158 research outputs found

    Two distinct forms of Chlamydia psittaci associated with disease and infertility in Phascolarctos cinereus (Koala)

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    While several diseases associated with Chlamydia psittaci infection have been reported in Phascolarctos cinereus (koala), it is still unclear whether one or more chlamydial strains are responsible. In this study, we provide evidence, obtained by restriction enzyme and gene probe analysis, that two quite distinct strains of C. psittaci infect koalas; one strain was isolated from the conjunctivae, and the other was isolated from the urogenital tract and the rectum. A gene probe, pFEN207, containing the coding sequence for an enzyme involved in the biosynthesis of the chlamydial genus-specific lipopolysaccharide antigen, and a separate probe, pCPML-4N, prepared from a DNA fragment of a koala-infecting strain of C. psittaci, were used to determine the patterns of hybridization in the koala-infecting strains; these patterns were found to be quite distinct from those observed with C. psittaci isolates from other animals. We also demonstrated by hybridization analysis with an avian strain plasmid that all three koala urogenital isolates contain a plasmid and that there is no evidence for the presence of a homologous plasmid in any of the ocular isolates

    Induction of Systemic Resistance in Maize and Antibiofilm Activity of Surfactin From Bacillus velezensis MS20

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    Surfactin lipopeptide is an eco-friendly microbially synthesized bioproduct that holds considerable potential in therapeutics (antibiofilm) as well as in agriculture (antifungal). In the present study, production of surfactin by a marine strain Bacillus velezensis MS20 was carried out, followed by physico-chemical characterization, anti-biofilm activity, plant growth promotion, and quantitative Reverse Transcriptase-Polymerase Chain Reaction (q RT-PCR) studies. From the results, it was inferred that MS20 was found to produce biosurfactant (3,300 mg L-1) under optimized conditions. From the physicochemical characterization [Thin layer chromatography (TLC), Fourier Transform Infrared (FTIR) Spectroscopy, Liquid Chromatography/Mass Spectroscopy (LC/MS), and Polymerase Chain Reaction (PCR) amplification] it was revealed to be surfactin. From bio-assay and scanning electron microscope (SEM) images, it was observed that surfactin (MIC 50 mu g Ml(-1)) has appreciable bacterial aggregation against clinical pathogens Pseudomonas aeruginosa MTCC424, Escherichia coli MTCC43, Klebsiella pneumoniae MTCC9751, and Methicillin resistant Staphylococcus aureus (MRSA) and mycelial condensation property against a fungal phytopathogen Rhizoctonia solani. In addition, the q-RTPCR studies revealed 8-fold upregulation (9.34 +/- 0.11-fold) of srfA-A gene compared to controls. Further, treatment of maize crop (infected with R. solani) with surfactin and MS20 led to the production of defense enzymes. In conclusion, concentration and synergy of a carbon source with inorganic/mineral salts can ameliorate surfactin yield and, application wise, it has antibiofilm and antifungal activities. In addition, it induced systemic resistance in maize crop, which makes it a good candidate to be employed in sustainable agricultural practices.Peer reviewe

    Exponential Tapered Balun with Different Sizes for UWB Elliptical Dipole Antenna

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    This work presents a broadband tapered balun with different sizes using nonlinear transition particularly suitable for planar and three-dimensional (3-D) dipole antennas for ultra-wideband (UWB) applications such as communication, radar systems and geolocation precision. Four baluns with wideband microstrip-to-parallel-strip transition using an elliptical structure for an elliptical dipole antenna are proposed. The initial balun structure consists of a nonlinear profile with a quarter-wavelength for both height and width. By studying the current distributions at the balun surface, it can be reduced to 25%, 50% and 75% from the original size. Measured results based on the reflection coefficients for all baluns are shown to be better than -10 dB from 1.0 GHz to 10 GHz. These baluns are integrated with an elliptical dipole which acts as a feeding circuit. Eight set of antennas with a planar and 3-D configurations with four different sizes are proposed in this work. The planar configurations are named as Planar 1, Planar 2, Planar 3 and Planar 4 while the 3-D configurations are named as 3D Dipole 1, 3D Dipole 2, 3D Dipole 3 and 3D Dipole 4, respectively. The results show that all antennas with the proposed baluns operates within the UWB frequency range

    An Inductive Link-Based Wireless Power Transfer System for Biomedical Applications

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    A wireless power transfer system using an inductive link has been demonstrated for implantable sensor applications. The system is composed of two primary blocks: an inductive power transfer unit and a backward data communication unit. The inductive link performs two functions: coupling the required power from a wireless power supply system enabling battery-less, long-term implant operation and providing a backward data transmission path. The backward data communication unit transmits the data to an outside reader using FSK modulation scheme via the inductive link. To demonstrate the operation of the inductive link, a board-level design has been implemented with high link efficiency. Test results from a fabricated sensor system, composed of a hybrid implementation of custom-integrated circuits and board-level discrete components, are presented demonstrating power transmission of 125 mW with a 12.5% power link transmission efficiency. Simultaneous backward data communication involving a digital pulse rate of up to 10 kbps was also observed

    C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.

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    STUDY DESIGN: A multicenter, retrospective review of C5 palsy after cervical spine surgery. OBJECTIVE: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery. METHODS: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ(2) tests or Fisher exact tests for categorical variables. RESULTS: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%). CONCLUSION: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date

    3-D Volumetric Evaluation of Human Mandibular Growth

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    Bone growth is a complex process that is controlled by a multitude of mechanisms that are not fully understood.Most of the current methods employed to measure the growth of bones focus on either studying cadaveric bones from different individuals of different ages, or successive two-dimensional (2D) radiographs. Both techniques have their known limitations. The purpose of this study was to explore a technique for quantifying the three dimensional (3D) growth of an adolescent human mandible over the period of one year utilizing cone beam computed tomography (CBCT) scans taken for regular orthodontic records. Three -dimensional virtual models were created from the CBCT data using mainstream medical imaging software. A comparison between computer-generated surface meshes of successive 3-D virtual models illustrates the magnitude of relative mandible growth. The results of this work are in agreement with previously reported data from human cadaveric studies and implantable marker studies. The presented method provides a new relatively simple basis (utilizing commercially available software) to visualize and evaluate individualized 3D (mandibular) growth in vivo

    Encapsulated deep eutectic solvent for esterification of free fatty acid

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    A novel encapsulated deep eutectic solvent (DES) was introduced for biodiesel production via a two-step process. The DES was encapsulated in medical capsules and were used to reduce the free fatty acid (FFA) content of acidic crude palm oil (ACPO) to the minimum acceptable level (< 1%). The DES was synthesized from methyltriphenylphosphonium bromide (MTPB) and p-toluenesulfonic acid (PTSA). The effects pertaining to different operating conditions such as capsule dosage, reaction time, molar ratio, and reaction temperature were optimized. The FFA content of ACPO was reduced from existing 9.61% to less than 1% under optimum operating conditions. This indicated that encapsulated MTPB-DES performed high catalytic activity in FFA esterification reaction and showed considerable activity even after four consecutive recycling runs. The produced biodiesel after acid esterification and alkaline transesterification met the EN14214 international biodiesel standard specifications. To our best knowledge, this is the first study to introduce an acidic catalyst in capsule form. This method presents a new route for the safe storage of new materials to be used for biofuel production. Conductor-like screening model for real solvents (COSMO-RS) representation of the DES using σ-profile and σ-potential graphs indicated that MTPB and PTSA is a compatible combination due to the balanced presence and affinity towards hydrogen bond donor and hydrogen bond acceptor in each constituent

    Remarkable sequence relatedness in the DNA encoding the major outer membrane protein of Chlamydiapsittaci (koala type I) and Chlamydia pneumoniae

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    DNA encoding the major outer membrane protein (MOMP) of the koala type-I strain of Chlamydia psittaci (pathogen responsible for blindness and infertility in koalas) was cloned and sequenced. Comparison with momp gene sequences from other chlamydial species revealed a remarkable degree of homology (>97%) with that of the human pathogen, Chlamydia pneumoniae. In comparison, the sequence only shared 75% DNA sequence homology with other C. psittaci members and 69% homology with C. trachomatis. The open reading frame consisted of 1167 bp encoding a 389-amino acid (aa) pre-MOMP including a leader sequence of 23 aa, similar to the C. pneumoniae gene. These genes were closely related even within the four variable domains (86-100% homology). Specific antibodies were capable of distinguishing between koala type I and C. pneumoniae. This very high degree of relatedness between C. pneumoniae, a human pathogen, and an individual strain of C. psittaci in the momp gene raises further questions on the host specificity, classification and evolutionary relationships of the different chlamydial species

    Azotemia protects the brain from osmotic demyelination on rapid correction of hyponatremia

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    Osmotic demyelination syndrome (ODS) is a dreadful, irreversible and well-recognized clinical entity that classically occurs after rapid correction of hyponatremia. However, it has been observed that when hyponatremia is rapidly corrected in azotemic patients by hemodialysis (HD), patients do not necessarily develop ODS. We studied the effect of inadvertent rapid correction of hyponatremia with HD in patients with azotemia. Fifty-two azotemic patients, who underwent HD at the Sindh Institute of Urology and Transplantation, having pre-HD serum sodium level <125 mEq/L and post-HD serum sodium levels that increased by ≥12 mEq/L from their pre-dialysis level, were studied. Serum sodium was analyzed before and within 24 h after a HD session. HD was performed using bicarbonate solution, with the sodium concentration being 140 meq/L. The duration of the dialysis session was based on the discretion of the treating nephrologist. Patients were examined for any neurological symptoms or signs before and after HD and for up to two weeks. Magnetic resonance imaging was performed in required cases. None of the 52 patients with azotemia, despite inadvertent rapid correction of hyponatremia with HD, developed ODS. This study suggests that patients with azotemia do not develop ODS on rapid correction of hyponatremia by HD, which suggests a possible protective role of azotemia on the brain from osmotic demyelination. However, the mechanism by which azotemia protects the brain from demyelination in humans is largely hypothetical and further studies are needed to answer this question

    Towards An Enterprise Self-healing System against Botnets Attacks

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    noProtecting against cyber attacks is no longer a problem of organizations and home users only. Cyber security programs are now a priority of most governments. Cyber criminals have been using botnets to gain control over millions of computer, steel information and commit other malicious activities. In this paper we propose a self-healing architecture that was originally inspired from a nature paradigm and applied in the computer field. Our solution is designed to work within a network domain. We present the initial design of our solution based on the principles of self healing systems and the analysis of botnet behaviour. We discuss how to either neutralize or reverse (correct) their actions ensuring that network operations continue without disruption
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