Averaging of nonsmooth systems using dither

It was shown by Zames and Shneydor and later by Mossaheb that a high-frequency dither signal of a quite arbitrary shape can be used to narrow the effective nonlinear sector of Lipschitz continuous feedback systems. In this paper, it is shown that also discontinuous nonlinearities of feedback systems can be narrowed using dither, as long as the amplitude distribution function of the dither is absolutely continuous and has bounded derivative. The averaged system is proven to approximate the dithered system with an error of the order of dither period.     

Sequential intraluminal endoscopic and laparoscopic treatment for bile duct stones associated with gallstones

BACKGROUND: On the basis of a flowchart including prior or current jaundice or pancreatitis, abnormal liver function, ultrasound or IV cholangiography, bile duct (BD) stones were suspected in 71/593 patients referred for gallstones. METHODS: When endoscopic retrograde cholangiography detected BD stones, endoscopic sphincterotomy (ES) and endoscopic BD clearance were attempted, followed by laparoscopic cholecystectomy (LC). BD stones were found in 44/71 patients. The sensitivity values of preoperative conditions were: 92% for IV cholangiography, 88% for abnormal liver function, 50% for ultrasound, and 37% for jaundice at admission. RESULTS: Endoscopic clearance succeeded in 37 patients and LC was completed in 33 patients. Conversion to open surgery (9%) was comparable with the rate in patients without BD stones. The median hospital stay for the sequential endoscopic and laparoscopic treatments was 13 days (range 4-54) or 22 days if open surgery was used. CONCLUSIONS: In conclusion, BD stones can be endoscopically cleared preoperatively in most patients without interfering with LC.     

Rate-distortion optimized tree-structured compression algorithms for piecewise polynomial images.

This paper presents novel coding algorithms based on tree-structured segmentation, which achieve the correct asymptotic rate-distortion (R-D) behavior for a simple class of signals, known as piecewise polynomials, by using an R-D based prune and join scheme. For the one-dimensional case, our scheme is based on binary-tree segmentation of the signal. This scheme approximates the signal segments using polynomial models and utilizes an R-D optimal bit allocation strategy among the different signal segments. The scheme further encodes similar neighbors jointly to achieve the correct exponentially decaying R-D behavior (D(R) - c(o)2(-c1R)), thus improving over classic wavelet schemes. We also prove that the computational complexity of the scheme is of O(N log N). We then show the extension of this scheme to the two-dimensional case using a quadtree. This quadtree-coding scheme also achieves an exponentially decaying R-D behavior, for the polygonal image model composed of a white polygon-shaped object against a uniform black background, with low computational cost of O(N log N). Again, the key is an R-D optimized prune and join strategy. Finally, we conclude with numerical results, which show that the proposed quadtree-coding scheme outperforms JPEG2000 by about 1 dB for real images, like cameraman, at low rates of around 0.15 bpp.     

Conformal proton therapy for prostate carcinoma

The suppression of apoptosis may contribute to the carcinogenicity of the peroxisome proliferators (PPs), a class of non-genotoxic rodent hepatocarcinogens. Our previous work demonstrated that the PP nafenopin suppressed both spontaneous and transforming growth factor beta1 (TGFbeta1)-induced hepatocyte apoptosis both in vivo and in vitro. Here, we extend these observations by demonstrating the ability of nafenopin to suppress apoptosis induced by other major candidates for the signalling of cell death in the liver. Treatment of rat or mouse hepatocyte monolayers with TGFbeta1 or the DNA damaging drugs etoposide or hydroxyurea induced high levels of apoptosis. Western blot analysis did not support a role for either p53 or p21waf1 in etoposide-induced apoptosis in rat hepatocytes. Treatment of mouse hepatocytes with an agonistic anti-Fas antibody also resulted in an induction of high levels of apoptosis. Pre-addition and continued exposure to nafenopin suppressed apoptosis induced by all three stimuli. Overall, our studies demonstrate that the ability of nafenopin to protect hepatocytes from apoptosis is not restricted to species or apoptotic stimulus. It is possible, therefore, that the PPs may suppress apoptosis by acting on diverse signalling pathways. However, it seems more likely that nafenopin suppresses hepatocyte apoptosis elicited by each death stimulus by impinging on a core apoptotic mechanism.     

Deconvolution with partially known kernel of nonnegative signals

This paper extends the Bayesian direct deconvolution method to the case in which the convolution kernel depends on few unknown nuisance parameters. Moreover, an acceleration procedure is proposed that drastically reduces the computational burden. Finally, the implementation of the method by means of the fast Fourier transform is fully discussed in the multidimensional case.     

An infrastructure for smart hospitals

In healthcare facilities most of the daily activities require strict coordination between clinicians, who often operate under heavy workloads and minimal workforce conditions in environments filled with increasingly complex technology. Ubiquitous Computing applications constitute a suitable solution for both reducing medical costs and improving patient safety by better supporting clinical processes. In this study we introduce an intelligent infrastructure for smart hospitals which implements basic services to optimize medical staff/patient interactions and grants ubiquitous and transparent access to clinical data stored in standard clinical databases. This infrastructure relies on the integration of Radio Frequency IDentification (RFID) and photosensor technologies to identify, locate and track clinicians and patients equipped with mobile devices and wearable RFID tags.     

Insights into the Action Mechanism of the Antimicrobial Peptide Lasioglossin III

Lasioglossin III (LL-III) is a cationic antimicrobial peptide derived from the venom of the eusocial bee Lasioglossum laticeps. LL-III is extremely toxic to both Gram-positive and Gram-negative bacteria, and it exhibits antifungal as well as antitumor activity. Moreover, it shows low hemolytic activity, and it has almost no toxic effects on eukaryotic cells. However, the molecular basis of the LL-III mechanism of action is still unclear. In this study, we characterized by means of calorimetric (DSC) and spectroscopic (CD, fluorescence) techniques its interaction with liposomes composed of a mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-rac-phosphoglycerol (POPG) lipids as a model of the negatively charged membrane of pathogens. For comparison, the interaction of LL-III with the uncharged POPC liposomes was also studied. Our data showed that LL-III preferentially interacted with anionic lipids in the POPC/POPG liposomes and induces the formation of lipid domains. Furthermore, the leakage experiments showed that the peptide could permeabilize the membrane. Interestingly, our DSC results showed that the peptide-membrane interaction occurs in a non-disruptive manner, indicating an intracellular targeting mode of action for this peptide. Consistent with this hypothesis, our gel-retardation assay experiments showed that LL-III could interact with plasmid DNA, suggesting a possible intracellular target.     

The two-spin model of a tracking chamber: a phase-space perspective

We study the dynamics of classical localization in a simple, one-dimensional model of a tracking chamber. The emitted particle is represented by a superposition of Gaussian wave packets moving in opposite directions, and the detectors are two spins in fixed, opposite positions with respect to the central emitter. At variance with other similar studies, we give here a phase-space representation of the dynamics in terms of the Wigner matrix of the system. This allows a better visualization of the phenomenon and helps in its interpretation. In particular, we discuss the relationship of the localization process with the properties of entanglement possessed by the system.