Investigations into the functioning of a supply air window in relation to solar energy as determined by experiment and simulation

‘Supply air windows’ under optimum flow conditions function as an efficient heat reclaim device. Heat escaping from the room, through the inner glass pane, is entrained in the air flow between the inner and outer sashes and returned to the room. A low-E coating to the inner glass acts as a barrier to radiation heat loss across the window so very low U-values can be achieved. These same characteristics enable the window to function as a passive solar component. Its efficiency is inferior to that of a dedicated passive solar device due to its transparency, but even so at modest levels of incident solar gain a worthwhile proportion is entrained into the air flow and supplied to the rooms as pre-heated ventilation air supply. These characteristics have been established by laboratory, test cell investigations, and simulations using computational fluid dynamics and ESP-r, a whole building dynamic thermal modelling tool.     

Abdominal wound tumor recurrence after open and laparoscopic-assisted splenectomy in a murine model

PURPOSE: The cause of abdominal wall tumor recurrences after laparoscopic surgery for cancer remains unknown. A recent study from our laboratory using a murine splenic tumor model suggests that poor surgical technique (i.e., crushing of the tumor) and not the CO2 pneumoperitoneum is responsible for port wound tumors. However, in that experiment no actual laparoscopic procedure or manipulation was performed. The purpose of the current study was to determine the rate of abdominal wound tumors after laparoscopic-assisted splenectomy performed via a CO2 pneumoperitoneum vs. open splenectomy using the mouse splenic tumor model. METHODS: To establish splenic tumors, female BALB/c mice (N=72) were given subcapsular splenic injections of a 0.1-ml suspension containing 10(5) C-26 colon adenocarcinoma cells via a left flank incision at the initial procedure. Eight days later, animals were randomized into one of two groups: 1) laparoscopic-assisted splenectomy, or 2) open splenectomy. Laparoscopic-assisted splenectomy animals had three laparoscopic ports placed and then underwent laparoscopic mobilization of the spleen under a CO2 pneumoperitoneum followed by extracorporeal splenectomy via a subcostal incision. Group 2 animals underwent open splenectomy via a subcostal incision after three port incisions were made in the same locations as for laparoscopic-assisted splenectomy mice. The incision was closed after 20 minutes in both groups. Ten days later, the mice were killed and inspected for abdominal wall tumor implants. The experiment was performed via two separate trials. RESULTS: When results of the two trials were combined, there was no significant difference in the incidence of animals in each group with at least 1 port tumor (open, 21 percent; laparoscopic-assisted splenectomy, 33 percent; P=0.14). However, the overall incidence of port site tumors (number of ports with tumors/total number of ports for each group) was significantly higher in the laparoscopic-assisted splenectomy group than in the open group (20 vs. 7 percent; P=0.01). The subcostal incisional tumor recurrence rate was also higher in the laparoscopic-assisted splenectomy group (50 vs. 21 percent; P=0.02). as was the perioperative mortality rate (21 vs. 7 percent; P=0.08). Results of the two individual trials were also considered separately. The incidence of port wound tumors decreased significantly from the first to the second laparoscopic-assisted splenectomy trial (36 vs. 9 percent; P=0.003), although the incidence of tumors at the subcostal incision and the mortality rate for the two laparoscopic-assisted splenectomy group trials were not significantly different. The open group tumor incidences did not change from trial to trial. CONCLUSIONS: Overall, significantly more port and incisional tumors were noted in the laparoscopic-assisted group. Although not statistically significant, mortality rate of the laparoscopic-assisted group was higher than the open group. The reasons for these findings are unclear. Laparoscopic mobilization was quite difficult and required excessive splenic manipulation, which may have liberated tumor cells from the primary tumor and facilitated port tumor formation. With increased experience, less manipulation was required to complete mobilization. Of note, the incidence of port tumors in the laparoscopic-assisted splenectomy group decreased significantly from the first to the second trials; therefore, it is possible that surgical technique is a factor in port tumor formation. However, the persistently high tumor incidence at the subcostal incision site argues against the hypothesis that the second trial's laparoscopic mobilizations were less traumatic. The CO2 pneumoperitoneum may also be a factor. Further studies are warranted to clarify these issues.     

The successful use of continuous negative extrathoracic pressure in a child with Glenn shunt and respiratory failure

Following a Glenn shunt, an infant required mechanical ventilation (IPPV) for pneumonia, a phrenic nerve palsy and chylothoraces. In order to improve her deteriorating clinical condition, we used continuous negative extrathoracic pressure (CNEP) to minimise the deleterious effects of IPPV on pulmonary blood flow. She was successfully weaned from IPPV and supported with CNEP.     

The analogy between the Butler matrix and the neural-networkdirection-finding array

The Butler matrix and the neural network have been compared to provide insights about the neural-network behavior for a direction-finding array. The goal of the paper has been tutorial, since the two systems are only really comparable in the very limited case considered: an ideal array with equal element spacings, no failures, and using the orthogonal beam locations as training points. Within the constraints of this specialized case, the comparison illustrates the role of pre- and post-processing, the function of the Gaussian radial basis function, and the considerations in determining the weights applied to the Gaussian or modified sine function node outputs. In addition, the comparison points out the basic similarity of the two procedures, and reveals some insights about the operation of a neural network from the perspective of antenna engineering     

Colon adenocarcinoma and B-16 melanoma grow larger following laparotomy vs. pneumoperitoneum in a murine model

BACKGROUND: The purpose of our study was to find out whether bleeding symptoms are predictive factors of subsequent gynecological or urinary cancers among women screened negative. METHODS: The data stemmed from the Finnish Mass Screening Registry, and were linked to the National Cancer Registry: 37,596 screening negative women in the nationwide population-based mass screening program for cervical cancer were classified by their bleeding symptom (bloody discharge, coital bleeding, irregular bleeding, postmenopausal bleeding) at the time of screening (1985-1990) and followed up (1985-1994) in order to assess the subsequent risk of cancer. RESULTS: Bleeding symptoms with prevalence of 5.9% were more likely to be signs of preinvasive than invasive cervical cancer with the exception of coital bleeding, nevertheless relative risk of cervical cancer (SIR 1.1, 95% CI 0.8-1.4) was not significantly increased during the total follow-up of maximum 10 years. Women with any bleeding symptom had increased risk of cancer of the corpus uteri (SIR 2.1, 95% CI 1.6-2.6), postmenopausal bleeding was the strongest symptom (RR 3.6, 95% CI 2.0-6.0). None of the bleeding symptoms increased subsequent risk of ovarian, vaginal or vulvar carcinoma. The risk of kidney cancer was increased (SIR 1.7, 95% CI 1.0-2.6). CONCLUSIONS: The prevalence of bleeding symptoms was small and relative risks for cancers were low for them to be suitable as predictive factors of cancer neither in clinical practice nor for public health purposes, e.g. in developing selective screening based on this high risk group. Only 34 gynecological cancers during 220,000 person-years in women with bleeding symptoms were attributable to bleeding. Relative risks remained increased only for a short time after screening. Therefore, short term surveillance is important, but due to the fact that relative risks approached unity during the follow-up, reassurance of a woman that she is cancer-free should be emphasized more in the long term after the bleeding symptoms.     

Source synthesis for training array neural networks

The authors introduce techniques for synthesising realistic multiple source antenna `measurements' from single source measurements and for recalibrating single source baseline measurements after subsequent array failure. Synthesised data are compared with measured data and used to train a neural network to perform direction finding     

An experimental completely overlapped subarray antenna

A completely overlapped subarray antenna was designed, fabricated, and tested to demonstrate its broad-band, low sidelobe, wide scan angle performance. It uses time delay steering at the inputs to a transform feed, which illuminates a phase-shifter steered objective lens. The transform feed is a Rotman lens and the objective is a cylindrical bootlace lens, both of which are parallel plate waveguide cavities with coaxial probe elements. The signal bandwidth goal of 20 percent (8.1-9.9 GHz) at55degscan was met easily, however, achieving the peak sidelobe goal of - 30 dB proved more difficult because of internal reflections in the Rotman lens beamformer. A brief summary is presented of the completely overlapped subarray antenna (COSA) concept to explain the detailed design of our experimental model. Antenna pattern and S-parameter measurements illustrate the operating principles, the difficulties encountered, and the results achieved.     

The Brighton resuscitation ambulances: a continuing experiment in prehospital care by ambulance staff

Two ambulances from the existing fleet in Brighton and one in Hove are equipped with portable defibrillator-oscilloscope units. Selected attendants have been trained not only to defibrillate patients but also to perform endotracheal intubation and administer intravenous atropine and lignocaine for carefully defined indications. In the two years up to December 1975 the ambulances responded to 2253 calls which were considered possible emergencies. Retrospective analysis showed that half of these had been for patients with myocardial infarction, coronary insufficiency, or angina. The ambulances took a median time of five minutes to reach a patient. Attempts at resuscitation were made in 207 patients with circulatory arrest, of whom 160 had ventricular fibrillation. Coordinated rhythm was restored at least transiently in 66 patients, and 27 of them survived to leave hospital. Sixteen of the survivors had been in ventricular fibrillation before the arrival of the ambulance. The delay before admission to hospital was reduced: over 50% of patients carried in the ambulances were admitted within two hours of the onset of major symptoms. No extra ambulance staff have been employed for the scheme. The increased load on hospital services has been limited by encouraging a rational admission policy and also by early discharge.     

The effect of peritoneal air exposure on postoperative tumor growth

Botulinum toxin A has been used to treat wrist and finger spasticity mainly through injection of the forearm flexor muscles. This case study describes its first reported use in managing spastic lumbricals of the hand. A 19-year-old male had significant flexion deformity and hypertonicity of the left wrist and hand, particularly the second through fifth metacarpophalangeal joints, after traumatic brain injury. By using the 0-4 Ashworth scale, spasticity of the lumbricals across the second to fourth metacarpophalangeal joints was rated 2, with persistent clonus of the finger flexors as confirmed by electromyography to the middle and ring fingers, even after botulinum toxin A injection of the flexor digitorum sublimis and profundus muscles. By using the electromyography-guided technique, botulinum toxin A was injected into the first lumbrical of the index finger (12 units), second and third lumbricals of the middle and ring fingers, respectively (15 units each), and fourth lumbrical of the little finger (10 units). At follow-up, clinical and electromyographic examination revealed a significant reduction in tone and clonus of the injected lumbricals. Ashworth scores of the lumbricals from the index to little finger improved to 1. Botulinum toxin A injection of the lumbricals can be beneficial in managing spasticity of these muscles. It is well tolerated and effective at doses of 10 to 15 units. Lumbrical injection of botulinum toxin A is a useful adjunct in our percutaneous armamentarium for managing the spastic hand.