User level performance analysis of multi-hop in-band backhaul for 5G

In recent years, mobile access networks operating at millimeter wavelengths have received a great deal of attention, as they promise previously unattainably high mobile data rates. At these frequencies, mobile access links are expected to use highly directional beamforming antennas, which are also well suited to backhaul links. Therefore, access points can efficiently act as self-backhauled relays by using the same spectrum, circuits and antennas for mobile access and backhaul links, thus forming a multi-hop in-band backhaul network. The contributions of our paper are extensive simulations to investigate user level performance in such multi-hop networks. We specifically take into account the momentary data traffic of every link in order to calculate the interference. Results quantify the detrimental effect of interference on user level performance. Furthermore, the potential benefit of using the combination of in-band and dedicated backhaul links is evaluated. Additionally, this paper investigates the user level effects of the sudden loss of a link in the backhaul mesh network, and underlines the importance of effective rerouting algorithms. The feasibility of the in-band concept is demonstrated, and we can confirm that the user level experience will surpass the performance provided by previous generation mobile networks.     

Energy-efficient neighbor discovery protocol for mobile wireless sensor networks

Low energy consumption is a critical design requirement for most wireless sensor network (WSN) applications. Due to minimal transmission power levels, time-varying environmental factors and mobility of nodes, network neighborhood changes frequently. In these conditions, the most critical issue for energy is to minimize the transactions and time consumed for neighbor discovery operations. In this paper, we present an energy-efficient neighbor discovery protocol targeted at synchronized low duty-cycle medium access control (MAC) schemes such as IEEE 802.15.4 and S-MAC. The protocol effectively reduces the need for costly network scans by proactively distributing node schedule information in MAC protocol beacons and by using this information for establishing new communication links. Energy consumption is further reduced by optimizing the beacon transmission rate. The protocol is validated by performance analysis and experimental measurements with physical WSN prototypes. Experimental results show that the protocol can reduce node energy consumption up to 80% at 1–3 m/s node mobility.     

Indoor Planning for High Speed Downlink Packet Access in WCDMA Cellular Network

The aim of this paper is to show the special characteristics of the indoor environment related to radio propagation and furthermore to radio network planning. The aspects of the radio network planning are highlighted especially for Wideband Code Division Multiple Access (WCDMA) radio access technology that is used widely in the third generation mobile networks. Moreover, the detailed planning parameters in indoor environment are studied for High Speed Downlink Packet Access (HSDPA) in order to support high throughput data applications in Universal Mobile Telecommunications System (UMTS). The final target of the paper is to compare pico cell, distributed antenna system (DAS), and radiating cable network configurations in indoor environment to provide the optimal radio conditions for the data applications, and thus to serve highest number of mobile users. Several measurement campaigns with different antenna configurations have been conducted in order to study the effect of multi path related parameters, as delay spread of the signal. Also other capacity related parameters as received signal levels, interference, throughput, and transmit power levels have been studied in order to find out the optimal solution for HSDPA in UMTS. The results clearly show that pico cells and distributed antenna system have outstanding performance in indoor propagation channel compared to radiating cable. In sense of signal quality, pico cell performance is slightly better compared to distributed antenna system. However, measurements with HSDPA indicate that practical capacity of DAS outperforms pico cells. The measurements also show that separation of the antennas is a key capacity related parameter when planning WCDMA based indoor systems.     

Physical and sensory properties of low-salt phosphate-free frankfurters composed with various ingredients

The physical properties and sensory attributes of phosphate-free frankfurters were examined using response surface methodology by varying the amounts of five compositional variables: salt, modified tapioca starch-, sodium citrate (NaC)- and wheat bran and fat in the batter. Altogether, 20 different types of frankfurters were prepared. When the frankfurters were made without phosphate, additional non-meat ingredients were needed at salt contents of less than 1.5%. Modified tapioca starch and sodium citrate decreased frying loss, with the former also improving water and fat binding.     

Dissolution of Suppositories III: Effect of Insoluble Polyvinylpyrrolidone on Acetaminophen Release

Previously reported studies from this laboratory have demonstrated the usefulness of a new apparatus for suppository dissolution study. Acetaminophen suppositories gave slow release and it was posited that addition of a disintegrating agent commonly used in tablet manufacture would increase this release rate. To test the hypothesis, four PEG blends were used as bases as in the previous studies. Each contained 320 mg acetaminophen and 1%, 5%, or 10% of insoluble polyvinylpyrrolidone (Polyplasdone XL^R). One thousand milliliters of phosphate buffer, pH 8.0 to approximate rectal pH was employed as the dissolution media and maintained at 37.5°. A constant agitation rate of 2 5 and 50 rpm was used. Acetaminophen was assayed spectrophotometrically at 243 nm. Comparative dissolution profiles at the various agitation rates and with the concentrations of polyvinylpyrrolidone were developed. Addition of insoluble polyvinylpyrrolidone increased the dissolution rate constant and dissolution half-times at the two agitation rates. While the disintegration aid increased release, this release was not linear with respect to disintegrating agent concentration.

Release of acetaminophen from suppositories and the bioavailability of acetaminophen Erom suppository bases have not received much study. Feldman reported that the rate of bioavailability of suppositories was extremely variable and might not produce a clinically noted response (1). Maron and Ickes, however, reported that acetaminophen suppositories were clinically as effective an antipyretic as were tablets (2).

Pagay, et al. studied the influence of the vehicle on the bioavailability of acetaminophen suppositories using a modified beaker method with a media of pH 7.0 and an agitation of 25 rpm (3). These researchers correlated the dielectric constant of the base to acetaminophen bioavailability. Commercial suppositories were not discussed.

A recent report by Palmieri (4) discussed release of acetaminophen from laboratory prepared PEG bases and commercially available suppositories. Dissolution half-times for laboratory prepared suppositories at 50 rpm ranged from 8 minutes for Base A to 22 minutes for Base D. The commercially available acetaminophen suppositories had a dissolution half-time of 90 minutes at 50 rpm. Because of these apparently slow release rates, it was posited that addition of a disintegrating agent would increase the release of acetaminophen from the polyethylene glycol base sup-positores. Polyplasdone XLR, (5) a crosslinked insoluble homopolymer of n-vinyl-2-pyrrolidone was used in an attempt to increase the release rate.     

Mechanical behavior,structure, and reinforcement processes of TEMPO‐oxidized cellulose reinforced poly(lactic) acid

Poly(lactic) acid (PLA) was reinforced with acetylated TEMPO‐oxidized fibrillated cellulose (TOFC) prepared from birch pulp. Composite films were studied using dynamic mechanical thermal analysis, differential scanning calorimetry (DSC), as well as static mechanical testing. The storage modulus as well as tensile strength of PLA was improved on the addition of 30 wt% of TOFC by approximately 50% and 40%, respectively. Thermal stability as well as strength properties in moist environments (up to 90% relative humidity) was significantly improved at 15, 20, 25, and 30 wt% of TOFC. DSC showed that crystallization from solution took place during preparation of the composite films and was much greater than melt crystallization. POLYM. COMPOS., 2012. © 2013 Society of Plastics Engineers     

A digital process for additive manufacturing of occlusal splints: a clinical pilot study

The aim of this study was to develop and evaluate a digital process for manufacturing of occlusal splints. An alginate impression was taken from the upper and lower jaws of a patient with temporomandibular disorder owing to cross bite and wear of the teeth, and then digitized using a table laser scanner. The scanned model was repaired using the 3Data Expert software, and a splint was designed with the Viscam RP software. A splint was manufactured from a biocompatible liquid photopolymer by stereolithography. The system employed in the process was SLA 350. The splint was worn nightly for six months. The patient adapted to the splint well and found it comfortable to use. The splint relieved tension in the patient''s bite muscles. No sign of tooth wear or significant splint wear was detected after six months of testing. Modern digital technology enables us to manufacture clinically functional occlusal splints, which might reduce costs, dental technician working time and chair-side time. Maximum-dimensional errors of approximately 1 mm were found at thin walls and sharp corners of the splint when compared with the digital model.     

Do electromagnetic fields enhance the effects of environmental carcinogens?

Epidemiological studies have reported an increased risk of leukaemia in children who are exposed to extremely low-frequency (ELF) magnetic fields (MF), suggesting that ELF MFs may be carcinogenic to humans. No carcinogenic effects have been found in animal studies that have tested ELF MFs alone. Similarly, genotoxicity studies have generally not shown effects from MFs alone. However, ELF MFs have been reported to enhance the effects of known carcinogenic or mutagenic agents in a few animal studies and in several in vitro studies. This paper discusses the findings of studies on such combined effects. The majority of in vitro studies have reported positive findings, which supports the conclusion that MFs of 100 microT or higher interact with other chemical and physical agents. Further studies should address biophysical mechanisms and dose-response relationship below 100 microT. Animal studies designed according to the classical initiation-promotion concept may not be sufficient for studying the cocarcinogenic effects of MFs, and further studies using novel study designs would be useful. Epidemiological data on the interaction between MFs and other environmental agents are scant and inconclusive, and any further studies may be difficult because of the scarcity of subjects with suitable combined exposures.     

Use of in-line near-infrared spectroscopy in combination with chemometrics for improved understanding of pharmaceutical processes

High shear granulation is a complex unit operation with several interacting process parameters. No generally accepted real-time in-line tools are available to gain insight into this process, and in practice, a highly experienced process formulator and operator are needed to develop a wet granulated solid dosage form. In this study, the use of in-line near-infrared (NIR) spectroscopy as a process analytical tool for high shear granulation was investigated. In combination with principal component-based methods, process analysis of three separate phases of high shear wet granulation (mixing, spraying, and wet massing) was facilitated. Critical information, both chemical and physical, was collected during processing. Chemical information included the homogeneity of the formulation and the amount of water in wet mass. In addition, physical information related to the particle size of granules was extracted. Principal component loadings were fully interpreted to validate the conclusions drawn from scores and predictions. Thus NIR spectroscopy could be used to determine the end points of the three subphases of high shear wet granulation and, as such, provide a fast in-line quality control tool.     

Improved understanding of factors contributing to quantification of anhydrate/hydrate powder mixtures

Different spectroscopic approaches have proved to be excellent analytical tools for monitoring process-induced transformations of active pharmaceutical ingredients during pharmaceutical unit operations. In order to use these tools effectively, it is necessary to build calibration models that describe the relationship between the amount of each solid-state form of interest and the spectroscopic signal. In this study, near-infrared (NIR) and Raman spectroscopic methods have been evaluated for the quantification of hydrate and anhydrate forms in pharmaceutical powders. Process type spectrometers were used to collect the data and the role of the sampling procedure was examined. Multivariate regression models were compared with traditional univariate calibrations and special emphasis was placed on data treatment prior to multivariate modeling by partial least squares (PLS). It was found that the measured sample volume greatly affected the performance of the model whereby the calibrations were significantly improved by utilizing a larger sampling area. In addition, multivariate regression did not always improve the predictability of the data compared to univariate analysis. The data treatment prior to multivariate modeling had a significant influence on the quality of predictions with standard normal variate transformation generally proving to be the best preprocessing method. When the appropriate sampling techniques and data analysis methods were utilized, both NIR and Raman spectroscopy were found to be suitable methods for the quantification of anhydrate/hydrate in powder systems, and thus the method of choice will depend on the conditions in the process under investigation.