A Tale of Two Mounts: The History of Chemistry at the Hebrew University of Jerusalem

This is the story of the establishment of the Hebrew University (HU), and within it, the sub-story of the first school of chemistry in the Land of Israel, from 1923. It spans more than 100 years, from the publication of the pamphlet, Eine Jüdische Hochschule, in 1902, all the way to 2015. The story starts with a dream, almost in the realm of science fiction, the audacious vision of building a university in a stateless and impoverished region, and all the way to an Institute of Chemistry of HU that has served as the mother of chemistry in the State of Israel.     

A Comparative Study of Non-Viral Gene Delivery Techniques to Human Adipose-Derived Mesenchymal Stem Cell

Mesenchymal stem cells (MSCs) hold tremendous potential for therapeutic use in stem cell-based gene therapy. Ex vivo genetic modification of MSCs with beneficial genes of interest is a prerequisite for successful use of stem cell-based therapeutic applications. However, genetic manipulation of MSCs is challenging because they are resistant to commonly used methods to introduce exogenous DNA or RNA. Herein we compared the effectiveness of several techniques (classic calcium phosphate precipitation, cationic polymer, and standard electroporation) with that of microporation technology to introduce the plasmid encoding for angiopoietin-1 (ANGPT-1) and enhanced green fluorescent protein (eGFP) into human adipose-derived MSCs (hAD-MSCs). The microporation technique had a higher transfection efficiency, with up to 50% of the viable hAD-MSCs being transfected, compared to the other transfection techniques, for which less than 1% of cells were positive for eGFP expression following transfection. The capability of cells to proliferate and differentiate into three major lineages (chondrocytes, adipocytes, and osteocytes) was found to be independent of the technique used for transfection. These results show that the microporation technique is superior to the others in terms of its ability to transfect hAD-MSCs without affecting their proliferation and differentiation capabilities. Therefore, this study provides a foundation for the selection of techniques when using ex vivo gene manipulation for cell-based gene therapy with MSCs as the vehicle for gene delivery.     

Implementation of Advanced Tunnel Field Effect Transistor (DP-TFET) for High Power Switching Applications

Silicon - As the technology advances to the nanoscale, advanced Tunnel Field-Effect Transistors are very prominent as a part of integrated circuits in the present trend. Advanced Tunnel FET devices...     

Dye-sensitized solar cells incorporating a "liquid" hole-transporting material

We present the first application of an amorphous "liquid" organic semiconductor in an optoelectronic device, demonstrating that it is highly suited for use as a hole-transporting material in nanostructured dye-sensitized solar cells. For such devices, we obtain power conversion efficiencies of up to 2.4% under simulated air mass 1.5 solar spectrum at 100 mWcm(-2), and incident photon-to-electron quantum efficiencies in excess of 50%.     

Superconducting Properties of Hg0.8Cu0.15Sb0.05Ba2Ca2Cu3O8+δ Ceramic with Controlling Sintering Conditions

Hg_0.8Cu_0.15Sb_0.05Ba₂Ca₂Cu₃O_8+?? High temperature superconducting samples were prepared by using a standard solid-state reaction method with different sintering temperatures of 1073, 1093, 1113, 1133 and 1153?K. The electrical resistivity measurements showed that the sintering conditions have major effects on the transition temperature of the superconducting compound. The samples prepared at 1113 and 1153?K have transition temperatures at zero resistivity T _c(offset)=107,112?K and T _c(onset)=121,128?K respectively. Meanwhile, the sample prepared at 1133 has highest transition temperature T _c(offset)=121?K and T _c(onset)=134?K. However, the samples which were prepared at 1073 and 1093?K showed metallic behavior with respect to temperature, but this could not help us to obtain the values of T _c(off) because they were less than the point of liquid nitrogen. The effect of sintering times on the transition temperature has been investigated by using the samples prepared at 1133 K. The value of T _c(offset) at the sintering times of 16?C24 hours rises from 121?K to 126?K. The XRD data collected from various samples were all polycrystalline. It was found that the increase of sintering temperatures from 1073?C1153?K caused an extremely high amount of decomposition of the low-phase (1212) superconductor and produced high-phase (1223) superconductors. The oxygen content (??), volume fraction V _Ph(1223) and the lattice parameters were changing with the increase of the sintering temperature.     

Microwave-assisted epoxidation of styrene with molecular O2 over sulfated Co–Y–ZrO2 solid catalyst

The microwave-assisted styrene epoxidation reaction with molecular O₂ as an oxidant was studied over a sulfated Co–Y-doped ZrO₂ solid catalyst. The microwave irradiation (400 W) resulted in similar styrene conversion and styrene oxide selectivity, in reduced time, as compared to conventional thermal heating. Higher power (800 W) of microwave irradiation decreased the styrene oxide selectivity as well as leading to the formation of styrene glycol. DMF was found to be the most suitable solvent for epoxidation of styrene with molecular O₂ under microwave irradiation and yielded maximum oxide selectivity (91%) at 120 °C. The microwave-assisted oxidation reaction resulted in time saving and is energy conserving method.     

Nanocrystal Shape Control: Synthesis and Structure–Property Correlation in Shape‐Controlled ZnO Nanoparticles Prepared by Chemical Vapor Synthesis and their Application in Dye‐Sensitized Solar Cells (Adv. Funct. Mater. 6/2009)

Here, the large scale synthesis of nanocrystalline ZnO spheres and tetrapods in the size range of 8–40 nm by chemical vapor synthesis using zinc metal as precursor is described. A detailed study of the effect of experimental parameters on the morphology and yield is presented. High‐resolution transmission electron microscopy images of the tetrapods show that they are formed by the self assembly of four nanorods in the vapor phase. The tetrapods have optical absorption coefficients that are one order of magnitude greater than the spheres and show intense UV luminescence whereas the spheres show only the green emission. The observed differences in the optical properties are related to the presence of surface defects present in the nanospheres. The tetrapods have increased efficiencies for application in dye sensitized solar cells when compared to spheres.     

Surface Design in Solid‐State Dye Sensitized Solar Cells: Effects of Zwitterionic Co‐adsorbents on Photovoltaic Performance

In solid‐state dye sensitized solar cells (SSDSCs) charge recombination at the dye‐hole transporting material interface plays a critical role in the cell efficiency. For the first time we report on the influence of dipolar co‐adsorbents on the photovoltaic performance of sensitized hetero‐junction solar cells. In the present study, we investigated the effect of two zwitterionic butyric acid derivatives differing only in the polar moiety attached to their common 4 carbon‐chain acid, i.e., 4‐guanidinobutyric acid (GBA) and 4‐aminobutyric acid (ABA). These two molecules were implemented as co‐adsorbents in conjunction with Z907Na dye on the SSDSC. It was found that a Z907Na/GBA dye/co‐adsorbent combination increases both the open circuit voltage (V_oc) and short‐circuit current density (J_sc) as compared to using Z907Na dye alone. The Z907Na/ABA dye/co‐adsorbent combination increases the J_sc. Impedance and transient photovoltage investigations elucidate the cause of these remarkable observations.     

Deep Learning Based Face Detection and Identification of Criminal Suspects

Occurrence of crimes has been on the constant rise despite the emerging discoveries and advancements in the technological field in the past decade. One of the most tedious tasks is to track a suspect once a crime is committed. As most of the crimes are committed by individuals who have a history of felonies, it is essential for a monitoring system that does not just detect the person’s face who has committed the crime, but also their identity. Hence, a smart criminal detection and identification system that makes use of the OpenCV Deep Neural Network (DNN) model which employs a Single Shot Multibox Detector for detection of face and an auto-encoder model in which the encoder part is used for matching the captured facial images with the criminals has been proposed. After detection and extraction of the face in the image by face cropping, the captured face is then compared with the images in the Criminal Database. The comparison is performed by calculating the similarity value between each pair of images that are obtained by using the Cosine Similarity metric. After plotting the values in a graph to find the threshold value, we conclude that the confidence rate of the encoder model is 0.75 and above.