Notes: Infrared-to-visible upconversion emission enhancement through thermal effects in Yb3+-sensitized Pr3+-doped fluoroindate glasses excited at 1.064 μm is investigated. A twentyfold increase in the 485 nm blue emission intensity as the sample temperature was varied from 20 to 260 °C was observed. The visible upconversion fluorescence enhancement is ascribed to the temperature dependent multiphonon-assisted anti-Stokes excitation of the ytterbium sensitizer and excited-state absorption of the praseodymium acceptor. A model based upon conventional rate equations considering a temperature dependent effective absorption cross section for the 2F7/2→2F5/2 transition of the Yb3+ and 1G4→3P0 excited-state absorption of the Pr3+, agrees very well with the experimental results. © 2000 American Institute of Physics.

Notes: Efficient energy upconversion of cw radiation at 1.064 μm into blue, red, and near infrared emission in Tm3+-doped Yb3+-sensitized 60TeO2-10GeO2-10K2O-10Li2O-10Nb2O5 glasses is reported. Intense blue upconversion luminescence at 485 nm corresponding to the Tm3+ 1G4→3H6 transition with a measured absolute power of 0.1 μW for 800 mW excitation power at room temperature is observed. The experimental results also revealed a sevenfold enhancement in the upconversion efficiency when the sample was heated from room temperature to 235 °C yielding 0.7 μW of blue absolute fluorescence power for 800 mW pump power. High brightness emission around 800 nm (3F4→3H6) in addition to a less intense 655 nm (1G4→3H4 and 3F2,3→3H6) fluorescence is also recorded. The energy upconversion excitation mechanism for thulium emitting levels is assigned to multiphonon-assisted anti-Stokes excitation of the ytterbium-sensitizer followed by multiphonon-assisted sequential energy-transfer processes. © 2001 American Institute of Physics.

Notes: Generation of 120 μW average power blue-violet light at 440 nm through efficient frequency tripling of 1.319 μm Nd:YAG laser pulses in bulk GeO2-SiO2 and Er3+-doped GeO2-SiO2 glasses is reported. Third-harmonic signal light enhancement owing to two- and three-photon resonant pumping of erbium ions in doped samples is also reported. © 1996 American Institute of Physics.

Notes: Upconversion fluorescence emission of Er3+/Yb3+-doped Bi2O3–Na2O–Nb2O5–GeO2 heavy metal glass samples excited at 1.06 μm is experimentally investigated. The results reveal the existence of intense emission bands centered around 520, 545, and 655 nm. The germano-niobate based host glass presents high transparency in the region of 400–2700 nm, the capability of incorporating high dopant concentrations, high melting temperature, and large resistance to atmospheric moisture. The observed intensity of the green fluorescence emission, suggested that the niobium based host glass material plays an important role in the efficiency of the upconversion process. Emission lines centered at 425, 483, 503, 608, and 628 nm were also observed. © 1997 American Institute of Physics.

Notes: Optical temperature sensing using upconversion fluorescence emission in Er3+/Yb3+-codoped Ga2S3:La2O3 chalcogenide glass excited at 1.06 μm is reported. Temperature measurements in the region of 20–225 °C with a resolution of approximately 0.5 °C using excitation powers of a few tens of milliwatts were obtained. The temperature sensing mechanism is independent of variations in the excitation intensity, possible fluctuations of transmission, and utilizes a simple signal detection and processing system. The results also revealed that the glass host material plays an important role in the performance of the sensing system. © 1998 American Institute of Physics.

Notes: Frequency upconversion of cw infrared radiation at 1.06 μm into the visible in Er3+/Yb3+-codoped Ga2S3:La2O3 chalcogenide glass samples is presented. Intense green and red emission bands around 530, 555, and 670 nm, respectively, are observed in addition to near-infrared 830 and 925 nm less intense signals. Energy transfer processes and nonradiative phonon-assisted decays account for the population of the 2H11/2, 4S3/2, and 4F9/2 emitting levels. The dependence of the red emission with the Yb3+ concentration is also analyzed. The potential application of the Er/Yb-codoped Ga2S3:La2O3 glass for upconversion based optical devices is discussed. © 1998 American Institute of Physics.

Notes: Thermally induced threefold infrared-to-visible upconversion emission enhancement in Er3+/Yb3+-codoped Ga2S3:La2O3 chalcogenide glasses excited at 1.064 μm is reported. The times three upconversion efficiency enhancement was achieved by heating the sample in the temperature range of 23–155 °C, and is assigned to the temperature-dependent multiphonon-assisted anti-Stokes sideband excitation process of the ytterbium sensitizer. A theoretical analysis based upon rate equations considering the sensitizer absorption cross section as a function of the phonon occupation number in the host material exhibited very good agreement with experimental data. © 1999 American Institute of Physics.

Notes: Abstract. The aim of the present study was to describe the periodontal tissue that formed after GTR when different resorbable barriers were applied to degree III furcation defects. The study was performed in 5 foxhound dogs. The 2nd and 4th premolars in both sides of the mandible were extracted. Degree III furcation defects were produced in the 3rd mandibular premolars. 5 weeks later. GTR therapy using a barrier composed by a polylactide-glycolide copolymer was performed on one quadrant (group A). In the contralateral quadrant, a barrier made of polylactide and citric acid ester (group B) was used. The dogs were sacrificed 6 months after reconstructive therapy. Tissue blocks containing the experimental teeth were excised, demineralised in EDTA and embedded in paraffin. Serial sections were cut in the mesio-distal plane and parallel with the long axis of the roots. The microtome was set at 7 μm. The sections were stained in hematoxyline and eosin. From each biopsy, 3 sections representing the central part of the furcation were selected for light microscopic examination. In the healed furcation sites, descriptive histological analysis and histomorphometric measurements of the newly formed tissues were performed. In both groups the root surface of the healed furcation defects was covered by a cellular, extrinsic-intrinsic fibers type cementum. The composition of the newly formed periodontal ligament was similar in both groups. The proportions of bone, bone marrow and periodontal ligament, however, were substantially larger in group A than in group B. In Group B, an area in the previous furcation defect was consistently occupied by a granuloma. It is suggested that the presence of the granuloma in the healed furcation defect prevented bone regrowth.

Notes: Abstract. The aim of the present study was to evaluate the effect of enamel matrix proteins (EMD) on periodontal wound healing in degree III furcation defects in dogs. The experiment was performed in 5 foxhound dogs, 2 months prior to the start of the experiment, the 2nd and 4th lower premolars were extracted. Degree Iii furcation defects were created in the 3rd mandibular premolars (2P3). The furcation defects were subsequently exposed to reconstructive surgery, Buccal and lingual full thickness flaps were elevated in the lower premolar regions. The exposed root surfaces of the experimental teeth were planed. A notch was placed in the roots at the base of the defect. In one side of the mabdible (Test group), phosphoric acid gel was applied over the root surfaces for 15 s. The acid was removed by flushing the root surfaces with sterile saline. Subsequently, a gel of EMD was applied to cover all instrumented root surfaces. Following gel application, a resorbable barrier membrane was adjusted to cover the buccal and lingual entrances of the furcation defect. The flaps were repositioned to cover the barrier and sutured. The contralateral premolar (Control group) received the same treatment, but acid etching was not performed and EMD was not applied prior to barrier installation, 4 months after reconstructive surgery, the animals were sacrificed and biopsies from the 3P3 regions harvested. The biopsies were placed in a fixative, demineralized in EDTA, dehydrated and embedded in paraffin, 3 mesiodistal sections, representing the central portion of the furcation site, were selected for histological analysis of the defect. The furcation defects of both the Test and Control groups were clinically closed and were found to harbor bone and periodontal ligament tissue which appeared to be in structural continuity with a newly formed root cementum. The relative amounts of mineralized bone, bone marrow and periodontal ligament tissue that had formed were similar in the Test and the Control group. In the Test group, however, the cementum that had formed in the apical portion of the furcation detect was different from the corresponding tissue in the coronal portion, and also different from the cementum observed in the Control group. In the apical portion of the test defect a thin (12 μm) acellular cementum had been laid down, while in the coronal portion a thick (32 μm) cellular cementum, similar to the cementum found in the Control group. could be observed. The current observation, hence, seems to confirm that EMD when applied onto an instrumented and acid etched dentine surface may create an environment conducive for the formation of acellular cementum.