Serum antibodies to Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in juvenile periodontitis and adult periodontitis (part I)

Recent microbiological studies support the concept that specific gram negative bacteria play a major role in the etiology and pathogenesis of human chronic inflammatory periodontal disease. Actinobacillus actinomycetemcomitans has been isolated frequently from juvenile periodontitis and Porphyromonas gingivalis has been shown to be a prominent species in adult periodontitis in humans. The purpose of this study was to determine levels of the specific antibodies to A.actinomycetemcomitans and P.gingivalis in 17 patients with juvenile and 15 patients with adult periodontitis and 24 healthy subjects. IgG and IgM antibody titers against these antigens were determined by enzyme-linked immunosorbent assay (ELISA). The levels of antibodies against A.actinomycetemcomitans were significantly higher in the juvenile periodontitis compared to the adult periodontitis patients and controls. Anti-P.gingivalis antibodies were elevated in adult periodontitis compared to juvenile periodontitis patients and controls.     

99mTc-citrate versus 67Ga-citrate for the scintigraphic visualization of inflammatory lesions

Citric acid was labeled with 99mTc with an efficiency of > 99%. The biodistribution of 99mTc-citrate was studied in mice with turpentine-induced abscesses in comparison to 67Ga-citrate. The max. abscess/muscle concentration ratios were 4.61 +/- 1.92 (3 h) for 99mTc-citrate and 4.76 +/- 2.04 (4 h) for 67Ga-citrate. Arthritis was induced in 10 rabbits by intra-articular injection of ovalbumin Scintigrams obtained 4 days later and at 3 h post-injection of 99mTc-citrate showed increased activity involving the synovium. The max. arthritic/contralateral knee ratio was 3.19 +/- 1.29 (3 h) and 6.47 +/- 3.71 (24 h) for 99mTc- and 67Ga-citrate, respectively. The blood clearance curve of 99mTc-citrate in rabbits was biexponential with a fast (T1/2 = 36 min) and a slow (T1/2 = 18 h) component, compared to mono-exponential clearance of 67Ga-citrate (T1/2 = 23 h). In 10 patients with rheumatoid arthritis whole-body scintigrams and spot images of involved joints indicated localization of the tracer in inflamed tissues. The mean target-to-soft tissue ratios were 3.04 +/- 0.81 and 4.95 +/- 2.56 for 99mTc-citrate and 99mTc-MDP, respectively. Renal clearance of radioactivity was evident from the scintigrams. Our results demonstrated that 99mTc-citrate is effective as a radiopharmaceutical for the visualization of inflammatory lesions and may be preferred to 67Ga-citrate due to the ideal physical characteristics of the radionuclide, easy preparation, low cost, early accumulation and the preference for the renal route of excretion.     

Design of Miniature UWB-Based Antenna by Employing a Tri-Sectional SIR Feeder

A novel ultra-wideband (UWB)-based microstrip antenna is presented in this work by using a slotted patch resonator, a tri-sectional stepped impedance resonator (SIR) feeder, as well as a reduced ground plane. The whole structure was realized on an FR4 substrate. The impact of incorporating several cases of ground planes on the input reflection has been thoroughly investigated under the same tri-sectional SIR feeder and by employing a slotted patch radiator. Since the complete ground plane presents an inadequate frequency response, by reducing the ground plane, the induced UWB responses are apparent while the antenna exhibits higher impedance bandwidth. The impact of both the uniform impedance resonator (UIR) as well as the SIR feeder on the input reflection has also been examined by following the same adopted reduced ground technique and using a slotted patch radiator. As a result, the UIR feeder exhibits a dual-band frequency response, when a wide notched band is incorporated in the range from 4.5–6.5 GHz. The dual-band response of the bi-sectional SIR feeder is still apparent with a narrower notched band in the frequency range from 4–5 GHz. As far as the tri-sectional SIR feeder is concerned, the UWB response is discernible without recording the existence of a notched band. Additionally, the antenna displays a higher impedance bandwidth compared with the previously reported steps. Our proposed antenna configuration is designed with highly compact dimensions and an overall size of 14 × 27.2 mm². Moreover, it operates under the impedance bandwidth of 2.86–10.31 GHz that can be leveraged for numerous applications where wireless systems are used. Our approach presents several advantages compared with the other reported UWB-based antennas in the literature, whereas the measured S₁₁ pattern is in good agreement with the simulated one.     

Real‐time temperature and photon transmission measurements for monitoring phase separation during the formation of poly(N‐isopropylacrylamide) gels

Phase separation during the formation of poly(N‐isopropylacrylamide) (PNIPA) hydrogels was investigated using real‐time photon transmission and temperature measurements. The hydrogels were prepared by free‐radical crosslinking polymerization of N‐isopropylacrylamide (NIPA) in the presence of N,N′‐methylenebisacrylamide (BAAm) as a crosslinker in an aqueous solution. The onset reaction temperature T₀ was varied between 20 and 28°C. Following an induction period, all the gelation experiments resulted in exothermic reaction profiles. A temperature increase of 6.5 ± 0.6°C was observed in the experiments. It was shown that the temperature increase during the formation and growth process of PNIPA gels is accompanied by a simultaneous decrease in the transmitted light intensities I_tr. The decrease in I_tr at temperatures below the lower critical solution temperature of PNIPA was explained by the concentration fluctuations due to the inhomogeneity in the gel network. At higher temperatures, it was shown that the gel system undergoes a phase transition via a spinodal decomposition process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3589–3595, 2002     

Effects of cyclization and pendant vinyl group reactivity on the swelling behavior of polyacrylamide gels

A series of polyacrylamide (PAAm) gels were prepared by free-radical crosslinking copolymerization of acrylamide and N,N′-methylenebis(acrylamide) (BAAm) in water at various crosslinker (BAAm) and chain transfer agent (isopropyl alcohol, IPA) concentrations. It was shown that only 5% of the crosslinker used in the feed forms effective crosslinks in the final hydrogels. At BAAm contents as high as 3 mole%, the equilibrium swelling ratio of the gels in water is independent of the crosslinker content in the feed. This is due to the prevailing multiple crosslinking reactions during the gel formation process. At a fixed crosslinker content, the onset of gelation is shifted towards higher conversions and reaction times as the amount of IPA increases. Addition of IPA in the monomer mixture also increases the equilibrium swelling ratio of PAAm gels. It was shown that the gel crosslinking density increases on rising IPA concentration in the feed due to the increasing rate of intermolecular crosslinking reactions. Received: 30 May 1997/Accepted: 26 June 1997     

Bit Impact Factor: Towards making fair vulnerability comparison

Reliability is becoming a major design concern in contemporary microprocessors since soft error rate is increasing due to technology scaling. Therefore, design time system vulnerability estimation is of paramount importance. Architectural Vulnerability Factor (AVF) is an early vulnerability estimation methodology. However, AVF considers that the value of a bit in a clock cycle is either required for Architecturally Correct Execution (i.e. ACE-bit) or not (i.e. unACE-bit); therefore, AVF cannot distinguish the vulnerability impact level of an ACE-bit. In this study, we present a new dimension which takes into account the vulnerability impact level of a bit. We introduce Bit Impact Factor metric which, we believe, will be helpful for extending AVF evaluation to provide a more accurate vulnerability analysis.     

Satisfying agent goals by executing different task semantics: HTN, OWL-S or plug one yourself

In this paper, we propose a plan execution architecture which supports different task semantics. This way, each goal that is identified during the deliberation cycle of an agent can be satisfied through tasks defined in different semantics. The capability of supporting different task semantics provides two main advantages. The first advantage is the reuse of legacy artifacts within agent plans. The second advantage is simplifying the adaptation of an agent architecture to different standards of a business organization. In order to integrate various task semantics within a plan execution architecture, we have used a smoothly revised version of a previously articulated workflow model into which different task semantics would be reduced before execution. We have integrated hierarchical task network and OWL-S semantics into our plan execution architecture to test the strength of it in terms of support for executing different task semantics in an agent architecture. We think that such a plan execution architecture will contribute to the industrialization of agent architectures.     

Dodecyl methacrylate as a crosslinker in the preparation of tough polyacrylamide hydrogels

Copolymerization of acrylamide with dodecyl methacrylate (C12) solubilized in aqueous micelles of sodium dodecyl sulfate produces tough hydrogels exhibiting moduli of elasticity around 1 kPa. Swelling and gel fraction measurements show that the hydrophobic associations acting as temporary crosslinks are too strong to be destroyed in water during the expansion of the gel network. An order of magnitude larger value of loss factor tan δ of the hydrogels formed using the hydrophobe C12 as compared to the conventional hydrogels indicates the dynamic nature of their crosslink zones. The hydrogels are more homogeneous than the corresponding gels prepared by a chemical crosslinker, as determined by the static light scattering measurements. Mechanical tests indicate that, in addition to the dodecyl domains, permanent crosslinks are also needed to obtain hydrogels that are mechanically stable up to 250% elongation ratios.     

Experimental Investigation of Aluminum Alloy and Steel Core Buckling Restrained Braces (BRBs)

International Journal of Steel Structures - Buckling restrained braces (BRBs) display balanced hysteretic behavior under reversed cyclic tension and compression forces and dissipate a significant...