Development of Structured Illumination Microscope Using Transmission Diffraction Grating Obtained by Analog Microfilming Method.

We present the development of a custom-built structured illumination microscope (SIM) featuring a specially designed transmission diffraction grating. Employing the analog microfilming method, we fabricated transmission diffraction gratings suited to the specific requirements of our system. This robust and cost-effective method allows for the fabrication of diffraction gratings with customized constants, ensuring excellent transmission in both the visible and near-infrared spectra.

Application of the Knife-Edge Technique on Transition Metal Dichalcogenide Monolayers for Resolution Assessment of Nonlinear Microscopy Modalities.

We report application of the knife-edge technique at the sharp edges of WS2 and MoS2 monolayer flakes for lateral and axial resolution assessment in all three modalities of nonlinear laser scanning microscopy: two-photon excited fluorescence (TPEF), second- and third-harmonic generation (SHG, THG) imaging. This technique provides a high signal-to-noise ratio, no photobleaching effect and shows good agreement with standard resolution measurement techniques. Furthermore, we assessed both the lateral resolution in TPEF imaging modality and the axial resolution in SHG and THG imaging modality directly via the full-width at half maximum parameter of the corresponding Gaussian distribution.

Highly Active Oxidation Catalysts through Confining Pd Clusters on CeO Nano-Islands.

CeO-supported noble metal clusters are attractive catalytic materials for several applications. However, their atomic dispersion under oxidizing reaction conditions often leads to catalyst deactivation. In this study, the noble metal cluster formation threshold is rationally adjusted by using a mixed CeO-AlO support.

Highly loaded bimetallic iron-cobalt catalysts for hydrogen release from ammonia.

Ammonia is a storage molecule for hydrogen, which can be released by catalytic decomposition. Inexpensive iron catalysts suffer from a low activity due to a too strong iron-nitrogen binding energy compared to more active metals such as ruthenium. Here, we show that this limitation can be overcome by combining iron with cobalt resulting in a Fe-Co bimetallic catalyst.

Efficient noble metal promoted bimetallic cobalt catalysts in the selective synthesis of acetaldehyde dimethyl acetal.

Herein we report the one-pot cobalt catalysed synthesis of the dimethylacetal of acetaldehyde from synthesis gas and methanol. The product can be used as a fuel additive either as it is or after transacetalisation with long-chain alcohols. The product is obtained at moderate temperatures in good selectivities and high CO-conversions.

The Reliability of PCL/Anti-VEGF Electrospun Scaffolds to Support Limbal Stem Cells for Corneal Repair.

Since only few reported studies propose anti-vascular endothelial growth factor (anti-VEGF) delivery through electrospun scaffolds, this study greatly contributes to the potential prevention of patient's vision loss, as it explores electrospun polycaprolactone (PCL) coated with anti-VEGF for the blockage of abnormal cornea vascularization. In terms of physicochemical properties, the biological component increased the PCL scaffold fiber diameter (by ~24%) and pore area (by ~82%), while ut slightly reduced its total porosity as the anti-VEGF solution filled the voids of the microfibrous structure. The addition of the anti-VEGF increased the scaffold stiffness almost three-fold at both strains of 5 and 10%, as well as its biodegradation rate (~36% after 60 days) with a sustained release profile after Day 4 of phosphate buffered saline incubation.

Shape-Dependent CO Hydrogenation to Methanol over CuO Nanocubes Supported on ZnO.

The hydrogenation of CO to methanol over Cu/ZnO-based catalysts is highly sensitive to the surface composition and catalyst structure. Thus, its optimization requires a deep understanding of the influence of the pre-catalyst structure on its evolution under realistic reaction conditions, including the formation and stabilization of the most active sites. Here, the role of the pre-catalyst shape (cubic vs spherical) in the activity and selectivity of ZnO-supported Cu nanoparticles was investigated during methanol synthesis.

Supported Intermetallic PdZn Nanoparticles as Bifunctional Catalysts for the Direct Synthesis of Dimethyl Ether from CO-Rich Synthesis Gas.

The single-step syngas-to-dimethyl ether (STD) process entails economic and technical advantages over the current industrial two-step process. Pd/ZnO-based catalysts have recently emerged as interesting alternatives to currently used Cu/ZnO/Al O catalysts, but the nature of the active site(s), the reaction mechanism, and the role of Pd and ZnO in the solid catalyst are not well established. Now, Zn-stabilized Pd colloids with a size of 2 nm served as the key building blocks for the methanol active component in bifunctional Pd/ZnO-γ-Al O catalysts.

Formation Mechanism of the First Carbon-Carbon Bond and the First Olefin in the Methanol Conversion into Hydrocarbons.

The elementary reactions leading to the formation of the first carbon-carbon bond during early stages of the zeolite-catalyzed methanol conversion into hydrocarbons were identified by combining kinetics, spectroscopy, and DFT calculations. The first intermediates containing a C-C bond are acetic acid and methyl acetate, which are formed through carbonylation of methanol or dimethyl ether even in presence of water. A series of acid-catalyzed reactions including acetylation, decarboxylation, aldol condensation, and cracking convert those intermediates into a mixture of surface bounded hydrocarbons, the hydrocarbon pool, as well as into the first olefin leaving the catalyst.

Role of Amine Functionality for CO2 Chemisorption on Silica.

The mechanism of CO2 adsorption on primary, secondary, and bibasic aminosilanes synthetically functionalized in porous SiO2 was qualitatively and quantitatively investigated by a combination of IR spectroscopy, thermogravimetry, and quantum mechanical modeling. The mode of CO2 adsorption depends particularly on the nature of the amine group and the spacing between the aminosilanes. Primary amines bonded CO2 preferentially through the formation of intermolecular ammonium carbamates, whereas CO2 was predominantly stabilized as carbamic acid, when interacting with secondary amines.

Photoswitching in nanoporous, crystalline solids: an experimental and theoretical study for azobenzene linkers incorporated in MOFs.

In this article, we use the popular photoswitchable molecule, azobenzene, to demonstrate that the embedding in a nanoporous, crystalline solid enables a precise understanding of light-induced, reversible molecular motion. We investigate two similar azobenzene-containing, pillared-layer metal-organic frameworks (MOFs): Cu2(AzoBPDC)2(BiPy) and Cu2(NDC)2(AzoBiPy). Experimental results from UV-vis spectroscopy and molecular uptake experiments as well as theoretical results based on density-functional theory (DFT) show that in the Cu2(AzoBPDC)2(BiPy) MOF structure, the azobenzene side groups undergo photoisomerization when irradiated with UV or visible light.

Postsynthetic Metal and Ligand Exchange in MFU-4l: A Screening Approach toward Functional Metal-Organic Frameworks Comprising Single-Site Active Centers.

The isomorphous partial substitution of Zn(2+) ions in the secondary building unit (SBU) of MFU-4l leads to frameworks with the general formula [M(x)Zn(5-x)Cl4(BTDD)3], in which x≈2, M = Mn(II), Fe(II), Co(II), Ni(II), or Cu(II), and BTDD = bis(1,2,3-triazolato-[4,5-b],[4',5'-i])dibenzo-[1,4]-dioxin. Subsequent exchange of chloride ligands by nitrite, nitrate, triflate, azide, isocyanate, formate, acetate, or fluoride leads to a variety of MFU-4l derivatives, which have been characterized by using XRPD, EDX, IR, UV/Vis-NIR, TGA, and gas sorption measurements. Several MFU-4l derivatives show high catalytic activity in a liquid-phase oxidation of ethylbenzene to acetophenone with air under mild conditions, among which Co- and Cu derivatives with chloride side-ligands are the most active catalysts.

Scorpionate-type coordination in MFU-4l metal-organic frameworks: small-molecule binding and activation upon the thermally activated formation of open metal sites.

Postsynthetic metal and ligand exchange is a versatile approach towards functionalized MFU-4l frameworks. Upon thermal treatment of MFU-4l formates, coordinatively strongly unsaturated metal centers, such as zinc(II) hydride or copper(I) species, are generated selectively. Cu(I)-MFU-4l prepared in this way was stable under ambient conditions and showed fully reversible chemisorption of small molecules, such as O2, N2, and H2, with corresponding isosteric heats of adsorption of 53, 42, and 32 kJ mol(-1), respectively, as determined by gas-sorption measurements and confirmed by DFT calculations.

Adsorption structure determination of a large polyaromatic trithiolate on Cu(111): combination of LEED-I(V) and DFT-vdW.

The adsorption geometry of 1,3,5-tris(4-mercaptophenyl)benzene (TMB) on Cu(111) is determined with high precision using two independent methods, experimentally by quantitative low energy electron diffraction (LEED-I(V)) and theoretically by dispersion corrected density functional theory (DFT-vdW). Structural refinement using both methods consistently results in similar adsorption sites and geometries. Thereby a level of confidence is reached that allows deduction of subtle structural details such as molecular deformations or relaxations of copper substrate atoms.

Control of intermolecular bonds by deposition rates at room temperature: hydrogen bonds versus metal coordination in trinitrile monolayers.

Self-assembled monolayers of 1,3,5-tris(4'-biphenyl-4"-carbonitrile)benzene, a large functional trinitrile molecule, on the (111) surfaces of copper and silver under ultrahigh vacuum conditions were studied by scanning tunneling microscopy and low-energy electron diffraction. A densely packed hydrogen-bonded polymorph was equally observed on both surfaces. Additionally, deposition onto Cu(111) yielded a well-ordered metal-coordinated porous polymorph that coexisted with the hydrogen-bonded structure.

[Diagnostic relevance of fine needle aspiration cytology in nodular thyroid lesions].

Background/aim: Fine needle aspiration cytology (FNAC) of the thyroid gland has been used as an initial investigative procedure of thyroid nodule(s) in the Department of Pathology at the Institute of Oncology of Vojvodina for more than 20 years. This procedure is rapid, inexpensive and technologically simple, yet it has found only limited, albeit increasing acceptance in medical practice in Serbia. The aim of the study was to evaluate our FNAC findings by correlating cytological results with histological diagnosis and to define the sensitivity, diagnostic accuracy and positive predictive value of FNAC.

Reversible gas-phase redox processes catalyzed by Co-exchanged MFU-4l(arge).

Postsynthetic metal ion exchange in a benzotriazolate-based MFU-4l(arge) framework leads to a Co(II)-containing framework with open metal sites showing reversible gas-phase oxidation properties.

Determination of CO, H2O and H2 coverage by XANES and EXAFS on Pt and Au during water gas shift reaction.

The turn-over-rate (TOR) for the water gas shift (WGS) reaction at 200 degrees C, 7% CO, 9% CO(2), 22% H(2)O, 37% H(2) and balance Ar, of 1.4 nm Au/Al(2)O(3) is approximately 20 times higher than that of 1.6 nm Pt/Al(2)O(3).

Density functional theory based screening of ternary alkali-transition metal borohydrides: a computational material design project.

We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K (M(1)); and 1 alkali, alkaline earth or 3d/4d transition metal atom (M(2)) plus two to five (BH(4))(-) groups, i.e.

An enzyme histochemical and biochemical study of the activity of three oxidative enzymes in the developing rat parotid gland.

Information on ductal differentiation in the developing rat parotid gland is sparse. One of the main functions of the striated and excretory ducts in this gland is the selective exchange of electrolytes from the primary fluid secreted by the acini. These ducts are rich in a number of enzymes involved in this task, suggesting that they might be useful as markers of ductal differentiation.

Soft tissue cephalometric analysis: diagnosis and treatment planning of dentofacial deformity.

This article will present a new soft tissue cephalometric analysis tool. This analysis may be used by the orthodontist and surgeon as an aid in diagnosis and treatment planning. The analysis is a radiographic instrument that was developed directly from the philosophy expressed in Arnett and Bergman "Facial keys to orthodontic diagnosis and treatment planning, Parts I and II" (Am J Orthop Dentofacial Orthod 1993; 103:299-312 and 395-411).

Correcting vertically altered faces: orthodontics and orthognathic surgery.

Traditional methods of model and cephalometric examination are often unreliable for diagnosis and treatment planning. This article presents soft tissue cephalometric analysis that measures the face, analyzes important dentoskeletal structures that determine facial appearance, and reveals the etiology of malocclusions. A technique for cephalometric treatment planning for guiding esthetic facial changes and the method of occlusal correction are also described.

[Recognition of tissue oxygen debt in clinical settings].

Despite intensive treatment, a great proportion of ICU patients is resuscitated incompletely. Presence of tissue oxygen debt is the crucial pathophysiologic element of multiple organ failure development and death in these patients. Parameters of oxygen metabolism, monitored in time, except prognostic value give us the possibility of therapeutic intervention, oriented to the prevention of multiple organ failure.