NOViSE: a virtual natural orifice transluminal endoscopic surgery simulator

Purpose: Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a novel technique in minimally invasive surgery whereby a flexible endoscope is inserted via a natural orifice to gain access to the abdominal cavity, leaving no external scars. This innovative use of flexible endoscopy creates many new challenges and is associated with a steep learning curve for clinicians. Methods: We developed NOViSE - the first force-feedback enabled virtual reality simulator for NOTES training supporting a flexible endoscope. The haptic device is custom built and the behaviour of the virtual flexible endoscope is based on an established theoretical framework – the Cosserat Theory of Elastic Rods. Results: We present the application of NOViSE to the simulation of a hybrid trans-gastric cholecystectomy procedure. Preliminary results of face, content and construct validation have previously shown that NOViSE delivers the required level of realism for training of endoscopic manipulation skills specific to NOTES Conclusions: VR simulation of NOTES procedures can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. In the context of an experimental technique, NOViSE could potentially facilitate NOTES development and contribute to its wider use by keeping practitioners up to date with this novel surgical technique. NOViSE is a first prototype and the initial results indicate that it provides promising foundations for further development

Biodegradation of Crude Oil by Penicillin sp and Mortierella sp. Isolated from Oil-Contaminated Soil in Auto Mechanic Workshops

Biodegrading capability of fungi isolated from oil-contaminated soil in three auto-mechanic workshops in Minna, Nigeria was determined by mycelial extension rate measurement method. Penicillium strain 8 I 0 IF, 8201 F and B202F and Mortierel/a strain B I 002F were identified as best crude oil (lagoma light) degraders compared to the other isolates such Aspergillus strain BI02F, BI04F and Bll9F, Fusarium strain 8501F and Trichoderma strain K602F and K561F. The optimum pH and temperature forB I 0 IF and B l 002F to degrade crude oil were 5.0 and 28 •c respectively. When complex nutrient such as maize bran was used as nitrogen source with crude oil in minimal salt liquid medium (MSLM) omitting NaN03, the optimum growth reached on 14tl' day of fermentation for both the isolates. BIOIF and BI002F were capable of using crude oil as both carbon and energy source in minimal salt medium. In view of their ability to utilize crude oil as carbon and nitrogen source, these organisms may be used in mitigating the pollution arising out of oil spills in the environmen

Prediction of Natural Gas Compressibility Factor in a Single-Phase Gas Reservoir: A Comparative Study

Natural gas compressibility factor plays important roles in pipeline design, reserve estimation and gas metering. The aim of this study is to presents the most accurate and reliable method of computing gas compressibility factor in a single-phase gas reservoir at various reservoir pressures. In this study, the gas compositions and the specific gravity of the respective gas compounds were retrieved from literatures. This specific gravity determine the pseudo critical and the pseudo reduced properties (temperature and pressure) of the respective gas compounds being studied. The predicted methods studied are Papay correlation, Hall-Yarborough equation of state (EOS), viral EOS, Beggs and Brill and Dranchuk-Abu-Kassem correlation. The methods are expressed as functions of the pseudo-reduced temperature and pressure, thereby predicting the compressibility factor of the predicted methods. The accuracy and the performance of the methods were tested by comparing the results obtained from the methods studied with experimental z-factor values obtained from the literatures. The experimental z-factor values were set as standard for the predicted methods studied. Six (6) statistical parameters and various charts (line and column charts) were used to attest the effectiveness and the precision of the methods. The statistical tools are average absolute error (AAE), average absolute relative error (AARE), root mean square error (RMSE), residual sum of square (RSS), mean square error (MSE) and coefficient of determination (R2). The results of the study shows that, the Papay correlation has the highest coefficient of regression, R2= 92%, rated as the most accurate, reliable and best method. The Hall-Yarborough equation of state has R2 of 86%. The Viral equation of state has R2 of 83%. The Beggs and Brill correlation has R2 of 42%. The Dranchuk-Abu-Kassem correlation has R2 of 10.5%. The Beggs and Brills correlation method is not suitable for application, if the pseudo-reduced pressure is less than 0.92. The Dranchuk-Abu-Kassem correlation is only applicable, if the pseudo-reduced properties are within the range of 0.2<Ppr<15, 1.0<Tpr<3.0. The Hall-Yarborough equation of state cannot be used if the pseudo-reduced temperature is less than one

Observations of solar small-scale magnetic flux-sheet emergence

Aims. Moreno-Insertis et al. (2018) recently discovered two types of flux emergence in their numerical simulations: magnetic loops and magnetic sheet emergence. Whereas magnetic loop emergence has been documented well in the last years, by utilising high-resolution full Stokes data from ground-based telescopes as well as satellites, magnetic sheet emergence is still an understudied process. We report here on the first clear observational evidence of a magnetic sheet emergence and characterise its development. Methods. Full Stokes spectra from the Hinode spectropolarimeter were inverted with the SIR code to obtain solar atmospheric parameters such as temperature, line-of-sight velocities and full magnetic field vector information. Results. We analyse a magnetic flux emergence event observed in the quiet-sun internetwork. After a large scale appearance of linear polarisation, a magnetic sheet with horizontal magnetic flux density of up to 194 Mx/cm$^{2}$ hovers in the low photosphere spanning a region of 2 to 3 arcsec. The magnetic field azimuth obtained through Stokes inversions clearly shows an organised structure of transversal magnetic flux density emerging. The granule below the magnetic flux-sheet tears the structure apart leaving the emerged flux to form several magnetic loops at the edges of the granule. Conclusions. A large amount of flux with strong horizontal magnetic fields surfaces through the interplay of buried magnetic flux and convective motions. The magnetic flux emerges within 10 minutes and we find a longitudinal magnetic flux at the foot points of the order of $\sim$$10^{18}$ Mx. This is one to two orders of magnitude larger than what has been reported for small-scale magnetic loops. The convective flows feed the newly emerged flux into the pre-existing magnetic population on a granular scale.Comment: 6 pages, 5 figures, accepted as a letter in A&

Standalone General Purpose Data Logger Design and Implementation

This paper describes the design of a general purpose data logger that is compatible with a variety of transducers, potentially permitting the measurement and recording of a wide range of phenomena. The recorded data can be retrieved to a PC via an RS-232 serial port. The standalone general purpose data logger centered on a single microcontroller unit (MCU) the PIC18F4520. The circuit takes an input range of 15 – 30V DC in addition; an in-built 9V rechargeable battery provides backup power in the absence of an external source.  The microcontroller input form the Transduceroutput was conditioned within the allowable voltage range, the ADC calculates a binary value that is equivalent to its input (analog) voltage.  The in-built 10-bit ADC of the PIC18F4520 converts the analog input to a digital output by successive approximation, the 8 MSBs of the ADC are stored whereas the 2 LSBs are discarded which makes the output of the ADC varies from 0 to 255. Although the PIC18F4520 features 256 bytes of non-volatile EEPROM data memory, four AT24C256 2-wire serial EEPROM chips were used for data storage. The four chips were cascaded to form a memory bank that connects to the MCU via a common single 2-wire bus.The hardware employed to achieve the RS-232 serial interface was a 9-pin D-shell serial connector and a voltage level translator chip (Maxim’s MAX232). The connector simply allows the device to be coupled to a serial port of a PC using a standard serial cable. The TIMER1 module of the PIC18F4520 was configured such that its 16-bit register is incremented on the rising edge of the external clock signal applied to its input pin (pin 16). The input pins of the MCU that are dedicated to the switches are pulled up by resistors R11, R12, R13, R14, R15 and R16.  The push buttons temporarily pull down the input signal when depressed. The output devices consist of a “Liquid Crystal Display” (LCD) device, four general purpose LEDs, and a buzzer. The LCD displays the momentary status of the data-logger in terms of date, time, sampling rate and nature of logged data.  The LEDs are used to display the four MSBs of the measured data and the buzzer is used to raise an alarm if and when necessary but may be disabled in hardware by opening jumper J4. The design was implemented and simulated on Labcenterproteus and the components were mounted on a double layered PCB (Printed Circuit Board) that provides the tracks that make up the circuit.The prototype design realized was found to work satisfactorily.http://dx.doi.org/10.4314/njt.v34i2.18

Prognosis of diabetes complications and efficacy of Guiera senegalensis aqueous leaf extract in streptozotocin induced-diabetic rats

Diabetes epidemics pose a serious health care problems and a huge burden on the economy of both developed and developing nations. Precise prognosis and the discovery of cost effective drugs for its management would serve as catalyst to economic recovery. This study is aimed at evaluating the prognosis of diabetes complications and the efficacy of Guiera senegalensis aqueous leaf extract in streptozotocin (STZ) induced-diabetic rats. Twelve (12) adult male Wistar rats were used in this study. Diabetes was induced by administration of 60 mg/kg of streptozotocin. Diabetic rats were treated orally with the aid of a gavage 500 mg/kg of aqueous extract of Guiera senegalensis for 21 days. Fasting blood glucose and body weight were monitored at intervals of 7 days. Some antioxidant enzymes, lipid profile and indices of renal function were assayed after the 21st day. Post administration of 60 mg/kg of STZ produced significant (P<0.05) increases in fasting blood glucose, total cholesterol, triglycerides, Na+, and K+ levels. Body weight, catalase and HDLcholesterol levels were reduced. Related biochemical indices (superoxide dismutase, glutathione peroxidase, LDL cholesterol, urea, creatinine, Cl− and bicarbonate) were similarly modulated by STZ but the effects were not significant relative tothe normal control. Administration of extract of Guiera senegalensis reverses the effects of STZ on these parameters. Although they were not completely brought back to normal in some cases. These findings are indications that Guiera senegalensis has the capacity to attenuate some complications of diabetes mellitus and could be considered as a potent anti-diabetic plant.Keywords: Attenuate, catalyst, epidemics, gavage, prognosis, streptozotoci

Acoustic Events in the Solar Atmosphere from Hinode/SOT NFI observations

We investigate the properties of acoustic events (AEs), defined as spatially concentrated and short duration energy flux, in the quiet sun using observations of a 2D field of view (FOV) with high spatial and temporal resolution provided by the Solar Optical Telescope (SOT) onboard \textit{Hinode}. Line profiles of Fe \textsc{i} 557.6 nm were recorded by the Narrow band Filter Imager (NFI) on a $82" \times 82"$ FOV during 75 min with a time step of 28.75 s and 0.08$"$ pixel size. Vertical velocities were computed at three atmospheric levels (80, 130 and 180 km) using the bisector technique allowing the determination of energy flux in the range 3-10 mHz using two complementary methods (Hilbert transform and Fourier power spectra). Horizontal velocities were computed using local correlation tracking (LCT) of continuum intensities providing divergences. The net energy flux is upward. In the range 3-10 mHz, a full FOV space and time averaged flux of 2700 W m$^{-2}$ (lower layer 80-130 km) and 2000 W m$^{-2}$ (upper layer 130-180 km) is concentrated in less than 1% of the solar surface in the form of narrow (0.3$"$) AE. Their total duration (including rise and decay) is of the order of $10^{3}$ s. Inside each AE, the mean flux is $1.6 10^{5}$ W m$^{-2}$ (lower layer) and $1.2 10^{5}$ W m$^{-2}$ (upper). Each event carries an average energy (flux integrated over space and time) of $2.5 10^{19}$ J (lower layer) to $1.9 10^{19}$ J (upper). More than $10^{6}$ events could exist permanently on the Sun, with a birth and decay rate of 3500 s$^{-1}$. Most events occur in intergranular lanes, downward velocity regions, and areas of converging motions.Comment: 18 pages, 10 figure

A not so massive cluster hosting a very massive star

We present the first physical characterization of the young open cluster VVV CL041. We spectroscopically observed the cluster main-sequence stellar population and a very-massive star candidate: WR62-2. CMFGEN modeling to our near-infrared spectra indicates that WR62-2 is a very luminous (10$^{6.4\pm0.2} L_{\odot}$) and massive ($\sim80 M_{\odot}$) star.Comment: 1 page, 1 figure, to be published in the "International Workshop on Wolf-Rayet Stars conference proceedings" by Universit\"atsverlag Potsdam (editors: W.-R. Hamann, A. Sander, and H. Todt