The system design and evaluation of a microprocessor controlled dispenser using a radar ground-speed sensor

This experimental research focused on the design of a new approach to control seed dispensers and to analyze the performance characteristics of a Doppler radar ground speed sensor for a microprocessor control dispenser. The research focused on comparing the effectiveness of using a radar unit with a fifth-wheel encoder for measuring ground speed when both were connected to a microprocessor controlled seed dispenser. The system designed for this study consisted of hardware and a computer program in 6502 assembly language. The hardware for this study consisted of a monitor device, microprocessor control unit, stepper motor, fifth-wheel encoder, Doppler radar and the device for the planting of seeds. the software was designed by the researcher during an internship at Rawson Control Systems Corporation. Laboratory tests and field tests were used in the study to test the Doppler radar and microprocessor control unit. Laboratory tests were conducted to determine the accuracy of the microprocessor based speedometer, seed spacing control and the output waveforms from the Doppler radar and the fifth-wheel encoder under controlled conditions. The laboratory provided an environment for controlling the variables of this research. Field tests were conducted to test the accuracy and variability of the seed spacing control under actual conditions. The resultanat data were analyzed using the t test, F test and one-way ANOVA. The most important findings were: 1. There was a significant difference between the mean indicated ground speeds of the Doppler radar and the fifth-wheel encoder controlled dispensing devices (calculated by the microcomputer in M. P. H.) when an input signal was varied from 1 Hz to 574 Hz to the control box. The Doppler radar was more sensitive to frequency changes than the fifth-wheel encoder. 2. Under the laboratory tests, without considering the slippage of the wheel, there was no significant difference between using the fifth-wheel encoder and the Doppler radar as sensors in dispensing seed at a uniform spacing. 3. In the field tests, a significant difference was found between using the Doppler radar sensor and a fifth-wheel encoder with regard to dispensed seeds at a uniform spacing, due to possible wheel slippage. The Doppler radar controlled unit dispensed seeds at a more uniform spacing than the fifth-wheel encoder control unit. 4. There was a significant difference between using the the Doppler radar sensor and a fifth-wheel encoder with regard to variability of output sigals from the sensors. The Doppler radar provided a less variable output signal than the fifth-wheel encoder. 5. During the field test, the researcher observed that one problem of using the Doppler radar unit was the slight vibration of the Doppler radar caused by the engine of the tractor. This caused some erroneous input signals to the microprocessor control unit because the monitor displayed a fractional part of a ground speed (MPH) while the tractor was stationary. The results obtained from the data analyses show that using the Doppler radar unit as a sensor in the field tests will provide a more uniform spacing control. In general, the Doppler radar controlled unit was considered to be more accurate than the fifth-wheel encoder control unit

Printed circuit board design in a school computer laboratory

Printed Circuit Boards replaced conventional wiring in most electronic equipment after World War II, reducing the size and weight of equipment while improving reliability and uniformity. PCBs are used in all kinds of electrical and electronic products because they can be mass-produced with greater circuit density and also enable easier trouble-shooting. Computer Aided Design (CAD) is critical in teaching PCB layout design but it is a challenge for school and college instructors with limited budgets. After discussion of current trends in PCB design and development, as well as basic PCB design criteria, an affordable PCB design using an " educational" microcomputer is presented

Bmi-1 Regulates Snail Expression and Promotes Metastasis Ability in Head and Neck Squamous Cancer-Derived ALDH1 Positive Cells

Recent studies suggest that ALDH1 is a putative marker for HNSCC-derived cancer stem cells. However, the regulation mechanisms that maintain the stemness and metastatic capability of HNSCC-ALDH1+ cells remain unclear. Initially, HNSCC-ALDH1+ cells from HNSCC patient showed cancer stemness properties, and high expression of Bmi1 and Snail. Functionally, tumorigenic properties of HNSCC-ALDH1+ cells could be downregulated by knockdown of Bmi-1. Overexpression of Bmi-1 altered in expression property ALDH1− cells to that of ALDH1+ cells. Furthermore, knockdown of Bmi-1 enhanced the radiosensitivity of radiation-treated HNSCC-ALDH1+ cells. Moreover, overexpression of Bmi-1 in HNSCC-ALDH1− cells increased tumor volume and number of pulmonary metastatic lesions by xenotransplant assay. Importantly, knock-down of Bmi1 in HNSCC-ALDH1+ cells significantly decreased distant metastases in the lungs. Clinically, coexpression of Bmi-1/Snail/ALDH1 predicted the worst prognosis in HNSCC patients. Collectively, our data suggested that Bmi-1 plays a key role in regulating Snail expression and cancer stemness properties of HNSCC-ALDH1+ cells

Sexually transmitted disease surveillance 2007

Division of STD Prevention."December 2008."Also available via the World Wide Web as an html or an Acrobat .pdf file (7.3 MB, 194 p.).Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance, 2007. At lanta, GA: U.S. Department of Health and Human Services; December 2008

Stem Cell-Based Neuroprotective and Neurorestorative Strategies

Stem cells, a special subset of cells derived from embryo or adult tissues, are known to present the characteristics of self-renewal, multiple lineages of differentiation, high plastic capability, and long-term maintenance. Recent reports have further suggested that neural stem cells (NSCs) derived from the adult hippocampal and subventricular regions possess the utilizing potential to develop the transplantation strategies and to screen the candidate agents for neurogenesis, neuroprotection, and neuroplasticity in neurodegenerative diseases. In this article, we review the roles of NSCs and other stem cells in neuroprotective and neurorestorative therapies for neurological and psychiatric diseases. We show the evidences that NSCs play the key roles involved in the pathogenesis of several neurodegenerative disorders, including depression, stroke and Parkinson’s disease. Moreover, the potential and possible utilities of induced pluripotent stem cells (iPS), reprogramming from adult fibroblasts with ectopic expression of four embryonic genes, are also reviewed and further discussed. An understanding of the biophysiology of stem cells could help us elucidate the pathogenicity and develop new treatments for neurodegenerative disorders. In contrast to cell transplantation therapies, the application of stem cells can further provide a platform for drug discovery and small molecular testing, including Chinese herbal medicines. In addition, the high-throughput stem cell-based systems can be used to elucidate the mechanisms of neuroprotective candidates in translation medical research for neurodegenerative diseases

Reaction Kinetics and Formation Mechanism of TiO₂ Nanorods in Solution: An Insight into Oriented Attachment

The reaction kinetics and formation mechanism of oriented attachment for shaped nanoparticles in solution are not well-understood. We present the reaction kinetics and formation mechanism of organic-capped anatase TiO₂ nanorods in solution as a case study for the oriented attachment process using small-angle X-ray scattering (SAXS) and transmission electronic microscopy. The SAXS analysis qualitatively and quantitatively provides in-depth understanding of the mechanism, including the structural evolution, interparticle interaction, and spatial orientation of nanoparticles developed from nanodots to nanorods during the nucleation, isotropic, and anisotropic growth steps. The present study demonstrates the growth details of oriented attachment of nanoparticles in solution. An ordered lamellar structure in the solution is constructed by the balance of interaction forces among surface ligands, functional groups, and solvent molecules serving as a natural template. The template allows the alignment of spherical nanoparticles into ordered chain arrays and facilitates simultaneous transformation from spherical to rod shape via proximity attachment. The proposed model reveals an insight into the oriented attachment mechanism. This multistep formation mechanism of TiO₂ nanorods in solution can provide the fundamental understanding of how to tune the shape of nanoparticles and further control the aggregation of spatial nanorod networks in solution

Distribution of Crystalline Polymer and Fullerene Clusters in Both Horizontal and Vertical Directions of High-Efficiency Bulk Heterojunction Solar Cells

In this study, we used (i) synchrotron grazing-incidence small-/wide-angle X-ray scattering to elucidate the crystallinity of the polymer PBTC₁₂TPD and the sizes of the clusters of the fullerenes PC₆₁BM and ThC₆₁BM and (ii) transmission electron microscopy/electron energy loss spectroscopy to decipher both horizontal and vertical distributions of fullerenes in PBTC₁₂TPD/fullerene films processed with chloroform, chlorobenzene and dichlorobezene. We found that the crystallinity of the polymer and the sizes along with the distributions of the fullerene clusters were critically dependent on the solubility of the polymer in the processing solvent when the solubility of fullerenes is much higher than that of the polymer in the solvent. In particular, with chloroform (CF) as the processing solvent, the polymer and fullerene units in the PBTC₁₂TPD/ThC₆₁BM layer not only give rise to higher crystallinity and a more uniform and finer fullerene cluster dispersion but also formed nanometer scale interpenetrating network structures and presented a gradient in the distribution of the fullerene clusters and polymer, with a higher polymer density near the anode and a higher fullerene density near the cathode. As a result of combined contributions from the enhanced polymer crystallinity, finer and more uniform fullerene dispersion and gradient distributions, both the short current density and the fill factor for the device incorporating the CF-processed active layer increase substantially over that of the device incorporating a dichlorobenzene-processed active layer; the resulting power conversion efficiency of the device incorporating the CF-processed active layer was enhanced by 46% relative to that of the device incorporating a dichlorobenzene-processed active layer

Nanoparticle-Tuned Self-Organization of a Bulk Heterojunction Hybrid Solar Cell with Enhanced Performance

We demonstrate here that the nanostructure of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester (P3HT/PCBM) bulk heterojunction (BHJ) can be tuned by inorganic nanoparticles (INPs) for enhanced solar cell performance. The self-organized nanostructural evolution of P3HT/PCBM/INPs thin films was investigated by using simultaneous grazing-incidence small-angle X-ray scattering (GISAXS) and grazing-incidence wide-angle X-ray scattering (GIWAXS) technique. Including INPs into P3HT/PCBM leads to (1) diffusion of PCBM molecules into aggregated PCBM clusters and (2) formation of interpenetrating networks that contain INPs which interact with amorphous P3HT polymer chains that are intercalated with PCBM molecules. Both of the nanostructures provide efficient pathways for free electron transport. The distinctive INP-tuned nanostructures are thermally stable and exhibit significantly enhanced electron mobility, external quantum efficiency, and photovoltaic device performance. These gains over conventional P3HT/PCBM directly result from newly demonstrated nanostructure. This work provides an attractive strategy for manipulating the phase-separated BHJ layers and also increases insight into nanostructural evolution when INPs are incorporated into BHJs

Hedgehog signaling reprograms hair follicle niche fibroblasts to a hyper-activated state.

Hair follicle stem cells are regulated by dermal papilla fibroblasts, their principal signaling niche. Overactivation of Hedgehog signaling in the niche dramatically accelerates hair growth and induces follicle multiplication in mice. On single-cell RNA sequencing, dermal papilla fibroblasts increase heterogeneity to include new Wnt5ahigh states. Transcriptionally, mutant fibroblasts activate regulatory networks for Gli1, Alx3, Ebf1, Hoxc8, Sox18, and Zfp239. These networks jointly upregulate secreted factors for multiple hair morphogenesis and hair-growth-related pathways. Among these is non-conventional TGF-β ligand Scube3. We show that in normal mouse skin, Scube3 is expressed only in dermal papillae of growing, but not in resting follicles. SCUBE3 protein microinjection is sufficient to induce new hair growth, and pharmacological TGF-β inhibition rescues mutant hair hyper-activation phenotype. Moreover, dermal-papilla-enriched expression of SCUBE3 and its growth-activating effect are partially conserved in human scalp hair follicles. Thus, Hedgehog regulates mesenchymal niche function in the hair follicle via SCUBE3/TGF-β mechanism