Physicochemical features of rivers and lakes in pantanal wetland

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Periodontal and peri-implant wound healing following laser therapy

Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal nonsurgical and surgical treatment, osseous surgery and peri-implant treatment, focusing on postoperative wound healing of periodontal and peri-implant tissues, based on scientific evidence from currently available basic and clinical studies, as well as on case reports.

Radiolarian faunal turnover across the Oligocene/Miocene boundary in the equatorial Pacific Ocean

The global warming trend of the latest Oligocene was interrupted by several cooling events associated with Antarctic glaciations. These cooling events affected surface water productivity and plankton assemblages. Well-preserved radiolarians were obtained from upper Oligocene to lower Miocene sediments at Ocean Drilling Program (ODP) Leg 199 Sites 1218 and 1219 in the equatorial Pacific, and 110 radiolarian species were identified. Four episodes of significant radiolarian faunal changes were identified: middle late Oligocene (27.5 to 27.3 Ma), latest Oligocene (24.4 Ma), earliest Miocene (23.3 Ma), and middle early Miocene (21.6 Ma). These four episodes approximately coincide with increases and decreases of biogenic silica accumulation rates and increases in delta18O values coded as "Oi" and "Mi" events. These data indicate that Antarctic glaciations were associated with change of siliceous sedimentation patterns and faunal changes in the equatorial Pacific. Radiolarian fauna was divided into three assemblages based on variations in radiolarian productivity, species richness and the composition of dominant species: a late Oligocene assemblage (27.6 to 24.4 Ma), a transitional assemblage (24.4 to 23.3 Ma) and an early Miocene assemblage (23.3 to 21.2 Ma). The late Oligocene assemblage is characterized by relatively high productivity, low species richness and four dominant species of Tholospyris anthophora, Stichocorys subligata, Lophocyrtis nomas and Lithelius spp. The transitional assemblage represents relatively low values of productivity and species richness, and consists of three dominant species of T. anthophora, S. subligata and L. nomas. The characteristics of the early Miocene assemblage are relatively low productivity, but high species richness. The two dominant species present in this assemblage are T. anthophora and Cyrtocapsella tetrapera. The most significant faunal turnover of radiolarians is marked at the boundary between the transitional/early Miocene assemblages.

Relative abundances of selected radiolarian species in sediments of ODP Leg 199 sites

During Ocean Drilling Program (ODP) Leg 199, sediments were recovered from eight sites in the Central Pacific. Late Oligocene and early Miocene radiolarians are common to abundant and moderately well preserved in Cores 199-1218A-8H through 11H and 199-1219A-5H through 9H. More than 110 radiolarian species were encountered during this study. Of these species, 100 are identifiable forms and the rest are undescribed or unfamiliar forms. This report presents the relative abundances of described forms from the upper Oligocene to lower Miocene sediments.

Origin and evolution of Cycladophora davisiana (Radiolaria) in DSDP Hole 19-192, Northwest Pacific

This paper documents the evolutionary history of Cycladophora davisiana Ehrenberg from an uppermost Miocene to Pleistocene sedimentary record in the high-latitude Northwest Pacific. It apparently evolved from C. sakaii Motoyama through a series of intermediates. C. sakaii has a relatively large shell with an external spongy layer. The evolutionary transition is characterized by a relatively rapid decrease in thorax size with a reduction of the spongy appendage. This change occurred during about 0.4 m.y. from 2.8 to 2.4 Ma without cladogenesis. Following this interval, a decrease in thorax size continued gradually up to the Recent, resulting in a very small morphology. Although the population of C. davisiana first appeared at about 2.5 Ma, some morphotypic specimens may occur in earlier periods as indistinguishable very small endmembers in the C. sakaii populations. Timing of the first appearance events both of morphotypic specimens and of a population of C. davisiana in Site 192 and previously reported cores does not disprove the idea that C. davisiana evolved first in the Northwest Pacific region, and later migrated into other regions of the world ocean. Biometrics clearly indicate no direct phylogenetic relationships between C. davisiana and C. cornutoides Kling in the studied core. Thus, the latter species, which was originally described as a variation and later elevated to a subspecies of the former species, is separated from the former species and raised to the species rank.

Calcareous nannofossil abundance and datums of ODP Holes 171B-1051A and 171B-1052A

During Ocean Drilling Program Leg 171B, a thick sequence of lower to middle Eocene sediments was recovered from Sites 1051 and 1052 at Blake Nose in the North Atlantic Ocean. Calcareous nannofossils are moderately well preserved in the upper to middle Eocene sediments but are moderate to poorly preserved in the lower Eocene sediments. Calcareous nannofossils are diverse throughout the recovered sequence, which extends from nannofossil Zone CP8 to Subzone CP15a. The nannofossil biostratigraphy of these sites indicates the presence of a hiatus in Subzone CP12a in the middle Eocene, in which the major nannofossil assemblage changes dramatically from Toweius to reticulofenestrid; however, no major change in the nannoflora was observed across the Eocene/Paleocene boundary. Coccolith size evolution patterns were recognized. Coccolithus, Reticulofenestra, and Cribrocentrum specimens may suggest a trend of increasing size upward through the sedimentary sequence, but Dictyococcites does not show a similar simple trend. Most traditional zonal markers are present. The reworking of Discoaster sublodoensis and overgrowth of Tribrachiatus in the lower Eocene makes zonal subdivision of this part of the sequence difficult. For this reason, tentative nannofossil zonation is given for the lower Eocene.

Radiolarian assemblages of the late Neogene North Pacific

Radiolarian census and abundance data were collected from three deep-sea cores drilled by the Ocean Drilling Program Sites 884, 887 and 1151 to investigate patterns of ecologic changes in space and time during the last 16 million years for the mid-latitude to subarctic North Pacific. High concentrations of radiolarians occurred between 9.0 and 2.7 Ma. Radiolarian species richness was highest in the early middle Miocene at each site and gradually decreased up to about 7 Ma, coinciding with a well-established global cooling trend. A degree of overlap index calculated for radiolarian assemblages revealed 11 faunal change events, of which 8 corresponded to global cooling events and expansions of polar ice sheets. Three of the faunal change events were observed within the peak of radiolarian accumulation rate and were ascribed to changes in primary productivity in the North Pacific rather than global climatic changes. Our assemblage analyses revealed that north-south differentiation in radiolarian assemblages in the northwestern Pacific has existed since 16 Ma and became more distinct via major steps at 6.8 Ma and 2.7 Ma, coinciding with major glaciation events, and that east-west faunal contrasts in the subarctic region became obvious beginning at 11.7 Ma and changed to a different mode around 6.8 Ma. The observed east-west faunal differences possibly reflect east to west climate differences that were characterized by cooler temperatures in the east than the west during the late Miocene (11.7-6.8 Ma) and then by the opposite temperature trend (6.8 Ma-Recent). A severe glaciation at 2.7 Ma played a large role, particularly in temporal changes in radiolarian accumulation rate and assemblage composition.