Issues in representation of molecular structure the development of molecular connectivity.

Significant issues in the representation of molecular structure and the development of the molecular connectivity paradigm are presented. In the molecular connectivity paradigm, molecular structure is represented directly. Kier and Hall developed the method by creating ways to encode electronic information based on the paradigm developed from the Randi? branching index. The simple and valence delta values were created to encode atomic and valence-state electronic information through counts of sigma, pi, and lone pair electrons. A family of indices was created to provide a wide range of structure information. The key aspects of the development are presented and discussed in such a way as to reveal, at least in part, the imaginative thinking involved in the process. Possible future roles for molecular connectivity chi indices are discussed.     

Delamination detection with carbon nanotube thread in self-sensing composite materials

Laminated composite materials can reach high mechanical properties at low weight. Composite materials, however, are susceptible to damage due to their low interlaminar mechanical properties and poor heat and charge transport in the transverse direction to the laminate. Moreover, methods to inspect and ensure the reliability of composites are expensive and labor intensive. Recently carbon nanotube forests were spun into thread that is tough and electrically conductive. The thread was integrated into composite materials and used for the first time as a sensor to monitor strains and detect damage including delamination in the material. These self-sensing composites were found to be very sensitive to damage and will help to revolutionize the maintenance of composite structures, which will now be based on their condition and not their amount of use.     

High Dietary Fat Exacerbates Weight Gain and Obesity in Female Liver Fatty Acid Binding Protein Gene-Ablated Mice

Since liver fatty acid binding protein (L-FABP) facilitates uptake/oxidation of long-chain fatty acids in cultured transfected cells and primary hepatocytes, loss of L-FABP was expected to exacerbate weight gain and/or obesity in response to high dietary fat. Male and female wild-type (WT) and L-FABP gene-ablated mice, pair-fed a defined isocaloric control or high fat diet for 12 weeks, consumed equal amounts of food by weight and kcal. Male WT mice gained weight faster than their female WT counterparts regardless of diet. L-FABP gene ablation enhanced weight gain more in female than male mice—an effect exacerbated by high fat diet. Dual emission X-ray absorptiometry revealed high-fat fed male and female WT mice gained mostly fat tissue mass (FTM). L-FABP gene ablation increased FTM in female, but not male, mice—an effect also exacerbated by high fat diet. Concomitantly, L-FABP gene ablation decreased serum β-hydroxybutyrate in male and female mice fed the control diet and, even more so, on the high-fat diet. Thus, L-FABP gene ablation decreased fat oxidation and sensitized all mice to weight gain as whole body FTM and LTM—with the most gain observed in FTM of control vs high-fat fed female L-FABP null mice. Taken together, these results indicate loss of L-FABP exacerbates weight gain and/or obesity in response to high dietary fat.     

Design and implementation of multipattern generators in analog VLSI

In recent years, computational biologists have shown through simulation that small neural networks with fixed connectivity are capable of producing multiple output rhythms in response to transient inputs. It is believed that such networks may play a key role in certain biological behaviors such as dynamic gait control. In this paper, we present a novel method for designing continuous-time recurrent neural networks (CTRNNs) that contain multiple embedded limit cycles, and we show that it is possible to switch the networks between these embedded limit cycles with simple transient inputs. We also describe the design and testing of a fully integrated four-neuron CTRNN chip that is used to implement the neural network pattern generators. We provide two example multipattern generators and show that the measured waveforms from the chip agree well with numerical simulations.     

A Low-Power Integrated Circuit for a Wireless 100-Electrode Neural Recording System

Recent work in field of neuroprosthetics has demonstrated that by observing the simultaneous activity of many neurons in specific regions of the brain, it is possible to produce control signals that allow animals or humans to drive cursors or prosthetic limbs directly through thoughts. As neuroprosthetic devices transition from experimental to clinical use, there is a need for fully-implantable amplification and telemetry electronics in close proximity to the recording sites. To address these needs, we developed a prototype integrated circuit for wireless neural recording from a 100-channel microelectrode array. The design of both the system-level architecture and the individual circuits were driven by severe power constraints for small implantable devices; chronically heating tissue by only a few degrees Celsius leads to cell death. Due to the high data rate produced by 100 neural signals, the system must perform data reduction as well. We use a combination of a low-power ADC and an array of "spike detectors" to reduce the transmitted data rate while preserving critical information. The complete system receives power and commands (at 6.5 kb/s) wirelessly over a 2.64-MHz inductive link and transmits neural data back at a data rate of 330 kb/s using a fully-integrated 433-MHz FSK transmitter. The 4.7times5.9 mm² chip was fabricated in a 0.5-mum 3M2P CMOS process and consumes 13.5 mW of power. While cross-chip interference limits performance in single-chip operation, a two-chip system was used to record neural signals from a Utah Electrode Array in cat cortex and transmit the digitized signals wirelessly to a receiver     

Tandem transplantation with peripheral autologous hematopoietic blood stem cells in treatment of oncologic and hematologic malignancies. Initial results of the Donauspital, Vienna

10 patients were subjected to tandem transplantation for breast cancer (n = 3), ovarian cancer (n = 2) and multiple myeloma (n = 5), at the Second Department of Medicine, Donauspital, Vienna. The breast cancer patients were in stages 2 and 3, respectively, at diagnosis and entered complete remission thereafter. 2 of them developed lymph node metastasis and additional local recurrence, the 3rd patient presented with distant metastasis. The 2 patients with ovarian cancer were in stages Figo III and IV, respectively, at the time of diagnosis, and showed minimal residual disease at second-look-operation. 5 patients with multiple myeloma were in stage 3 pretransplant. Peripheral stem cells were obtained after either high-dose cyclophosphamide or FEC induction and application of cytokines. In 4 patients, tandem transplantation has been completed. 1 patient with multiple myeloma, who had received total body irradiation in combination with chemotherapy for the 2nd transplant, succumbed from idiopathic interstitial pneumonia. No severe clinical complications were observed in all other patients. All patients with solid tumors entered complete remission after the 1st transplantation. 3 of them completed tandem transplantation. Of these, 2 remain in continuous complete remission, the 3rd patient relapsed in lymph nodes day 485. In patients who received only 1 course of high dose chemotherapy with stem cell transplantation, relapses occurred on days 29 and 75, respectively. All patients with multiple myeloma entered only partial remission. We conclude that supralethal chemotherapy with peripheral blood stem cell support is a safe procedure that may at least induce prolonged remissions in solid tumors and hematologic malignancies.(ABSTRACT TRUNCATED AT 250 WORDS)     

The radiology of transsphenoidal hypophysectomy: a review of 100 cases

This report describing the radiology of transsphenoidal hypophysectomy based on a review of 100 consecutive surgical procedures. Preoperative laminographic evaluation of the sphenoid sinus is an important aid in planning the most direct surgical approach to the pituitary. It is also useful in defining the many anatomic structures that may be injured inadvertently at the time of surgery. Intraoperative radiography or fluoroscopy is helpful in identifying the sella floor and as an aid in preventing loss of orientation within a capacious sinus. Various changes occur within the sphenoid sinus following surgery, some transient and others persistent. The surgical defect is usually difficult to identify on routine roentgenograms but is clearly visible on lateral laminography. A persistent soft tissue mass within the sinus is usually a manifestation of fascia and fat placed as a seal within the sinus.     

Fluorescence Techniques Using Dehydroergosterol to Study Cholesterol Trafficking

Cholesterol itself has very few structural/chemical features suitable for real-time imaging in living cells. Thus, the advent of dehydroergosterol [ergosta-5,7,9(11),22-tetraen-3β-ol, DHE] the fluorescent sterol most structurally and functionally similar to cholesterol to date, has proven to be a major asset for real-time probing/elucidating the sterol environment and intracellular sterol trafficking in living organisms. DHE is a naturally occurring, fluorescent sterol analog that faithfully mimics many of the properties of cholesterol. Because these properties are very sensitive to sterol structure and degradation, such studies require the use of extremely pure (>98%) quantities of fluorescent sterol. DHE is readily bound by cholesterol-binding proteins, is incorporated into lipoproteins (from the diet of animals or by exchange in vitro), and for real-time imaging studies is easily incorporated into cultured cells where it co-distributes with endogenous sterol. Incorporation from an ethanolic stock solution to cell culture media is effective, but this process forms an aqueous dispersion of DHE crystals which can result in endocytic cellular uptake and distribution into lysosomes which is problematic in imaging DHE at the plasma membrane of living cells. In contrast, monomeric DHE can be incorporated from unilamellar vesicles by exchange/fusion with the plasma membrane or from DHE-methyl-β-cyclodextrin (DHE-MβCD) complexes by exchange with the plasma membrane. Both of the latter techniques can deliver large quantities of monomeric DHE with significant distribution into the plasma membrane. The properties and behavior of DHE in protein-binding, lipoproteins, model membranes, biological membranes, lipid rafts/caveolae, and real-time imaging in living cells indicate that this naturally occurring fluorescent sterol is a useful mimic for probing the properties of cholesterol in these systems.