Quantum authentication with key recycling

We show that a family of quantum authentication protocols introduced in [Barnum et al., FOCS 2002] can be used to construct a secure quantum channel and additionally recycle all of the secret key if the message is successfully authenticated, and recycle part of the key if tampering is detected. We give a full security proof that constructs the secure channel given only insecure noisy channels and a shared secret key. We also prove that the number of recycled key bits is optimal for this family of protocols, i.e., there exists an adversarial strategy to obtain all non-recycled bits. Previous works recycled less key and only gave partial security proofs, since they did not consider all possible distinguishers (environments) that may be used to distinguish the real setting from the ideal secure quantum channel and secret key resource.Comment: 38+17 pages, 13 figures. v2: constructed ideal secure channel and secret key resource have been slightly redefined; also added a proof in the appendix for quantum authentication without key recycling that has better parameters and only requires weak purity testing code

Optical properties of MgH2 measured in situ in a novel gas cell for ellipsometry/spectrophotometry

The dielectric properties of alpha-MgH2 are investigated in the photon energy range between 1 and 6.5 eV. For this purpose, a novel sample configuration and experimental setup are developed that allow both optical transmission and ellipsometric measurements of a transparent thin film in equilibrium with hydrogen. We show that alpha-MgH2 is a transparent, colour neutral insulator with a band gap of 5.6 +/- 0.1 eV. It has an intrinsic transparency of about 80% over the whole visible spectrum. The dielectric function found in this work confirms very recent band structure calculations using the GW approximation by Alford and Chou [J.A. Alford and M.Y. Chou (unpublished)]. As Pd is used as a cap layer we report also the optical properties of PdHx thin films.Comment: REVTeX4, 15 pages, 12 figures, 5 table

Severe Respiratory Syncytial Virus Bronchiolitis in Infants Is Associated with Reduced Airway Interferon Gamma and Substance P

Severe human respiratory syncytial virus (hRSV) bronchiolitis in previously well infants may be due to differences in the innate immune response to hRSV infection. Aim: to determine if factors mediating proposed mechanisms for severe bronchiolitis differ with severity of disease

Septata intestinalis frequently isolated from stool of AIDS patients with a new cultivation method

Two species of microsporidia, Enterocytozoon bieneusi and Septata intestinalis have been reported as intestinal parasites of AIDS patients. In attempts to establish E. bieneusi in vitro, spores were concentrated from stool samples from 4 AIDS patients with biopsy-proven E. bieneusi infections. After sterilization of the concentrate in antibiotic solution, the spores were added to monolayers of RK13 cells grown on the membranes of Transwells. Cultures were established from 7 stool samples from the 4 patients but in every case the species established was S. intestinalis not E. bieneusi. On retrospective examination of the stools, a very small number of spores of a size comparable to that of S. intestinalis was found but this species was not detected in biopsies. Typical septate vacuoles containing Type I tubules were observed in vitro but in contrast to the original description, meronts were intravacuolar and sporogony was mainly disporoblastic. The cultivation system, used for the first time for microsporidia, revealed the presence of unsuspected S. intestinalis infections and indicates that this species may be much more common than hitherto suspected. S. intestinalis has not previously been culture

Diagnosis of intestinal and disseminated microsporidial infections in patients with HIV by a new rapid fluorescence technique.

AIMS--To assess the value of a new rapid fluorescence method for the diagnosis of microsporidiosis in HIV seropositive patients. METHODS--Microsporidian spores in stools were demonstrated by using the fluorochrome stain Uvitex 2B. The new technique was evaluated in three groups of HIV seropositive patients with diarrhoea. Group 1: 19 patients with biopsy confirmed E bieneusi infection (186 stool samples); group 2: 143 consecutive patients from whom faeces were submitted for routine investigation of diarrhoea (318 samples); group 3: 16 patients with small intestinal biopsy specimens negative for microsporidia (55 samples). The new method was used to monitor spore shedding during experimental treatment with paromomycin and albendazole in four patients. RESULTS--Brightly fluorescent spores were detected in all stool samples of patients in group 1. In group 2 16 (11%) patients had spores in their stool samples. E bieneusi was found in 11 patients; in the other five another genus of microsporidia, Encephalitozoon, was recognised. Encephalitozoon spores were also found in the urine of three of these patients and in the maxillary sinus aspirate of two of them, suggesting disseminated infection. The results were confirmed by electron microscopic examination. In group 3 negative biopsy specimens were confirmed by negative stool samples in all cases. Treatment with albendazole and paromomycin did not affect the spore shedding in three patients with E bieneusi infection. By contrast, in a patient with Encephalitozoon sp infection albendazole treatment resulted in clinical improvement together with complete cessation of spore excretion in the stool. CONCLUSION--The Uvitex 2B fluorescence method combines speed, sensitivity, and specificity for the diagnosis and treatment evaluation of intestinal and disseminated microsporidiosis