Si racetrack optical modulator based on the III-V/Si hybrid MOS capacitor.

We have fabricated a Si racetrack optical modulator based on a III-V/Si hybrid metal-oxide-semiconductor (MOS) capacitor. The III-V/Si hybrid MOS optical phase shifter was integrated to a Si racetrack resonator with a coupling length of 200 µm and a coupling gap of 700 nm. The fabricated Si racetrack resonator demonstrated a small VπL of 0.059 Vcm. For 10-dB optical intensity modulation, the Si racetrack resonator showed a 60% smaller driving voltage than a Mach-Zehnder interferometer modulator with the same phase shifter, leading to a better balance between high energy efficiency and large modulation bandwidth.

Ultra-power-efficient 2 × 2 Si Mach-Zehnder interferometer optical switch based on III-V/Si hybrid MOS phase shifter.

We have demonstrated an ultra-power-efficient 2 × 2 Si Mach-Zehnder interferometer optical switch with III-V/Si hybrid metal-oxide-semiconductor (MOS) phase shifters. The efficient low-loss phase modulation enables low-crosstalk and broadband switching in conjunction with multimode interference couplers consisting of tapered input and output ports. Owing to the negligible gate leakage current in the hybrid MOS capacitor, the power consumption required for switching is 0.18 nW, approximately 107 times smaller than that of a Si thermo-optic phase shifter. We also demonstrated a switching time of less than 20 ns. The III-V/Si hybrid MOS phase shifter is promising for fabricating large-scale Si photonic integrated circuits that require efficient, low-loss, and high-speed optical phase control.

Ovo-vegetarian diet is associated with lower systemic blood pressure in Taiwanese women.

OBJECTIVE: This study was designed to investigate blood pressure (BP) profiles among Taiwanese women with different dietary patterns. STUDY DESIGN: Cross-sectional study. METHODS: A total of 269 non-hypertensive Taiwanese women, 40 years of age or older, were surveyed using structured questionnaires, and measurements of BP and physiological parameters were made. To assess differences among vegans, ovo-vegetarians, and meat eaters in terms of BP, demographic, and health behavior data, the chi-squared and Fisher's exact tests were employed for categorical variables, and analysis of variance and independent t-tests were performed for continuous variables. Multiple regression analysis was used to examine the relationship between BP and dietary patterns while controlling for potential confounding factors. RESULTS: A significant difference was found among the three test groups in terms of age, education, employment, stress, and waist-hip ratio. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) significantly differed among the three groups. After controlling for age, body weight, waist circumference, and hip circumference, the three groups were observed to be a significant risk factor of the SBP and DBP. The SBP and DBP of the ovo-vegetarian group were significantly lower than those of the meat-eater group. No significant differences were found between the vegan and meat-eater groups in terms of SBP and DBP. CONCLUSION: Dietary pattern is a likely risk factor for SBP and DBP outcomes in Taiwanese women. In particular, the SBP and DBP of ovo-vegetarians are the lowest among the values observed for all dietary patterns. This finding suggests that an ovo-vegetarian diet is beneficial for long-term BP control and prevention of hypertension in females.

Autonomic dysreflexia and myocardial ischemia.

STUDY DESIGN: A case report of silent myocardial ischemia in a man with C5 AIS A (American Spinal Injury Association Impairment Scale) tetraplegia during an episode of autonomic dysreflexia (AD). OBJECTIVE: The aim of this study was to show a clinical presentation of myocardial ischemia in individuals with spinal cord injury (SCI). CASE REPORT: A 45-year-old man with chronic C5 complete SCI presented with an episode of uncontrolled AD. He denied any symptoms of typical myocardial ischemia. Despite initiation of the AD management protocol, his blood pressure remained elevated. Additional testing revealed an unexpected horizontal ST depression in the lateral leads with a significant elevation of troponins. A follow-up cardiac angiography and MIBI cardiac perfusion scan revealed normal left ventricular contractility and no evidence of coronary artery occlusion. CONCLUSIONS: In individuals with SCI, the loss of sensory input from the myocardium to supraspinal structures predisposes them to asymptomatic myocardial ischemia. Furthermore, during an episode of AD, a significant increase in visceral sympathetic activity with coronary artery constriction can result in myocardial ischemia, even in the absence of coronary artery disease.

Amyloidosis complicating idiopathic myelofibrosis.

An 84-year-old man presented with ankle edema, significant proteinuria, and mild impairment of renal function soon after treatment was started for idiopathic myelofibrosis. Renal amyloidosis was found on biopsy. The amyloid deposit was resistant to potassium permanganate treatment and showed no immunoreactivity to immunoglobulin light chains, beta-amyloid protein, or amyloid A component. A review of the literature showed that the occurrence of amyloidosis in idiopathic myelofibrosis is very rare, and the chemical nature of the amyloid involved remains unclear.

The immunochemical characterization of the light chains in the mesangial IgA deposits in IgA nephropathy.

The immunochemical characterization of the light chains of the mesangial immunoglobulin A (IgA) deposits were studied in 45 patients with IgA nephropathy. Kappa and lambda light chains were detected with direct immunofluorescence (IF) method, using monospecific rabbit anti-human anti-kappa and anti-lambda anti-sera. The glomeruli of 42 renal biopsies studied were strongly positive for lambda light chain, while only 25 specimens were positive for kappa light chain. Sixty-five percent of the biopsies showed a predominance of lambda light chain IF staining in the mesangial deposits. This IF pattern is unique as compared with similar studies on renal biopsies from patients with systemic lupus erythematosus, idiopathic membranous nephropathy, and normal postmortem renal tissue. The results indicate that mesangial IgA deposits in IgA nephropathy consist mainly of IgA with lambda light chains despite the fact that the normal ratio of kappa to lambda light-chain-containing immunoglobulin in human serum is two to one.

An overlapping syndrome of IgA nephropathy and lipoid nephrosis.

The authors studied eight cases of IgA nephropathy presenting with nephrotic syndrome. Renal biopsy revealed only mild mesangial proliferation or minor glomerular changes on light microscopic examination but typical features of IgA nephropathy on immunofluorescent and electron microscopic examination. A satisfactory response characterized by correction of hypoalbuminemia, clearance of proteinuria, and an increase of endogenous creatinine clearance occurred with corticosteroid therapy. These cases represent a variant of IgA nephropathy associated with a nephrotic syndrome that resembles lipoid nephrosis in its responsiveness to steroid.

Magnetic resonance imaging of the elbow.

The application of magnetic resonance imaging to elbow imaging holds great promise in view of the ability to demonstrate the complex anatomy of the elbow in multiple imaging planes with high soft-tissue contrast. Inflammatory or noninflammatory processes and traumatic disorders all may be well assessed by magnetic resonance imaging, particularly articular disorders or marrow and surrounding soft-tissue lesions. Evaluation and staging of neoplasms also may be done using magnetic resonance imaging.

Sunlight exposure, antioxidant status, and cataract in Hong Kong fishermen.

STUDY OBJECTIVES: The aim was to test whether cataract is associated with higher lifetime exposure to sunlight, and whether antioxidants protect against cataract. DESIGN: This was a cross sectional survey of eye disease, with assessment of antioxidant status in a subgroup. SETTING: Hong Kong fishing communities in 1989. PARTICIPANTS: 685 men and women aged 55 to 74 years old were included in the study, of whom 367 (54%) attended hospital for detailed examination. MEASUREMENTS AND MAIN RESULTS: At a mobile clinic visual acuity and lens opacities were assessed, and using a questionnaire, occupational history and lifetime exposure to sunlight. At hospital ophthalmic measurements were repeated and blood was taken for measurement of plasma vitamin C, vitamin E, and total carotenoids, and red cell activities of glucose-6-phosphate dehydrogenase, glutathione peroxidase, superoxide dismutase, and catalase. Higher grades of cataract (particularly nuclear cataract) tended to be more common in subjects with the most sun exposure, although not to the point of statistical significance. In contrast to earlier studies, no association was found with antioxidant status. CONCLUSIONS: The findings give some support to the hypothesis that sunlight causes cataract. The absence of a relation to antioxidant status may be because blood levels of antioxidants at one point in time do not adequately reflect a subject's past metabolic state, and particularly the past activity of antioxidants in the lens.

Corticosteroid therapy in IgA nephropathy with nephrotic syndrome: a long-term controlled trial.

A randomized prospective study of 34 patients with IgA nephropathy and nephrotic syndrome was conducted to determine the therapeutic value of corticosteroid therapy. The patients were divided into two groups: Group A, 17 patients receiving oral prednisolone/prednisone for four months; and Group B, 17 patients receiving no corticosteroid therapy and acting as controls. The groups are comparable in age of presentation, sex ratio, and duration of study. No difference in serum creatinine levels, creatinine clearance, serum IgA levels, severity of renal histopathological changes, incidence of hypertension or incidence of impaired renal function could be demonstrated but the Group A patients had significantly heavier proteinuria. During the mean study period of 38 months (range 12-106), no significant difference in serum creatinine levels and creatinine clearance was demonstrated between the two groups. Forty percent of the Group A patients developed complications related to steroid therapy. Despite the overall lack of therapeutic value in IgA nephropathy with nephrotic syndrome as reflected by change in renal function, corticosteroid treatment resulted in excellent remission of nephrotic syndrome in 80% of patients with mild glomerular histopathological changes. Our findings suggest that corticosteroid therapy is only beneficial to selected groups of patients with IgA nephropathy and nephrotic syndrome but its indiscriminate use should be discouraged.

MR imaging of tendon injuries in the elbow.

Tendon injuries are among the more common sources of elbow pain, resulting from occupational and sports activities as well as the activities of daily living. The exquisite soft-tissue contrast resolution and multiplanar capability of MR imaging have proven ideal for evaluating, diagnosing, and managing tendon injuries. Familiarity with normal anatomy, the spectrum of tendon derangement from tendinosis to complete tears, and the typical injury mechanisms involved in tendinopathy about the elbow are all invaluable for appropriate MR imaging examination and interpretation.

MR imaging of rotator interval, long biceps, and associated injuries in the overhead-throwing athlete.

The rotator interval between supraspinatus and subscapularis is proving to be an important anatomic and functional region of the shoulder. Appreciation of the anatomic structures, functional importance, and mechanisms of injury are invaluable in appropriate assessment, both by physical examination and diagnostic MR imaging. The long biceps tendon; the superior labrum and labral-biceps anchor; the coracohumeral ligament merging with the rotator interval capsule and the superior glenohumeral ligament; the ligamentous reflection pulley for the long biceps tendon at the far lateral margin of the interval extending to the lesser tuberosity and proximal bicipital groove, bounded by the distal superior margin of the subscapularis and anterior margin of the supraspinatus tendons; and the transverse humeral ligament extending between the lesser and greater tuberosities along the proximal bicipital groove all are intimately associated in this region and may be injured together. Understanding of the anatomy and function of the rotator interval continues to evolve. Rotator interval injury may be better understood as a complex or spectrum rather than an isolated lesion. When any one of the spectrum of associated injuries is suspected or found, all of the other possible associated injuries should be considered and evaluated, both on clinical and MR imaging evaluations.

MR imaging of knee anterior cruciate ligament and associated injuries in skiers.

Tears of the ACL have become widespread in the skiing population. Understanding of the mechanisms and patterns of associated injury of such ACL tears has benefited from and contributed greatly to clinical and imaging evaluation and management. MR imaging of the injured knee has become the gold standard comprehensive imaging examination for evaluating the ACL tear and associated soft-tissue and osseous injuries and assisting the treating physician in planning management, as the isolated ACL tear has proven to be the exception rather than the rule in skiing knee injuries.

Role of MR imaging in the management of injuries in professional football players.

This article discusses the effectiveness of MR imaging in evaluating the injuries of both upper and lower extremities in the professional football player. Topics include bone, joint and soft tissue disorders, and injuries resulting from overuse or trauma of the shoulder, elbow, forearm, and wrist; the pelvis and hip, lower extremity muscle and tendon, knee, and ankle.

Role of MR imaging in sports medicine research. Basic science and clinical research studies.

The advent and advancement of MR imaging have provided an entire new dimension for medical imaging. MR imaging has been especially useful because of its capacity to image nonmineralized tissues with a very high degree of resolution. Although modalities such as ultrasound and scintigraphy have proven useful for specific purposes, it is MR imaging that has the most utility and capabilities, especially in the area of sports-induced injuries. The technology associated with MR imaging has expanded greatly, and it continues to evolve at a rapid pace. The result has been an ever-increasing diagnostic capability that has become more economic with time. As described previously, MR imaging is gaining importance in the area of comparative medicine for animal athletes as well. It is also interesting to note that MR imaging now has a greater potential for monitoring physiological and biochemical changes as well as anatomic ones. Some newer MR units actually include physiologic data acquisition components. Consequently, new bioassays and nondestructive tissue tests can be performed to further understand the molecular biology and ongoing cellular processes in any given condition. Coupled with MR spectroscopy, the enhanced MR techniques should continue to contribute to the overall information that will be integrated into the training and rehabilitation of patients with sports-induced inflammation and injuries. The authors support and encourage ongoing efforts in the area of MR imaging research, both basic science and clinical studies.

MR imaging of the thrower's shoulder. Internal impingement, latissimus dorsi/subscapularis strains, and related injuries.

In conclusion, internal impingement apparently occurs in nearly all patients and is demonstrable on MR imaging. Pathologic changes associated with internal impingement seem to develop with repetitive placement of the arm into a position of extreme external rotation and abduction. Findings may include lesions of the posterior superior labrum, undersurface irritation, or tearing of the supraspinatus-infraspinatus junction near the attachment site and cystic changes of the posterior superior glenoid and posterior lateral greater tuberosity. There is no evidence for a particular sequence of pathologic changes. Instability may be associated with but does not appear to be a prerequisite for the development of the pathologic lesions of internal impingement.