Cavity-Enhanced Room-Temperature Broadband Raman Memory.

Broadband quantum memories hold great promise as multiplexing elements in future photonic quantum information protocols. Alkali-vapor Raman memories combine high-bandwidth storage, on-demand readout, and operation at room temperature without collisional fluorescence noise. However, previous implementations have required large control pulse energies and have suffered from four-wave-mixing noise. Here, we present a Raman memory where the storage interaction is enhanced by a low-finesse birefringent cavity tuned into simultaneous resonance with the signal and control fields, dramatically reducing the energy required to drive the memory. By engineering antiresonance for the anti-Stokes field, we also suppress the four-wave-mixing noise and report the lowest unconditional noise floor yet achieved in a Raman-type warm vapor memory, (15±2)×10^{-3} photons per pulse, with a total efficiency of (9.5±0.5)%.

Reference-frame-independent quantum-key-distribution server with a telecom tether for an on-chip client.

We demonstrate a client-server quantum key distribution (QKD) scheme. Large resources such as laser and detectors are situated at the server side, which is accessible via telecom fiber to a client requiring only an on-chip polarization rotator, which may be integrated into a handheld device. The detrimental effects of unstable fiber birefringence are overcome by employing the reference-frame-independent QKD protocol for polarization qubits in polarization maintaining fiber, where standard QKD protocols fail, as we show for comparison. This opens the way for quantum enhanced secure communications between companies and members of the general public equipped with handheld mobile devices, via telecom-fiber tethering.

Perioperative factors as predictors of operative mortality and morbidity in pneumonectomy.

Pneumonectomy for lung cancer is associated with significant morbidity and mortality. Risk factors for the morbidity and mortality have been reported, but consistent conclusive data are undetermined. Current accepted 30-day mortality rates for pneumonectomy range from 7 to 11 per cent. The objective of this study is to determine whether various perioperative factors can serve as predictors of morbidity and mortality in pneumonectomy patients and to review outcome data on patients undergoing pneumonectomy for lung cancer. A total of 105 patients undergoing pneumonectomy for lung cancer from 1988 through 1998 are studied in a retrospective chart review. The main outcome measure is the 30-day operative mortality and morbidity. Complications occurring in 10 per cent or more of the patients included atrial fibrillation (33.3%), respiratory failure (23.8%), pneumonia (21.9%), and bronchopleural fistula (12.4%). The 30-day mortality rate was 10.5 per cent (11 deaths). By Fisher's exact test for Chi-square only three statistically significant mortality factors were identified: respiratory failure (P < 0.021), sepsis (P < 0.008), and male sex (P < 0.031); respiratory failure, sepsis, and sex were predictors of death. Significant correlation could not be made to predict postoperative morbidity. Overall long-term clinical outcome for pneumonectomy as lung cancer treatment was poor. Clinical judgment remains an essential factor when considering pneumonectomy as an option for lung cancer treatment.

Bridge to recovery for postcardiotomy failure: is there still a role for centrifugal pumps?

BACKGROUND: Early implantation of centrifugal devices in patients with postcardiotomy cardiogenic shock may provide a bridge to recovery and allow subsequent long-term survival. METHODS: Since January 1989, 62 patients were supported with centrifugal pumps because of failure to wean from cardiopulmonary bypass. Indications were postcardiotomy cardiogenic shock (PCCS) (n = 60), bridge to cardiac retransplantation (n = 1), and right ventricular failure (n = 1). Patients' ages ranged from 23 to 78 years; 40 were men (65%), and 22 were women (35%). Twenty-two patients (35%) had a left ventricular assist device; 9 patients (15%) had a right ventricular assist device; and 31 patients (50%) had a biventricular assist device. Length of support ranged from 1 day to 19 days. RESULTS: Forty-two patients (68%) were weaned successfully; 27 patients survived to discharge (44%). Complications included bleeding (n = 41, 66%), renal failure (n = 28, 45%), and respiratory failure (n = 26, 42%). Currently, 23 patients survived 10 or more years (n = 1), 6 to 10 years (n = 7), 1 to 5 years (n = 10), and less than 1 year (n = 5). CONCLUSIONS: Centrifugal pumps are available, easy to use, and relatively inexpensive. Our experience justifies their continued use as a bridge to recovery for patients with postcardiotomy cardiogenic shock, despite the availability and increasing use of more expensive devices.

Evaluation of the potential of transferrin-adriamycin conjugates in the treatment of bladder cancer.

OBJECTIVE: To assess the ability of a transferrin-adriamycin conjugate (Tf-ADR) to target transferrin receptor (TfR)-positive cancer cells selectively and to overcome drug resistance in bladder cancer cell lines. MATERIALS AND METHODS: Two paired sets of cell lines were used: the first was Chinese hamster ovary (CHO) cells (TfR-negative TRVb cells, as a model for normal resting cells, and TRVb-1 cells which were transfected with human TfR), and the second was a pair of bladder cancer cell lines (ADR-sensitive MGH-U1 cells and ADR-resistant MGH-U1R cells). Cell survival curves were determined after treatment with ADR, Tf and Tf-ADR. RESULTS: MGH-U1, TRVb and TRVb-1 cells required similar concentrations of ADR and Tf-ADR for 50% inhibition of growth; MGH-U1R cells were resistant to both ADR and TF-ADR. CONCLUSION: Tf-ADR did not prevent toxicity to the TfR-negative cells nor did it overcome the resistance of the ADR-resistant cells. These results imply that Tf-ADR does not provide a better cytotoxic drug delivery system for the treatment of bladder cancer.

A review of intestinal injury from blunt abdominal trauma.

Eighty-five patients who suffered blunt trauma to the small intestine and/or to the colon were treated at either the Royal Brisbane Hospital (RBH), Brisbane, Queensland or the Flinders Medical Centre (FMC), Adelaide, South Australia, between 1980 and 1991. Data were collected by retrospective review of case notes from the medical records departments of both hospitals and analysed with respect to the cause, the anatomical distribution, the diagnostic methods and the mortality of these injuries. There were 129 intestinal injuries (44 colonic and 85 small bowel). Five (5.9%) deaths were recorded. Seventy-two patients (84.7%) were injured in vehicular accidents. Fifty-three patients (62.4%) underwent laparotomy based on clinical findings alone. Diagnostic peritoneal lavage (DPL) was used in 24 cases and was positive in 22 (91.7%). The most common small bowel injury was ¿blowout' perforation on the antimesenteric border of the bowel (55.5%). The most common colonic injury was a serosal tear/bruise (62.2%).

Restrained occupants on the nonstruck side in lateral collisions.

Of injury-producing collisions with high seat belt use, some 25% to 30% are lateral collisions. This paper describes some of the characteristics of those collisions as they relate to the front-seat occupant sitting on the side opposite to the impact. The data came from a stratified sample of in-depth crash investigations conducted in the Birmingham region in the period 1983 to 1989 involving current model cars. Crash severity was assessed using the Vehicle Deformation Index (VDI) of the Collision Deformation Classification (CDC) ratings and velocity change. Injury severity was assessed using AIS 85 for each body region. 193 cases of restrained occupants in nonstruck side collisions were examined. Of those occupants with head injuries of AIS < or = 2, 35% came out of the shoulder section of the seat belt. Of abdominal injuries of AIS < or = 2, 72% came from the seat belt itself. Interaction between front seat occupants was not a frequent cause of injury to the nonstruck side occupant. Some aspects of seat belt geometry might be changed so that the trajectory and loading of the nonstruck side occupant are improved.

Prolonged ventricular support using a centrifugal pump.

The Biomedicus centrifugal pump was required to provide prolonged ventricular support to 13 patients with hemodynamic instability: 11 after cardiovascular surgical procedures, 1 after myocardial infarction and 1 after failure of a heart transplant. The duration of support ranged from 3.5 hours to 9 days (mean 72 hours). Complications included bleeding in six patients, renal insufficiency in three and central nervous system deficit in three. Six patients (46%) were successfully weaned from the pump. The patient with graft failure had hyperacute rejection of a second heart. Five patients were discharged from the hospital. There was one death 8 months postoperatively. Prolonged ventricular support with the centrifugal pump may allow recovery of potentially reversible ventricular dysfunction in selected patients after cardiac surgical procedures.

Severity of Illness Index and the Adverse Patient Occurrence Index. A reliability study and policy implications.

Seven hundred fifty-two randomly selected charts from seven teaching hospitals were rated by pairs of medical record analysts. The Severity of Illness Index was unreliable with an interrater-agreement rate of 73% (kappa statistic = 0.41), and demonstrated a significant (P less than 0.0001) association with the Adverse Patient Occurrence (APO) Index. This suggests that the Severity of Illness Index is not differentiating severity of illness from quality of care. The fair to poor field reliability stems from underlying instrument subjectivity, lack of clear referent groups, and time pressure. The APO Index was also found to be unreliable (r = 0.33 and range = -0.05-0.58). Greater attention should be directed to improving objective discharge abstract, billing, and laboratory data for measuring patient severity and adverse patient occurrences.

Prevention of lipid accumulation in experimental vein bypass grafts by antiplatelet therapy.

The ameliorative effect of antiplatelet therapy on atherogenesis of vein grafts was assessed in autologous cephalic veins grafted into femoral arteries of 16 normolipemic and 11 hyperlipemic stump-tailed macaque monkeys. Before grafting, one half of each vein was distended at high pressure (700 mm Hg) and the other half at low pressure (350 mm Hg). Eight normolipemic monkeys were treated with aspirin, 80 mg/day, and dipyridamole, 50 mg/day, and eight were controls. When grafts were harvested at 12 weeks, tissue cholesterol and beta-apoprotein content in grafts from untreated monkeys were significantly higher than in ungrafted, uninjured veins. Antiplatelet therapy eliminated the increase in lipid content of vein segments distended at low pressure, and significantly lowered lipid content of segments distended at high pressure, though not to be control levels of ungrafted veins. Seven of the 11 hyperlipemic monkeys received antiplatelet drugs and four did not. The lipid content of all graft segments was significantly higher than in grafted or ungrafted veins from normolipemic monkeys. Antiplatelet therapy again significantly reduced the lipid content in vein segments distended at both levels of pressure, and also reduced the elevated cholesterol content in ungrafted veins. Although this animal preparation differs in many ways from human coronary bypass operations, these observations may be pertinent to the prevention of atherosclerosis in human vein bypass grafts.

Effect of gastric bypass on gastric secretion.

Gastric bypass as a 90 per cent gastric exclusion operation was used in 393 patients with massive obesity to limit food intake. Stomal ulcer has occurred in 1.8 per cent of such patients or one ulcer per 140 man years of observation. The studies of indwelling fundic pH and of gastric acid secretion from the excluded stomach indicate that acid secretion is reduced after gastric bypass but that the acid, unbuffered by food in the excluded stomach, results in a lowered gastrin secretion after a meal. Thus, gastric bypass in inhibitory to acid secretion in most morbidly obese patients who do not have known acid peptic disease.

Aneurysmectomy in the aged.

The records of 206 aneurysmectomy patients over the age of 70 years were reviewed. Increased three- and five-year mortality was seen with a variety of risk factors--cerebral vascular disease, cardiac disease, diastolic hypertension, renal disease, and cigarette smoking--but 30-day mortality was not affected. Age was not a significant risk factor. It is recommended that patients with aneurysms less than 7.5 cm be observed if multiple risk factors are present. Almost all patients with aneurysms greater than 7.5 cm should have resection to prevent death from rupture, although this will be short-term palliation in patients with multiple risk factors.