Search

Single input multiple output (SIMO) buck converter is a good solution to enhance the area efficiency of the power management unit. Because the SIMO type buck converter uses only one inductor to buffer the transferred energy for the multiple output ports, it usually suffers from severe transient cross regulation in a continuous conduction mode. Most of the well‐known approaches to suppress the transient cross regulation are either to create the additional free‐wheeling loop or to refine the controller loop. The control logic is usually quite specific which may not apply to the other controller types controller. A phase sequence interchange (PSI) scheme is proposed to mitigate the transient cross regulation without modifying the original control design. Compared to the other techniques, the proposed method can be easily applied, but not limited to the compensator‐based control or the non‐compensator‐based control in the buck converter. This study starts with the illustration of the reason why the PSI can mitigate the transient cross regulation. Detail designs are then presented to implement the proposed scheme on both the compensator type and the non‐compensator type controls. Experimental results show that the suppression of the cross regulation is comparable to the other state of the arts.

Background and objectives We previously demonstrated that intense pulsed light (IPL) irradiation prior to wounding improved the wound healing in rats with diabetes mellitus (DM). Also, we found that IPL upregulated the expression of aquaporin 3 (AQP3), a protein that is crucial for wound healing, in normal rats. This present study aimed to examine the involvement of AQPs in the IPL-enhanced wound healing in diabetic rats. Study design/materials and methods Streptozotocin was used to induce diabetes in Sprague-Dawley rats. Animals were divided into four groups: normal group, DM only group, DM rats with IPL treatment 2 weeks before wounding (DM + IPL-Pre group), and DM rats with concurrent IPL irradiation and wounding (DM + IPL-Con group). Wounds were created on the dorsal skin of rats. The expressions of AQP1, 3, 4, 7, and 9 in the pre-injured skin, periwound, and wound were determined. Results Among all the AQPs analyzed, only the expressions of AQP3 and AQP7 were significantly altered. Unirradiated diabetic rats showed much higher expression level of AQP3 in the regenerating skin compared with normal rats. IPL pretreatment, but not concurrent treatment, attenuated the expression toward the level detected in the normal wounds. In contrast, a lower expression level of AQP7 was noted in the regenerating skin of DM only rats and IPL pretreatment upregulated the expression to a level similar to that in the normal rats. Conclusion The beneficial effect of IPL pretreatment on the wound healing in diabetic rats might involve a mechanism by which the expression of AQPs is regulated. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Solid-state near-infrared (NIR) light-emitting devices have recently received considerable attention as NIR light sources that can penetrate deep into human tissue and are suitable for bioimaging and labeling. In addition, solid-state NIR light-emitting electrochemical cells (LECs) have shown several promising advantages over NIR organic light-emitting devices (OLEDs). However, among the reported NIR LECs based on ionic transition-metal complexes (iTMCs), there is currently no iridium-based LEC that displays NIR electroluminescence (EL) peaks near to or above 800 nm. In this report we demonstrate a simple method for adjusting the energy gap between the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) of iridium-based iTMCs to generate NIR emission. We describe a series of novel ionic iridium complexes with very small energy gaps, namely NIR1-NIR6, in which 2,3-diphenylbenzo[g]quinoxaline moieties mainly take charge of the HOMO energy levels and 2,2'-biquinoline, 2-(quinolin-2-yl)quinazoline, and 2,2'-bibenzo[d]thiazole moieties mainly control the LUMO energy levels. All the complexes exhibited NIR phosphorescence, with emission maxima up to 850 nm, and have been applied as components in LECs, showing a maximum external quantum efficiency (EQE) of 0.05 % in the EL devices. By using a host-guest emissive system, with the iridium complex RED as the host and the complex NIR3 or NIR6 as guest, the highest EQE of the LECs can be further enhanced to above 0.1 %.

Background Titanium-zirconium alloy (TiZr1317) is a new material used for biological implants. There are several studies on the effects of TiZr implants on the biological characteristics of human bone mesenchymal stem cells (hBMSCs). Purpose The purpose of this study was to investigate the biological responses of hBMSCs to implant holes affected by the physicochemical properties of oral implants (TiSLA , TiSLActive , TiZrSLA , and TiZrSLActive ). Materials and methods Grade 4 Ti and TiZr (13-17% Zr) substrates were modified by sand-blasted large-grit acid-etched (SLA) or hydrophilic sand-blasted large-grit acid-etched (SLActive), resulting in four types of surface with complex microstructures corresponding to the commercially-available implants SLA, RoxolidSLA, SLActive, and RoxolidSLActive (Institute Straumann AG, Basel, Switzerland). Physicochemical properties were detected and the biological responses of hBMSCs were observed. Results Surface morphology characterization by scanning electron microscopy and atomic force microscopy revealed differences between the four groups. SLActive had higher surface energy/wettability than SLA, indicating that increased surface energy/wettability can promote the absorption of osteogenic proteins and enhance osseointegration. hBMSCs seeded on SLActive substrates exhibited better performance in terms of cell attachment, proliferation and osteoblastic differentiation than cells seeded on SLA. Conclusion Because of their more suitable physicochemical properties, TiSLActive and TiZrSLActive materials demonstrated more pronounced effects on the biological responses of hBMSCs compared with TiSLA and TiZrSLA .

The Standards for Educational and Psychological Testing emphasize the importance of documenting and describing the procedures followed in developing valid test content. As a result, the Joint Commission on National Dental Examinations, the testing agency responsible for administering the National Board Dental Examination Part I and Part II, routinely communicates information about the validity of Part II to dental schools and other communities of interest. Since 2000, the content of Part II has been validated through the use of three practice analyses. This article provides an overview of these practice analyses, including procedures and findings. In general, the findings confirm that the content of Part II is valid in determining the qualifications of individuals seeking dental licensure.

SUMMARY Regulating reserve is generally deployed to support system frequency. Because the moment-to-moment load fluctuations require continuous frequency control, allocating the reserve for this kind should be flexible to support the function of automatic generation control. Because fast response units not only are assigned to support automatic generation control but also are utilized to deal with credible frequency events, the regulating reserve may be planned as a portion of contingency reserve for security concern, especially for an isolated power system. Without inter-tie to mutually support system frequency, frequency of an isolated system is much more sensitive to the disturbances than that in the interconnection. Therefore, the scheduling of regulating reserve for an isolated system should be more cautious to take both security and economy into account. This paper describes a methodology that adaptively schedules the regulating reserve based on the dynamic security margin as well as the ongoing demand of the system. Compared with the conventional way of using the historical data, the proposed scheduling method is proven to be more capable of dealing with the change of system condition and furthermore potentially reducing the extraneous reserve. More operational cases will be presented to show the merits of the proposed method that is applied to the ancillary service market. Copyright © 2011 John Wiley & Sons, Ltd.

Aim: The prodromal symptoms of schizophrenia are difficult to differentiate from other common psychiatric illnesses or stress reactions. Despite the development of new diagnostic instruments, non-specificity and poor awareness of this clinical entity are still major barriers to early identification of individuals at risk for schizophrenia. This study was conducted to assess differences among three types of mental health professionals in the recognition of prepsychotic phenomena. Methods: A questionnaire was developed that presented 11 case vignettes. The vignettes represented a hypothetical gradient of clinical severity, including stress reactions; very early stage, intermediate-risk stage and very high-risk stage of the schizophrenia prodrome; and full-blown psychosis. The questionnaire was completed by 57 psychiatrists, 44 clinical psychologists and 50 school counsellors. For each vignette, respondents indicated their top three choices among nine different diagnostic considerations. Results: As a group, psychiatrists were most likely to consider schizophrenia for all stages of clinical severity, whereas school counsellors were least likely to. Still, only about half of psychiatrists selected schizophrenia as their first choice for very high-risk cases, and even fewer psychologists and counsellors did so. A proportion of school counsellors failed to recognize full-blown psychosis. Despite the differential propensity in recognition of prepsychotic phenomena, a gradient in considering schizophrenia as a possible diagnosis across the stages of clinical severity was obvious. Conclusions: Psychiatrists, clinical psychologists and school counsellors all need further education, targeting their group-specific proclivities, to improve their sensitivity and specificity in early identification of individuals at risk for schizophrenia.

– Intermaxillary fixation (IMF) with the arch bars or looped wires has been widely used to treat mandible fractures. However, manipulation of these appliances takes time and the medical staff is endangered by wire stabbing injuries. A modified method, the direct bonding technique combined with orthodontic appliances, simplifies the IMF concept to overcome these problems. It is faster, safer and easier to apply while the response of patients, with respect to treatment results, ease of the living and oral hygiene is more favorable. This report presents two cases of mandible fractures treated according to this protocol which resulted in good outcomes as expected.

In this article, we propose a backward group preserving scheme (BGPS) on the advection-dispersion equation (ADE) for tackling of the contamination problems. The BGPS has been successfully applied on the backward heat conduction problems as well as the backward in time Burgers equation, but it has never been applied to solve the ADE. The BGPS is able to recover the spatial distribution of groundwater contaminant concentration in this work. Several numerical examples are worked out, and we show, based on those numerical examples, that the BGPS is applicable to the ADE and the method can also handle the ADE with piecewise constant dispersion coefficients. When a steep gradient is appeared in the solution, several steps of the BGPS can be used to retrieve the desired initial data and its result is better than the marching-jury backward beam equation (MJBBE) method as far as our examples are concerned. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010

Summary Single-molecule spectroscopy and detection are powerful techniques for the study of single fluorescent particles and their interaction with their environment. We present a low-cost system for simultaneous real-time acquisition, storage of inter-photon arrival times and the calculation and display of the fluorescence time trace, autocorrelation function and distribution of delays histogram for single-molecule experiments. From a hardware perspective, in addition to a multi-core computer, only a standard low-cost counting board is required as processing is software-based. Software is written in a parallel programming environment with time crucial operations coded in ANSI-C. Crucial to system performance is a simple and efficient real-time autocorrelation algorithm (acf) optimized for the count rates (approximately 104 cps) encountered in single-molecule experiments. The algorithm's time complexity is independent of temporal resolution, which is maintained at all time delays. The system and algorithm's performance was validated by duplicating the signal from the photon detector and sending it to both the ordinary counter board and a commercial correlator simultaneously. The data acquisition system's robustness under typical single-molecule experimental conditions was tested by observing the diffusion of Rhodamine 6G molecules in deionized water.

Treatment of methyl 2-[6-substituted-3(Z)-hexen-1,5 -diynyl]benzoates (1) with five mol% of palladium chloride and three equivalents of cupric chloride in refluxing acetonitrile gave dibenzo[b,d ]pyran-6-ones (2) in modest to good yields.

Thickness-dependent crystal structure, surface morphology, surface energy, and molecular structure and microstructure of a series of polycrystalline pentacene films with different film thickness ranging from several monolayers to the several hundred nanometers have been investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), contact angle meter, and Raman spectroscopy. XRD studies indicate that thin film polymorphs transformation behaviours are from the orthorhombic phase to the thin-film phase and then to the triclinic bulk phase as measured by the increased tilt angle (θtilt) of the pentacene molecule from the c-axis toward the a-axis. We propose a growth model that rationalizes the θtilt increased along with increasing film thickness in terms of grain size and surface energy varying with film growth using AFM combined with contact angle measurements. The vibrational characterizations of pentacene molecules in different thickness films were investigated by Raman spectroscopy compared to density functional theory calculations of an isolated molecule. In combination with XRD and AFM the method enables us to distinguish the molecular microstructures in different thin film polymorphs. We proposed a methodology to probe the microscopic parameters determining the carrier transport properties based on Davydov splitting and the characteristics of aromatic C–C stretching modes in Raman spectra. When compared to the triclinic bulk phase at a high thickness, we suggest that the first few monolayer structures located at the dielectric surface could have inferior carrier transport properties due to weak intermolecular interactions, large molecular relaxation energy, and more grain boundaries.

Dental enamel is the outermost layer of teeth and the hardest mineralized tissue in the human body. It consists of nanorod-like hydroxyapatite (HA) crystals arranged into a highly organized micro-architectural unit called an enamel prism. These special units play an important role in determining the unique physicochemical properties of dental enamel. Cells (ameloblasts) and enamel proteins are thought to be intimately involved in vivo in producing this unique structure. The aim of this research was to create a similar structure directly by crystal growth without using cells and/or enamel proteins. Using a hydrothermal method we have been able to synthesize these prism-like structures, consisting of fluorapatite (FA) crystals, which are similar to the dimensions of those seen in human enamel. Dental pulp stem cells (DPSCs) were cultured on these crystals and showed the excellent biocompatibility of the FA crystals. The growth mechanism of this structure is outlined and its use in tissue repair is discussed. Ninety-five percent (by volume) of human enamel is comprised of nanorod-like calcium hydroxyapatite crystals, which have an approximate cross section of 25–100 nm and an undetermined length of 100 nm to 100 lm or longer along the c-axis. The typical human enamel prism structure is approximately 5 lm in cross section, and can span the entire enamel thickness, that is, approximately 1–2 mm in length. The prevailing theory is that the ameloblasts secrete amelogenin, a major enamel protein constituting approximately 90 % of all organic matrix material in developing enamel, and this protein plays a vital role in enabling crystallites to form a well-organized prism pattern. These prisms project from the dentino–enamel junction to the enamel surface. The prisms are aligned parallel to each other and separated by an interprismatic structure to form a densely compacted enamel layer. Unlike other calcified tissues, such as dentin and bone, there are no living cells in the mature enamel. The ameloblast cells die after the enamel is formed. Thus, when the enamel is damaged, the body has no ability to regenerate it. The approach to create artificial bone and tooth structures has attracted the interest of many researchers. Kniep and co-workers have described a fluorapatite–gelatine system that resembles the biosystem hydroxyapatite–collagen in both bone and dentine. Recently, Yamagishi et al. have reported a paste of fluoridated hydroxyapatite that could be used to repair a small carious lesion. Although the interface between the precipitated layer from the paste and the tooth surface contains elongated crystals some of which are orientated towards the tooth surface, the unique enamel prism structure is not visible from the transmission electron microscopy (TEM) images. In our previous paper, we reported a way to mimic the natural biomineralization process to create these special structures by modifying synthetic hydroxyapatite nanorods with surfactants that allow the nanorods to self-assemble into an enamel prismlike structure at a water/air interface. However, those self-assembled enamel prism-like structures are small, only about 400 nm in length and 100 nm in cross section, and dispersed randomly. Very recently, Fowler et al. reported that they were able to synthesize an HA bundle structure directly from a solution containing the surfactant bis(2-ethylhexyl)sulfosuccinate sodium salt (AOT), water, and oil. These bundles were only 750 nm to 1 lm in length, 250–350 nm wide and they were dispersed randomly. These unique structures, therefore, have limited applications, and the introduction of other chemicals, for example AOT may cause unnecessary biological effects. The development of nanotechnology has created many ways to grow 1D nanostructures. Among them, the hydrothermal method is a widely adopted technique to create nanorods, nanowires, and whiskers and has already been shown to be an effective way to create long hydroxyapatite nanorods and whiskers. In this study, we demonstrate a direct growth method to produce fluorapatite dental enamel prismlike structures using a hydrothermal technique. A film of compacted well-aligned FA crystals, which was grown on metal plates, had a structure C O M M U N IC A TI O N S

Neurofibromas may arise anywhere along a nerve from the dorsal root ganglion to the terminal nerve branches; however, peroneal nerve involvement is not common. Surgical resection of neurofibroma with total preservation of nerve function had been thought to be difficult. Here, we report a case of an intermuscular intraneural neurofibroma derived from the deep peroneal nerve in a patient with neurofibromatosis type 1. The diagnostic criteria, characteristics of imaging studies, and operative approach are described. The function of the deep peroneal nerve was preserved, with satisfactory results.

Both flow injection methodology and square-wave voltammetry were developed and evaluated for determining codeine in human plasma and pharmaceutical formulations using a Nafion/ruthenium oxide pyrochlore chemically modified electrode. Combining the electrocatalytic function of the ruthenium-oxide pyrochlore with charge-exclusion and the preconcentration features of Nafion perform well in codeine detection. Compared to a bare glassy carbon electrode, the chemically modified electrode exhibits a shift of the oxidation potential in cathodic direction and a marked enhancement of the current response. A linear calibration plot is obtained over the 0–32 μM range in 0.05 M HClO4 solution with a detection limit (3σ) of 10 nM in the square-wave voltammetric method. While, in flow-injection analysis, a linear calibration plot is obtained over the 0.5–40 μM range with a detection limit of 0.86 ng. Quantitative analysis was performed by the standard addition method for codeine content in human plasma and a commercially available drug.

Studies on the solution conformation of the cyclic depsipeptide antibiotic enopeptin A have been carried out using 2D NMR and molecular modelling techniques. The proton resonances of the antibiotic in DMSO-d6 have been assigned by the use of TOCSY and ROESY experiments. The interproton distance information obtained from the ROESY experiments have been used as the basis for elucidating the probable structures in solution. The restrained molecular dynamics technique was applied to calculate the structures in solution, and six resultant structures with fewer distance constraint violations were obtained that satisfy the experimental restraints very well. The conformation of the cyclic moiety of the molecule is well defined whereas the aliphatic chain segment is disordered.

Treatment of methyl 2-[6-substituted-3(Z)-hexen-1,5 -diynyl]benzoates (1) with five mol% of palladium chloride and three equivalents of cupric chloride in refluxing acetonitrile gave dibenzo[b,d ]pyran-6-ones (2) in modest to good yields.

The molecular size of the benzodiazepine (BZ) receptor in the synaptic membrane of brain cortex (bovine or rat) was determined by an improved version of the radiation inactivation method to be 220,000. An identical size was found simultaneously for the associated gamma-aminobutyric acid (GABA) receptor and for the component binding beta-carboline esters. It is proposed that all three activities reside in a single protein or protein complex in the membrane. The size in solution, after extraction into Triton X-100 medium from exhaustively washed membranes, was estimated by sedimentation constant (9.4S) and by gel filtration ( approximately 230,000 apparent MW), again with the BZ and GABA binding activities behaving identically. This size applies to the component that undergoes photoaffinity labelling by [3H]flunitrazepam in the membrane, and contains a 51,000 Mr polypeptide as the BZ-binding subunit. It is concluded that a protein complex or oligomer of 200,000-220,000 MW carries a class of BZ-binding sites and an associated class of GABAA sites.

The application of the RRKM theory to the reverse bimolecular reaction of the amine–borontrifluoride system has been made. The results are in good agreement with experiments.

The thermal decomposition of azomethane-d6 has been studied. There is a short chain reaction, and measurements have been made of the rate of production of N2, CD4, and C2D6. A mechanism is suggested which accounts for these results fairly well. A comparison is made with some similar results of Forst for azomethane. Measurements have also been made of the reaction inhibited by NO. It is believed that the N2 production, extrapolated to zero NO pressure, measures the rate of the initial step CD3N2CD3 2 CD3 + N2. This has an activation energy at high pressures of 50.7 kcal per mole and an Arrhenius A·factor of 1015.49 sec−1. This is to be compared to values of 55.5 and 1017.3 found by Forst and Rice for CH3N2CH3 2 CH3 + N2. The pressure fall-off behavior for CD3N2CD3 2 CD3 + N2 has also been investigated and compared to the theoretical curves, which seem to fit satisfactorily except at the lowest pressure, where experimental errors may be large. Unexpectedly, the fall-off curve crosses that for CH3N2CH3 2 CH3 + N2. It is suggested that the extrapolation to zero NO pressure may not be entirely correct in the CH3N2CH3 case where the chain is longer than with CD3N2CD3. It is believed that the decomposition of azomethane-d6 is a better example for unimolecular-rate theory than is that of azomethane.