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Notes: Lateral patterning of highly doped silicon-on-insulator films allows us to observe conductance oscillations due to single-electron charging effects. In our devices, silicon nanostructures are embedded into a metal–oxide–silicon configuration. The single-electron effects can be tuned both by an in-plane sidegate, as well as by a metallic topgate, a technology which is compatible with large-scale integration of single-electron devices with dimensions down to 10 nm. We compare the influence of different gating electrodes, important for ultralarge scale integration, on the electron islands. © 2001 American Institute of Physics.

Notes: Introduction:  Cyclophilin C-associated protein (CyC-AP) expression is up-regulated during wound healing. CyC-AP deletion causes greater expression of TNFα, MMP-3, MMP-13, and MMP-14 during cutaneous repair. Furthermore, CyC-AP is a mediator for fibronectin-fragment induced MMP-13 expression. In order to understand the effects of the deletion of CyC-AP at the cellular level, we investigated the intracellular signal transduction pathways of CyC-AP null and wild-type mice during skin wound healing.Methods:  Two-month-old CyC-AP null or wild-type mice were anesthetized and two 0.6 cm diameter excisional skin wounds were made on the dorsum of each mouse. Wounds were collected up to 10 days after injury. Total protein was purified from each wound and the protein expression of TNFα converting enzyme (TACE), integrin beta 1, ERK 1, ERK 2, p38, PCNA, and smooth muscle actin (sm-actin) was analyzed by immunoblot.Results:  TNFα expression was higher in CyC-AP null mice in unwounded skin. However, the elevated TNFα in CyC-AP null wounds was lower compared to the wild-type mice. To further understand the relationship of CyC-AP and TNFα, TACE expression was examined. TACE expression was less in the skin of CyC-AP null mice compared to wild-type mice. Expression of p38 and PCNA increased while sm-actin decreased in both unwounded and wounded CyC-AP null skin compared to wild type. PCNA expression in CyC-AP null fibroblasts was also higher compared to wild type, supporting our in vivo observations. In addition, the expression of integrin beta 1 was lower during wound healing.Conclusion:  The increased PCNA and decreased sm-actin expression suggests that CyC-AP null fibroblasts have higher proliferation and lower differentiation rates compared to wild types. These effects might be regulated through the p38 signaling pathway, which was increased in CyC-AP null mice. The decreased TACE expression in CyC-AP null skin suggests CyC-AP may also regulate TACE via the altered expression of integrin beta 1. Our data suggest CyC-AP is involved in TNFα activation.

Notes: The fetus heals skin wounds without scar formation. Human fetal skin that is transplanted to a subcutaneous location on an adult athymic mouse and subsequently wounded heals without scar formation, whereas the same skin heals with scar formation when transplanted to a cutaneous location. In situ hybridization with species-specific DNA probes and immunohistochemistry were performed to characterize the healing process of human fetal skin in these two locations. Species-specific human and mouse DNA probes were constructed and used to probe graft wounds under high stringency in situ hybridization conditions. Immunostaining for species-specific fibroblasts, macrophages, and neutrophils was also performed. We found that the cutaneous human fetal grafts healed with scar and showed an influx of mouse fibroblasts and macrophages. In contrast, subcutaneous human fetal grafts showed exclusively human fetal fibroblasts in the wound environment, an absence of inflammatory cells, and scar-free repair. We conclude that the highly organized collagen deposition in scarless human fetal wound repair appears to be intrinsic to the human fetal fibroblasts and occurs in the absence of an adult-like inflammatory response.

Notes: Surgical researchers were among the first to describe the different phases of wound healing and the events in tissue repair and regeneration that were taking place during each phase. The understanding of these events has been significantly enhanced in recent years by modern techniques in molecular and cellular biology. In this article, we discuss new findings in scarless fetal repair, angiogenesis in wound healing, and keloid pathogenesis. This serves to highlight the advances that have been made and also how much remains to be understood. (WOUND REP REG 2003;11:411–418)

Notes: To elucidate the role for transforming growth factor-β isoforms (β1, -β2, and -β3) in wound repair, we used isoform-specific antibodies to detect the spatial and temporal expression of the latent and mature/active transforming growth factor-β isoforms by immunohistochemical localization through 21 days after excisional and incisional wounding of ovine skin. Although incisional and excisional wounds showed similar patterns of transforming growth factor-β immunoreactivity, we found a differential temporal and spatial expression of the latent and mature transforming growth factor-β isoforms throughout wound repair. Specifically, 1 day after wounding, there was a marked increase in transforming growth factor-β isoforms in the epithelium adjacent to the wound, epidermal appendages, and the cells and matrix of the granulation tissue. At this time, transforming growth factor-β3 isoform was the most abundant. Most notably, the epidermis adjacent to the wound was intensely immunoreactive for all transforming growth factor-β isoforms 1 day after injury. However, the migrating epithelium, derived from both the hair follicles and the wound margins, was completely devoid of immunoreactive transforming growth factor-β until reepithelialization was complete. Within the inflammatory exudate, there was a distinct band of leukocytes that was immunoreactive for transforming growth factor-β2 and -β3 1 day after injury and 1 day later for transforming growth factor-β1. Although transforming growth factor-β1 and -β2, latent transforming growth factor-β2, transforming growth factor-β3, and latent transforming growth factor-β3 immunostaining was present in the numerous fibroblasts and other dermal cells, latent transforming growth factor-β1 was only associated with the extracellular matrix. In general, immunoreactivity remained high until day 7 after wounding and slowly subsided over time. However, by day 21, immunostaining had not returned to normal and the original wound was replete with immunoreactive fibroblasts and a dense, immunostained extracellular matrix. Thus, although the dynamic presence of transforming growth factor-β isoforms exemplifies its positive role in the wound repair process, its persistence together with its known potent effects on matrix accumulation, supports its role in scar formation.

Notes: We define superconducting constrictions by ploughing a deposited Aluminum film with a scanning probe microscope. The microscope tip is modified by electron-beam deposition to form a nanoplough of diamond-like hardness which allows the definition of highly transparent Josephson junctions. Additionally, a dc superconducting quantum interference device is fabricated in order to verify the junction's behavior. The devices are easily integrated in mesoscopic devices as local radiation sources and can be used as tunable on-chip millimeter-wave sources. © 1998 American Institute of Physics.

Notes: X-ray diffraction measurements in the region of small incidence and exit angles on thin amorphous silicon/germanium films on laterally structured surfaces are performed. From fits of the data we obtain directly how the Fourier components of the substrates propagate through the evaporated films without being influenced by the intrinsic statistical roughness of the interfaces. The results show that a replication factor extracted from a given model can be quantitatively tested with our measurements. © 1996 American Institute of Physics.

Notes: Single-electron transistors utilizing Coulomb blockade effects are promising candidates for future silicon based nanoelectronics. We present the fabrication of such transistors and measurements that reveal Coulomb blockade behavior. Various silicon quantum dots are investigated up to room temperature. We employ a dual gate configuration with which we are able to control our devices by both a metallic top gate as well as by an in-plane gate. This design principle enhances the integration density. © 2001 American Institute of Physics.

Notes: We describe a novel technique using an atomic force microscope (AFM) for integrated nanometer-scale lithography on various mask materials such as photoresist or gold covering a mesa-etched GaAs-AlGaAs heterostructure at ambient conditions. The generated patterns can be transferred to the two-dimensional electron gas by wet chemical etching or by ion beam irradiation. We succeed in fabricating hole arrays with a periodicity down to 35 nm and a hole diameter of only a few nanometers. In magnetoresistance studies on so-called antidot devices with 95 nm period at T=4.2 K we can clearly observe commensurability oscillations, demonstrating the successful pattern transfer to the electron system. With the AFM we can also pattern lines of varying width and depth into prefabricated devices. © 1994 American Institue of Physics.

Notes: Magnetotransport of high-mobility electrons in quasi-one-dimensional quantum wires in Si/Si0.7Ge0.3 heterostructures is studied. Arrays of shallow and deep etched wires with a period of 480 nm are defined by laser holography and patterned by reactive ion etching. Typical features of transport in narrow electron channels, such as oscillations due to the depopulation of quasi-one-dimensional subbands and an anomalous resistance maximum at low magnetic fields are observed. The narrowest channels have an effective width of ≈70 nm and a sublevel spacing of 1 meV. © 1995 American Institute of Physics.