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A 4-year review of surgical and oncological outcomes of endoscopic endonasal transpterygoid nasopharyngectomy in salvaging locally recurrent nasopharyngeal carcinoma
No full textPurpose: To study the surgical and oncological outcomes of endoscopic endonasal transpterygoid nasopharyngectomy (EETN) in salvaging locally recurrent nasopharyngeal carcinoma (NPC). Method: This was a retrospective clinical record review study carried out at a tertiary centre from June 2013 until May 2017. A total of 55 locally recurrent NPC patients (rT1–rT4) underwent EETN performed by single skull base surgeon with curative intention with postoperative adjuvant chemotherapy but without postoperative radiotherapy. Results: There were 44 (80.0%) males and 11 (20.0%) females, with mean age of 52.5 years. The mean operating time was 180 min (range 150–280 min). 85% (47/55) of patients achieved en bloc tumour resection. 93% (51/55) of patients obtained negative microscopic margin based on postoperative histopathological evaluation. Intraoperatively, one (1.8%) patient had internal carotid artery injury which was successfully stented and had recovered fully without neurological deficit. There were no major postoperative complications reported. During a mean follow-up period of 18-month (range 12–48 months) postsurgery, five patients (9.1%) had residual or recurrence at the primary site. All five patients underwent re-surgery. One patient at rT3 passed away 6 months after re-surgery due to distant metastasis complicated with septicaemia. The 1-year local disease-free rate was 93% and the 1-year overall survival rate was 98%. Conclusions: EETN is emerging treatment options for locally recurrent NPC, with relatively low morbidity and encouraging short-term outcome. Long-term outcome is yet to be determined with longer follow-up and bigger cohort study. However, a successful surgical outcome required a very experienced team and highly specialised equipment. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature
Investigating the impact of wind on sea level rise using multilayer perceptron neural network (MLP-NN) at coastal area, Sabah
No full textThis study investigating the impact of wind on sea level rise (SLR) using Multilayer Perceptron Neural Network (MLP-NN) at Coastal Area, Sabah. The mean sea level (MSL) and four meteorology parameters namely; wind direction (WD), wind speed (WS), rainfall and mean cloud cover. These meteorological parameter and MSL were monitored regularly each month over a period from January 2007 to December 2016 at three different locations which is Kudat, Kota Kinabalu and Sandakan. Due to small amount of data set, both method the input data were divided into 80 % for training and 20% for testing data respectively.In this study, two scenarios were introduced; the scenario 1 (with wind) WD and WS as input parameter while scenario 2 (without wind)rainfall and mean cloud cover to predict sea level at each stations. Then by using previous monthly sea water level records the model was performed by predicting SLR for1 year, 5 years, 10 years, 30 years, and 50 years ahead in the future. The performance of the models was evaluated according to three statistical indices in terms of the correlation coefficient (R), root mean square error (RMSE) and scatter index (SI). Investigation results indicate that, when compared to measurements, for 50 years prediction, all three models in scenario 2 perform well (with average values of R = 0.6, RMSE = 0.2 cm and SI = 0.4)
Defining a threshold for tacrolimus intra-patient variability associated with late acute cellular rejection in paediatric kidney transplant recipients
No full textBackground: Late acute cellular rejection (LACR) is associated with poorer graft outcomes and non-adherence. Non-adherence to tacrolimus can be indirectly assessed by the intra-patient variability (IPV) of tacrolimus trough levels. The threshold of IPV associated with rejection is not known. Methods: We conducted a case-control study comparing 25 patients with biopsy-proven LACR against 25 stable controls matched for age group, primary diagnosis and time post-transplant. IPV was calculated using coefficient of variance (CV) and mean absolute deviation (MAD) using tacrolimus levels in the preceding 12 months. We also assessed the percentage time for tacrolimus levels < 4 μg/L (Tac < 4) and the concentration/weight-adjusted dose (C/D) ratio as a proxy marker of tacrolimus metaboliser status. Results: LACR patients had higher CV (median, IQR 44%, 36–61% v. 24%, 19–35%, p < 0.0001) and higher MAD (33%, 25–48% v. 19%, 15–26%, p < 0.0001). The MAD was less affected by outlying tacrolimus results. Receiver operating curve analysis of the MAD resulted in a sensitivity of 76% and specificity of 76% at a threshold of 26% (AUC 0.85, p < 0.05). LACR patients had more Tac < 4 (50% v. 26%, p < 0.05). There was no difference in C/D suggesting that good IPV can be maintained in fast metabolisers. Patients with LACR had significantly increased creatinine at 12-month follow-up despite treatment (108 v. 5 umol/L increase from baseline) and four patients lost their allograft. Conclusions: Monitoring of tacrolimus IPV using the MAD may be a clinical marker for LACR. A threshold IPV of 26% can potentially be used as a therapeutic target pending further validation studies. © 2019, IPNA
Elastic reversible valves on centrifugal microfluidic platforms
No full textReversible valves on centrifugal microfluidic platforms facilitate the automation of bioanalytical assays, especially of those requiring a series of steps (such as incubation) in a single reaction chamber. In this study, we present fixed elastic reversible (FER) valves and tunable elastic reversible (TER) valves that are easy to fabricate, implement and control. In the FER valve the compression of an elastic barrier/patch against a microchamber's outlet prevents the release of liquid. The valve sealing pressure was determined by adjusting the engraving depth of the valve-seat at which the elastic patch was located, this allows to set the sealing pressure during disc fabrication. In the TER valve, the patch compression value and sealing pressure is controlled by the penetration depth of a plastic screw into the valve-seat. The ER valves prevent liquid flow until the centrifugal force overcomes their sealing pressure. Moreover, at a constant spin speed, turning the screw of a TER valve reduces its sealing pressure and opens the valve. Therefore, the TER valve allows for controlling of the liquid transfer volume at various spin speeds. The FER and TER valves' behavior is mathematically described and equations for the prediction of their operation under centrifugal forces are provided. As a point-of-care (POC) application of ER valves, we have developed a microfluidic disc with a series of TER valves and peptide microarrays for automated multiplexed detection of five different proteins from a single serum sample. © The Royal Society of Chemistry
Revealing customers’ satisfaction and preferences through online review analysis: The case of Canary Islands hotels
No full textTravelers can enjoy a wide range of choices with the assistance of online review websites such as TripAdvisor. Online reviews provided by customers are an important portion of hotels' online business worldwide as they have value in terms of understanding customers' observations of hotels' product and service features. Hotel managers seek to understand travelers' satisfaction and hotel preferences through online reviews to improve their marketing strategy and decision making. This research uses the travelers' generated content in online hotel reviews to provide reasonable and benchmarking understandings about customers' satisfaction and preferences. Hence, the aim of this study is identifying the important factors for hotel selection based on previous travelers' reviews on TripAdvisor. Accordingly, we develop a new method for the use of Multi-Criteria Decision-Making (MCDM) and soft computing approaches. Concentrating on the case study of the Canary Islands hotels, we show how this method can be applied to determine the satisfaction and preferences among travelers that impact their decision in hotel choices. The results help to identify four customer segments for Canary Islands hotels. These segments are “Highly Satisfied Travelers”, “Satisfied Travelers”, “Moderately Satisfied Travelers”, and “Unsatisfied Travelers”, showing that different travelers have various degrees of satisfaction with dissimilar preferences. We found that travelers' preference and satisfaction segmentation is a crucial stage in travelers' behavior analysis to improve the quality of hotels' products and services. This form of analysis can enhance hotel managers' understanding of different market segments according to customers’ satisfaction level and their preferences. The findings of this study will help managers to set priority instructions for improving the corresponding hotel features and use online customer reviews to improve customer satisfaction and hotel performance. © 2019 Elsevier Lt
Molybdenum tungsten disulphide (MoWS2) as a saturable absorber for a passively Q-switched thulium/holmium-codoped fibre laser
No full textIn this work, a passively Q-switched Thulium/Holmium-doped fibre laser (THDFL) using a molybdenum tungsten disulphide (MoWS 2 ) saturable absorber (SA) is proposed and demonstrated. The MoWS 2 nanosheets are prepared by hydrothermal exfoliation and then suspended in a polyvinyl alcohol (PVA) thin film host. Q-switching of the THDFL at a maximum 1550 nm pump power of 445.2 mW gives a maximum repetition rate and minimum pulse width of 36.3 kHz and 2.8 µs with a corresponding pulse energy of 86.4 nJ and peak power of 31.1 mW. The MoWS 2 based Q-switched THDFL's output has a very high signal-to-noise value of ∼62.2 dB which strongly indicates that the laser is working in a stable operation. To the best of our knowledge, this is the first demonstration of MoWS 2 as a passive SA in a THDFL for operation in the 2.0 µm region. The proposed laser would have significant medical and sensing applications, particularly at the biologically active 2.0–2.1 µm regions. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group
Influence of boron nitride nanoparticles in the electrical and photoconduction characteristics of planar boron nitride-graphene oxide composite layer
No full textA modified Iummer’s method is used to obtain a photoconducting material based on boron nitride (BN)– graphene oxide (GO) composite layer. The proposed silver/BN–GO/silver Schottky photodetector was fabricated using a drop-casting technique and electron beam evaporation. It was characterized using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The confine element composition of boron, nitrogen, carbon, and oxygen showed excellent photoconduction toward laser wavelength of a50 nm and output power of 0.7 mW. The dark and illuminated current–voltage characteristics were used to determine the ideality factor and barrier height, which inevitably simplified the transport mechanism in the device. The reported ideality factor of 2.58 suggests the charge transport at the junction and formation of non-amorphous BN–GO composite layer. © 2019 by American Scientific Publishers All rights reserved
An audio encryption based on synchronization of robust BAM FCNNs with time delays
No full textIn this work, authors’ proposed an audio encryption based on synchronization of hybrid bidirectional associative memory (BAM) and fuzzy cellular neural networks (FCNNs) with time delays. Here, the significant effort is to find the values of the parameters A,B,D,α,β,Ã,B~,D~,α~,β~,L,L~,Od,Õd,Oa,Õa,Ob,Õb, of the given robust BAM FCNNs system to obtain the dynamical signal (chaotic) which are used to encrypt an audio file and satisfy the condition of Linear matrix inequality (LMI) by choosing suitable Lyapunov-Krasovskii functional (LKF). Further, the key sensitivity of order 1 0 − 10 of this proposed method have massive key space to make brute-force attack infeasible. Numerical simulations, results and discussions along with comparison are provided to illustrate the effectiveness and merits of the proposed scheme. © 2018, Springer Science+Business Media, LLC, part of Springer Nature
Experimental Investigation on Fatigue Behavior of Wide-Flange Steel I-Beams Strengthened Using Different CFRP End Cutting Shapes
No full textIn recent decades, the application of carbon fibre-reinforced polymer (CFRP) composites for strengthening structural elements has become an efficient option to meet the increased cyclic loads, or repair due to fatigue cracking. The premature failure due to end-debonding is a key limitation to achieve high fatigue performance of strengthened steel beams with externally bonded CFRP plates. The objective of this study is to explore the reinforcing techniques using the CFRP in-plane end cutting shapes and the triangular spew fillet of adhesive at the tips of the plate to care for fatigue damaged of wide-flange steel I-beams due to end-debonding. Four in-plane CFRP end cutting shapes were chosen, namely: rectangular, semi-elliptical, semi-circular and trapezoidal. The application of the trapezoidal end shape was found to be the best configuration for delaying the end-debonding failure mode and high fatigue life compared to the other CFRP in-plane end cutting shapes. Applying the triangular spew fillets of adhesive significantly increased the end-debonding and steel beam fracture initiation life of the strengthened beams. © 2018, Korean Society of Steel Construction
Theoretical Diagnostics of Second and Third-order Hyperpolarizabilities of Several Acid Derivatives
No full textThe density functional theory (DFT) at B3LYP/ 6-31G(d) level has been utilized to achieve the electric dipole moment (μ), static dipole polarizability (α) and first hyperpolarizability (β) values for ferulic acid (1) and chenodeoxycholic acid (2). The time-dependent Hartree-Fock (TDHF) technique as a powerful quantum chemical method has been implemented to reveal the dynamic α, β and third-order hyperpolarizabilities (γ) of the examined compounds. Our computational conclusions have been compared with the results of similar materials in the literature. The first and second frontier molecular orbitals (MOs) and their band gaps have also been investigated by means of DFT. © 2019 A. Karakas et al., published by De Gruyter