Eugenia Klein

• Ph. D. Physical Chemistry
• Consultant at Weizmann Institute of Science

Teeth are subjected to compressive loads during mastication. Under small loads the soft tissue periodontal ligament (PDL) deforms most. However when the loads increase and the PDL is highly compressed, the tooth and the alveolar bone supporting the tooth, begin to deform. Here we report on the structure of this alveolar bone in the upper furcation...

The endothelial cytoskeleton is a barrier for leukocyte transendothelial migration (TEM). Mononuclear and polymorphonuclear leukocytes generate gaps of similar micron-scale size when squeezing through inflamed endothelial barriers in vitro and in vivo. To elucidate how leukocytes squeeze through these barriers, we co-tracked the endothelial actin f...

The realization of high-quality optoelectronic properties in halide perovskite semiconductors through low-temperature, low energy processing is unprecedented. Understanding the unique aspects of the formation chemistry of these semiconductors is a critical step toward understanding the genesis of high quality material via simple preparation procedu...

Cephalaspidean gastropods are common marine mollusks with a unique digestive apparatus containing 3 hardened plates of millimeter size inside the muscular esophageal crop (gizzard). The gizzard plates are reported to either grind or crush shelled prey. The current study aims at better understanding the manner in which the gizzard plates of the ceph...

The microstructure and chemical composition of eight faience beads from an early Iron Age (12th century BCE) assemblage found in the ancient city port of Ashkelon (Israel) are determined by means of FTIR spectrometry, pXRF, microRaman and SEM-EDS analysis. The results are compared with published data of Egyptian and Near Eastern artifacts. Each sam...

Monocyte-derived macrophages are essential for recovery after spinal cord injury, but their homing mechanism is poorly understood. Here, we show that although of common origin, the homing of proinflammatory (M1) and the "alternatively activated" anti-inflammatory (M2) macrophages to traumatized spinal cord (SC) was distinctly regulated, neither bei...

Biofilms are consortia of bacteria that are held together by an extracellular matrix. Cyanobacterial biofilms, which are highly ubiquitous and inhabit diverse niches, are often associated with biological fouling and cause severe economic loss. Information on the molecular mechanisms underlying biofilm formation in cyanobacteria is scarce. We identi...

Chemokines presented by the endothelium are critical for integrin-dependent adhesion and transendothelial migration of naive and memory lymphocytes. Here we found that effector lymphocytes of the type 1 helper T cell (T(H)1 cell) and type 1 cytotoxic T cell (T(C)1 cell) subtypes expressed adhesive integrins that bypassed chemokine signals and estab...

The sessile nature of plants demands the development of seed-dispersal mechanisms to establish new growing loci. Dispersal strategies of many species involve drying of the dispersal unit, which induces directed contraction and movement based on changing environmental humidity. The majority of researched hygroscopic dispersal mechanisms are based on...

Kindlin-3 is a key lymphocyte function-associated antigen-1 (LFA-1) coactivator deleted in leukocyte adhesion deficiency-III (LAD-III). In the present study, we investigated the involvement of this adaptor in lymphocyte motility and TCR-triggered arrest on ICAM-1 or on dendritic cells (DCs). Kindlin-3-null primary T cells from a LAD-III patient mig...

A method is described for creating microscale-patterned surfaces by direct-write lithography. A tightly focused, low-power infrared laser beam is applied to a homogeneous precursor solution containing soluble reagents. When the laser is focused directly at a glass-solution interface, it initiates the local precipitation of a solid product that atta...

The iron storage protein, ferritin, provides an important endogenous MRI contrast that can be used to determine the level of tissue iron. In recent years the impact of modulating ferritin expression on MRI contrast and relaxation rates was evaluated by several groups, using genetically modified cells, viral gene transfer and transgenic animals. Thi...

Amyloids are pathological fibrillar aggregates of proteins related to over 20 diseases. Amyloid fibers are characterized by the cross-beta motif, which is minimally defined as a series of beta-strands extended perpendicular to the fiber axis, joined by hydrogen bonds parallel to the fiber direction. Several structures, all in agreement with the cro...

The nuclear envelope of higher eukaryotic cells reforms at the exit from mitosis, in concert with the assembly of nuclear pore complexes (NPCs). The first step in postmitotic NPC assembly involves the "seeding" of chromatin with ELYS and the Nup107-160 complex. Subsequent steps in the assembly process are poorly understood and different mechanistic...

Endothelial chemokines are instrumental for integrin-mediated lymphocyte adhesion and transendothelial migration (TEM). By dissecting how chemokines trigger lymphocyte integrins to support shear-resistant motility on and across cytokine-stimulated endothelial barriers, we found a critical role for high-affinity (HA) LFA-1 integrin in lymphocyte cra...

Water, collagen and mineral are the three major components of bone. The structural organization of water and its functions within the bone were investigated using the environmental scanning electron microscope and by analyzing dimensional changes that occur when fresh equine osteonal bone is dehydrated and then rehydrated. These changes are attribu...

Author Summary Two fundamental events in viral life cycles are the delivery of viral genomes into host cells and the packaging of these genomes into viral protein capsids. In bacteriophages and herpesviruses, these processes occur linearly along the genome, base pair after base pair, through a single portal located at a unique site in the viral ca...

A key to understanding control over mineral formation in mollusk shells is the microenvironment inside the pre-formed 3-dimensional organic matrix framework where mineral forms. Much of what is known about nacre formation is from observations of the mature tissue. Although these studies have elucidated several important aspects of this process, the...

Electron Tomogram of an Infected Amoeba Host Cell at Late Infection Stage The tomogram includes a large number of mature, intracellular Mimivirus particles at a late (12 h post infection) stage of the infection cycle. At this stage, the virions are crammed within the host cytoplasm. All morphological aspects of the stargates can be discerned in the...

Electron Tomogram of a Procapsid Undergoing DNA Packaging at the Periphery of a Viral Factory (Figure 7A) Note the stargate structure at the opposite site of the DNA packaging site. Each frame of the movie is an average of ten 2.7-nm slices of a thick section of a Mimivirus particle. (2.02 MB MPG)

Electron Tomogram of a Late Phagosome Enclosing Three Mimivirus Particles at Early, Advanced, and Final Uncoating Stages (Figure 3A) In the particle at the upper right side of the phagosome, the vertex containing the stargate is clearly visible. The tomogram provides an interpretation to the observation that two vertices appear to be modified, by s...

Osteoclasts are bone-degrading cells, which play a central role in physiological bone remodeling. Unbalanced osteoclast activity is largely responsible for pathological conditions such as osteoporosis. Osteoclasts develop specialized adhesion structures, the so-called podosomes, which subsequently undergo dramatic reorganization into sealing zones....

Relation between podosome radial fibers. Osteoclast ventral membranes were labeled for paxillin and actin, and simultaneously prepared for HR-SEM. (A) an over-view of a cluster of podosomes, visualized under the HR-SEM. (B) fluorescence labeling of actin (green) and paxillin (red). (C) Merged image between (A) and (B). Note paxillin colocalization...

Sealing zone dynamics of a resorbing osteoclast. Movie taken on live GFP-actin osteoclasts plated on bone. Frames were recorded at 1 minute intervals by time-lapse microscopy for 3.5 hours. (0.98 MB MOV)

Macrophages podosomes. Ventral membranes of IC21 macrophages were prepared for SEM. (A) An over-view of macrophage. (B) Higher magnification view of podosomes at the leading edge of the cell. Note the similarity in podosome organization to osteoclasts. (1.99 MB TIF)

Most of the mineral crystals in bone are platelets of carbonated apatite with thicknesses of a few nanometers embedded in a collagen matrix. We report that spherical to cylindrical shaped nanosized particles are also an integral part of bone structure observed by high resolution scanning electron microscopy. High resolution back scattered electron...

The giant polyelectrolyte glycosaminoglycan hyaluronan (1-10 MDa) is a major component of the pericellular coat on a variety of cells, where it is an important modulator and mediator of early cell adhesion events. This pericellular layer can reach 5 mum thickness on cells that produce cartilage (chondrocytes), and up to 2 mum on Xenopus laevis kidn...

The skeletons of adult echinoderms comprise large single crystals of calcite with smooth convoluted fenestrated morphologies, raising many questions about how they form. By using water etching, infrared spectroscopy, electron diffraction, and environmental scanning electron microscopy, we show that sea urchin spine regeneration proceeds via the ini...

Bacteria belonging to the family Deinococcaceae survive exposure to 1.5 megarads of ionizing irradiation or to extreme desiccation without lethality or mutagenesis (2, 31, 35). This tolerance derives from the ability of these species to accurately mend numerous double-strand DNA breaks (DSBs), thus reassembling an intact genome from hundreds of fra...

Hyaluronan is a megadalton glycosaminoglycan composed of repeating units of D-N-acetylglucosamine-beta-D-Glucuronic acid. It is known to form a highly hydrated pericellular coat around chondrocytes, fibrosarcoma, and smooth muscle cells. Using environmental scanning electron microscopy we detected fully hydrated hyaluronan pericellular coats around...

A new method of laser-induced lithography for direct writing of carbon on a glass surface is described, in which deposition occurs from a transparent precursor solution. At the glass–solution interface where the laser spot is focused, a micro-explosion process takes place, leading to the deposition of pure carbon on the glass surface. Transmission...

The nonisothermal crystallization of multiwall carbon nanotube (MWNT)/isotactic polypropylene (iPP) nanocomposites was investigated. The results derived from the differential scanning calorimetry curves (onset temperature, melting point, supercooling, peak temperature, half-time of crystallization, and enthalpy of crystallization) were compared wit...

A method for creating microscale-patterned surfaces by direct-write lithography is described. A tightly focused, low-power infrared laser beam is applied to a homogeneous precursor solution containing soluble reagents. When the laser is focused directly at a glass–solution interface, it initiates the local precipitation of a solid product that atta...

Thin alkali halide "lms are currently used as transmissive UV-photocathodes and as protecting layers for visible photocathodes. The surface morphology of 20 and 75 nm thick evaporated CsI, NaI and CsBr "lms was investigated by means of a scanning electron microscope, to which the samples were transferred, under vacuum, with practically no contact w...

Thin alkali halide films are currently used as transmissive UV-photocathodes and as protecting layers for visible photocathodes. The surface morphology of 20 and 75 nm thick evaporated CsI, NaI and CsBr films was investigated by means of a scanning electron microscope, to which the samples were transferred, under vacuum, with practically no contact...

We applied the electron counting method, in low-density gas, for ultra-soft X-ray spectroscopy. The method is based on the spatial expansion of photon-induced ionization electron clusters, and the recording of pulse trails formed by individual electron avalanches in a fast multiplication element.A detector, operating at room temperature with low ga...

Thin films of WSe2 were prepared by high temperature selenization of vacuum evaporated WO3 films on quartz in an open tube furnace. The films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and optical absorption. They were found to consist of the hexagonal 2H phase. It was established that the...

The solubility of Fe in CdSe crystal has been studied in detail in the past. Using powder diffraction and atomic absorption spectroscopy, it was concluded that the upper limit for the solubility of iron in CdSe is 12–15%, and the actual Fe concentration in a solid solution agrees with the nominal Fe concentration (calculated from the concentration...

The preparation of frozen‐hydrated samples for scanning electron microscopy to observe symbionts in Azolla is described and compared to the conventional method of chemical fixation followed by critical‐point drying. The frozen‐hydrated specimens preserve the structure of the associating symbionts and the liquid phase in the Azollaleaf cavity. The l...

Azospirillum brasilense Cd localization in wheat roots was studied by light microscopy, by scanning, and by transmission electron microscopy.A. brasilense Cd cells were specifically identified immunocytochemically around and within root tissues.A. brasilense Cd cells found both outside and inside inoculated roots were intensively labeled with collo...

The dilute magnetic semiconductor Cd0.95Mn0.05Se was investigated as a photoelectrode in a photoelectrochemical cell. It is found that a short photoelectrochemical etching produces the highest photoresponse of this material. The effective energy gap is found to be higher than expected by about 130 meV. This observation can be attributed to the onse...

Cold stage Scanning Electron Microscopy (SEM) with a rapid cooling technique makes it possible to investigate the water phase within unsaturated porous media. It is thought that this technique preserves the main features of the micromorphology of the water menisci as it exists in the liquid phase in soils. Saddle-shaped elements, as well as pendula...

A micromethod is used to determine singlet exciton diffusion lengths in anthracene crystal normal to the ab plane. It is found that these lengths are significantly longer when measurements are performed on smooth, rather than non-smooth, areas of the surface.

On the basis of the structure of pyrene crystal we argue that excitation in the crystals localized at sites consisting of pairs of close-spaced molecules, i.e., that we are dealing with a Frenkel exciton. We postulate potentials for ground- and excited-state pairs in which both in-plane and out-of-plane vibrations play a role. Using these potential...