Magnetic-field-controlled reconfigurable semiconductor logic.

Logic devices based on magnetism show promise for increasing computational efficiency while decreasing consumed power. They offer zero quiescent power and yet combine novel functions such as programmable logic operation and non-volatile built-in memory. However, practical efforts to adapt a magnetic device to logic suffer from a low signal-to-noise ratio and other performance attributes that are not adequate for logic gates. Rather than exploiting magnetoresistive effects that result from spin-dependent transport of carriers, we have approached the development of a magnetic logic device in a different way: we use the phenomenon of large magnetoresistance found in non-magnetic semiconductors in high electric fields. Here we report a device showing a strong diode characteristic that is highly sensitive to both the sign and the magnitude of an external magnetic field, offering a reversible change between two different characteristic states by the application of a magnetic field. This feature results from magnetic control of carrier generation and recombination in an InSb p-n bilayer channel. Simple circuits combining such elementary devices are fabricated and tested, and Boolean logic functions including AND, OR, NAND and NOR are performed. They are programmed dynamically by external electric or magnetic signals, demonstrating magnetic-field-controlled semiconductor reconfigurable logic at room temperature. This magnetic technology permits a new kind of spintronic device, characterized as a current switch rather than a voltage switch, and provides a simple and compact platform for non-volatile reconfigurable logic devices.

Ferromagnet-Free All-Electric Spin Hall Transistors.

The spin field-effect transistor, an essential building block for spin information processing, shows promise for energy-efficient computing. Despite steady progress, it suffers from a low-output signal because of low spin injection and detection efficiencies. We demonstrate that this low-output obstacle can be overcome by utilizing direct and inverse spin Hall effects for spin injection and detection, respectively, without a ferromagnetic component. The output voltage of our all-electric spin Hall transistor is about two orders of magnitude larger than that of previously reported spin transistors based on ferromagnets or quantum point contacts. Moreover, the symmetry of the spin Hall effect allows all-electric spin Hall transistors to effectively mimic n-type and p-type devices, opening a way of realizing the complementary functionality.

Cardiopulmonary and anesthetic effects of the combination of butorphanol, midazolam and alfaxalone in Beagle dogs.

OBJECTIVE: To evaluate the physiological variables, arterial blood gas values, induction of anesthesia quality, and recovery quality using the combination of butorphanol, midazolam and alfaxalone in dogs. ANIMALS: Ten healthy adult Beagle dogs weighing 8.3 ± 3.1 kg. METHODS: Rectal temperature (T), pulse rate (PR), respiratory rate (f(R)), mean arterial pressure (MAP), and arterial blood gases were measured and recorded prior to intravenous (IV) administration of butorphanol, prior to administration of both midazolam and alfaxalone IV 10 minutes later, then every 5 minutes for 20 minutes. M-mode echocardiographic left ventricular (LV) indices were measured before and 5 minutes after administration of alfaxalone. Qualitative scores for induction of anesthesia and recovery were allocated, duration of anesthesia and recovery were calculated, and adverse events were recorded. RESULTS: Scores for induction and recovery quality were excellent. No significant adverse events were observed. Mean ± SD time from induction to extubation and to standing (full recovery) was 29 ± 6 and 36 ± 8 minutes, respectively. There were statistically significant changes in PR, f(R) and MAP after drug administration. Transient hypercarbia developed after alfaxalone injection. The echocardiographic LV indices were reduced after alfaxalone injection, although those changes were not statistically significant. CONCLUSIONS AND CLINICAL RELEVANCE: The combination of butorphanol, midazolam and alfaxalone provided excellent quality of induction of anesthesia and exerted minimal cardiopulmonary effects in healthy dogs.

Interaction between Rashba and Zeeman effects in a quantum well channel.

The applied field induced Zeeman effect interferes with Rashba effect in a quantum well system. The angle dependence of Shubnikov-de Haas oscillation shows that the in-plane term of the applied field changes the intrinsic Rashba induced spin splitting. The total effective spin-orbit interaction parameter is determined by the vector sum of the Rashba field and the applied field.

Harmful gases including carcinogens produced during transurethral resection of the prostate and vaporization.

OBJECTIVE: To determine the chemical composition of surgical smoke produced during transurethral resection of the prostate (TURP) and vaporization. METHODS: A total of 12 smoke samples were collected from a continuous irrigation suction drainage system to a Tenax absorber at a 0.05L/min flow rate during TURP and vaporization. The gases were quantitatively and qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS) equipped with a purge and trap sample injector. RESULTS: The main chemical constituents of surgical smoke produced during TURP and vaporization include propylene, allene, isobutylene, 1,3-butadiene, vinyl acetylene, mecaptomethane, ethyl acetylene, diacetylene, 1-pentene, EtOH, piperylene, propenylacetylene, 1,4-pentadiene, cyclopentadiene, acrylnitrile and butyrolactone. Three of the constituents are very toxic and carcinogenic (1,3-butadiene, vinyl acetylene and acrylonitrile). The amount (mean±standard deviation) of chemical components in the 45L of gas and room air mixture produced during TURP and vaporization were as follows: propylene, 0.80±0.52mg; isobutylene, 212.85±75.65mg; 1,3-butadiene, 0.93±0.34mg; ethyl acetylene, 0.09±0.05mg; 1-pentene, 6.75±1.62mg; 1,4-pentadiene, 0.06±0.02mg; and acrylonitrile, 1.62±1.19mg. CONCLUSIONS: Three of the toxic gases generated during TURP and vaporization are carcinogens (1,3-butadiene, vinyl acetylene and acrylonitrile). Therefore, higher quality filter masks, smoke evacuation devices and/or smoke filters should be developed for the safety of the operating room personnel and patients during TURP and vaporization.

Multi-terminal spin valve in a strong Rashba channel exhibiting three resistance states.

In a strong spin-orbit interaction system, the existence of three resistance states were observed when two ferromagnetic (FM) contacts were used as current terminals while a separate normal metal contact pair was used as voltage terminals. This result is strikingly different from ordinary spin valve or magnetic tunnel junction devices, which have only two resistance states corresponding to parallel (RP) and antiparallel (RAP) alignments of the FM contacts. Our experimental results on a quantum well layer with a strong Rashba effect clearly exhibit unequal antiparallel states, i.e., RAP(1) > RP > RAP(2), up to room temperature. The three-states are observed without any degradation when the distance between the non-magnetic voltage probe and the ferromagnetic current probe was increased up to 1.6 mm.

Complementary spin transistor using a quantum well channel.

In order to utilize the spin field effect transistor in logic applications, the development of two types of complementary transistors, which play roles of the n- and p-type conventional charge transistors, is an essential prerequisite. In this research, we demonstrate complementary spin transistors consisting of two types of devices, namely parallel and antiparallel spin transistors using InAs based quantum well channels and exchange-biased ferromagnetic electrodes. In these spin transistors, the magnetization directions of the source and drain electrodes are parallel or antiparallel, respectively, depending on the exchange bias field direction. Using this scheme, we also realize a complementary logic operation purely with spin transistors controlled by the gate voltage, without any additional n- or p-channel transistor.

Large spin accumulation and crystallographic dependence of spin transport in single crystal gallium nitride nanowires.

Semiconductor spintronics is an alternative to conventional electronics that offers devices with high performance, low power and multiple functionality. Although a large number of devices with mesoscopic dimensions have been successfully demonstrated at low temperatures for decades, room-temperature operation still needs to go further. Here we study spin injection in single-crystal gallium nitride nanowires and report robust spin accumulation at room temperature with enhanced spin injection polarization of 9%. A large Overhauser coupling between the electron spin accumulation and the lattice nuclei is observed. Finally, our single-crystal gallium nitride samples have a trigonal cross-section defined by the (001), () and () planes. Using the Hanle effect, we show that the spin accumulation is significantly different for injection across the (001) and () (or ()) planes. This provides a technique for increasing room temperature spin injection in mesoscopic systems.

Buccal adhesive nanofibers containing human growth hormone for oral mucositis.

Due to a lack of proper drug carriers to deliver treatments for mucositis, many cancer patients suffer from oral mucositis caused by chemotherapy and radiotherapy. We prepared a double-layered electrospun nanofibrous sheets composed of Eudragit and chitosan to accelerate the healing rate of oral mucous ulcer. Human growth hormone (hGH) and Eudragit in a mixture of dimethylacetamide and ethanol were co-electrospun to nanofibrous sheets. The electrospun fibrous mat was subsequently layered with chitosan by a dip-coating method. Chitosan-layered sheets showed attenuated mass erosion while uncoated sheets were instantly melted at the physiological condition. The released hGH was trapped on the chitosan layer by the ionic interaction between positively charged chitosan and negatively charged hGH, and a large number of entrapped proteins remained on the SIS membrane due to the muco-adhesive properties of chitosan. hGH-incorporated sheets significantly increased proliferation of human dermal fibroblasts. In vivo study employing oral ulcers in dogs, the ulcers dressed with chitosan-layered sheets showed enhanced wound recovery and the chitosan layers on the sheet greatly assisted prolonged recovery. Therefore, chitosan-layered Eudragit nanofibrous sheets can be potentially applied to developing muco-adhesive wound dressing materials with pH-dependent drug release by adjusting the thickness of chitosan sheath on the sheets. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1396-1406, 2016.

Electrical detection of coherent spin precession using the ballistic intrinsic spin Hall effect.

The spin-orbit interaction in two-dimensional electron systems provides an exceptionally rich area of research. Coherent spin precession in a Rashba effective magnetic field in the channel of a spin field-effect transistor and the spin Hall effect are the two most compelling topics in this area. Here, we combine these effects to provide a direct demonstration of the ballistic intrinsic spin Hall effect and to demonstrate a technique for an all-electric measurement of the Datta-Das conductance oscillation, that is, the oscillation in the source-drain conductance due to spin precession. Our hybrid device has a ferromagnet electrode as a spin injector and a spin Hall detector. Results from multiple devices with different channel lengths map out two full wavelengths of the Datta-Das oscillation. We also use the original Datta-Das technique with a single device of fixed length and measure the channel conductance as the gate voltage is varied. Our experiments show that the ballistic spin Hall effect can be used for efficient injection or detection of spin polarized electrons, thereby enabling the development of an integrated spin transistor.

Electric-field-induced spin injection enhancement.

The spin diffusion process can be modified by the electric field in a semiconductor channel. The electric field generated by the bias current improves the spin injection efficiency as well as the spin diffusion length at a ferromagnet-semiconductor hybrid system. Spin-polarized electrons from the ferromagnetic electrode were electrically investigated in an inverted heterostructure with an In0.53Ga0.47As active layer. Using local and non-local spin valve geometries, the interfacial spin polarizations with and without an electric field are extracted from the magnitude of spin transport signals. The interfacial spin polarization is increased from 3.2% to 7.0% with a current of 1 mA at T = 20 K. When the electric field assists the spin injection at the junction, the interfacial spin polarization remains 7% at the temperature ranged from 20 K to 200 K. Temperature dependence of the injected polarization shows that the electric field can compensate the thermal smearing of injection efficiency even at higher temperature.

Comparison of harmful gases produced during GreenLight High-Performance System laser prostatectomy and transurethral resection of the prostate.

OBJECTIVE: To compare the gases generated from GreenLight High-Performance System (HPS) laser prostatectomy with Urosol or normal saline solution and transurethral resection and vaporization of the prostate (TURVP) with Urosol. METHODS: A total of 36 smoke samples were collected from a continuous irrigation suction system attached to a Tenax absorber during transurethral surgery of the prostate. The gases were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry equipped with a purge and trap sample injector. RESULTS: The gas produced during TURVP contained propylene, allene, isobutylene, 1,3-butadiene, vinyl acetylene, mercaptomethane, ethyl acetylene, diacetylene, 1-pentene, ethanol, piperylene, propenylacetylene, 1,4-pentadiene, cyclopentadiene, acrylnitrile, and butyrolacton. The types and amount of gas produced during HPS laser prostatectomy were fewer and smaller than during TURVP. However, 1,3-butadiene, a well-known human carcinogen, was also generated by HPS laser prostatectomy. HPS laser prostatectomy with saline produced a greater amount and number of gases than HPS laser prostatectomy with Urosol. CONCLUSION: The surgical smoke produced from TURVP and HPS laser prostatectomy contains potentially harmful chemical compounds, although HPS laser prostatectomy produced less surgical smoke than TURVP. Urosol produced fewer types and a smaller amount of gas than normal saline during HPS laser prostatectomy.

Is warm temperature necessary to prevent urethral stricture in combined transurethral resection and vaporization of prostate?

OBJECTIVES: To compare the effect of warm and room temperature irrigation solution on the incidence of urethral stricture during combined transurethral resection and vaporization of the prostate (CTURVP). Urethral stricture after transurethral surgery of the prostate is a bothersome complication. Warm irrigation improves the blood flow and might decrease the incidence of urethral stricture compared with the use of room temperature irrigation, which decreases the blood flow in the urethral mucosa, resulting in ischemic injury. METHODS: The patients who underwent CTURVP were divided into those receiving only room temperature irrigation solution (group 1, 75 patients) or warm irrigation solution with a system maintaining the temperature of the ventral penile skin at about 36 degrees C continuously (group 2, 78 patients). At follow-up, 1, 3, and 6 months later, the International Prostate Symptom Score and peak urine flow rate were evaluated. RESULTS: The temperature of the ventral penile skin was 20 degrees C and 36 degrees C in groups 1 and 2, respectively. The rate of urethral stricture was 21.3% in group 1 and 6.3% in group 2 at the end of 6 months of follow-up (P = .002). CONCLUSIONS: The results of our study have shown that maintaining the temperature of the urethra with warm irrigation solution during CTURVP probably decreases the incidence of urethral stricture. The temperature in the urethra could be another important factor in stricture formation after CTURVP.

Control of spin precession in a spin-injected field effect transistor.

Spintronics increases the functionality of information processing while seeking to overcome some of the limitations of conventional electronics. The spin-injected field effect transistor, a lateral semiconducting channel with two ferromagnetic electrodes, lies at the foundation of spintronics research. We demonstrated a spin-injected field effect transistor in a high-mobility InAs heterostructure with empirically calibrated electrical injection and detection of ballistic spin-polarized electrons. We observed and fit to theory an oscillatory channel conductance as a function of monotonically increasing gate voltage.