A New Low Complexity Angle of Arrival Algorithm for 1D and 2D Direction Estimation in MIMO Smart Antenna Systems.

This paper proposes a new low complexity angle of arrival (AOA) method for signal direction estimation in multi-element smart wireless communication systems. The new method estimates the AOAs of the received signals directly from the received signals with significantly reduced complexity since it does not need to construct the correlation matrix, invert the matrix or apply eigen-decomposition, which are computationally expensive. A mathematical model of the proposed method is illustrated and then verified using extensive computer simulations. Both linear and circular sensors arrays are studied using various numerical examples. The method is systematically compared with other common and recently introduced AOA methods over a wide range of scenarios. The simulated results show that the new method has several advantages in terms of reduced complexity and improved accuracy under the assumptions of correlated signals and limited numbers of snapshots.

Myxoid malignant fibrous histiocytoma mimicking papular mucinosis.

Malignant fibrous histiocytoma is the most common type of soft tissue sarcoma in late adulthood. The myxoid variant of malignant fibrous histiocytoma, also known as myxofibrosarcoma, can develop in subcutaneous rather than deep soft tissue, and the true extent of these superficial tumors is often underestimated. Patients with these low-grade myxoid malignant fibrous histiocytomas have an excellent 5-year survival rate, and it is therefore important to recognize them. We present a case with a superficial cutaneous accumulation of mucin that was diagnosed clinically and histologically as papular mucinosis. In retrospect, a subcutaneous presentation of myxofibrosarcoma should have been considered.

A renin secreting ovarian steroid cell tumour associated with secondary polycythaemia.

A 67-year-old woman presented with dry skin, facial hair, hoarse voice, and weight gain. She was hypertensive (168/ 96 mm Hg), her haemoglobin concentration was 19 g/l, and haematocrit was 55.7%. The diagnosis of probable secondary polycythaemia was made. Blood testosterone concentration was 44 nmol/l (normal < 5) and was not suppressed by dexamethasone, suggesting a neoplastic source rather than a pituitary abnormality. Transvaginal ultrasound revealed a hypoechoic solid mass in the left ovary suggestive of a solid ovarian tumour. Hysterectomy and bilateral salpingo-oophorectomy were performed following which testosterone concentration returned to normal. Immunocytochemistry provided evidence of renin synthesis. This is a case of an unusual steroid cell tumour that caused virilisation accompanied by symptoms of secondary polycythaemia presumably as a result of erythropoietin production. This is the second case of a steroid cell tumour with an erythropoietic effect and the first that shows evidence of renin synthesis.

Sequential malt lymphomas of the stomach, small intestine, and gall bladder.

Low grade lymphomas of mucosa associated lymphoid tissue (MALT) are indolent neoplasms that, although tending to remain localised for many years, may spread to other mucosal sites. A 53 year old woman treated by total gastrectomy for low grade MALT lymphoma of the stomach developed a recurrence in the small bowel 18 years later, and a further recurrence involving the gall bladder after three years in complete clinical remission after chemotherapy. In situ hybridisation showed that the small intestine and gall bladder recurrences had the same pattern of light chain restriction. Tumour from all three sites was shown to be derived from a single clone by the demonstration of an identical immunoglobulin heavy chain gene rearrangement by the polymerase chain reaction. The case illustrates the propensity of MALT lymphomas to "home" to mucosal sites and gives an insight into their behavior over an extended follow up.

Effusion cytology of hepatocellular carcinoma with in situ hybridisation for human albumin.

While the cytological features of hepatocellular carcinoma on fine needle aspiration cytology are well described, cases of hepatocellular carcinoma with malignant cells in ascitic fluid and their characteristics are not. A patient is described with cirrhosis resulting from chronic hepatitis B virus infection, ascites, and hepatocellular carcinoma diagnosed by effusion cytology. The malignant cells in the effusion were shown to be positive for alpha fetoprotein using immunocytochemistry, and for human albumin using in situ hybridisation, confirming the diagnosis of hepatocellular carcinoma. Further investigations in a terminally ill patient were thus avoided.

Osteochondroma of the tongue.

A case is described of osteochondroma of the tongue and the literature on osteomata, chondromata and osteochondromata of the tongue is reviewed. The tendency for these tumours to arise in the region of the foramen caecum has been noted in previous reports as has the female preponderance. It has been suggested that they arise from remnants of branchial arch cartilage. The variation in the duration and age at presentation of the lesion has not been explained and an alternative theory is suggested.

Hypernatraemic dehydration in patients in a large hospital for the mentally handicapped.

OBJECTIVE: To determine the prevalence of hypernatraemic dehydration and to assess the hydration and nutritional state of patients in a large hospital for the mentally and physically handicapped; also to assess the efficacy of an intervention programme to reduce the prevalence of hypernatraemic dehydration in the hospital. DESIGN: Prospective study of patients admitted with hypernatraemic dehydration from a large hospital for mentally and physically handicapped patients (hospital A) to a district general hospital between 1986 and 1988. In 1986 the hydration and nutritional state of a random sample of patients from hospital A was compared with a random sample of patients from a small hospital for the physically and mentally handicapped (hospital B) and with control groups from the community. The hydration of the patients from hospital A examined in 1986 was reassessed in 1988. PATIENTS: 12 Patients were admitted from hospital A to the district general hospital during 1986-8 (seven women, five men; age range 29-82). In 1986, 72 patients were randomly selected for the assessment of hydration and nutritional state from hospital A, 33 who required help with feeding and 39 who could feed independently. Fifty patients were similarly selected from hospital B, half of them requiring help with feeding. In 1988 the hydration state of 60 of the 72 patients from hospital was reassessed. Control values were taken from two published studies. INTERVENTIONS: In 1987 nursing staff in hospital A were asked to provide between 2.5 and 3.0 litres of fluid daily for all patients. The use of hypertonic enemas was discontinued, and the ratio of staff to patients was increased. MAIN OUTCOME MEASURES: Serum concentrations of urea and electrolytes (hydration) and body mass index (nutritional state). RESULTS: Of the 10 patients admitted with hypernatraemic dehydration from hospital A to the district general hospital in 1986, four died of intercurrent infection. No patients were admitted from hospital B with hypernatraemic dehydration during the same time. In 1986 the hydration and nutritional state of patients in hospital A were inferior to those in patients from hospital B and control subjects from the community (serum urea concentrations were 6.1 (SD 1.8) mmol/l v 5.5 (1.9) and 5.6 (0.4) mmol/l, respectively) 50% (36/72) of patients in hospital A had a body mass index less than or equal to 20 compared with 34% (17/50) of patients from hospital B and 12% (1141/9434) of control subjects). After the initiation of the preventive programme only one patient was admitted with hypernatraemic dehydration in each of the years 1987 and 1988. The mean serum urea concentration of the 60 patients who were reassessed in 1988 fell significantly between 1986 and 1988 from 6.1 (SD 1.8) mmol/l to 5.7 (2.1) mmol/l, the value in a control group matched for age and sex. CONCLUSIONS: Hypernatraemic dehydration, subclinical underhydration, and undernutrition were common in a large hospital for the mentally and physically handicapped. The problem of hypernatraemic dehydration was successfully dealt with by the hospital management team. Similar problems may be encountered in hospitals for patients who are mentally and physically handicapped and mentally ill, including psychogeriatric units.