On Multiple Deletion Codes

In 1965 Levenshtein introduced the deletion correcting codes and found an asymptotically optimal family of 1-deletion correcting codes. During the years there has been a little or no research on t-deletion correcting codes for larger values of t. In this paper, we consider the problem of finding the maximal cardinality L2(n;t) of a binary t-deletion correcting code of length n. We construct an infinite family of binary t-deletion correcting codes. By computer search, we construct t-deletion codes for t = 2;3;4;5 with lengths n ≤ 30. Some of these codes improve on earlier results by Hirschberg-Fereira and Swart-Fereira. Finally, we prove a recursive upper bound on L2(n;t) which is asymptotically worse than the best known bounds, but gives better estimates for small values of n

Implantological treatment of toothless jaws with locators and complete dentures

Развитието на технологиите и материалите в денталната медицина и тяхното приложение създадоха много нови възможности за подобряване на зъбната естетика, като все по-често се използват техники с никакви или минимални отнемания на твърда зъбна тъкан, като част от стремежа е да се постигнат красиви и съразмерни, добре изглеждащи, функционално ефективни зъби за цял живот. Локаторите са специфични надстройки за импланти, които позволяват ефективното задържане на снемаеми протезни конструкции. Разбира се, има изисквания и към местата на поставяне на имплантите. Най-често са приложими за долна челюст в предния участък, като се поставят минимум два, a най-добре четири импланта, които да са взаимно успоредни и на симетрични места. Предимство на локаторно задържаните протезни конструкции е лесната им поддръжка от хигиенна гледна точка, особено от възрастни пациенти. В настоящия доклад ще се представи клиничен случай на съвременно дентално лечение при тежка атрофия на челюстните кости. Поставянето на импланти е възможно само в областта на брадичката на долна челюст, където все още има запазена кост с достатъчна височина. Лечебният план включва поставяне на 4 броя импланти на долна челюст едновременно с екстрахиране на непълноценното остатъчно съзъбие и изработване след 4 месеца на снемаема протеза със задръжни елементи тип локатори и нова тотална протеза на горна челюст. Протезите са изработени от термопластична пластмаса VERTEX Thermosens.The development of technologies and materials in dentistry and their application have created many new opportunities for improving dental aesthetics, with the use of techniques with no or minimal rigid dental tissue utilization, as part of the quest to achieve beautiful and proportionate good-looking, functionally effective teeth for life. Locators are specific implant superstructures that allow effective retention of removable prosthetic structures. Certainly, there are also requirements for the placement of implants. Most commonly they are applicable to the lower jaw in the anterior stretch by placing at least two, and most preferably four, implants that are mutually parallel and symmetrical. An advantage of locally retained prosthetic structures is their easy maintenance from a hygienic point of view, especially from elderly patients. This report will present a clinical case of contemporary dental treatment for severe atrophy of the jawbone. Implant placement is possible only in the area of the chin of the lower jaw where there is still preserved bone of sufficient height. The treatment plan includes placing 4 implants on the lower jaw together with extraction of the minor residual dentition and production, after 4 months, of a removable denture with locator-type locking elements and new complete upper jaw dentures. The dentures are made of thermoplastic VERTEX ThermoSens

Radiation Characteristics of 3D Resonant Cavity Antenna with Grid-Oscillator Integrated Inside

A three-dimensional (3D) rectangular cavity antenna with an aperture size of 80 mm × 80 mm and a length of 16 mm, integrated with a four-MESFET transistor grid-oscillator, is designed and studied experimentally. It is found that the use of 3D antenna resonant cavity in case of small or medium gain microwave active cavity antenna leads to effective and stable power combining and radiation. The lack of lateral cavity diffraction and radiation helps in producing a directive gain of about 17 dB and radiation aperture efficiency bigger than 75% at a resonance frequency of 8.62 GHz. Good DC to RF oscillator efficiency of 26%, effective isotropic radiated power (EIRP) of 5.2 W, and SSB spectral power density of −82 dBc/Hz are found from the measured data. The 3D antenna cavity serves also as a strong metal container for the solid-state oscillator circuitry

HBNHB^N: An HB-like protocol secure against man-in-the-middle attacks

We construct a simple authentication protocol whose security is based solely on the problem of Learning Parity with Noise (LPN) which is secure against Man-in-the-Middle attacks. Our protocol is suitable for RFID devices, whose limited circuit size and power constraints rule out the use of more heavyweight operations such as modular exponentiation. The protocol is extremely simple: both parties compute a noisy bilinear function of their inputs. The proof, however, is quite technical, and we believe that some of our technical tools may be of independent interest

Radiation Characteristics of 3D Resonant Cavity Antenna with Grid-Oscillator Integrated Inside

A three-dimensional (3D) rectangular cavity antenna with an aperture size of 80 mm × 80 mm and a length of 16 mm, integrated with a four-MESFET transistor grid-oscillator, is designed and studied experimentally. It is found that the use of 3D antenna resonant cavity in case of small or medium gain microwave active cavity antenna leads to effective and stable power combining and radiation. The lack of lateral cavity diffraction and radiation helps in producing a directive gain of about 17 dB and radiation aperture efficiency bigger than 75% at a resonance frequency of 8.62 GHz. Good DC to RF oscillator efficiency of 26%, effective isotropic radiated power (EIRP) of 5.2 W, and SSB spectral power density of −82 dBc/Hz are found from the measured data. The 3D antenna cavity serves also as a strong metal container for the solid-state oscillator circuitry

Signing on Elements in Bilinear Groups for Modular Protocol Design

A signature scheme is called structure-preserving if its verification keys, messages, and signatures are group elements and the verification predicate is a conjunction of pairing product equations. We answer to the open problem of constructing a constant-size structure-preserving signature scheme. The security is proven in the standard model based on a novel non-interactive assumption that can be justified and has an optimal bound in the generic bilinear group model. We also present efficient structure-preserving signature schemes with advanced properties including signing unbounded number of group elements, allowing simulation in the common reference string model, signing messages from mixed groups in the asymmetric bilinear group setting, and strong unforgeability. Among many applications, we show two examples; an adaptively secure round optimal blind signature scheme and a group signature scheme with efficient concurrent join. As a bi-product, several homomorphic trapdoor commitment schemes and one-time signature schemes are presented, too. In combination with the Groth-Sahai non-interactive proof system, these schemes contribute to give efficient instantiations to modular constructions of cryptographic protocols

Detection of fractures of hand and forearm in whole-body CT for suspected polytrauma in intubated patients

Background: The aim of this study was to evaluate the potential of whole-body CT for diagnosis of hand and forearm fractures in intubated patients with suspected polytrauma. Methods: We performed a retrospective analysis on data collected from two trauma centres in Germany, including demographics, ISS, clinical symptoms, depiction in whole-body CT, and time to diagnosis. Results: Out of 426 patients included in the study, 66 (15.5%) suffered a hand or forearm fracture. The total number of fractures was 132, the whole-body CT report mentioned 98 (74.2%). 16 (12,1%) fractures of 12 patients were diagnosed later than 24 h after admission. Late diagnoses of fractures of the hand occurred more often if the hand was not fully included in the CT scan field. The sensitivity of whole-body CT for cases with fractures of hand and/or forearm with full inclusion of the corresponding area in the scan field was 80.2%. Conclusions: This study shows that whole-body CT is a valuable diagnostic tool for hand fractures in polytrauma patients. Hands should be evaluated regardless of clinical presentation in intubated patients after suspected polytrauma if they are included in the whole-body CT. © 2020 The Author(s)

Composable & Modular Anonymous Credentials: Definitions and Practical Constructions

It takes time for theoretical advances to get used in practical schemes. Anonymous credential schemes are no exception. For instance, existing schemes suited for real-world use lack formal, composable definitions, partly because they do not support straight-line extraction and rely on random oracles for their security arguments. To address this gap, we propose unlinkable redactable signatures (URS), a new building block for privacy-enhancing protocols, which we use to construct the first efficient UC-secure anonymous credential system that supports multiple issuers, selective disclosure of attributes, and pseudonyms. Our scheme is one of the first such systems for which both the size of a credential and its presentation proof are independent of the number of attributes issued in a credential. Moreover, our new credential scheme does not rely on random oracles. As an important intermediary step, we address the problem of building a functionality for a complex credential system that can cover many different features. Namely, we design a core building block for a single issuer that supports credential issuance and presentation with respect to pseudonyms and then show how to construct a full-fledged credential system with multiple issuers in a modular way. We expect this flexible definitional approach to be of independent interest

Cold Atmospheric Plasma Treatment of Chondrosarcoma Cells Affects Proliferation and Cell Membrane Permeability

Chondrosarcoma is the second most common malign bone tumor in adults. Surgical resection of the tumor is recommended because of its resistance to clinical treatment such as chemotherapy and radiation therapy. Thus, the prognosis for patients mainly depends on sufficient surgical resection. Due to this, research on alternative therapies is needed. Cold atmospheric plasma (CAP) is an ionized gas that contains various reactive species. Previous studies have shown an anti-oncogenic potential of CAP on different cancer cell types. The current study examined the effects of treatment with CAP on two chondrosarcoma cell lines (CAL-78, SW1353). Through proliferation assay, the cell growth after CAP-treatment was determined. A strong antiproliferative effect for both cell lines was detected. By fluorescein diacetate (FDA) assay and ATP release assay, alterations in the cell membrane and associated translocation of low molecular weight particles through the cytoplasmic membrane were observed. In supernatant, the non-membrane-permeable FDA and endogenously synthesized ATP detected suggest an increased membrane permeability after CAP treatment. Similar results were shown by the dextran-uptake assay. Furthermore, fluorescence microscopic G-/F-actin assay was performed. G-and F-actin were selectively dyed, and the ratio was measured. The presented results indicate CAP-induced changes in cell membrane function and possible alterations in actin-cytoskeleton, which may contribute to the antiproliferative effects of CAP. © 2020 by the authors. Licensee MDPI, Basel, Switzerland