342 research outputs found
Current Applications and Future Directions of Bioengineering Approaches for Bladder Augmentation and Reconstruction
End-stage neurogenic bladder usually results in the insufficiency of upper urinary tract, requiring bladder augmentation with intestinal tissue. To avoid complications of augmentation cystoplasty, tissue-engineering technique could offer a new approach to bladder reconstruction. This work reviews the current state of bioengineering progress and barriers in bladder augmentation or reconstruction and proposes an innovative method to address the obstacles of bladder augmentation. The ideal tissue-engineered bladder has the characteristics of high biocompatibility, compliance, and specialized urothelium to protect the upper urinary tract and prevent extravasation of urine. Despite that many reports have demonstrated that bioengineered bladder possessed a similar structure to native bladder, few large animal experiments, and clinical applications have been performed successfully. The lack of satisfactory outcomes over the past decades may have become an important factor hindering the development in this field. More studies should be warranted to promote the use of tissue-engineered bladders in clinical practice
The Deuterium Abundance at z=0.701 towards QSO 1718+4807
We present constraints on the deuterium to hydrogen ratio (D/H) in the
metal-poor gas cloud at redshift towards QSO 1718+4807. We use new
Keck spectra in addition to Hubble Space Telescope (HST) and International
Ultraviolet Explorer (IUE) spectra. We use an improved redshift and a lower \HI
column density to model the absorption. The HST spectrum shows an asymmetric
Lyman- (\lya) feature which is produced by either \HI at a second
velocity, or a high abundance of D. Three models with a single simple H+D
component give (95%), a much
larger range than reported by Webb et al (1997a,b). A more sophisticated
velocity distribution, or a second component is necessary for lower D/H. With
two components, which could be a part of one absorbing structure, or separate
clouds in a galaxy halo, we find . We do not know if
this second component is present, but it is reasonable because 40 -- 100% of
absorption systems with similar redshifts and \HI column densities have more
than one component.Comment: 13 pages, 4 figures, to appear in the Astronomical Journal (Jan 1999
Upper urinary dilatation and treatment of 26 patients with diabetes insipidus: A single-center retrospective study
ObjectiveTo describe the urinary tract characteristics of diabetes insipidus (DI) patients with upper urinary tract dilatation (UUTD) using the video-urodynamic recordings (VUDS), UUTD and all urinary tract dysfunction (AUTD) systems, and to summarize the experience in the treatment of DI with UUTD.MethodsThis retrospective study analyzed clinical data from 26 patients with DI, including micturition diary, water deprivation tests, imaging data and management. The UUTD and AUTD systems were used to evaluate the urinary tract characteristics. All patients were required to undergo VUDS, neurophysiologic tests to confirm the presence of neurogenic bladder (NB).ResultsVUDS showed that the mean values for bladder capacity and bladder compliance were 575.0 ± 135.1 ml and 51.5 ± 33.6 cmH2O in DI patients, and 42.3% (11/26) had a post-void residual >100 ml. NB was present in 6 (23.1%) of 26 DI patients with UUTD, and enterocystoplasty was recommended for two patients with poor bladder capacity, compliance and renal impairment. For the 24 remaining patients, medication combined with individualized and appropriate bladder management, including intermittent catheterization, indwelling catheter and regular voiding, achieved satisfactory results. High serum creatinine decreased from 248.0 ± 115.8 μmoI/L to 177.4 ± 92.8 μmoI/L in 12 patients from a population with a median of 108.1 μmoI/L (IQR: 79.9-206.5 μmoI/L). Forty-four dilated ureters showed significant improvement in the UUTD grade, and the median grade of 52 UUTD ureters decreased from 3 to 2.ConclusionBladder distension, trabeculation and decreased or absent sensations were common features for DI patients with UUTD. Individualized therapy by medication combined with appropriate bladder management can improve UUTD and renal function in DI patients
My traces learn what you did in the dark: recovering secret signals without key guesses
In side channel attack (SCA) studies, it is widely believed that unprotected implementations leak information about the intermediate states of the internal cryptographic process. However, directly recovering the intermediate states is not common practice in today\u27s SCA study. Instead, most SCAs exploit the leakages in a guess-and-determine way, where they take a partial key guess, compute the corresponding intermediate states, then try to identify which one fits the observed leakages better. In this paper, we ask whether it is possible to take the other way around---directly learning the intermediate states from the side channel leakages. Under certain circumstances, we find that the intermediate states can be efficiently recovered with the well-studied Independent Component Analysis (ICA). Specifically, we propose several methods to convert the side channel leakages into effective ICA observations. For more robust recovery, we also present a specialized ICA algorithm which exploits the specific features of circuit signals. Experiments confirm the validity of our analysis in various circumstances, where most intermediate states can be correctly recovered with only a few hundred traces. To our knowledge, this is the first attempt to directly recover the intermediate states in a completely non-profiled setting. Our approach brings new possibilities to the current SCA study, including building an alternative SCA distinguisher, directly attacking the middle encryption rounds and reverse engineering with fewer restrictions. Considering its potential in more advanced applications, we believe our ICA-based SCA deserves more research attention in the future study
Optimizing AES Threshold Implementation under the Glitch-Extended Probing Model
Threshold Implementation (TI) is a well-known Boolean masking technique that provides provable security against side-channel attacks. In the presence of glitches, the probing model was replaced by the so-called glitch-extended probing model which specifies a broader security framework. In CHES 2021, Shahmirzadi et al. introduced a general search method for finding first-order 2-share TI schemes without fresh randomness (under the presence of glitches) for a given encryption algorithm. Although it handles well single-output Boolean functions, this method has to store output shares in registers when extended to vector Boolean functions, which results in more chip area and increased latency. Therefore, the design of TI schemes that have low implementation cost under the glitch-extended probing model appears to be an important research challenge. In this paper, we propose an approach to design the first-order glitch-extended probing secure TI schemes when quadratic functions are employed in the substitution layer. This method only requires a small amount of fresh random bits and a single clock cycle for its implementation. In particular, the random bits in our approach are reusable and compatible with the changing of the guards technique. Our dedicated TI scheme for the AES cipher gives 20.23% smaller implementation area and 4.2% faster encryption compared to the TI scheme of AES (without using fresh randomness) proposed in CHES 2021. Additionally, we propose a parallel implementation of two S-boxes that further reduces latency (about 39.83%) at the expense of increasing the chip area by 9%. We have positively confirmed the security of AES under the glitch-extended probing model using the verification tool - SILVER and the side-channel leakage assessment method - TVLA
Lattice-based Fault Attacks on Deterministic Signature Schemes of ECDSA and EdDSA
The deterministic ECDSA and EdDSA signature schemes have found plenty of applications since their publication and standardization. Their theoretical security can be guaranteed under certain well-designed models, while their practical risks from the flaw of random number generators can be mitigated since no randomness is required by the algorithms anymore. But the situation is not completely optimistic, since it has been gradually found that delicately designed fault attacks can threaten the practical security of the schemes.
We present a lattice-based fault analysis method to the deterministic ECDSA and EdDSA algorithms. The underlying fault injection model is a special case of the random fault model in~\cite{MMF2019}. By noticing the algebraic structures of the deterministic algorithms, we show that, when providing with some valid faulty signatures and an associated correct signature of the same input message, some instances of lattice problems can be constructed to recover the signing key. This makes the allowed faulty bits close to the size of the signing key, and obviously bigger than that of the existing differential fault attacks. Moreover, the lattice-based approach supports much more alternative targets of fault injection when comparing with the existing approaches, which further improves its applicability.
Experiments are performed to validate the effectiveness of the key recovery method. It is demonstrated that, for 256-bit deterministic ECDSA/EdDSA, the signing key can be recovered efficiently with significant probability even if the targets are affected by 250 (or 247) faulty bits. This is, however, impractical for the existing faulty pattern enumerating approaches
Psoralen and Bakuchiol Ameliorate M-CSF Plus RANKL-Induced Osteoclast Differentiation and Bone Resorption Via Inhibition of AKT and AP-1 Pathways in Vitro
Background/Aims: Psoralen and bakuchiol are the main active compounds found in the traditional Chinese medicine Psoralea corylifolia L., and have been used to treat osteoporosis. This study aims to investigate the anti-osteoporosis effects of these two compounds using osteoclasts precursor differentiation and bone absorption assays in vitro. Methods: Primary mouse osteoclasts precursor cells were induced by M-CSF (macrophage colony stimulating factor) plus RANKL (receptor activator of nuclear factor kappa-B ligand) in vitro. TRACP (tartrate-resistant acid phosphatase) enzyme activity and toluidine blue staining were used to observe the effects of psoralen and bakuchiol on osteoclast differentiation and bone resorption, respectively. Gelatin zymography was used to assess MMP (matrix metalloproteinase) activity, and ELISA was performed to measure cathepsin K activity. Western blotting analysis for expression of phosphorylated AKT, ERK, NF-kB, and c-jun; and immunofluorescence analysis for c-jun and p65 nuclear translocation in induced osteoclasts were then used to determine the mechanism of anti-bone resorption of psoralen and bakuchiol. Results: Mature osteoclasts were induced by M-CSF plus RANKL from primary bone marrow macrophages in vitro. Both psoralen and bakuchiol significantly inhibited TRACP enzyme activity and slightly decreased the number of TRACP+ multinuclear osteoclasts induced by M-CSF plus RANKL. Bakuchiol significantly decreased bone lacunae area and attenuated MMP-2 activity induced by M-CSF plus RANKL in osteoclasts. Both psoralen and bakuchiol significantly decreased the expression and nuclear translocation of phosphorylated c-jun stimulated by M-CSF plus RANKL, but no significant effect on p65 translocation was observed in osteoclasts. Additionally, bakuchiol significantly attenuated the increased of M-CSF plus RANKL-induced phosphorylation of AKT in osteoclasts. Conclusions: Psoralen and bakuchiol ameliorated M-CSF plus RANKL-induced osteoclast differentiation and bone resorption via inhibition of AKT and AP-1 pathways activation in vitro
Large-scale structure, the cosmic microwave background, and primordial non-gaussianity
Since cosmic-microwave-background (CMB) and large-scale-structure (LSS) data
will shortly improve dramatically with the Microwave Anisotropy Probe (MAP) and
Planck Surveyor, and the Anglo-Australian 2-Degree Field (2dF) and Sloan
Digital Sky Survey (SDSS), respectively, it is timely to ask which of the CMB
or LSS will provide a better probe of primordial non-gaussianity. In this paper
we consider this question, using the bispectrum as a discriminating statistic.
We consider several non-gaussian models and find that in each case the CMB will
provide a better probe of primordial non-gaussianity. Since the bispectrum is
the lowest-order statistic expected to arise in a generic non-gaussian model,
our results suggest that if CMB maps appear gaussian, then apparent deviations
from gaussian initial conditions in galaxy surveys can be attributed with
confidence to the effects of biasing. We demonstrate this precisely for the
spatial bispectrum induced by local non-linear biasing.Comment: 6 pages, 2 figures, submitted as a letter to MNRA
Short-term exposure to high-intensity sound induces hearing loss and apoptosis in guinea pigs
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