671 research outputs found
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Proton-pump inhibitor use is associated with a broad spectrum of neurological adverse events including impaired hearing, vision, and memory.
Proton-pump inhibitors, PPIs, are considered effective therapy for stomach acid suppression due to their irreversible inhibition of the hydrogen/potassium pump in the gastric parietal cells. They are widely prescribed and are considered safe for over-the-counter use. Recent studies have shown an association between PPI use and Alzheimer dementia, while others have disputed that connection. We analyzed over ten million United States Food and Drug Administration Adverse Event Reporting System reports, including over forty thousand reports containing PPIs, and provided evidence of increased propensity for memory impairment among PPI reports when compared to histamine-2 receptor antagonist control group. Furthermore, we found significant associations of PPI use with a wide range of neurological adverse reactions including, migraine, several peripheral neuropathies, and visual and auditory neurosensory abnormalities
Performance Evaluation of a Tracking Total Station as a Position Reference forDynamic GNSS Accuracy Testing
The dynamic accuracy of a tracking total station (TTS) was evaluated using a rotary test fixture to determine the viability of using a TTS as a position reference for dynamic global navigation satellite-based system (GNSS) accuracy testing. Tests were performed at angular velocities ranging from 0 to 3.72 rad/s at a radius of 0.635 m. A technique was developed to determine the average latency of the TTS measurement serial data output. TTS measurements were interpolated at a GNSS sampling interval to provide a method for direct comparison between TTS and GNSS position measurements. The estimated latency from the TTS serial data output was shown to be consistently near 0.25 s for all angular velocities and less variable when using a reflector-based machine target versus a prism-based target. Average positional error in the TTS position measurement increased with angular velocity from 3 to 90 mm, partly due to internal filtering which caused the magnitude of the TTS position measurement to decrease under stead-state sinusoidal motion. The standard deviation of error ranged from less than 1 to 20 mm as angular velocity increased. Sight distance from the TTS to the target was shown to have very little effect on accuracy between 4 and 30 m. The TTS was determined to be an adequate benchmark for most dynamic GNSS and vehicle auto-guidance testing but is limited by relatively large position measurement errors at high angular velocities
Risk factors in oral carcinoma and the relationship between tumor thickness and regional nodal involvement: a pilot study in a semi urban population in New Delhi, India
Background: Oral squamous cell carcinoma (OSCC) is a major public health problem worldwide, with approximately 275,000 cases annually and a strong association with risk factors like smoking. It is a subtype of head & neck cancer involving the oral cavity. The present study evaluated the role of various risk factors in the development of oral carcinoma among our patient population.Methods: A total of 40 cases of oral carcinoma with radical neck dissection were evaluated. Data on the age, personal history and presenting clinical features were analyzed. The depth of the tumor and the maximum tumor thickness were carefully evaluated. Also, pathological T-stage, the presence/absence of vascular and peri-neural infiltration was evaluated in each case. The presence of nodal metastases and the stage of the tumor was assessed. Data was tabulated and correlation of nodal metastasis with tumor thickness, pathological T-stage, vascular invasion, and peri-neural infiltration was evaluated by appropriate statistical analysis method.Results: A total of 40 cases, 82.5% males and 17.5% females, were all smokers with history of consumption of smoking or smokeless or both. Tongue was the most common site of oral carcinoma (37.5%) involvement, histological characterization of all were Squamous cell carcinoma with majority of the patients in pathological stage II. A significant association between the tumor thickness and metastasis was also seen.  Conclusions: The tumor thickness of oral squamous cell carcinoma was found to be an important prognostic indicator for the occurrence of metastases to the regional cervical lymph nodes
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A community-engaged infection prevention and control approach to Ebola.
The real missing link in Ebola control efforts to date may lie in the failure to apply core principles of health promotion: the early, active and sustained engagement of affected communities, their trusted leaders, networks and lay knowledge, to help inform what local control teams do, and how they may better do it, in partnership with communities. The predominant focus on viral transmission has inadvertently stigmatized and created fear-driven responses among affected individuals, families and communities. While rigorous adherence to standard infection prevention and control (IPC) precautions and safety standards for Ebola is critical, we may be more successful if we validate and combine local community knowledge and experiences with that of IPC medical teams. In an environment of trust, community partners can help us learn of modest adjustments that would not compromise safety but could improve community understanding of, and responses to, disease control protocol, so that it better reflects their 'community protocol' (local customs, beliefs, knowledge and practices) and concerns. Drawing on the experience of local experts in several African nations and of community-engaged health promotion leaders in the USA, Canada and WHO, we present an eight step model, from entering communities with cultural humility, though reciprocal learning and trust, multi-method communication, development of the joint protocol, to assessing progress and outcomes and building for sustainability. Using examples of changes that are culturally relevant yet maintain safety, we illustrate how often minor adjustments can help prevent and treat the most serious emerging infectious disease since HIV/AIDS
A Simple Model of Heat Distribution at Various Rayleigh Number in Silicon Elastomer
In order to investigate the two-dimensional flow of a non-Newtonian fluid, such as an elastomer liquid over a cylinder, a simplified model is applied. The analysis is carried out to study the thermophysical properties of the melt elastomer flow with Prandtl variable in the presence of internal heat generation. The temperature-dependent physical properties such as velocity, contour temperature, surface temperature as a function of contour velocity, and pressure are considered and discussed. Moreover, the exchange of energy from the surface to the fluids is examined through the variation in the Rayleigh number
Mobile Device-Based Location Services Accuracy
The objective of this study was to characterize the expected position accuracy when using popular mobile devices for location-based agricultural decision-making activities. This study utilized Android-based Nexus 7 tablets and tested the operation of the three location services available on this system in a 24-h fixed location test and a shorter duration multiple location field test. In the 24-h test, the “network” location system had a measured error of 37.19 m while reporting an accuracy of 55.56 m. The “gps” location system had a measured error of 2.57 m and a reported accuracy of 3.20 m. Multiple tests were conducted with the location system added by Google Services code be cause the measured error was much higher than the reported accuracy. With this system, the measured errors were 14.13, 3.4, 24.08, 14.01, and 16.15 m with reported accuracies of 3.95, 4.83, 3.99, 7.18, and 6.68 m, respectively. All the tests with the Google Services location system had much higher variability in location estimates than the “gps” location system. For both services, the high values for reported accuracy did not correspond with high values for measured error. Field testing was only performed with the Google Services and “gps” location systems as the “network” location system did not operate in the test field. Statistical analysis confirmed that the “gps” system was more accurate in this testing but the difference was not as dramatic as in the 24-h testing. The average reported accuracy level was 3.0 m in all field tests with the “gps” system and 3.9 m in all field tests with the Google Services system. The field test data were also used to estimate areas of 0.14-ha rectangular plots. Among all three tests with the “gps” system and all three tests with the Google Services system, the mean absolute area percent error varied from 4% to 7%, and in every test at least one plot was over- or underestimated by at least 10%. The error characteristics and patterns for all but the “gps” service differed significantly from the random walk pattern and/or other characteristics of GNSS locators to which precision farming engineers have become accustomed. Mobile platform creators like Apple and Google are either requiring (Apple) or strongly encouraging (Google) developers to switch to newer services that don’t provide access to the underlying locating mechanism. Therefore, it is clear that careful consideration of these differences and what they may mean to location based apps in agriculture will be important. This work highlights the importance of testing any “smart” devices to determine actual location accuracy before relying on them for making agricultural decisions based on their output
Scalable Control Architecture for Variable-Rate Turn Compensation
The objective of this study was to determine if a CAN bus could be used to implement variable-rate turn compensation in a manner that is scalable by encoding application rates for an entire implement into a single data message. A variable-rate turn compensation test fixture was developed that used a CAN bus to communicate application rates to 16 individual nodes using a 2-byte data message (80-bit extended identifier CAN messages). The system assumed that the physical structure of an implement was linear and that the control nodes were equally spaced. Application rates for the outer-most nodes were broadcasted and the remaining nodes calculated their application rate using a linear interpolation method. Node locations were determined using a 4-bit binary thumbwheel switch located at each control node, allowing all nodes to run an identical program. Servo-controlled gauges were used to visualize node application rate across the test fixture. A joystick interface was developed to simulate vehicle movements and desired application rates. The system transmitted Bluetooth serial messages at a rate of 20 Hz, which were received by the test fixture and converted to CAN messages before being broadcasted to the control nodes. Two USB to CAN interfaces were connected to the CAN bus to insert additional traffic and measure bandwidth utilization. Due to the minimal amount of bandwidth required (\u3c1%) to transmit variable-rate control messages, the system functioned properly when the CAN bus was heavily loaded with traffic up to 99% of the available bandwidth of 250 kbps. The variable-rate turn compensation test fixture demonstrated that a CAN bus is a suitable protocol for communicating variable-rate data. The scalable encoding technique developed in this study resulted in a single message required to update all nodes, regardless of the number of nodes in the system. The system has broad applicability in future planting, fertilizing, and chemical application systems where deposition points are evenly spaced along an implement
Flow, Spray Pattern, And Droplet Spectra Characteristics Of An Electronically Actuated Variable-Orifice Nozzle
The purpose of this study was to develop and evaluate the flow rate, spray pattern, and droplet spectra characteristics of an actively controlled variable-orifice nozzle at constant carrier pressures. A commercially available variable- orifice nozzle (VariTarget) was modified to allow for direct electromechanical control of the metering stem. The modified system was tested at five carrier pressures ranging from 138 to 414 kPa and five metering stem (and thus orifice) positions. The metering stem position range was chosen because it provided a linear response in flow rate at each carrier pressure. Flow rate testing indicated a turndown ratio of 2.4:1 at each carrier pressure, with a total turndown ratio of 4.8:1 across the range of carrier pressures using the selected metering stem positions. Spray pattern testing indicated acceptable coefficients of variation for the metering stem positions and carrier pressures for nozzle spacings of 38.1 and 51.0 cm. Droplet spectra test results showed that the particle sizes remained in the range of extremely coarse to ultra coarse for all metering stem positions and carrier pressures. Orifice control using the modified system resulted in slightly larger droplet sizes compared to the original spring-actuated nozzle; however, the potential for spray drift would be reduced. The results of this study show that active control of the VT nozzle metering stem could provide potential for improvements in pesticide application. Nozzle flow rates could be controlled via the proposed system with little negative effects on spray pattern or droplet spectra. In addition to compensating for sprayer ground speed changes, a system consisting of these nozzles could potentially be used to solve application errors generated from sprayer turning movements
Performance Validation of a Multi-Channel LiDAR Sensor: Assessing the Effects of Target Height and Sensor Velocity on Measurement Error
The objective of this study was to determine the effects of sensor velocity and target height above ground level on height measurement error when using a multi-channel LiDAR sensor. A linear motion system was developed to precisely control the dynamics of the LiDAR sensor in an effort to remove uncertainty in the LiDAR position and velocity while under motion. The linear motion system allowed the LiDAR to translate forward and backward in one direction parallel to the ground. A user control interface was developed to operate the system under different velocity profiles and to log LiDAR data synchronous to the motion of the system. The performance of the linear motion system was validated with a tracking total station, and the results showed that the position and velocity control errors were negligible as compared to the LiDAR accuracy. The LiDAR was then validated using 25 test targets at varying heights above ground level (0.1, 0.3, 0.5, 0.6, and 0.8 m) with five different velocity profiles (0.1, 0.5, 1.0, 1.5, and 2.2 m s-1) and six replications to determine the effects of sensor velocity and target height on measurement error. The targets were painted white on one side and black on the other to determine the effect of relative intensity on LiDAR height measurement error. Generalized linear mixed models were fitted with the measurement error and the standard deviation of the measurement error as the responses. Sensor velocity, target height, and their interaction were considered as fixed effects to determine if there were significant differences in average error and standard deviation of error for different sensor velocities and target heights. The results indicated that the velocity of the LiDAR was a significant factor affecting the average error and standard deviation of error in height measurements. However, higher velocities tended to result in only slightly larger average errors. A three-fold increase in the standard deviation was observed when increasing the velocity from 0.1 to 2.2 m s-1. Height of the target was either a weakly significant or insignificant factor in average error and a weakly significant factor affecting the standard deviation of the LiDAR measurements, representing mixed results. The average error and standard deviation were less than 10 and 30 mm, respectively, for all replications. Relative intensities of the LiDAR measurements were 88.2% and 5.4% for white and black targets, respectively, and the different target colors exhibited a 4.7 mm shift in average estimated height error. These uncertainties may not be substantial for agricultural applications, where other sources of error, such as moving crop canopies or error in resolving the position of the sensor, are more likely to dominate overall measurement error
Recalibration Methodology to Compensate for Changing Fluid Properties in an Individual Nozzle Direct Injection Systems
Limited advancement of direct injection pesticide application systems has been made in recent years, which has hindered further commercialization of this technology. One approach to solving the lag and mixing issues typically associated with injection-based systems is high-pressure individual nozzle injection. However, accurate monitoring of the chemical concentrate flow rate can pose a challenge due to the high pressure, low flow, and changing viscosities of the fluid. A methodology was developed for recalibrating high-pressure chemical concentrate injectors to compensate for fluid property variations and evaluate the performance of this technique for operating injectors in an open-loop configuration. Specific objectives were to (1) develop a method for continuous recalibration of the chemical concentrate injectors to ensure accurate metering of chemicals of varying viscosities and (2) evaluate the recalibration method for estimating individual injector flow rates from a system of multiple injectors to assess potential errors. Test results indicated that the recalibration method was able to compensate for changes in fluid kinematic viscosity (e.g., from temperature changes and/or product variation). Errors were less than 3.4% for the minimum injector duty cycle (DCi) (at 10%) and dropped 0.2% for the maximum DCi (at 90%) for temperature changes of up to 20°C. While larger temperature changes may be expected, these test results showed that the proposed method could be successfully implemented to meet desired injection rates. Because multiple injectors would be used in commercial deployment of this technology, a method was developed to calculate the desired injector flow rate using initial injector calibration factors. Using this multi-injector recalibration method, errors ranged from 0.23% to 0.66% between predicted and actual flow rates for all three injectors
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