Salivary bacterial leakage into implant-abutment connections: preliminary results of an in vitro study

OBJECTIVE: The occurrence of bacterial leakage in the internal surface of implants, through implant-abutment interface (IAI), is one of the parameters for analyzing the fabrication quality of the connections. The aim of this in vitro study is to evaluate two different types of implant-abutment connections: the screwed connection (Group 1) and the cemented connection (Group 2), analyzing the permeability of the IAI to bacterial colonization, using human saliva as culture medium. PATIENTS AND METHODS: A total of twelve implants were tested, six in each experimental group. Five healthy patients were enrolled in this study. Two milliliters of non-stimulated saliva were collected from each subject and mixed in a test tube. After 14 days of incubation of the bacteria sample in the implant fixtures, a PCR-Real Time analysis was performed. Fisher's exact test was used to compare the proportions of implant-abutment assembled structures detected with bacterial leakage. Differences in the bacterial counts of the two groups were compared using the Mann-Whitney U test. A p value < 0.05 was considered significant. RESULTS: The results showed a decreased stability with the screwed implant-abutment connections compared to the cemented implant-abutment connections. A mean total bacterial count of 1.2E+07 (± 0.25E+07) for Group 1 and of 7.2E+04 (± 14.4E+04) for Group 2 was found, with a high level of significance, p = .0001. CONCLUSIONS: Within the limitations of this study it can be concluded that bacterial species from human saliva may penetrate along the implant-abutment interface in both connections, however the cemented connection implants showed the lowest amount of bacterial colonization

Monolithic zirconia and digital impression: case report

The aim of this study is to present a clinical case of a full arch prosthetic rehabilitation on natural teeth, combining both digital work-flow and monolithic zirconi

Single-Event Upset Analysis and Protection in High Speed Circuits

The effect of single-event transients (SETs) (at a combinational node of a design) on the system reliability is becoming a big concern for ICs manufactured using advanced technologies. An SET at a node of combinational part may cause a transient pulse at the input of a flip-flop and consequently is latched in the flip-flop and generates a soft-error. When an SET conjoined with a transition at a node along a critical path of the combinational part of a design, a transient delay fault may occur at the input of a flip-flop. On the other hand, increasing pipeline depth and using low power techniques such as multi-level power supply, and multi-threshold transistor convert almost all paths in a circuit to critical ones. Thus, studying the behavior of the SET in these kinds of circuits needs special attention. This paper studies the dynamic behavior of a circuit with massive critical paths in the presence of an SET. We also propose a novel flip-flop architecture to mitigate the effects of such SETs in combinational circuits. Furthermore, the proposed architecture can tolerant a single event upset (SEU) caused by particle strike on the internal nodes of a flip-flo

Critical behaviour of the O(3) nonlinear sigma model with topological term at theta=pi from numerical simulations

We investigate the critical behaviour at theta=pi of the two-dimensional O(3) nonlinear sigma model with topological term on the lattice. Our method is based on numerical simulations at imaginary values of theta, and on scaling transformations that allow a controlled analytic continuation to real values of theta. Our results are compatible with a second order phase transition, with the critical exponent of the SU(2)_1 Wess-Zumino-Novikov-Witten model, for sufficiently small values of the coupling.Comment: Revised version. 24 pages, 7 figure

A Systematic Approach for Evaluating Satellite Communications Systems

The aerospace environment imposes straight opera- tive conditions so every electronic system usually needs to be validated for these. The same way, communica- tion systems need to be evaluated before their intro- duction in aerospace applications. In the paper we present a new methodology for the evaluation of com- munication systems in space applications. The meth- odology aims, by abstraction, at identifying all the critical aspects for the evaluation and at defining a standard and reusable framework in order to be appli- cable to any Communication Systems. The methodol- ogy has been applied for the evaluation of three Data Bus for satellite communications: 1553, 1-Wire and Profibus DP RS 485 based systems have been analyzed and evaluate

Lidar observations of mesospheric sodium over Italy

We have developed a lidar system for the measurements of the mesospheric atomic sodium (Na) number density profile. The performances and the main characteristics of the system are evaluated showing the first observations: Na number density profiles can be obtained with a resolution of 300 m in altitude and of 200 s in time, the relative uncertainty is between 5% and 10%. These features also allow to discuss the capability of the system to detect the time and space variability of Na density profiles, which is typical of the gravity wave propagation. The preliminary analysis of the sodium profile dynamics along a 7 hours measurement session, started from 19:30UT on 10 April 1997, shows the presence of wave-like perturbations with characteristics typical of propagating gravity waves

Fundamental Limits of Low-Density Spreading NOMA with Fading

Spectral efficiency of low-density spreading non-orthogonal multiple access channels in the presence of fading is derived for linear detection with independent decoding as well as optimum decoding. The large system limit, where both the number of users and number of signal dimensions grow with fixed ratio, called load, is considered. In the case of optimum decoding, it is found that low-density spreading underperforms dense spreading for all loads. Conversely, linear detection is characterized by different behaviors in the underloaded vs. overloaded regimes. In particular, it is shown that spectral efficiency changes smoothly as load increases. However, in the overloaded regime, the spectral efficiency of low- density spreading is higher than that of dense spreading

Corrosion behavior of dental implants immersed into human saliva: Preliminary results of an in vitro study

Over the years, dif- ferent implant surfaces have been used to try to maximize bone to implant contact. The aim of this study was to compare levels of metallic ions and particles dissolution collected from two dif- ferent dental implants surfaces immersed into human saliva. PATIENTS AND METHODS: A total of 60 den- tal implants were tested. Group A: sanded with aluminium oxide medium grade particles and ac- id-etched; Group B: micro-sanded with calcium phosphate powders and acid-etched. Forty im- plants were immersed in 20 ml of human saliva, twenty, as a control, in sterile saline solution. ICP-MS was performed to detect any metallic ions released from dental implants at T0, on day 1 (T1), on day 3 (T2), after one week (T3), on day 14 (T4), after 3 months (T5) and after 6 months (T6). RESULTS: Dissolution of metallic particles of titanium and nickel, absent in human saliva (T0), were found after one week (T3) for Group B and after 3 months (T5) for Group A. Vanadium was already detected in small concentrations in either group after 1 day, with an exponential growth for Group B. CONCLUSIONS: Preliminary results reported signi cant values of Ti, Ni and V released by Group B, showing for the rst time statistically signi cant values of vanadium

Guest Editorial: Special section on emerging trends and computing paradigms for testing, reliability and security in future VLSI systems

With the rapid advancement of computing technologies in all domains (i.e., handheld devices, autonomous vehicles, medical devices, and massive supercomputers), testability, reliability and security of electronic systems are crucial issues to guarantee safeness of human life. Emerging technologies coupled with new computing paradigms (e.g., approximate computing, neuromorphic computing, in-memory computing) are together exacerbating these problems posing significant challenges to researchers and designers. To address this increased complexity in the hardware testing/reliability/security domain, it is imperative to employ design and analysis methods working at all levels of abstraction, starting from the system level down to the gate level. In this context, the selected papers span from the important field of the yield analysis and modeling, which is becoming fundamental for the manufacturing of modern technologies to the error detection, correction and recovery when the new devices are operative on field. At the same time, papers do not forget that the fault tolerance can be achieved by a cross-layer approach to the dependability that includes the analysis of the effect of faults and the techniques and methodologies to deploy more resilient devices by means of hardening of the design. Eventually, the dependability of the systems is nowadays deeply linked with the security aspects, including the impact on the design trade-offs and the test and validation. The IEEE VLSI Test Symposium (VTS) invited the highest-ranked papers to be included in this special issue of IEEE Transactions on Emerging Technologies in Computing (TETC) in 2020. All aspects of design, manufacturing, test, monitoring and securing of systems affected by defects and malicious attacks are covered by the accepted paper. It is our great pleasure to publish this special issue containing 12 high-quality papers covering all aspects of the emerging trends on testing and reliability: - FTxAC: Leveraging the Approximate Computing Paradigm in the Design of Fault-Tolerant Embedded Systems to Reduce Overheads by Aponte-Moreno, Alexander; Restrepo-Calle, Felipe; Pedraza, Cesar, the design of Fault-Tolerant systems is exploited by means of approximate computing techniques to reduce the implicit overhead of the common redundancy. - A Statistical Gate Sizing Method for Timing Yield and Lifetime Reliability Optimization of Integrated Circuits by Ghavami, Behnam; Ibrahimi, Milad; Raji, Mohsen, the reliability of CMOS devices is improved tackling the joint effect of process variation and transistor aging. - 3D Ring Oscillator based Test Structures to Detect a Trojan Die in a 3D Die Stack in the Presence of Process Variations by Alhelaly, Soha; Dworak, Jennifer; Nepal, Kundan; Manikas, Theodore; Gui, Ping; Crouch, Alfred, the issue of Trojan insertion into 3D integrated circuits has been explored from the use of in-stack circuitry and various testing procedures point of view, showing their detection capability. - Defect Analysis and Parallel Testing for 3D Hybrid CMOS-Memristor Memory by Liu, Peng; You, Zhiqiang; Wu, Jigang; Elimu, Michael; Wang, Weizheng; Cai, Shuo; Han, Yinhe, a new parallel March-like test is proposed to test CMOS Molecular architectures. - Attacks toward Wireless Network-on-Chip and Countermeasures by Biswas, Arnab Kumar; Chatterjee, Navonil; Mondal, Hemanta; Gogniat, Guy; DIGUET, Jean-Philippe, Wireless Network-on-Chip security vulnerabilities are described and their countermeasures proposed. - A Novel TDMA-Based Fault Tolerance Technique for the TSVs in 3D-ICs Using Honeycomb Topology (by Ni, Tianming; Yang, Zhao; Chang, Hao; Zhang, Xiaoqiang; Lu, Lin; Yan, Aibin; Huang, Zhengfeng; Wen, Xiaoqing) proposes a chain-type time division multiplexing access (TDMA)-based fault tolerance technique showing huge area overheads reduction. - Design and analysis of secure emerging crypto-hardware using HyperFET devices by Delgado-Lozano, Ignacio María; Tena-Sánchez, Erica; Núñez, Juan; Acosta, Antonio J., Power Analysis attacks against FinFET device have been tackled by incorporating HyperFET devices to deliver an x25 factor security level improvement. - Detection, Location, and Concealment of Defective Pixels in Image Sensors by TAKAM TCHENDJOU, Ghislain; SIMEU, Emmanuel, image sensors are empowered with online diagnosis and self-healing methods to improve their dependability. - Defect and Fault Modeling Framework for STT-MRAM Testing by Wu, Lizhou; Rao, Siddharth; Taouil, Mottaqiallah; Cardoso Medeiros, Guilherme; Fieback, Moritz; Marinissen, Erik Jan; Kar, Gouri Sankar; Hamdioui, Said, a framework to derive accurate STT-MRAM fault models is described, together with its employment to model resistive defects in interconnect and pinhole defects in MTJ devices, allowing test solutions for detecting those defects. - Online Safety Checking for Delay Locked Loops via Embedded Phase Error Monitor by Huang, Shi-Yu; Chu, Wei, the Automotive Safety Integrity Level (ASIL) is targeted by proposing a phase error monitoring scheme for Delay-Locked Loops (DLLs). - Protecting Memories against Soft Errors: The Case for Customizable Error Correction Codes by Li, Jiaqiang; Reviriego, Pedro; Xiao, Li; Wu, Haotian, the memory protection is supported by a tool able to automate the error correction code design. - Autonomous Scan Patterns for Laser Voltage Imaging by Tyszer, Jerzy; Cheng, Wu-Tung; Milewski, Sylwester; Mrugalski, Grzegorz; Rajski, Janusz; Trawka, Maciej, authors demonstrate how to reuse on-chip EDT compression environment to generate and apply Laser Voltage Imaging-aware scan patterns for advanced contactless test procedures. We sincerely hope that you enjoy reading this special issue, and would like to thank all authors and reviewers for their tremendous efforts and contributions in producing these high-quality articles. We also take this opportunity to thank the IEEE Transactions on Emerging Topics in Computing (TETC) Editor-in-Chief (EIC) Prof. Cecilia Metra, past Associate Editor Ramesh Karri, the editorial board, and the entire editorial staff for their guidance, encouragement, and assistance in delivering this special issue