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Objectives: The objectives of the study were to determine the association of gingival biotype and secondary stability of orthodontic mini-implants using resonance frequency analysis. Materials and Methods: Twenty patients, each receiving two mini-implants, were divided into two groups; thick and thin gingival biotype based on the thickness of gingiva before mini-implant placement. Implant stability was assessed at the time of placement; at the 1st, 2nd, 3rd, and 4th month by resonance frequency analysis. Peri-implant soft-tissue conditions were also examined at each month till 4 months interval using periodontal indices. Results: Thick and thin gingival biotype groups showed statistically different implant stability quotient (ISQ). Mini-implants showing signs of failure consistently displayed lesser ISQ. Statistically significant difference was observed in the scores of peri-implant indices of failure and no failure group of mini-implants. Conclusion: Mini-implants in thin gingival biotype are more susceptible to failure and peri-implantitis compared to thick gingival biotype. Longitudinal assessment of mini-implant stability may help predict failure so as to avoid long duration and cost of orthodontic treatment.

Driven by the strong need for cheap and integrable Si-based optoelectronic devices for a wide range of applications, continuing endeavors have been made to develop structures for light emission, modulation, and detection in this material system. Here, we report the realization of room-temperature stimulated emission in the technologically crucial 1.5 micron wavelength range from Er-doped GaN/AlN multiple-quantum wells on silicon and sapphire. Employing the well-acknowledged variable stripe technique, we have demonstrated an optical gain up to 170 cm-1 in the multiple-quantum well structures. The observation of the stimulated emission is accompanied by the characteristic threshold behavior of emission intensity as a function of pump fluence, spectral linewidth narrowing and excitation length. The demonstration of room-temperature lasing at the minimum loss window of optical fibers and in the eye-safe wavelength region of 1.5 micron are highly sought-after for use in many applications including defense, industrial processing, communication, medicine, spectroscopy and imaging. As the synthesis of Er-doped GaN epitaxial layers on silicon and sapphire has been successfully demonstrated, the results laid the foundation for achieving hybrid GaN-Si lasers providing a new pathway towards full photonic integration for silicon optoelectronics.

Graphene-based photodetectors have attracted attention for realizing optoelectronic devices including photodetectors. We report a graphene field effect transistor on silicon for broadband light detection from the ultraviolet to near-infrared region, which is compatible with the silicon technology and does not need a complicated fabrication process. The photodetectors show an improved responsivity. Specifically, fabricated graphene photodetectors shows a photo-responsivity of ~980 A/W at room temperature. These results provide a promising for the development of graphene-based optoelectronic applications with the broadband photodetection from the ultraviolet to near-infrared region.

Graphene-based photodetectors have attracted strong interest for realizing optoelectronic devices, including photodetectors. Here we report a simple fabrication of graphene-germanium quantum dots for broadband light detection from visible to infrared region. The photodetectors show an improved responsivity and response speed. Specifically, the fabricated germanium quantum dots on graphene photodetector shows a responsivity of 1,500 A/W at room temperature and the response time is as fast as ~ 1 ms. These results address key challenges for broadband photodetectors from visible to infrared region, and are promising for the development of graphene-based optoelectronic applications.

Background Postoperative suction drains are used after total knee arthroplasty to avoid intra-articular hematoma formation although they can increase blood loss due to a negative suction effect. The use of tranexamic acid to reduce blood loss may nullify this. The aim of this study was to compare outcomes in patients undergoing total knee arthroplasty with or without drains and to analyze whether the drain's diameter also has an impact. Methods This is a prospective randomized study of patients undergoing unilateral total knee arthroplasty performed by a single surgeon. The study population was divided into three groups (A, 10G drain; B, 12G drain; and C, no drain). Pain, blood loss, swelling, wound-related complications, functional outcomes and questionnaire-based outcomes were assessed postoperatively. Results Each group had 35 patients comparable in most demographic and pre- and intraoperative characteristics. During the first 6 hours postoperatively, opioid consumption was significantly higher when the drain was not used (p = 0.036). At 3 months postoperatively, new Knee Society Score (NKSS) was highest with the use of 12G drain (p = 0.018). However, NKSS at 1 year was comparable across the three groups. With the use of tranexamic acid, blood loss and incidence of soakage of dressing were unaffected by the presence or absence of a drain. The calf girth, suprapatellar girth, soakage of dressing and range of motion were comparable in all three groups. There was no incidence of surgical site infection or deep vein thrombosis. Conclusions Presence of a suction drain significantly reduces opioid consumption during the first 6 hours after total knee arthroplasty. Use of a drain made no difference to the functional outcome at 1 year postoperatively. With the use of tranexamic acid in total knee arthroplasty, the total blood loss and the requirement of blood transfusion were unaffected by the presence or absence of closed suction drainage or by the bore of the drain used. The clinical parameters such as swelling, range of motion, infection and deep vein thrombosis also remained the same.

Ulnar nerve compression at guyon’s canal is rare and very few cases have been reported in literature. It can be missed due to its rarity. Symptoms vary from pain and paresthesia to wasting and significant loss of muscle strength, with significant deformities of the hand. The diagnosis is made by detailed history and examination, electromyography, nerve conduction velocity test, ultrasound and magnetic resonance imaging. Early decompression of nerve is treatment of choice. Here we are presenting a case of compression of ulnar nerve in guyon’s canal due to ganglionic cyst.

The last couple of years have seen a growing momentum toward using the Internet for conducting business. Web-based electronic commerce applications are one of the fastest growing segments of the Internet today. A key enabler for e-commerce applications is the ability to setup secure private channels over a public network. The Secure Sockets Layer protocol provides this capability and is the most widely used security protocol in the Internet. We take a close look at the working principles behind SSL with an eye on performance. We benchmark two of the popular Web servers in wide use in a number of large e-commerce sites. Our results show that the overheads due to SSL can make Web servers slower by a couple of orders of magnitude. We investigate the reason for this deficiency by instrumenting the SSL protocol stack with a detailed profiling of the protocol processing components. In light of our observations, we outline architectural guidelines for large e-commerce sites.

ZnO and Al doped ZnO films were produced by spray pyrolysis. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and photoluminescence. Their photocatalytic activity was evaluated by the decomposition of the methyl orange dye using different light sources: ultraviolet light, artificial white light, and direct sunlight. The films were also tested under darkness for comparison. The ZnO films were able to degrade the test pollutant under UV and sunlight in more than a 60% after 180 min of irradiation and a scarce degradation was obtained using white light. However, the Al doped ZnO films presented a very high degradation rate not only under UV and sunlight (100% degradation), but also under white light (90% degradation after the same irradiation time). An unexpected high degradation was also obtained in the dark, which indicates that a nonphotonic process is taking place parallel to the photocatalytic process. This can be due to the extra electrons—provided by the aluminum atoms—that migrate to the surface and produce radicals favoring the decomposition process even in the dark. The high activity achieved by the ZnO: Al films under natural conditions can be potentially applied to water treatment processes.

Publisher Summary This chapter presents the design, implementation, and initial performance evaluation of a hybrid performance modeling framework called Countach, which faithfully and efficiently captures application behavior while predicting system performance. After a small manual step of replacing hardware interactions in the system software with simulated events, a set of automated postprocessing steps converts an application to a processor model that captures memory performance and enforces tight time synchronization with the simulator. Multiple processors or hardware execution contexts can be modeled in this framework. Actual workload generators can be used unmodified to drive the performance analysis. Countach models various kinds of network servers that utilize network-processor-based network interfaces. It is a very useful tool, because it allows users to experiment with the entire spectrum of design choices, including hardware design, a rich variety of operating system optimizations, and choices of function split between the host and the network processors.

As more business applications have become web enabled, the web server architecture has evolved to provide performance isolation, service differentiation, and QoS guarantees. Various server mechanisms that provide QoS extensions, however, rely on external administrators to set the right parameter values for their desirable performance. Due to the complexity of handling varying workloads and bursty traffic, configuring such parameters optimally becomes a challenge. In this paper, we describe an observation-based approach for self-managing web servers that can adapt to changing workloads while maintaining the QoS requirements of different classes. In this approach, the system state is monitored continuously and parameter values of various system resources-primarily the accept queue and the CPU-are adjusted to maintain the system-wide QoS goals. We implement our techniques using the Apache web server and the Linux operating system. We first demonstrate the need to manage different resources in the system depending on the workload characteristics. We then experimentally demonstrate that our observation-based system monitors such as workload changes and adjusts the resource parameters of the accept queue and CPU schedulers in order to maintain the QoS requirements of the different classes.

The exponential growth in Internet traffic has motivated the development of a new breed of microprocessors called network processors, which are designed to address the performance problems resulting from the explosion in Internet traffic. The development efforts of these network processors concentrate almost exclusively on streamlining their data paths to speed up network packet processing, which mainly consists of routing and data movement. Rather than blindly pushing the performance of packet processing hardware, an alternative approach is to avoid repeated computation by applying the time-tested architecture idea of caching to network packet processing. Because the data streams presented to network processors and general-purpose CPUs exhibit different characteristics, detailed cache design tradeoffs for the two also differ considerably. This research focuses on cache memory design specifically for network processors. Using a trace-drive simulation methodology, we evaluate a series of three progressively more aggressive routing-table cache designs. Our simulation results demonstrate that the incorporation of hardware caches into network processors, when combined with efficient caching algorithms, can significantly improve the overall packet forwarding performance due to a sufficiently high degree of temporal locality in the network packet streams. Moreover, different cache designs can result in up to a factor of 5 difference in the average routing table lookup time, and thus in the packet forwarding rate.

Suez is a high-performance real-time packet router that supports fast best-effort packet routing and scalable QoS-guaranteed packet scheduling, and is built on a hardware platform consisting of a cluster of commodity PCs connected by a gigabit/sec system area network. The major goal of the Suez project is to demonstrate that the PC cluster architecture can be as cost-effective a platform for high-performance network packet routing as for parallel computing. Suez features a cache-conscious routing-table search algorithm that exploits CPU caching hardware for fast lookup by treating IP addresses directly as virtual addresses. To scale the number of real-time connections supportable with the link speed, Suez implements a fixed-granularity fluid fair queuing (FGFFQ) algorithm that completely eliminates the per-packet sorting overhead associated with conventional weighted fair queuing algorithms. This paper presents the architectural features of Suez, and reports the performance measurements of the Linux-based Suez prototype, which is built on four Pentium-II 400 MHz machines and Myrinet.

Server providers that support e-commerce applications as a service for multiple e-commerce Web sites traditionally use a tiered server architecture. This architecture includes an application tier to process requests for dynamically generated content. How this tier is provisioned can significantly impact a provider's profit margin. In this article we study methods to provision servers in the application serving tier that increase a server provider's profits. First, we examine actual traces of request arrivals to the application tier of an e-commerce site, and show that the arrival process is effectively Poisson. Next, we construct an optimization problem in the context of a set of application servers modeled as M / G /1/ PS queueing systems, and derive three simple methods that approximate the allocation that maximizes profits. Simulation results demonstrate that our approximation methods achieve profits that are close to optimal, and are significantly higher than those achieved via simple heuristics.