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Maintaining high average fields between the gate and drain is imperative in achieving near theoretical performance in ultra-wide band gap semiconductors like $\beta $ -Ga2O3. In this letter we report on a field management strategy to reduce the peak electric field at the drain side corner of the gate by using a composite dielectric layer consisting of an extreme permittivity dielectric like BaTiO3 and a low- $\kappa $ dielectric like SiO2 overlapped over the gate electrode. Using this strategy in $\beta $ -(Al0.18Ga0.82)2O3/ Ga2O3 double heterojunction field effect transistor, we achieved a record average breakdown field of 5.5 MV/cm at a gate-drain spacing of $1.15~\mu \text{m}$ along with an improved power figure of merit of 408 MW/cm2. The reported works shows the effectiveness of integrating extreme dielectric materials with ultra-wide band gap semiconductors in significantly improving breakdown performance.

The performance of ultra-wide bandgap semiconductors like ${\beta }$ -Ga2O3 is critically dependent on achieving high average electric fields within the active region of the device. In this article, we show that dielectrics like BaTiO3 with extremely high dielectric constant can provide an efficient field management strategy by improving the uniformity of electric field profile within the gate–drain region of lateral field-effect transistors. Using this strategy, we achieved high average breakdown field of 1.5 and 4 MV/cm at gate–drain spacing ( ${L}_{\text {gd}}$ ) of 6 and $0.5~{\mu }\text{m}$ , respectively in ${\beta }$ -Ga2O3, at a high channel sheet charge density of $1.6\,\,{\times }\,\,10^{{13}}$ cm−2. The high channel charge density along with the high breakdown field enabled a record power figure of merit ( ${V}_{\text {br}}^{{2}}/{R}_{\text {ON}}$ ) of 376 MW/cm2 at a gate–drain spacing of ${3}~{\mu }\text{m}$ .

A novel edge-termination concept using extreme permittivity dielectrics is proposed to effectively manage electric fields in vertical power-devices. This method is expected to be particularly significant for wide band-gap semiconductors, where field termination is a significant challenge due to material and process limitations. Detailed two-dimensional device simulation is used to prove the efficacy of this idea, and to demonstrate that peak electric fields are significantly reduced by this method. We also show an analytical model that gives an intuitive picture into the mechanism of high-permittivity dielectric field plate. Low process complexity and flexibility in the design of power devices can be achieved. We show that junction termination efficiency can be increased from 22.7% (no junction termination) and 50% (conventional field plate) to 73% (high-permittivity-terminated device).

This report discusses the design and demonstration of β-(Al0.17Ga0.83)2O3/Ga2O3 modulation doped heterostructures to achieve high sheet charge density. The use of a thin spacer layer between the Si delta-doping and the heterojunction interface was investigated in a β-(AlGa)2O3/Ga2O3 modulation doped structure. It is shown that this strategy enables a higher two-dimensional electron gas (2DEG) sheet charge density up to 4.7 × 1012 cm−2 with an effective mobility of 150 cm2/V s. The presence of a degenerate 2DEG channel was confirmed by the measurement of a low temperature effective mobility of 375 cm2/V s and the lack of carrier freeze out from low temperature capacitance voltage measurements. The electron density of 4.7 × 1012 cm−2 is the highest reported 2DEG density obtained without parallel conducting channels in a β-(AlxGa(1−x))2O3/Ga2O3 heterostructure system.

We report on the origin of high Si flux observed during the use of Si as a doping source in plasma assisted MBE growth of β-Ga2O3. We show on the basis of secondary ion mass spectroscopy analysis that Si flux is not limited by the vapor pressure of Si but by the formation of volatile SiO. The low sublimation energy of SiO leads to a weak dependence of the SiO flux of Si cell temperature and a strong dependence on the background oxygen pressure. Extended exposure to activated oxygen results in reduction of SiO flux due to the formation of SiO2 on the Si surface. The work reported provides key understanding for incorporating Si into future oxide-based semiconductor heterostructure and device MBE growth.

Drug development in the United States has undergone many changes in the past 25 years, but relatively few fully realize the complexities involved in developing a new drug. Once a promising compound is identified, it must undergo preclinical testing, have an Investigational New Drug Application filed with the U.S. Food and Drug Administration (FDA), and proceed through clinical testing. When sufficient information is gained, a marketing application is filed with the FDA, who identifies it as a New Drug Application for drugs or a Biologics License Application for biologics. After FDA review and approval, postmarketing studies are frequently performed. The FDA and Congress have undertaken several initiatives to expand access and to accelerate drug development and review of investigational drugs for life-threatening and/or serious illnesses. Although the ultimate goal is to bring safer and more effective medical products to patients in a timely manner, multiple challenges face those who participate in drug development.

In this 5-year prospective study, we determined the feasibility of reducing polypharmacy in a long-term care institution by a systematic review of the pharmacy records. At 6-month intervals, the computer printout of all medications prescribed to patients in a 550-bed institution was reviewed. After patients taking more than 10 different drugs were identified, their physician was notified and was asked to review their medications according to specific guidelines. The number of patients taking 10 or more medications was reduced from 67, when the program was started, to 9. The average number of medications per patient was reduced from 5.5 to 4.6. This program reduced the prevalence of polypharmacy and had long-lasting effects on the physicians' prescribing habits. We also believe it led to improved patient care by reducing the potential for drug interactions and to cost savings for the pharmacy.

To determine the clinical presentation and manifestations of Paget's disease of the bone in patients older than 60 years, we reviewed the cases of 56 patients attending a bone clinic. Pain was the presenting symptom in 34 cases. It was attributed to the disease process in 21 cases, to osteoarthritis in 11, to trigeminal neuralgia in 1, and to osteosarcoma in 1. Other clinical manifestations included deformities (15 cases), diminished mobility and unsteady gait (9), hearing impairment (7), lethargy (4), diminished vision (3), cognitive deficit (3), sense of warmth in limbs (2), ill-fitting dentures (1), and fracture (1). We concluded that in patients older than 60 years, Paget's disease of the bone may present itself in a variety of ways, some of which may be mistakenly attributed to the "aging process" or some other disease. Furthermore, in this age group, osteoarthritis is responsible for the pain experienced by about one third of symptomatic patients.

To compare the efficacy and safety of nandrolone decanoate and calcium (NDC) with those of calcium alone (CAL) in men with idiopathic osteoporosis, a 12-month, randomized, prospective, controlled study, was performed in an outpatient clinic. Twenty-one men with idiopathic osteoporosis (as determined by radiological and dual energy x-ray absorptiometry findings) were randomly allocated to either 50 mg nandrolone decanoate intramuscularly (im) weekly and 1,000 mg oral calcium carbonate daily (NDC group) or to 1,000 mg oral calcium carbonate daily (CAL group). Bone densitometry (total body, left femur, and lumbar spine), serum, and urine biochemical parameters were measured at 3-month intervals. In the NDC group, bone mineral density initially increased, reached a plateau, and then decreased to near baseline levels at 12 months. Increases in lean muscle mass mirrored these changes. Free and total testosterone significantly decreased. Hemoglobin increased in all patients in this group. Patients in the CAL group exhibited no significant change in either total body or bone mineral density or biochemical parameters. Thus, nandrolone decanoate, 50 mg im weekly, transiently increases the bone mass of men with idiopathic osteoporosis in this preliminary study. Careful monitoring is necessary.

The purpose of the study was to determine the long-term effects of muscle weakness secondary to strokes on the bone mineral content of the hemiparetic limb. Patients who had experienced single recent strokes were studied. The bone mineral content of each limb was measured by Dual Energy X-ray Absorptiometry using the region of interest analysis program. Muscle strength of each muscle group was ranked using the Oxford scale, and the mean was calculated for each limb. Bone and muscle parameters were measured within seven days after the stroke and repeated thereafter at monthly intervals for up to 6 mo. A repeated measures analysis of variance, Newman-Keuls pair-wise comparisons, and orthogonal contrasts were done for each parameter. Significance levels were set at P < 0.05. Sixteen patients were included in this study. Demineralization was more pronounced in the upper than lower limbs. Demineralization of bones on the paralyzed side started during the first month after the stroke and gradually progressed. By the fourth month, the bone mineral content decreased by a mean of 9.3% (P = 0.01) and 3.7% (P = 0.01) in the upper and lower limbs, respectively, for the 11 patients followed for 4 mo. In the patients we followed for more than 4 mo, there was no further significant mineral loss. No change in bone mineral content was observed in the healthy nonparetic limbs. In conclusion, after a stroke, bone demineralization occurs in the paralyzed side and reaches its maximum within 3 to 4 mo. Arms are affected more than legs.