bluuebunny/crossref_metadata_2025 huggingface dataset:
Patents, Technology Adaptation, and Exports to Developing Countries
Authors: Briggs Kristie
Published: March 2012

This paper conducts a disaggregated analysis of high technology trade to determine which high technology goods, if any, developed countries export in the presence of stronger developing country patent rights. One argument for implementing strong patent rights in developing countries is that doing so will attract high technology exports from industrialized countries, which should consequently lead to economic growth. However, the impact of patent rights on high technology exports is not identical across all industries. This paper postulates that the role of developing country patent rights in increasing high technology imports depends on the production and adaptation costs of foreign innovating firms, and the usefulness of the high technology good in developing country production processes. When the cost of adapting a foreign innovation for use in developing countries is relatively low, and when the innovation is highly useful in the domestic production processes of developing countries, strengthening patent protection has little impact on attracting foreign innovations. However, when the cost of adapting the good for use in developing countries is relatively high, patent protection can be used as a policy tool to limit competition, raise the price received by innovating firms, and, ultimately, attract foreign high technology goods from abroad.
Clean Synthesis of 2-Methylglycidol over a Novel Titanosilica Catalyst - Ti-MWW under Autogenic Pressure
Authors: Fajdek Anna , Wróblewska Agnieszka , Milchert Eugeniusz
Published: March 2012

In this work the epoxidation of methallyl alcohol (MAA) with 30 wt% H2O2 over the Ti-MWW catalyst has been studied. The significant parameters for the MAA epoxidation were established as temperature (20-120°C), the molar ratio of MAA/H2O2 (1:1-5:1), methanol (solvent) concentration (5-90 wt%), Ti-MWW catalyst concentration (0-5.0 wt%), reaction time (5-300 min) and intensity of stirring (0-500 rpm). The process of MAA epoxidation was carried out the most effective at temperature of 100°C, the molar ratio of MAA/H2O2=1:1, methanol concentration of 40 wt%, the catalyst concentration of 2 wt%, the reaction time of 15 min and with the stirring intensity over 350 rpm. These the best technological parameters (mild and relatively safe) allow to obtain the selectivity of transformation to 2MG 37 mol%, the MAA conversion 52 mol%, and the selectivity of transformation to organic compounds in relation to H2O2 consumed 48 mol%.
Planting the Seeds of Change Inside? Functional Cooperation with Authoritarian Regimes and Socialization into Democratic Governance.
Authors: Freyburg Tina
Published: March 2012

Is functional cooperation with authoritarian regimes a blessing or a curse for democratization? Scholars predominantly view cooperation with authoritarian regimes as counterproductive in terms of democratization because it helps the incumbent government to remain in power by stabilizing the regime. This article presents evidence to suggest that functional cooperation can also be considered a promising way of yielding subtle processes of democratization that have hitherto been overlooked. It explores to what extent state officials become acquainted with democratic governance by participating in transgovernmental policy networks, notably the Twinning Program, set up by the European Union in order to implement functional cooperation with its Southern neighborhood. The study conducts regression analyses based on original survey data on Moroccan state officials’ attitudes toward democratic governance and complements these analyses with a qualitative comparison of different networks. The findings corroborate an optimistic reading of functional cooperation. By significantly shaping the attitudes toward democratic governance of involved state officials, cooperation appears to be able to plant seeds of change inside authoritarian regimes.
Party Identification, Leader Effects and Vote Choice in Italy, 1990-2008
Authors: Garzia Diego , Viotti Federico
Published: March 2012

Previous studies have portrayed the personalization of politics as a consequence of the changes in the electoral market and the resulting transformations at the party level. However, empirical research has not reached a consensus on the extent to which this process has actually exerted its impact on citizens’ voting calculus. Partisan identifications appear still central in voters’ behavior, whereas party leader evaluations seem to play only a marginal role. This paper tries to examine the electoral consequences of the personalization of politics employing an alternative perspective. In particular, we concentrate on the role played by leader evaluations in shaping voters’ feelings of identification with parties. Our case study focuses on the Italian case, a prototype of personalized parliamentary democracy. In the empirical section, we examine the ways in which leaders have influenced Italian voters’ behavior in the last two decades. The results show that the electoral effect of party leaders (once the mediating effect of party identification is taken into account) has steadily increased during the time frame under analysis.
Tailoring optical and non-optical properties of interference coating materials through the explicit use of small-scale optical inhomogeneities
Authors: Stenzel Olaf , Schulz Ulrike , Kaiser Norbert
Published: March 2012

Although optical coating deposition techniques have been perfected over decades to prepare optically homogeneous dense coatings with smallest surface roughness, nanostructuring of optical coatings has proven as an effective mechanism to further enhance their performance while reducing their thickness in special cases. Therefore, nanostructure effects can be tackled as additional degrees of freedom for coating design, and can even lead to useful property combinations that are inaccessible to ‘classical’ coatings prepared on the basis of the traditionally available coating materials. Examples include metal island films as building blocks for spectrally selective absorber coatings for color management or solar energy conversion purposes, as well as motheye structures for antireflection coatings and the combined optimization of optical and non-optical coating properties.
Effects of CYP2D6*10, CYP3A5*3, CYP1A2*1F, and ABCB1 C3435T polymorphisms on the pharmacokinetics of flecainide in healthy Chinese subjects
Authors: Hu Miao , Yang Ya-Ling , Fok Benny S.P. , Chan Sze-Wa , Chu Tanya T.W. , Poon Emily W.M. , Yin Ophelia Q.P. , Lee Vincent H.L. , Tomlinson Brian
Published: March 2012

Background: Although flecainide is thought to be meta­bolized predominantly by cytochrome P450 (CYP) 2D6, it shows pharmacokinetic interactions with drugs, such as verapamil and digoxin, which may suggest other CYP pathways or ATP-binding cassette (ABC) transporters might be involved. This study evaluated effects of common polymorphisms in Chinese in CYP2D6, CYP3A5, CYP1A2, and ABCB1 on flecainide pharmacokinetics.

Methods: Single oral 100-mg doses of flecainide were given to 15 healthy male Chinese subjects who were genotyped for the CYP2D6*2, *5, *10, CYP3A5*3, CYP1A2*1F and ABCB1 C1236T, G2677T/A, and C3435T polymorphisms.

Results: There was no significant difference in the pharmacokinetics of flecainide among CYP2D6 (mainly involving *10) genotypes. The CYP3A5*3/*3 subjects (n=8) had a 26% higher systemic exposure (AUC0–∞) and 17% lower apparent oral clearance of flecainide than the combined group of CYP3A5*1/*1 (n=6) and CYP3A5*1/*3 (n=1) subjects (p<0.05). Subjects homozygous for CYP1A2*1F tended to have lower systemic exposure and increased clearance of flecainide compared to those with CYP1A2*1A/1F in subjects with at least one CYP2D6 variant allele.

Conclusions: The disposition of flecainide appeared to be influenced by the CYP3A5*3 and possibly the CYP1A2*1F polymorphisms, particularly in subjects with CYP2D6 variant alleles.
Assessing the effects of identical task repetition and task-type repetition on learners' recognition and production of second language request downgraders
Authors: Takimoto, Masahiro
Published: March 2012

The present study explores the relative effectiveness of two types of task repetition for teaching polite request forms to Japanese learners of English: the identical task repetition (the repetition of the same task) and the task-type repetition (the repetition of the same type of task). The performance of a treatment group was compared to the performance of a control group on pre-, post-, and follow-up tests consisting of a discourse completion test and an acceptability judgment test. The results indicated that the two treatment groups outperformed the control group, with the identical task repetition group exhibiting more statistically significant improvement in the discourse completion test (a planned written-production test) and the acceptability judgment test (a planned written-judgment test). The results implied that identical task repetition stimulates deeper perceptual and mental processing than task-type repetition in learners' recognition and production of second language (L2) request downgraders.
Analysis of ill-posedness and numerical methods
of solving a nonlinear inverse problem in pharmacokinetics for the
two-compartmental model with extravascular drug administration
Authors: Ilyin A. , Kabanikhin S. I. , Nurseitov D. B. , Nurseitova A. T. , Asmanova N. A. , Voronov D. A. , Bakytov D.
Published: March 2012

A nonlinear inverse problem of pharmacokinetics for the
dual-compartment model with extravascular route of the drug
administration is considered. The problem is significantly ill-posed: its solution is not unique and is
unstable. We discuss nonuniqueness of the inverse problem and the degree of ill-posedness. The initial problem is reduced to a linear operator equation by linearization. It is demonstrated that the resolving ability
of the inverse problem can be improved by varying of the location of measurement data points. Results of numerical experiments are presented. The question of choosing the initial approximations is considered.
Inverse spectral problems for arbitrary order differential operators on noncompact trees
Authors: Yurko Vjacheslav Anatoljevich
Published: March 2012

We study inverse spectral problems for arbitrary order
ordinary differential equations on noncompact trees. As the main spectral
characteristics we introduce and investigate the so-called Weyl matrices
which are a generalization of the Weyl function for the classical
Sturm–Liouville operator. We provide a procedure for constructing the
solution of the inverse problem from the Weyl matrices and prove its
uniqueness.
Use of intense pulsed light sources in dermatology: Update 2012
Authors: Babilas Philipp
Published: March 2012

Intense pulsed light sources (IPLs) consist of flash lamps with bandpass filters and emit incoherent polychromatic pulsed light of a high intensity and determined wavelength spectrum, fluence, and pulse duration. The combination of prescribed wavelengths, fluencies, pulse durations, and pulse intervals facilitates the treatment of a wide spectrum of skin conditions. Hereby, IPLs follow the basic principle of a more or less selective thermal damage of the target. This review discusses the current literature on IPLs with regard to the treatment of unwanted hair growth, vascular lesions, pigmented lesions, and as a light source for photodynamic therapy and skin rejuvenation. It also summarizes the physics of IPLs and provides guidance for the practical use of IPLs.
Preparation of rigid polyurethane foams with powder filler
Authors: Paciorek-Sadowska Joanna , Czupryński Bogusław , Liszkowska Joanna , Piszczek Kazimierz
Published: March 2012

The diversified properties of polyurethane (PUR) foam plastics result from differences in the receipts applied during their preparation. The preparation of rigid polyurethane-polyisocyanurate foams (PUR-PIR) with application of different amounts of polyvinyl chloride (PVC) s-70 as a filler is described in this study. It was found that application of PVC s-70 has an effect on the prolongation of processing parameters, i.e., start time and, to a greater extent, expansion and gelation times. Moreover, it was found that introduction of filler into the foam composition causes a reduction in the capacity of the foam to absorb water; however, a distinct change in the amount of closed cells in comparison with standard foam was not observed. A favorable effect of filler on brittleness and flammability of PUR-PIR foams (significant reduction) as well as on compressive strength and softening point (a significant increase in these values) was observed.
Cerebellar Contributions to Reach Adaptation and Learning Sensory Consequences of Action
Authors: Izawa Jun , Criscimagna-Hemminger Sarah E. , Shadmehr Reza
Published: March 2012

When we use a novel tool, the motor commands may not produce the expected outcome. In healthy individuals, with practice the brain learns to alter the motor commands. This change depends critically on the cerebellum as damage to this structure impairs adaptation. However, it is unclear precisely what the cerebellum contributes to the process of adaptation in human motor learning. Is the cerebellum crucial for learning to associate motor commands with novel sensory consequences, called forward model, or is the cerebellum important for learning to associate sensory goals with novel motor commands, called inverse model? Here, we compared performance of cerebellar patients and healthy controls in a reaching task with a gradual perturbation schedule. This schedule allowed both groups to adapt their motor commands. Following training, we measured two kinds of behavior: in one case, people were presented with reach targets near the direction in which they had trained. The resulting generalization patterns of patients and controls were similar, suggesting comparable inverse models. In the second case, participants reached without a target and reported the location of their hand. In controls, the pattern of change in reported hand location was consistent with simulation results of a forward model that had learned to associate motor commands with new sensory consequences. In patients, this change was significantly smaller. Therefore, in our sample of patients, we observed that while adaptation of motor commands can take place despite cerebellar damage, cerebellar integrity appears critical for learning to predict visual sensory consequences of motor commands.
Temperature dependence of HOMO-LUMO levels and open circuit voltage for P3HT:PCBM organic solar cells
Authors: Shen Yang , Scudiero Louis , Gupta Mool C.
Published: March 2012

In this study, the open circuit voltage (VOC) of poly (3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk heterojunction (BHJ) organic solar cells was measured at temperatures ranging from 300 K to 400 K. The temperature dependence of the vacuum shift and of the highest occupied molecular orbital (HOMO) energy level of P3HT and PCBM were measured by ultraviolet photoelectron spectroscopy (UPS) in the same temperature range. The temperature dependence of the absorption edge was also studied in the same temperature range to obtain the temperature variation of the optical band gap energy (Eg). The measured VOC of the devices showed a clear decreasing trend with increasing operating temperature and the total decrease was found to be about 0.1 V. Although the origin of VOC is still not fully understood it is generally believed that the energy level offset between the HOMO of the donor and the LUMO of the acceptor minus the exciton binding energy (0.3 eV) directly determines the value of VOC. However, by utilizing the measured values of the HOMO for the P3HT (donor) and of the LUMO for the PCBM (acceptor), we have found that the calculated values of VOC and its temperature dependence do not agree with the measured VOC values. This indicates that factors other than the offset between the HOMO of the donor and the LUMO of the acceptor materials are impacting VOC.
Improved Resistive Switching Properties in HfO2-based ReRAMs by Hf/Au Doping
Authors: He Xiaoli , Tokranova Natalya A. , Wang Wei , Geer Robert E.
Published: March 2012

Emerging NVM devices have been extensively studied as candidates to extend density scaling and power reduction beyond Si-based flash. Recently, resistive-random-access-memory (ReRAM) devices in the form of metal-insulator-metal (MIM) structures have attracted substantial attention due to their potential scalability, low power operation, and high speed. HfO2 is attractive compared to other transition metal oxides from the vantage point of CMOS process compatibility. Here, we investigate doped HfO2 with a Pt top electrode on an n+-Si substrate. By doping HfO2 with Hf or Au, improved resistive switching properties have been demonstrated in terms of enhanced cycling endurance and lower switching voltages for SET and RESET. The improvements were attributed to doping-induced oxygen vacancies. In addition, Cu-doped HfO2 devices have exhibited multilevel resistive switching.
Heteroepitaxial growth of ZnO films on Gd3Ga5O12 garnet substrates
Authors: Ono Yosuke , Matsui Hiroaki , Tabata Hitoshi
Published: March 2012

This study focused on structural and optical properties of ZnO films grown epitaxially on Gd3Ga5O12 substrates. ZnO films (a = 3.2439 Å and c = 5.2036 Å) were deposited on the (001) and (111) planes of Gd3Ga5O12 (GGG: a = 12.383 Å) garnet substrates by a pulsed laser deposition method. From out-of-plane and in-plane X-ray diffraction measurements, the obtained ZnO films showed a single phase with the (0001) orientation on the GGG (001) and (111) substrates. The epitaxial relations between the ZnO film and GGG (001) substrate were [10-10] ZnO ‖ [100] GGG and [10-10] ZnO ‖ [010] GGG, while the epitaxial relations between the ZnO film and GGG (111) substrate were [10-10] ZnO ‖ [11-2] GGG ±21°. Furthermore, transmittance electron microscopy revealed sharp interfaces between ZnO films and GGG substrates. From photoluminescent spectra, the ZnO films showed donor bound emissions superimposed with free excitons at a low temperature of 10 K.
Preparation of Diamond Nanocrystallites in Powder by Using a Coaxial Arc Plasma Gun
Authors: Tominaga Aki , Hanada Kenji , Yoshida Tomohiro , Yoshitake Tsuyoshi
Published: March 2012

We suggest a new method for fabricating diamond nanoclusters by employing a coaxial arc plasma gun. Diamond powder comprised of diamond nanoclusters and amorphous carbon was fabricated in vacuum and a hydrogen atmosphere, and the diamond crystallite sizes were estimated to be 1.8, 2.3, and 2.3 nm for the powders prepared at hydrogen pressures of 0, 53.3, and 159.6 Pa respectively, from the X-ray diffraction peaks. The hydrogen ambient gas is not necessarily required for the diamond nanoclusters formation. We consider that this method enables us to form diamond nanoclusters in nucleation owing to a supersaturated condition at a facing plate located in front of an arc plasma gun.
Inertisation of copper by using blended cement pastes
Authors: Hekal Eisa E. , Kishar Essam A. , Mohamed Maha R. , Mohamed Badria A.
Published: March 2012

The inertisation of copper (II) by using ordinary Portland cement (OPC) or blended Portland cement with granulated blast furnace slag (GBFS) or metakaolin (MK) was studied. Various mixes were prepared by using a water/solid ratio (W/S) of 0·28 (by weight). Two ratios of copper ions (1·0 and 2·0% by weight of the solid binder) were incorporated by adding to the mixing water. The effects of copper chloride on the hydration characteristics of the different cement pastes were investigated by way of the examination of chemically combined water content and compressive strength, as well as X-ray diffraction analysis. Leaching of copper ions from the various hardened cement pastes was examined. The results showed that copper chloride retarded the cement hydration through the formation of double hydroxide of calcium and copper. The obtained leaching results showed a high degree of immobilisation of copper ions in the various cement pastes.
Chloride transport through unsaturated concrete: chloride profile simulations and experimental validation
Authors: Sleiman Hassan , Amiri Ouali , Ait-Mokhtar Abdelkarim , Loche Jean-Michel
Published: March 2012

To predict the chloride profile in unsaturated cement-based materials subjected to a saline environment, a mathematical model is proposed and experimental validation is carried out. Chloride transport in partially saturated concrete is coupled with moisture transport in the concrete. The model proposed in this study takes into account the diffusion, the convection by moisture transport (vapour and liquid water), the electrostatic coupling between ions of the pore solution and the chemical interactions considered through linear and non-linear isotherms. First, the simulations show that all these parameters affect the chloride profile mainly in the first 2 cm of the concrete cover. Also, it has been shown particularly that the water sorption isotherm has a great influence on the chloride profile. In fact, the chloride concentration increases with the water/cement ratio for the three sorption/desorption isotherms considered. For the Bradley isotherm, the chloride concentration is weaker than the Guggenheim–Anderson–De Boer (GAB) and Brunauer–Emmet–Teller (BET) isotherms. Second, the model shows a good agreement with the experimental results obtained in two cases: wetting and wick action tests.
Flood defence in an urban environment: the Lewes Cliffe scheme, UK
Authors: Burton Andrew , Maplesden Colin , Page Gary
Published: March 2012

Flood defences are designed to help reduce the risk of inundation to people and property in the urban environment. Yet these areas are often the most difficult to fit new infrastructure assets into, particularly given historical riverside development, planning regulations and constraints. The southern UK town of Lewes, near Brighton, has a history of significant flooding events. The 2000 event inundated over 800 properties in up to 3·6 m of water, causing many months of disruption. In response, lead flood operating authority the Environment Agency has recently installed new river defences through the Cliffe part of the town. The justification, design and construction of the scheme, in confined spaces, through a conservation area with listed structures, several landowners and in an affordable way for the taxpayer, have raised myriad issues. This paper looks at how this scheme progressed and fitted into the Environment Agency's capital programme, and identifies the key challenges for the designers which were particular to the project, but which have a wider application to other works. The paper examines how an iterative approach and close working within a multidiscipline team helped to resolve the many technical and managerial challenges, which has led to the award-winning project being successfully completed on time and within budget.
Clinical Evaluation of a Constant Force Electronic Probe
Authors: Quirynen Marc , Callens Ann , van Steenberghe Daniel , Nys Marken
Published: March 2012

This study aimed to compare, in vivo, a conventional pocket probe with an automatic, computerized, constant force, electronic probe with a discrimination ability up to 0.1 mm. Sixteen adults with moderate chronic periodontitis and free of supra‐ and subgingival calculus participated in this study. Eight patients were examined by 2 investigators who used both the conventional and the automatic probes, for a total of 4 probings per subject. The remaining 8 patients were examined 4 times by investigator 1, twice with each probe. For each patient the Ramfjord teeth were examined and 6 sites were considered per tooth. Although the pocket depth measurements recorded by the manual probe were consistently deeper than those of the electronic probe, a good correlation was found between both recordings. Moreover, intra‐ and inter‐examiner comparisons showed comparable standard deviations for both probes and small differences in absolute scores. The conventional probe was slightly more reproducible whereas the automated probe had the advantage of automatic registration. The results indicate that both probes can be considered as valuable in clinical practice. J Periodontal 1993; 64:35–39.
Periodontal Status of Women Taking Postmenopausal Estrogen Supplementation
Authors: Norderyd Ola M. , Grossi Sara G. , Machtei Eli E. , Zambon Joseph J. , Hausmann Ernest , Dunford Robert G. , Genco Robert J.
Published: March 2012

The association between supplementary estrogen intake and periodontal and gingival status in a total of 228 women 50 to 64 years of age was examined. Clinical parameters including visible supragingival plaque, subgingival calculus, probing pocket depth, clinical attachment level, alveolar bone height measurements, and number of remaining teeth were measured. Gingival status was recorded as gingival bleeding after gentle manipulation. Selected periopathogens, socio‐economic, demographic, smoking habits, and health care variables were assessed. Gingival bleeding was significantly lower in the estrogen supplement group (n = 57) compared to the control group (n = 171) (P = 0.009); the estrogen group also exhibited significantly lower visible plaque levels (P = 0.030) and fewer Capnocytophaga‐ssp. (P = 0.032). Dental care was more frequent (P < 0.001), and education levels were higher (P = 0.022) in the estrogen group. To investigate whether differences among the above parameters contributed to the difference in gingival bleeding, an age‐adjusted analysis of covariance (ANCOVA) was used. The final ANCOVA indicated non‐significant relationships for all parameters examined except estrogen intake (P = 0.044). Women taking estrogen exhibited lower gingival bleeding than the control group after correcting for these factors. The results indicate that estrogen supplementation is associated with less gingival bleeding in women aged 50 to 64, as compared to an age‐matched control group. J Periodontol 1993;64:957– 962.
HLA‐D and T Lymphocyte Reactivity to Specific Periodontal Pathogens in Type 1 Diabetic Periodontitis
Authors: Alley Catherine Seagren , Reinhardt Richard A. , Maze Connie A. , DuBois Linda M. , Wahl Timothy O. , Duckworth William C. , Dyer John K. , Petro Thomas M.
Published: March 2012

Bacterial antigen fragments complexed with class II major histocompatibility molecules (HLA‐D) on antigen presenting cells (APCs) stimulate CD4+ T lymphocyte proliferation, presumably to protect the host. This study examined these responses to antigens of two periodontal pathogens in four groups (n = 15) of age‐ (young adult) and sex‐matched Caucasian subjects with or without type 1 diabetes and moderate to severe periodontitis: Group DP = diabetics with Periodontitis; Group DnP = diabetics without periodontitis; Group nDP = nondiabetics with Periodontitis; and Group nDnP = nondiabetics without Periodontitis. HLA‐D phenotypes for each subject were determined by lymphocytotoxicity assays. T lymphocytes purified from peripheral blood were stimulated in cell culture with APC pulsed with various concentrations of tetanus toxoid, Porphyromonas gingivalis, and Capnocytophaga sputigena antigens. T lymphocyte reactivity (3H thymidine incorporation) was numerically lower in cultures from diabetics stimulated with unpulsed APC (not significant), and antigen‐pulsed cultures showed low proliferation and no significant differences among groups. Stimulation indices in cultures from diabetic patients stimulated with P. gingivalis or C. sputigena, however, were significantly elevated at all antigen concentrations compared to nondiabetic cultures. The occurrence of HLA‐DR4 was moderately associated with diabetes (P < 0.05) and highly associated with Periodontitis (P < 0.001, log‐linear model for categorical variables); and HLA‐DR53 and HLA‐DQ3 were significantly associated with Periodontitis (P ≤ 0.02). HLA‐DR was crucial to lymphocyte stimulation (anti‐HLA‐DR blocking experiments), but the low peripheral blood T cell reactivity to antigens of periodontal pathogens could not be linked with HLA‐D type or Periodontitis susceptibility. Therefore, certain HLAD types appear to be more highly associated with Periodontitis in young adults than diabetic status or lymphocyte reactivity. J Periodontol 1993; 64:974–979.
Guided Tissue Regeneration and Bone Grafts in the Treatment of Furcation Defects
Authors: Caffesse Raul G. , Nasjleti Carlos E. , Plotzke Anthony E. , Anderson Gissela B. , Morrison Edith C.
Published: March 2012

The present study evaluated the effects of guided tissue regeneration (GTR), with and without demineralized freeze‐dried cortical bone grafts, in the treatment of furcation defects in 4 female beagle dogs with naturally occurring periodontal disease. The root surfaces were thoroughly debrided. Four weeks later, full thickness facial and lingual mucoperiosteal flaps were reflected using inverse bevel incisions on both sides of the mandible involving the 2nd, 3rd, and 4th premolar, and the 1st molar teeth. Following debridement, notches were placed on the roots at the level of supporting bone. Test quadrants were randomly selected and furcations were filled with reconstituted, demineralized, freeze‐dried human cortical bone grafts. Following bone grafting, all defects were covered with an expanded polytetrafluoroethylene (ePTFE) membrane, which was sutured with 4‐0 sutures. Afterward, interproximal sutures were placed through the flaps, assuring the flaps covered the membranes completely. The contralateral side, serving as control, was treated by debridement only and application of ePTFE membrane. All membranes were removed 6 weeks after surgery. Dogs were sacrificed at 4 months after surgery. Both mesio‐distal and bucco‐lingual histologic sections were evaluated by descriptive histology. Linear measurements and surface area determination of the furcal tissues were carried out using the microscope attached to a digitizer. Twelve to 20 nonserial sections were made of the mid‐buccal aspects of each root of each treated tooth. Half of these sections were stained with Harris' hematoxylin and eosin (H&E) and the other half stained with Mallory's trichrome stain. Additionally, another group of 12 to 20 non‐serial sections cut in the mesio‐distal direction were secured for the surface area measurements of the furcations. Mean values for each dog were obtained for test and control teeth. ANOVA procedure for a split plot design was employed. Periodontal healing following the use of guided tissue regeneration procedures resulted in an increase in connective tissue and alveolar bone regeneration. Adjunctive bone grafting did not appear to enhance regeneration. J Periodontol 1993; 64:1145–1153.
The Role of Infection and Anti‐Infection Treatment in Regenerative Therapy
Authors: Newman Michael G.
Published: March 2012

Infection associated with regenerative therapy is becoming an increasingly important consideration as the frequency and numbers of regenerative procedures increase. Specific recommendations for antimicrobial treatment associated with membranes, grafts, and implants are presented in the context of establishing general principles of infection management. J Periodontol 1993; 64:1166–1170.
Postoperative Pain and Discomfort With and Without Periodontal Dressing in Conjunction With 0.2% Chlorhexidine Mouthwash After Apically Positioned Flap Procedure
Authors: Checchi Luigi , Trombelli Leonardo
Published: March 2012

The purpose of this study was to evaluate patient postoperative pain experience and discomfort with and without the use of a periodontal dressing in combination with a 0.2% Chlorhexidine mouthwash after internal bevelled, full thickness, apically positioned flap procedure. Twenty‐four patients requiring comparable bilateral flap procedures were selected. Using a split‐mouth design, one site received a periodontal dressing while the other site did not. A 0.2% chlorhexidine mouthwash (10 ml for 1 minute twice daily) was prescribed postoperatively for all patients. Pain assessment was made according to a structured, categorized scale (0 = no pain; 1 = mild pain; 2 = moderate pain; and 3 = severe pain). Analgesic drug consumption was recorded during the first postoperative week. After at least a one‐month period, the second flap procedure was performed using the alternate postoperative treatment. At the conclusion of the trial, a self‐administered questionnaire on postoperative experience was administered. Results indicated a similar trend for mean pain scores as assessed by patients for both dressed and undressed sides during the 7‐day postoperative period. Statistical analysis revealed no significant differences between treatment groups with respect to frequency distribution of patients who did or did not take analgesics or the daily and total consumption of analgesic drops. Although patients with dressing frequently experienced eating difficulty, most stated a psychological feeling of protection and well‐being with its use. J Periodontol 1993;64:1238– 1242.
Severe Progressive Periodontal Destruction Due to Radiation Tissue Injury
Authors: Yusof Zainal W. , Bakri Marina M.
Published: March 2012

Cancer radiotherapy to the head and neck region results in short‐ and long‐term radiation tissue injuries. Radiation bone injury is a long‐term manifestation which could progress to osteoradionecrosis. A case of radiation tissue injury to the periodontium is presented. The possible pathogenesis of these events is described as they relate to the sequential radiographic changes observed over a period of 6 years until the involved teeth were exfoliated. The post‐irradiation management of the teeth with advancing periodontal disease in the path of irradiation was by conservative means, including good personal oral hygiene care, scaling and root planing, periodic chlorhexidine irrigation, and topical fluoride application. J Periodontol 1993;64:1253–1258.
Development of the Murine Periodontium. I. Role of Basement Membrane in Formation of a Mineralized Tissue on the Developing Root Dentin Surface
Authors: MacNeil R. Lamont , Thomas Huw F.
Published: March 2012

The presence of basement membrane components on the forming root surface suggests a role for this structure during cementoblast differentiation. The purpose of this study was to investigate the role of root‐associated basement membrane (RBM) in murine cementogenesis using tissue separation and recombination techniques. Root dentin specimens, with or without RBM, were combined with dental sac tissue, cultured for 2 weeks, harvested, and examined by light, immunofluorescence, and electron microscopy. Recombinations in which RBM was preserved on the root dentin surface were characterized by formation of an adherent mineralized tissue resembling acellular cementum; recombinations in which RBM was excluded were characterized by formation of mineralized tissue which did not adhere to the root dentin surface. These results suggest that formation of an adherent mineralized tissue on the developing root dentin surface is dependent upon the presence of indigenous basement membrane components. J Periodontol 1993; 64:95–102.
The Effect of Treatment on the Activity of Salivary Proteases and Glycosidases in Adults With Advanced Periodontitis
Authors: Nieminen Anja , Nordlund Leila , Uitto Veli‐Jukka
Published: March 2012

Enzyme activity in whole saliva of trypsin‐like protease, elastase‐like protease, general protease, and three glycosidases was measured by colorimetric assays, using synthetic substrates. A study group of 24 adults with advanced periodontitis was compared to a control group of 25 subjects with healthy periodontium. Clinical parameters and levels of enzyme activity were assessed at baseline, after non‐surgical periodontal therapy (at 8 months), following the maintenance phase or periodontal surgery (at 15 months), and after the maintenance phase with or without systemic chemotherapy (at 20 months). The mean values of the proteolytic enzymatic activity and the activity of two glycosidases in whole saliva were significantly higher in the study group than in the control group at baseline. After the initial treatment phase at 8 months, all three proteases were reduced significantly, but the glycosidases were still high. After all treatment phases at 20 months, the activity of both the proteases and glycosidases approximated the values of the healthy group. In the saliva samples collected prior to treatment and following non‐surgical periodontal therapy, the activity of salivary elastase correlated significantly with the number of deep gingival pockets (PD ≥ 6 mm) and with either gingival index (GI) or the percentage of bleeding sites (BOP%). The enzyme activity in whole saliva appears to reflect the status of periodontal health. Salivary elastase shows good potential to serve as a novel adjunct to detect destructive periodontal inflammation and to follow periodontal healing after treatment. J Periodontol 1993;64:297–301.
Thick Free Gingival and Connective Tissue Autografts for Root Coverage
Authors: Jahnke Peter V. , Sandifer Johnny B. , Gher Marlin E. , Gray Jonathan L. , Richardson A. Charles
Published: March 2012

Studies have shown partial to complete root coverage of denuded root surfaces with the use of thick free gingival autografts (FGGs) or subepithelial connective tissue autografts (CTGs). The purpose of this study was to determine which technique would result in more predictable root coverage of Miller Class I and II marginal tissue recession defects. Paired defects in 10 patients were randomly selected for treatment with either the FGG or the CTG. With Stents as reference points, soft tissue recession was measured with a calibrated probe presurgically and 3 and 6 months postsurgically. No significant differences between paired sites in presurgical defect dimensions were found. One patient was dropped from the study for noncompliance with postoperative instmctions. The mean percentage of root coverage for the CTG 3 and 6 months postsurgery for the remaining 9 patients was 78% and 80%, respectively. The mean percentage of root coverage for the FGG was 43% at both periods. The difference in root coverage between the 2 techniques was significant (P< 0.03). Complete root coverage was gained in 5 of 9 CTGs but only in one of 9 FGGs. Both techniques resulted in a significant improvement in keratinized tissue and probing attachment level, with most of the changes having occurred during the first three months postoperatively. Results suggest that the CTG may provide a greater percentage of root coverage than the FGG and that both techniques will effectively increase the width of keratinized tissue. J Periodontol 1993; 64:315–322.
Effects of Treatment on Antibody Titer to Porphyromonas gingivalis in Gingival Crevicular Fluid of Patients With Rapidly Progressive Periodontitis
Authors: Johnson Vaughn , Johnson Bradley D. , Sims Tom J. , Whitney Coralyn W. , Moncla Bernard J. , Engel L. David , Page Roy C.
Published: March 2012

Twenty‐eight patients diagnosed as having rapidly progressive periodontitis (RPP) were enrolled in a study in which samples of subgingival microflora were harvested from test teeth and assayed for the presence of Porphyromonas gingivalis, and GCF collected and analyzed by ELISA for specific antibody for P. gingivalis. Clinical conditions were measured and recorded, and treatment by scaling and root planing provided at baseline and at 3, 6, 9, and 12 months. Reduction in pocket depth, stabilization of attachment level, and resolution of inflammation were comparable to previously reported values. By 3 months, mean and median specific antibody concentration had decreased, and continued to decrease through 12 months. The proportion of samples in which specific antibody was not detectable increased from 27% at baseline to 73% at month 12. GCF samples from sites at which P. gingivalis was present had greater than 2‐fold higher median specific antibody than samples from P. gingivalis‐negative sites. At baseline, specific antibody titer of 30‐second GCF samples positively correlated with pocket depth, and GCF volume significantly correlated with antibody titer and concentration, and with pocket depth. In addition, change in specific antibody titer of 30‐second samples from baseline to both 6 and 12 months correlated positively with pocket depths. Thus sites infected by P. gingivalis manifested high levels of specific antibody, and levels were related to clinical status. Following treatment, antibody levels decreased significantly as pocket depths decreased, attachment levels stabilized, and inflammation resolved. J Periodontol 1993; 64:559–565.
The Double Lateral Bridging Flap for Coverage of Denuded Root Surface: Longitudinal Study and Clinical Evaluation After 5 to 8 Years
Authors: Romanos G. E. , Bernimoulin J.‐P. , Marggraf E.
Published: March 2012

Longitudinal results of a 5 to 8 year follow‐up study of the double lateral bridging flap for coverage of gingival recessions (GR) are presented. On a total of 75 GR in 18 patients (31 surgical procedures) the majority of the teeth (58%) showed a root denudation reduction of 75% or more. Total coverage was observed on 18 teeth (24%). Examinations did not show a high correlation between the extent of recession and bone dehiscence after surgery, between the degree of root coverage and the initial width of keratinized gingiva, or between the GR before and after surgery. We conclude that neither the quantity of gingival recession nor the quality of the supporting tissues were a prerequisite for the success of this surgical technique. J Periodontol 1993; 64:683–688.
Effect of Therapy on Periodontal Infections
Authors: Socransky Sigmund S. , Haffajee Anne D.
Published: March 2012

Periodontal disease progression requires the simultaneous presence of high numbers of pathogens, low numbers of compatible or beneficial species, a conducive local environment, and a susceptible host. Effective therapy acts by altering one or more of these factors. Data from an ongoing study were used to examine the biological basis of treatment success or failure. Seventeen subjects showing disease progression were treated by Widman flap surgery at deep sites, scaling at shallow sites, and 1 of 4 randomlyassigned, systemically‐administered adjunctive agents including amoxicillin/clavulanate potassium (Au) (n = 3), ibuprofen (n = 3), tetracycline (n = 9), or a placebo (n = 2). Clinical measurements and microbiological samples (enumerated using DNA probes) taken from the mesial aspect of each tooth pre‐treatment and 12 months post‐treatment were compared and 418 pre‐ and 418 post‐therapy plaque samples were enumerated. Overall, the 4 treatments resulted in pocket depth reduction and “gain” in attachment. After therapy, the percentage of sites colonized by Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, and Bacteroides forsythus was decreased and counts > 106 were less frequent. Large attachment level gains were accompanied by major decreases in these species and were more frequent in subjects receiving antibiotics. A small number of sites in each treatment group became deeper and/or lost attachment. More than half of these sites were detected in 2 subjects who were older (65 vs. 44), had higher serum antibody to Actinobacillus actinomycetemcomitans serotype a (506 vs. 125 ELISA units), A. actinomycetemcomitans serotype b (518 vs. 130), and Campylobacter rectus (39 vs. 18). They also had the lowest mean total viable subgingival counts (1.1 vs. 12.3 × 106) and the lowest counts of each species pre‐therapy. In the total subject group, increased mean counts of P. gingivalis and B. forsythus were seen at sites showing attachment loss > 1 mm after therapy, while counts decreased at sites showing no attachment change or “gain” > 1 mm. J Periodontol 1993; 64:754–759.
Blocking Periodontal Disease Progression by Inhibiting Tissue‐Destructive Enzymes: A Potential Therapeutic Role for Tetracyclines and Their Chemically‐Modified Analogs
Authors: Rifkin Barry R. , Vernillo Anthony T. , Golub Lorne M.
Published: March 2012

Tetracyclines (TCs) have wide therapeutic usage as antimicrobial agents; these drugs (e.g., minocycline, doxycycline) remain useful as adjuncts in periodontal therapy. However, TCs also have non‐antimicrobial properties which appear to modulate host response. In that regard, TCs and their chemically‐modified analogs (CMTs) have been shown to inhibit the activity of the matrix metalloproteinase (MMP), collagenase. The activity of this enzyme appears crucial in the destruction of the major structural protein of connective tissues, collagen. Such pathologic collagenolysis may be a common denominator in tissue destructive diseases such as rheumatoid and Osteoarthritis, diabetes mellitus, bullous dermatologic diseases, corneal ulcers, and periodontitis. The mechanisms by which TCs affect and, possibly, diminish bone resorption (a key event in the pathogenesis of periodontal and other diseases) are not yet understood. However, a number of possibilities remain open for investigation including the following: TCs may 1) directly inhibit the activity of extracellular collagenase and other MMPs such as gelatinase; 2) prevent the activation of its proenzyme by scavenging reactive oxygen species generated by other cell types (e.g. PMNs, osteoclasts); 3) inhibit the secretion of other collagenolytic enzymes (i.e. lysosomal cathepsins); and 4) directly affect other aspects of osteoclast structure and function. Several recent studies have also addressed the therapeutic potential of TCs and CMTs in periodontal disease. These drugs reduced excessive gingival collagenase activity and severity of periodontal breakdown in rats infected with Porphyromonas gingivalis and in diabetic rats. Furthermore, the latter drug (CMT) was not associated with the emergence of TC‐resistant microorganisms. In human clinical trials, low‐dose doxycycline therapy substantially reduced collagenase activity in the gingiva and GCF, and prevented the loss of attachment in adult periodontitis. Clearly, the non‐antimicrobial properties of TCs have enormous medical and dental therapeutic potential since these drugs can inhibit the activity of MMPs and their degradation of non‐osseous and osseous connective tissues. J Periodontol 1993; 64:819–827.
Gingival Recession in Relation to History of Hard Toothbrush Use
Authors: Khocht Ahmed , Simon Gary , Person Philip , Denepitiya Joseph L.
Published: March 2012

Gingival recession studies in the U.S. have related primarily to sex and age with little consideration of toothbrush hardness. This preliminary study examined the relation between a history of hard toothbrush use and gingival recession. A total of 182 subjects, male and female, between 18 and 65 years of age, with a minimum of 18 natural teeth, no advanced periodontitis or history of periodontal surgery were examined. Gingival recession was scored as present whenever the free gingival margin was apical to the cemento‐enamel junction and root surface was exposed. History of hard toothbrush use was ascertained. Eighty‐two subjects had a history of hard toothbrush use, 77 did not, and 23 did not know. The percentage of subjects with recession increased with age from 43% to 81%, with a figure of 63% for all age groups combined. Males tended to show slightly greater levels of recession than females. Regression analysis showed that females had about 4 percentage points less receded surfaces than males. Recession was also found to be more pronounced for subjects with a history of hard toothbrush use, with a mean of 9.4% receded surfaces versus 4.7% for those who had never used a hard brush. For users of hard toothbrushes, the percent of surfaces with recession showed a significant and dramatic increase with increasing brushing frequency; this effect did not exist for those without a history of hard brush use. The relation with age was highly significant, with regression analysis showing that the percent of surfaces with recession tends to increase about 3.5 percentage points per decade. Regression analysis using brushing frequency, history of hard brush use, age, and sex in the same equation was significant with R2 = 0.31, P < 0.001; the coefficient for each independent variable was significant. J Periodontol 1993; 64:900–905.