Selective amplification of bacterial 16S rDNA sequence from clinical samples

Background: Conventional blood culture method is time consuming and less sensitive; when fastidious or un-culturalable organisms are involved. The use of PCR targeting the 16S rRNA allows detection of bacteria; however, these primers have ability to co-amplify human DNA. This Polymerase Chain Reaction (PCR) method is based on nucleic acid amplification test. Objective of the study: This study determined a method for selective amplification of bacterial DNA from clinical samples without co-amplification of human DNA. Materials and methods: Seventy one blood samples from clinically suspected cases of early onset neonatal sepsis were collected and analysed in parallel by culture and 16S rRNA amplification. DNA was extracted using commercial extraction QiAmp mini DNA kit and subjected to 16S rRNA amplification. The products were sequenced, analysed and compared with blood culture results. Positive and negative controls were used for extraction and amplification respectively. Results: Out of 71 samples analysed, 5 (7.0%) samples by blood culture were equally positive for 16S rRNA PCR; the PCR was also able to identified 16 (22.5%) more positive samples which blood culture could not identify, but only 1 (1.4%) sample was identified positive using blood culture while PCR identified it as negative. During the study, 7 (9.9%) samples were identified positive by conventional blood culture but later found to be contaminants. Conclusion: This study confirmed the presence of 16S rRNA among bacterial isolates and modification of PCR protocol with shorter denaturation temperature and time, leading to selective amplification of bacterial DNA. Therefore, there is need to carry-out this investigation on both culturable and unculturable specimens. Keywords:16SrRNA amplification; bacterial DNA; human DNA and Polymerase chai

Improvement of rheological and transient response of magnetorheological grease with amalgamation of cobalt ferrite

The time responsiveness of magnetorheological grease (MRG) towards magnetic field stimulus is crucial in order to ensure the high performance of MR devices. However, due to the thixotropic properties of grease, MRG has been restricted in terms of responding rapidly towards these magnetic fields. Therefore, polygonal shapes made up of 1–3 of cobalt-ferrite (CoFe2O4) particles with different concentrations from 0 to 5 wt.% were introduced to enhance the responsiveness of the MRG. The results revealed that the linear viscoelastic (LVE) region of the modified MRG improved between 29% and 43% during the off-state and on-state conditions, respectively. The absolute MR effect of MRG increased by at least 60% due to the improvement in the particle's chain alignment with that of the applied magnetic fields. In terms of transient responses, particularly within the highly acceptable LVE region (0.05%), the MRG with CoFe2O4 performed about 5–6 s faster as compared to pure MRG, which was attributed to the improvement in the particle's mobility in the grease medium.

Optimal control strategy for low speed and high speed four-wheel-active steering vehicle

In this work, based on the optimal control theory approach, a four-wheel-active steering (4WAS) system is proposed for low speed and high speed applications. A model following the control structure is adopted consisting of a feed-forward and feedback compensation strategy that serves as correction inputs to enhance the vehicle’s dynamic behavior. The velocity dependent feed-forward control inputs are based on the driver’s steering intention while the feedback control inputs are based on the vehicle’s state feedback errors, being the sideslip and yaw rate of the vehicle. Numerical simulations are conducted using the Matlab/Simulink platform to evaluate the control system’s performance. The performance of the 4WAS controller is tested in two designated open loop tests, being the constant steer and the lane change maneuver, to evaluate its effectiveness. A comparison with conventional passive front-wheel-steering (FWS) and conventional four-wheel-steering (4WS) systems shows the preeminent result performance of the proposed control strategy in terms of the response tracking capability and versatility of the controller to adapt to the system’s speed environment. In high speed maneuvers, the improvement in terms of yaw rate tracking error in rms is evaluated and the proposed active steering system considerably beat the other two structures with 0.2% normalized error compared to the desired yaw rate response. Meanwhile, in low speed, turning radius reductions of 25% and 50% with respect to the capability of normal or typical FWS vehicles are successfully achieve

Incorporation of cobalt ferrite on the field dependent performances of magnetorheological grease

Magnetorheological grease (MRG) is one of the smart materials that experiences a high off state viscosity, which hassles the operation of devices at the beginning and causes more energy consumption upon operation. Therefore, this paper investigates the off-state viscosity of MR lithium-based grease with various percentages of cobalt ferrite (CoFe2O4), as these particles are believed to potentially enhance the field-dependent stress of MRG by reducing the off-state viscosity and increasing mobility of the magnetic particles as the magnetic field applied. The MRG with various concentrations of CoFe2O4 at a ratio of 1 e5 wt.% were investigated via Field-Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) to analyze their morphology and magnetic properties, respectively. The rheological test of MRG samples in terms of viscosity, shear stress and yield stress were investigated upon shear rate, using rheometer. The results demonstrated that with the incorporation of 5wt.% CoFe2O4 particles, the initial off-state viscosity was reduced by 86% as compared to the pure MRG. The presence of CoFe2O4 particles triggered more chaotic motion thus restricted the formation of agglomeration of particles during shearing process. Meanwhile, the initial viscosity of MRG increased as a 0.64 T of magnetic field was applied along with the increased of CoFe2O4 particles. In fact, there was an enhancement of shear stress and yield stress on the CoFe2O4 incorporated MRG samples as compared with pure MRG. This study underlined the influence of CoFe2O4 particles, which could reduce the initial viscosity of MRG and improve the rheological properties upon the application of magnetic field

Cosmic Dynamics in F(R,ϕ)F(R,\phi) Gravity

In this paper we consider FRW cosmology in $F(R,\phi)$ gravity. It is shown that in particular cases the bouncing behavior may appears in the model whereas the equation of state (EoS) parameter may crosses the phantom divider. For the dynamical universe, quantitatively we also find parameters in the model which satisfies two independent tests:the model independent Cosmological Redshift Drift (CRD) test and the type Ia supernova luminosity distances.Comment: 15 pages, 12 figure

Age at first birth in women is genetically associated with increased risk of schizophrenia

Prof. Paunio on PGC:n jäsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe

Active Vibration Isolation System (AVIS) using a Voice Coil Actuator to improve Free Space Optics Communication

In Free Space Optic communication (FSOC), transmitter and receiver's alignment is vital to maintain the line of sight during the whole communication period. This is critical in data transmission over a long-distance. Vibration at either receiver or transmitter, causes misalignment and this affects FSOC. In this paper, AVIS, which can actively isolate FSO devices from low-frequency vibration from the ground, is designed and developed. The main goal is to reduce vibration from the top plate of the system where the telescope of the FSOC system is placed. An analytical model of the active vibration isolation is derived, and then the real prototype is fabricated. An imbalance mass system is used as an exciter for the system. Furthermore, for the cost-saving factor, a voice coil actuator which is modified from a conventional loudspeaker is used as an actuator for the system. LQR controller is implemented by using LabVIEW. The results show that the displacement level of the system with excitation frequencies 6 Hz, 12 Hz and 18 Hz are reduced more than 85 %. Moreover, it is proven that the loudspeaker not only costs lower but also gives a good performance for an AVIS. - 2019 IEEE.Scopu