation of a structure that is highly porous and has a unique surface area of 908 m2/g. The produced biosensor demonstrated a significant linear relationship between charge transfer resistance (Rct) and various concentrations of sarcosine in blood serum samples. The aptasensor had two linear ranges, spanning from 0.5 fM to 700 fM and 10 pM to 0.12 nM, respectively, with a detection limit of 0.15 fM. The incorporation of high surface area COFs in the aptasensor design offers a promising combination of sensitivity, stability, and specificity. This combination creates a valuable device for diagnosing and monitoring of prostate cancer and potentially other diseases.

Simultaneous electrochemical sensing of heavy metal ions (Zn2+, Cd2+, Pb2+, and Hg2+) in food samples using a covalent organic framework/carbon black modified glassy carbon electrode.

In this study, for the first time, a selective electrochemical sensor by glassy carbon electrode (GCE) modified with the covalent organic framework (COF) and carbon black (CB) was introduced and applied to simultaneous sensing of Zn2+, Cd2+, Pb2+, and Hg2+ via differential pulse anodic stripping voltammetry (DPASV). The COF is supplied through a condensation reaction between melamine and trimesic acid. The COF and CB, which are used to modify the GCE surface, increase electrochemical activity. The linearity to determine ions was achieved as Zn2+: 0.009-1100 nM, Cd2+: 0.005-1100 nM, Pb2+: 0.003-1100 nM, and Hg2+: 0.001-1100 nM. Besides, the detection limits for Zn2+, Cd2+, Pb2+, and Hg2+ have obtained 0.003, 0.002, 0.001 and 0.0003 nM, respectively. The CB-COF/GCE was applied to simultaneously measure the ions in food samples. For validation, atomic absorption spectrometry (AAS) was applied to measure the amount of target metal ions as a standard method in real samples.

Modeling stabilizing the of orchard managers on the shores of Lake Urmia against late spring frost.

Despite the adverse effects of late spring frost on the ecological and economic impact on agriculture, the management of these events are poorly investigated. Therefore, the grounded theory was used for extracting the livelihood stabilization model of orchardists on the shores of Lake Urmia against late spring frosts. The statistical population of this study in the qualitative part included 22 experts in the field of horticulture. In the quantitative study, they included all orchardists in the villages along with Lake Urmia, comprising 341 people, of which 236 were randomly selected. By carefully examining and linking the concepts and subcategories, the most important subcategories that were included six subcategories. The results of all calculated goodness-of-fit indexes (chi-square [P > 0.01], RMSEA = 0.000, NFI = 0.95, CFI = 0.91, and GFI = 0.92) showed the model provided an excellent fit for the data. Standardized regression coefficients showed that interfering factors had the greatest impact on the livelihood of orchardists against late spring frosts (ß = 0.47). Also, the background factors (ß = 0.43) and causal factors (ß = 0.39) were found to affect the livelihood of the orchardists in encountering late spring frost. The results of multiple square correlations of dependent variables also indicated that about 41% of the livelihood variance of small-scale orchardists was explained by the predictor variables (i.e. causal conditions, background factors and interfering factors). The findings of this study can assist policymakers, planners and relevant managers while paying more attention to orchardists in the region, so as to support decisions in order to achieve sustainable development.

Pt@Metal-Organic Framework (ZIF-8) Thin Films Obtained at a Liquid/Liquid Interface as Anode Electrocatalysts for Methanol Fuel Cells: Different Approaches in the Synthesis.

Smart membranes, nanodevices, chemical sensors, and catalytic coatings are some of the applications that make the metal-organic framework (MOF) thin films very important. Encapsulation of nanoparticles in the porous structure of MOFs can lead to the formation of effective catalysts with new unique properties and wide range of applications that may not be obtained by MOFs individually. Three main strategies, ship-in-a-bottle, bottle-around-the-ship, and in situ synthesis including the simultaneous formation of the two components, were applied for the synthesis of Pt(0)@zeolitic imidazolate framework-8 (ZIF-8) thin films at the toluene/water interface. The effects of platinum precursor transfer directions toward the interface on the properties of the films were investigated by using the [PtCl2(cod)] (where cod = cis,cis-1,5-cyclooctadiene) complex soluble in toluene as the upper phase and K2PtCl4 soluble in water as the lower phase. The six obtained films with different morphologies were applied as electrocatalysts for the methanol oxidation reaction. Considerable current density, mass activity, catalyst stability, activation energy, exchange current density, maximum power, and long-term poisoning rate are some of the advantages of the Pt(0)@ZIF-8 catalysts synthesized using the in situ strategy and K2PtCl4 as the platinum precursor. Furthermore, we report the formation of Pt@ZIF-8 nanorods at the interfaces without using any stabilizer or template. Our results suggest that the in situ strategy at the liquid/liquid interface is one of the best procedures for the synthesis of Pt(0)@ZIF-8 thin films as a suitable anode electrocatalyst for methanol fuel cells.

Tetranuclear rollover cyclometalated organoplatinum-rhenium compounds; C-I oxidative addition and C-C reductive elimination using a rollover cycloplatinated dimer.

The novel tetranuclear Pt(IV)-Re(VII) complex [Pt2Me4(OReO3)2(PMePh2)2(µ-bpy-2H)], 4, is synthesized through the reaction of silver perrhenate with a new rollover cycloplatinated(IV) complex [Pt2Me4I2(PMePh2)2(µ-bpy-2H)], 3. In complex 4, while 2,2'-bipyridine (bpy) acts as a linker between two Pt metal centers, oxygen acts as a mono-bridging atom between Pt and Re centers through an unsupported Pt(IV)-O-Re(VII) bridge. The precursor rollover cycloplatinated(IV) complex 3 is prepared by the MeI oxidative addition reaction of the rollover cycloplatinated(II) complex [Pt2Me2(PMePh2)2(µ-bpy-2H)], 2. Complex 2 shows a metal-to-ligand charge-transfer band in the visible region, which was used to investigate the kinetics and mechanism of its double MeI oxidative addition reaction. Based on the experimental findings, the classical SN2 mechanism was suggested for both steps and supported by computational studies. All complexes are fully characterized using multinuclear NMR spectroscopy and elemental analysis. Attempts to grow crystals of the rollover cycloplatinated(IV) dimer 3 yielded a new dimer rollover cyclometalated complex [Pt2I2(PMePh2)2(µ-bpy-2H)], 5, presumably from the C-C reductive elimination of ethane. The identity of complex 5 was confirmed by single crystal X-ray diffraction analysis.

Edge effects on the intrinsic magnetism in ferromagnetic triangular phosphorene quantum dots using fully spin-polarized calculations.

This project involves discovering the electronic and magnetic properties of nanometer-sized phosphorene structures with triangular shapes in both zigzag and armchair termination types. The goal is to discuss the relationship between the electronic states belonging to the different conditions of these phosphorene quantum dots and their intrinsic magnetic properties. For this purpose, we consider electronic interactions utilizing the spin-polarized density functional theory calculations, and then the results compare with the data generated from tight-binding calculations. Both descriptions yield mid-gap states in the spectrum of ferromagnetic structures. Our results in non-spin computations without any geometry optimization were matched by tight-binding calculations which shows that the tight-binding method is an inefficient approximation in analyzing the optimized spin samples. Unlike graphene, in our spin-polarized calculations, we have obtained empty mid-gap states in the spectrum of ferromagnetic triangular phosphorene quantum dots. The edge atoms of these structures are known as the magnetic atoms with an unequal contribution of spin up and spin down. To prevent deforming the initial structures, the dangling bonds at the edge atoms were passivated in two types, fully hydrogenated and partial passivation with oxygen atoms. Oxygen doping was required for introducing magnetism to the non-spin edges of the fully hydrogenated case.

Ligand-Controlled Csp2-H versus Csp3-H Bond Formation in Cycloplatinated Complexes: A Joint Experimental and Theoretical Mechanistic Investigation.

The cyclometalated platinum(II) complexes [PtMe(C∧N)(L)] [1PS: C∧N = 2-phenylpyridinate (ppy), L = SMe2; 1BS: C∧N = benzo[h]quinolate (bhq), L = SMe2; 1PP: C∧N = ppy, L = PPh3; and 1BP: C∧N = bhq, L = PPh3] containing two different cyclometalated ligands and two different ancillary ligands have been investigated in the reaction with CX3CO2H (X = F or H). When L = SMe2, the Pt-Me bond rather than the Pt-C bond of the cycloplatinated complex is cleaved to give the complexes [Pt(C∧N)(CX3CO2)(SMe2)]. When L = PPh3, the selectivity of the reaction is reversed. In the reaction of [PtMe(C∧N)(PPh3)] with CF3CO2H, the Pt-C∧N bond is cleaved rather than the Pt-Me bond. The latter reaction gave [PtMe(κ1N-Hppy)(PPh3)(CF3CO2)] as an equilibrium mixture of two isomers. For L = PPh3, no reaction was observed with CH3CO2H. The reasons for this difference in selectivity for complexes 1 are computationally discussed based on the energy barrier needed for the protonolysis of the Pt-Csp3 bond versus the Pt-Csp2 bond. Two pathways including the direct one-step acid attack at the Pt-C bond (SE2) and stepwise oxidative-addition on the Pt(II) center followed by reductive elimination [SE(ox)] are proposed. A detailed density functional theory (DFT) study of these protonations along with experimental UV-vis kinetics suggests that a one-step electrophilic attack (SE2) at the Pt-C bond is the most likely mechanism for complexes 1, and changing the nature of the ancillary ligand can influence the selectivity in the Pt-C bond cleavage. The effect of the nature of the acid and cyclometalated ligand (C∧N) is also discussed.

Ligand-Mediated C-Br Oxidative Addition to Cycloplatinated(II) Complexes and Benzyl-Me C-C Bond Reductive Elimination from a Cycloplatinated(IV) Complex.

Reaction of the Pt(II) complexes [PtMe2(pbt)], 1a, (pbt = 2-(2-pyridyl)benzothiazole) and [PtMe(C^N)(PPh2Me)] [C^N = deprotonated 2-phenylpyridine (ppy), 1b, or deprotonated benzo[h]quinoline (bhq), 1c] with benzyl bromide, PhCH2Br, is studied. The reaction of 1a with PhCH2Br gave the Pt(IV) product complex [PtBr(CH2Ph)Me2(pbt)]. The major trans isomer is formed in a trans oxidative addition (2a), while the minor cis products (2a' and 2a″) resulted from an isomerization process. A solution of Pt(II) complex 1a in the presence of benzyl bromide in toluene at 70 °C after 7 days gradually gave the dibromo Pt(IV) complex [Pt(Br)2Me2(pbt)], 4a, as determined by NMR spectroscopy and single-crystal XRD. The reaction of complexes 1b and 1c with PhCH2Br gave the Pt(IV) complexes [PtMeBr(CH2Ph)(C^N)(PPh2Me)] (C^N = ppy; 2b; C^N = bhq, 2c), in which the phosphine and benzyl ligands are trans. Multinuclear NMR spectroscopy ruled out other isomers. Attempts to grow crystals of the cycloplatinated(IV) complex 2b yielded a previously reported Pt(II) complex [PtBr(ppy)(PPh2Me)], 3b, presumably from reductive elimination of ethylbenzene. UV-vis spectroscopy was used to study the kinetics of reaction of Pt(II) complexes 1a-1c with benzyl bromide. The data are consistent with a second-order SN2 mechanism and the first order in both the Pt complex and PhCH2Br. The rate of reaction decreases along the series 1a ≫ 1c > 1b. Density functional theory calculations were carried out to support experimental findings and understand the formation of isomers.

PtSn Nanoalloy Thin Films as Anode Catalysts in Methanol Fuel Cells.

Reactions of SnX2 (X = Cl, Br) with [PtMe2(bipy)], 1, (bipy = 2,2'-bipyridine), followed by NaBH4 reduction at the toluene/water interface in the presence or absence of graphene oxide support rendered PtSn nanoalloy thin films. They were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The electrocatalytical activity of the PtSn thin films was investigated in the methanol oxidation reaction. Our studies showed that the PtSn/reduced-graphene oxide (RGO) thin film gave better catalytic results for MOR in comparison to bare PtSn or Pt thin films. A maximum jf/jb ratio (jf and jb are the maximum current densities in the forward and backward scans, respectively) of 6.77 was obtained for the PtSn/RGO thin film deriving from the 1 + SnBr2 + NaBH4 sequence.

Effects in rats of adolescent exposure to Cannabis sativa on emotional behavior and adipose tissue.

OBJECTIVE: Cannabis sativa L has remained the most widely used recreational and abused drug worldwide. This study determined adipose tissue histological changes and the anxiety-like behavior in elevated plus-maze tests in rats treated with C. sativa. METHODS: C. sativa L. was provided from Islamic Azad University Herbarium. To reach cannabis powder, a rotary evaporator was used. Forty-five male Wistar rats were randomly divided into three equal groups of experimental receiving 2 mg/kg of cannabis extract dissolved in 70 % ethanol in 0.6 mL volume subcutaneously daily for three weeks, the sham group subcutaneously injected with equal volume of 70 % ethanol and the control receiving just distilled water, identically. To assess the anxiety level, elevated plus maze was used. Histopathological changes in adipose tissue was evaluated after 7, 14, and 21 days post-intervention. RESULTS: After cannabis administration, inflammation, degeneration and necrosis in adipose tissue occured. Regarding the anxiety level for the percentage of time spent in open arm (OAT), the percentage of time spent in closed arm (CAT), the percentage of time spent in central parts, and head dipping over the side of the maze) after one week, no significant difference was noticed between the groups; but 2 and 3 weeks of cannabis use, the anxiety level significantly increased. CONCLUSION: Histological findings denoted to inflammation, degeneration and necrosis in adipose tissue after cannabis use. Behavioral assessment of anxiety level revealed that one week after cannabis, no changes were seen in anxiety, but 2 and 3 weeks after cannabis use, the anxiety level increased significantly (Fig. 5, Ref. 38).

The development of an electrochemical nanoaptasensor to sensing chloramphenicol using a nanocomposite consisting of graphene oxide functionalized with (3-Aminopropyl) triethoxysilane and silver nanoparticles.

In the present research, a nanoaptasensor is proposed for electrochemical measurement of chloramphenicol (CAP). To this purpose, the nanocomposite prepared from graphene oxide and functionalized with (3-Aminopropyl) triethoxysilane/silver nanoparticles to the abbreviated AgNPs/[NH2-Si]-f-GO, was utilized to modify the glassy carbon electrode (GCE). Furthermore, the modified electrode was also investigated using the electrochemical methods such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The AgNPs/[NH2-Si]-f-GO nanocomposite was investigated by UV-Vis spectrophotometry. Fourier transform infrared (FT-IR) spectrometry and transmission electron microscopy (TEM). Moreover, [Fe(CN)6]3-/4 solution in the role of an electrochemical probe was applied. The AgNPs/[NH2-Si]-f-GO nanocomposite was confirmed as a good layer to covalent immobilization of aptamer (Apt) onto the GCE surface. In this sense, the DPV was used as a sensitive electrochemical technique for the measurement of CAP with an appropriate linear concentration range which was found to be between 10 pM and 0.2 µM and, with a low limit of detection, it equaled 3.3 pM. CAP which was identified in the presence of other usual antibiotics existed in the real samples.

Chelating and Bridging Roles of 2-(2-Pyridyl)benzimidazole and Bis(diphenylphosphino)acetylene in Stabilizing a Cyclic Tetranuclear Platinum(II) Complex.

The reaction of complex [Pt(Me)(DMSO)(pbz)], 1, (pbz = 2-(2-pyridyl)benzimidazolate) with [PtMe(Cl)(DMSO)2], B, followed by addition of bis(diphenylphosphino)acetylene (dppac), gave the novel tetranuclear platinum complex [Pt4Me4(µ-dppac)2(pbz)2Cl2], 2, bearing both the pbz and dppac ligands. In this structure, the pbz ligands are both chelating and bridging to stabilize the tetraplatinum framework. The tetranuclear Pt(II) complex was fully characterized by NMR spectroscopy, X-ray crystallography, and mass spectrometry, and its electronic structure was investigated and supported by DFT calculations.

Impedimetric ultrasensitive detection of chloramphenicol based on aptamer MIP using a glassy carbon electrode modified by 3-ampy-RGO and silver nanoparticle.

In this research work, a biosensor with a dual recognition system was fabricated and founded on a combination of aptasensing and the molecular imprinting union of the chloramphenicol (CAP) selective detection. CAP, is an antibiotic, was applied in veterinary and human in order to treat gram-positive and gram-negative infections. It is worth mentioning that CAP residue brings about earnest side effects on human health. According to this, in this sensing system, 3-aminomethyl pyridine functionalized graphene oxide (GO) (3-ampy-RGO) has been coated on the surface of GCE. Afterwards, the silver nanoparticle (AgNPs) was coated on the 3-ampy-RGO/GCE and, then, the CAP complex-amino-aptamer (NH2-Apt[CAP]) was attached to the AgNP/3-ampy-RGO/GCE using a kind of bonding formation of Ag-N. In this sense, it is worth noting that the resorcinol electropolymerization around the complex of aptamer/CAP would confine the complex and, then, retain the aptamer. Following the CAP removal, the MIP cavity, as it was supposed, synergistically acted with that of the embedded aptamer in order to construct a nanohybrid receptor. Interestingly, the double exact property of the molecular imprinting polymers and aptamers led to the superb sensing properties. In the mentioned system it was illustrated that the linear range was from 1.0 pM to 1.0 nM with the detection limit of 0.3 pM; consequently, as observed, it was better than or as good as other similar assays. Moreover, the mentioned system whose activity was observed in the various interferences presence showed great selectivity in detected the CAP. Finally, the designed sensor exhibited outstanding results when applied to detect CAP in milk samples.

Effects of the number of cyclometalated rings and ancillary ligands on the rate of MeI oxidative addition to platinum(ii)-pincer complexes.

Organoplatinum(ii)-pincer complexes [Pt(C^N^C)(L)] (2a; L = PPh2Me, 2b; L = pyridine (py), 2c; L = 4-picoline (pic)) are synthesized by the reaction of [Pt(C^N^C)(DMSO)], 1, with 1 equiv. of L, where HC^N^CH = 2,6-diphenylpyridine. Complexes 2 have 5d(Pt) →π*(pincer) metal-to-ligand charge-transfer bands in the visible region, which were used to easily follow the kinetics of their reactions with MeI by using UV-vis spectroscopy. An SN2 mechanism is suggested and the proposed intermediates were supported by DFT calculations. Consistent with the proposed mechanism, the rates of the reactions at different temperatures were slower for L = PPh2Me than those for L = N-donor ligands and large negative ΔS‡ values were found for all oxidative addition reactions. The rates are almost 2 times slower for L = PPh2Me as compared to L = 4-picoline because of the steric effects and the electronic effects transmitted through the ligands. To investigate the effect of the number of cyclometalated rings on the rate of MeI oxidative addition, the kinetics of the reaction of [Pt(Ph)(ppy)(py)] (Hppy = 2-phenylpyridine) and [Pt(Ph)2(py)2] (having 1 and zero cyclometalated ring, respectively) with MeI were also studied and a correlation between the number of cyclometalated rings and the rate of the oxidative addition reaction was found.

A Bridging Peroxide Complex of Platinum(IV).

The photolysis of the allylplatinum(IV) complex [PtBr(C3H5)(4-MeC6H4)2(bipy)], 1, bipy = 2,2'-bipyridine, in air yielded [{PtBr(4-MeC6H4)2(bipy)}2(µ-O2)], 2, the first diplatinum(IV) complex containing a single bridging peroxide ligand. The PtO-OPt bond distance in 2 is 1.481(3) Å. Complex 2 is thought to be formed by homolysis of the allyl-platinum bond of 1, followed by reaction of the platinum(III) intermediate [PtBr(4-MeC6H4)2(bipy)] with oxygen.

Multi-metal nanomaterials obtained from oil/water interface as effective catalysts in reduction of 4-nitrophenol.

In this study Pt and Pd-based nanostructured thin films have been successfully fabricated by room temperature self-assembly of metal nanoparticles (NPs) at the interface between toluene and water without/with using stabilizers such as graphene oxide (GO) or aminoclay (AC). Successful formation of these thin films is investigated by transmission electron microscopy (TEM), energy dispersive analysis of X-ray (EDAX) and X-ray diffraction (XRD). Catalytic hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was investigated using thin film nanocatalysts. The as synthesized nanostructured thin films exhibit high catalytic activity toward hydrogenation reaction of 4-NP. This study highlights the value of nano alloy thin films and their ability as catalyst in catalytic hydrogenation reaction.

Ultrasonic assisted synthesis of palladium-nickel/iron oxide core-shell nanoalloys as effective catalyst for Suzuki-Miyaura and p-nitrophenol reduction reactions.

In this study, ultrasonic assisted synthesis of Pd-Ni/Fe3O4 core-shell nanoalloys is reported. Unique reaction condition was prepared by ultrasonic irradiation, releasing the stored energy in the collapsed bubbles and heats the bubble contents that leads to Pd(II) and Ni(II) reduction. Co-precipitation method was applied for the synthesis of Fe3O4 nanoparticles (NPs). Immobilized solution was produced by sonicating the aqueous mixture of Fe3O4 and mercaptosuccinic acid to obtain Pd-Ni alloys on Fe3O4 magnetic NP cores. The catalytic activity of the synthesized Pd-Ni/Fe3O4 core-shells was investigated in the Suzuki-Miyaura CC coupling reaction and 4-nitrophenol reduction, which exhibited a high catalytic activity in both reactions. These magnetic NPs can be separated from the reaction mixture by external magnetic field. This strategy is simple, economical and promising for industrial applications.

Interleukin-28B rs12979860 C/T Polymorphism and Acute Cellular Rejection after Liver Transplantation.

BACKGROUND: Interleukin-28 (IL-28B) rs12979860 C/T polymorphism is a known predictor of sustained virological response after antiviral treatment in hepatitis C. IL-28B affects the innate immune system as well as intrahepatic expression level of interferon-stimulated genes. OBJECTIVE: To investigate the effect of recipient IL-28B polymorphism on occurrence of acute rejection after liver transplantation. METHODS: 140 liver allograft recipients were selected. Acute rejection episodes were recorded in 39 patients (AR group); the remaining had normal graft function (non-AR group). 70 normal subjects were also studied as the control group. The IL-28B rs12979860 was genotyped through PCR-RFLP method. RESULTS: No significant difference was found between AR and non-AR groups in terms of genotype and allele frequency. However, the CC genotype was significantly (p<0.001) more frequent in patients than in the control group; the C allele variants increased the risk of end-stage liver disease (OR: 2.60). CONCLUSION: Liver damage in association with the carriage of IL-28B C allele is associated with a higher likelihood of developing cirrhosis.

Acute myeloid leukemia targets for bispecific antibodies.

Despite substantial gains in our understanding of the genomics of acute myelogenous leukemia (AML), patient survival remains unsatisfactory especially among the older age group. T cell-based therapy of lymphoblastic leukemia is rapidly advancing; however, its application in AML is still lagging behind. Bispecific antibodies can redirect polyclonal effector cells to engage chosen targets on leukemia blasts. When the effector cells are natural-killer cells, both antibody-dependent and antibody-independent mechanisms could be exploited. When the effectors are T cells, direct tumor cytotoxicity can be engaged followed by a potential vaccination effect. In this review, we summarize the AML-associated tumor targets and the bispecific antibodies that have been studied. The potentials and limitations of each of these systems will be discussed.