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The distribution of trace metals in active stream sediments from the mineralized Lom Basin has been evaluated. Fifty-five bottom sediments were collected and the mineralogical composition of six pulverized samples determined by XRD. The fine fraction (< 150 µm) was subjected to total digestion (HClO4 + HF + HCl) and analyzed for trace metals using a combination of ICP-MS and AAS analytical methods. Results show that the mineralogy of stream sediments is dominated by quartz (39-86%), phyllosilicates (0-45%) and feldspars (0-27%). Mean concentrations of the analyzed metals are low (e.g. As = 99.40 µg/kg, Zn = 573.24 µg/kg, V = 963.14 µg/kg and Cr = 763.93 µg/kg). Iron and Mn have significant average concentrations of 28.325 and 442 mg/kg, respectively. Background and threshold values of the trace metals were computed statistically to determine geochemical anomalies of geologic or anthropogenic origin, particularly mining activity. Factor analysis, applied on normalized data, identified three associations: Ni-Cr-V-Co-As-Se-pH, Cu-Zn-Hg-Pb-Cd-Sc and Fe-Mn. The first association is controlled by source geology and the neutral pH, the second by sulphide mineralization and the last by chemical weathering of ferromagnesian minerals. Spatial analysis reveals similar distribution trends for Co-Cr-V-Ni and Cu-Zn-Pb-Sc reflecting the lithology and sulphide mineralization in the basin. Relatively high levels of As were concordant with reported gold occurrences in the area while Fe and Mn distribution are consistent with their source from the Fe-bearing metamorphic rocks. These findings provide baseline geochemical values for common and parallel geological domains in the eastern region of Cameroon. Although this study shows that the stream sediments are not polluted, the evaluation of metal composition in environmental samples from abandoned and active mine sites for comparison and environmental health risk assessment is highly recommended. [ABSTRACT FROM AUTHOR]

Remote sampling of water from Yugama crater lake at Kusatsu-Shirane volcano, Japan, was performed using a drone. Despite the high altitude of over 2000 m above sea level, our simple method was successful in retrieving a 250 mL sample of lake water. The procedure presented here is easy for any researcher to follow who operates a drone without additional special apparatus. We compare the lake water sampled by drone with that sampled by hand at a site where regular samplings have previously been carried out. Chemical concentrations and stable isotope ratios are largely consistent between the two techniques. As the drone can fly automatically with the aid of navigation by Global Navigation Satellite System (GNSS), it is possible to repeatedly sample lake water from the same location, even when entry to Yugama crater lake is restricted due to the risk of eruption. [ABSTRACT FROM AUTHOR]

Magnetically guided cell delivery systems would be valuable to achieve effective macrophage-based cell therapy for colonic inflammatory diseases. In the current study, we developed a method for the efficient and simultaneous introduction of superparamagnetic iron oxide nanoparticles (SPIONs) and plasmid DNA (pDNA) into RAW264 murine macrophage-like cells using SPION-incorporated cationic liposome/pDNA complexes (magnetic lipoplexes). SPIONs and pDNA were introduced for magnetization and functionalization of the macrophages, respectively. We also evaluated the adhesive properties of magnetized RAW264 cells using magnetic lipoplexes in the murine colon under a magnetic field. Significant cellular association and gene expression without cytotoxicity were observed when magnetic cationic liposomes and pDNA were mixed at a weight ratio of 10:1, and SPION concentration and magnetic field exposure time was 0.1 mg/mL and 10 min, respectively. We also observed that cytokine production in magnetized RAW264 cells was similar to that in non-treated RAW264 cells, whereas nitric oxide production was significantly increased in magnetized RAW264 cells. Furthermore, magnetized RAW264 cells highly adhered to a Caco-2 cell monolayer and colon in mice, under a magnetic field. These results suggest that this magnetic cell delivery system can improve the colonic delivery of macrophages and its therapeutic efficacy against colonic inflammatory diseases. [ABSTRACT FROM AUTHOR]

Using a multidisciplinary approach to understand the subsurface processes behind the formation of maar‐diatreme volcanoes is of growing interest. While geophysical characterization can visualize the diatreme and the feeding dike system beneath the volcano at a reasonable scale, such data are rare and generally unavailable. Stratigraphic‐controlled sampling and geochemical analysis of pyroclasts within the ejecta ring can, however, provide substantial information on dike evolution and the influence of the magmatic plumbing system on the growth of these volcanoes. Such investigation is presented here for the Barombi Mbo Maar (BMM), a complex maar of the Cameroon Volcanic Line (CVL) composed of a pile of tephra units linked to multiple explosive phases that were grouped into three eruptive episodes. Major and trace element compositions of lavas collected from the different eruptive units indicate that the erupted magmas at BMM consist mainly of basalt, trachybasalt and basanite, with Oceanic Island Basalts (OIB) and high μ (μ = 238U/204Pb) (HIMU) signatures. Compositional modelling suggests that partial melting occurred at different degrees in the garnet‐to‐spinel transition zone from one episode to another. The repetition of eruptions with big gaps between them, the presence of another large adjacent old maar crater next to the 2.5 km crater of the BMM, and the overall similarity in geochemical compositions from one eruption to another suggest a deep high‐productive zone in the mantle beneath the BMM. The latter productive zone was capable of generating magma batches episodically to fuel several individual monogenetic eruptions at the same location. [ABSTRACT FROM AUTHOR]

Abstract A limnic eruption in 1986 at Lake Nyos in Cameroon was caused by sudden release of magmatic CO 2 dissolved in the lake water. For frequent measurements of CO 2 in the lake water, we developed a simple method of CO 2 monitoring using sound speed (SS) measurement. We measured the depth profile of sound speed at Lake Nyos in 2012, 2013, 2014, and 2015. Furthermore, in the 2014 and 2015 survey, we took movies of the underwater and the bottom of the lake using an underwater camera housed in a pressure-resistant container. The vertical change of transparency of water was checked by the visibility of reflectors set in front of the camera. A pressure sensor monitored the depth simultaneously. In both years, in addition to well-known red surface water, we discovered a cloudy layer near the upper chemocline around 100 m depth. The depth of chemocline is a good indicator of the change of total amount of CO 2 in Lake Nyos. Because the transparency can be detected by a simple optical sensor, we can now apply our low-cost monitoring tool to find the depth of chemocline for Lake Nyos. Highlights • Under-water camera system resistant to water pressure of 200 m was constructed. • Under-water movies of Lake Nyos were taken in 2014 and 2015 survey. • A script to quantify the brightness of the reflector in a movie was made and the transparency of lake water was evaluated. • We found a cloudy layer around the depth of the upper chemocline. [ABSTRACT FROM AUTHOR]

With the use of conventional hydrogeochemical techniques, multivariate statistical analysis, and stable isotope approaches, this paper investigates for the first time surface water and groundwater from the surrounding areas of Lake Monoun (LM), West Cameroon. The results reveal that waters are generally slightly acidic to neutral. The relative abundance of major dissolved species are Ca2+ > Mg2+ > Na+ > K+ for cations and HCO3− ≫ NO3− > Cl− > SO42− for anions. The main water type is Ca-Mg-HCO3. Observed salinity is related to water-rock interaction, ion exchange process, and anthropogenic activities. Nitrate and chloride have been identified as the most common pollutants. These pollutants are attributed to the chlorination of wells and leaching from pit latrines and refuse dumps. The stable isotopic compositions in the investigated water sources suggest evidence of evaporation before recharge. Four major groups of waters were identified by salinity and NO3 concentrations using the Q-mode hierarchical cluster analysis (HCA). Consistent with the isotopic results, group 1 represents fresh unpolluted water occurring near the recharge zone in the general flow regime; groups 2 and 3 are mixed water whose composition is controlled by both weathering of rock-forming minerals and anthropogenic activities; group 4 represents water under high vulnerability of anthropogenic pollution. Moreover, the isotopic results and the HCA showed that the CO2-rich bottom water of LM belongs to an isolated hydrological system within the Foumbot plain. Except for some springs, groundwater water in the area is inappropriate for drinking and domestic purposes but good to excellent for irrigation. [ABSTRACT FROM AUTHOR]

Describes the inner-salt structure of the compound, 2,2-dimorpholino-2-ethylium-1-dithioate in the crystal. Characteristics of the planes of carbenium and the thiocarboxylate moeities; Structure and reactivity of the compound; Bond lengths and angles.

We repeatedly measured isotopic compositions of noble gases and CO2 in volcanic gases sampled at six fumaroles around the Kusatsu-Shirane volcano (Japan) between 2014 and 2021 to detect variations reflecting recent volcanic activity. The synchronous increases in 3He/4He at some fumaroles suggest an increase in magmatic gas supply since 2018. The increase in magmatic gas supply is also supported by the temporal variations in 3He/CO2 ratios and carbon isotopic ratios of CO2. The 3He/40Ar* ratios (40Ar*: magmatic 40Ar) show significant increases in the period of high 3He/4He ratios. The temporal variation in 3He/40Ar* ratios may reflect changes in magma vesicularity. Therefore, the 3He/40Ar* ratio of fumarolic gases is a useful parameter to monitor the current state of degassing magma, which is essential for understanding the deep process of volcanic unrest and may contribute to identifying precursors of a future eruption. These results provide additional validation for the use of noble gas and carbon isotopic compositions of fumarolic gases for monitoring magmatic–hydrothermal systems. [ABSTRACT FROM AUTHOR]

• Magnetic liposomes enable the efficient magnetization of mesenchymal stem cells. • Magnetized MSCs were much retained in mouse skeletal muscle under a magnetic field. • Magnetized MSCs showed high immunomodulatory effects on inflamed skeletal muscle. Sarcopenia, an age-related reduction in skeletal muscle mass and strength, is mainly caused by chronic inflammation. Because mesenchymal stem cells (MSCs) have the capacity to both promote myogenic cell differentiation and suppress inflammation, they are a promising candidate for sarcopenia treatment. In this study, to achieve the long-term retention of MSCs in skeletal muscle, we prepared magnetized MSCs using magnetic anionic liposome/atelocollagen complexes that we had previously developed, and evaluated their retention efficiency and immunomodulatory effects in mouse inflamed skeletal muscle. Mouse MSCs were efficiently magnetized by incubation with magnetic anionic liposome/atelocollagen complexes for 30 min under a magnetic field. The magnetized MSCs differentiated normally into osteoblasts and adipocytes. Additionally, non-magnetized MSCs and magnetized MSCs increased IL-6 and inducible nitric oxide synthase mRNA expression and decreased TNF-α and IL-1β mRNA expression in C2C12 mouse skeletal muscle myotubes through paracrine effects. Moreover, magnetized MSCs were significantly retained in cell culture plates and mouse skeletal muscle after their local injection in the presence of a magnetic field. Furthermore, magnetized MSCs significantly increased IL-6 and IL-10 mRNA expression and decreased TNF-α and IL-1β mRNA expression in inflamed skeletal muscle. These results suggest that magnetized MSCs may be useful for effective sarcopenia treatment. [ABSTRACT FROM AUTHOR]

Even though ca 1746 people and over 3000 cattle were killed in 1986 by sudden release of about 800 million m3 of CO 2 from Lake Nyos volcano in northwest Cameroon, the lake's formation history is not known. Here we report results of a lithostratigraphic and petrogenetic study of Nyos volcano that allows us to confirm its phreatomagmatic (maar) origin. Eruptive products are divided into 2 units, the phases of each of which are closely related in time. Unit A comprises 4 phases, the last (A-4) represents the cataclysmic phreatomagmatic formation of Nyos maar and may have been triggered by collapse of the vent system of the previous (A-1 to A-3) phases, and/or reactivation of basement faults. After a repose period, activity shifted NE of the maar to form Unit B products. The B-1 phase of this unit deposited the scoria now covering most of the Lake Nyos area. Unit B-2 constructed the Fon's cone. A small lava flow (Unit B-3) represents the latest phase of volcanic activity of Nyos volcano. Based on area-thickness estimation methods, a total of ca 0.8 km3 of eruptive material was produced from the volcano. Geochemical data suggest that magma of the 2 units probably formed by melting of the same garnet-bearing OIB-like asthenospheric mantle source, and evolved mainly by crustal contamination and fractional crystallization in independent magma batches that erupted without mixing. Our results provide a basis for advice on general hazard mitigation in the Lake Nyos area. • Eruptive products from Nyos (0.8 km3) are divided into 2 units, each of which are from different monogenetic volcanoes. • Magma of 2 units generated by melting of same garnet-bearing OIB-like mantle source and evolved independently without mixing. • The results including lithostratigraphy, geologic map, magma genesis of Nyos provide an important basis for risk management. [ABSTRACT FROM AUTHOR]

Abstract The most important part of geochemical studies of lavas along the Cameroon Volcanic Line (CVL) has so far focused on the southern and central segments of the line leaving behind the northern-most part of the CVL with few and incomplete data. This study presents the case of the Gawar, Zamay and Minawao volcanoes, for which, for the first time, petrological and geochemical data comprising major and trace elements, and Strontium-Neodymium-Lead isotopes have been used to investigate the mantle source and the genetic relation between the felsic and mafic lavas in these areas. Volcanics in the Gawar are mainly basanites while those from Minawao and Zamay are essentially trachytes. The Nb/Ta and Zr/Hf ratios are similar for both the mafic and felsic rocks suggesting a dominant evolution of the magma by fractional crystallization. Primitive-mantle normalized multi-element diagrams of the mafic lavas are comparable to those reported in other volcanoes along the CVL; characterized by the depletion of Heavy Rare Earth Elements (HREE) and enrichment of Light Rare Elements (LREE), indicative of an enrichment and the presence of garnet in the source. Modeled results for melting using primitive mantle normalized values of Sm/Yb vs La/Sm indicate a low degree (<2%) of partial melting of a source with less than 4% garnet. This is consistent with chondrite normalized REE patterns characterized by the fractionation of HREE relative LREE. Trace elements composition and isotope data preclude the significant role of the continental crust in the magmatism of the mafic rocks. However, during evolution to the felsic lavas, the role of the crust became more important. The ranges for 87Sr/86Sr (0.70356–0.70362), 143Nd/144Nd (0.512928–0.512931), 206Pb/204Pb (19.62–19.72), 207Pb/204Pb (15.65–15.68) and 208Pb/204Pb (39.31–39.45) isotopic composition for mafic samples (Gawar) are limited and fall within the range of mafic lavas studied along the CVL. The isotopic signatures and trace element characteristics are consistent with an asthenospheric origin, however with contribution from the sub-continental lithospheric Mantle (SCLM). The two sources have imparted characteristics of more than two mantle components involving the Depleted MORB-like mantle, HIMU and Enriched mantle (EM1). Highlights • Geochemical data and Sr-Nd-Pb isotopes have been used to explore the mantle source. • Similar Nb/Ta and Zr/Hf ratios suggest magma evolution by fractional crystallization. • Sm/Yb vs La/Sm graph show <2% partial melting of a source with ≈4% garnet. • The ranges for isotopic data of mafic samples are within the range of CVL lavas. • Isotopic and trace element data are consistent with an asthenospheric origin. [ABSTRACT FROM AUTHOR]

Abstract After the catastrophic release of CO 2 gas from Lake Nyos in 1986, much emphasis has been put on the urgency of adopting an efficient strategy for reducing CO 2 accumulation at depth, but the environmental impacts of the degassing activity have been mostly neglected. The degassing pipes are continuously releasing highly concentrated ferrous iron water to the surface of the lake. The lake surface, which once used to be a deep blue, has now changed into reddish brown, due to the formation of colloidal ferric iron. From December 2001 to January 2011, one degassing pipe transported 560 tons of iron as colloidal ferric iron per year, and after late 2011, three pipes have been transporting about 1100 tons per year. The degassing fountain contains highly concentrated calcium and magnesium other than iron resulting in enrichment of those substances. Although the colloidal ferric iron might have adverse effect on fish and/or other aqueous biota, the lake water remained safe for domestic water use. Highlights • Surface color of Lake Nyos changed into reddish brown by colloidal ferric iron uplifted through CO 2 degassing pipes. • 560 ton/year of ferric iron was scattered through one pipe during 2001 to 2011. • 1,100 ton/year of ferric iron was scattered over after the installation of three pipes in late 2011. • Highly concentrated colloidal ferric iron might have adverse effects on fish or other aqueous biota. • Environmental impact of the degassing process was not significant to affect human health for domestic water use. [ABSTRACT FROM AUTHOR]

Abstract Lake Nyos is a meromictic lake with strong stratification separated into 4 distinct layers; shallow, intermediate, transitional, and bottom layers. This article discusses enrichment of Fe2+ in the bottom water in January 2003 when the effect of artificial degassing that started in January 2001 on the chemical structure of the lake was still minimal. In the bottom layer (205.5–209.5 m), Fe2+ and HCO 3 − are the major dissolved species and their concentrations increase sharply toward the bottom. Enrichment of Fe2+ and HCO 3 − is most likely caused by anaerobic microbial reduction of Fe(OH) 3 precipitates at the water-sediment interface. The Fe(OH) 3 precipitates sank to the bottom after atmospheric oxidation of Fe2+ dispersed by the degassing pipe. Lateritic hematite may also participate in the reduction reaction. Production of Fe2+ and HCO 3 − significantly increases the alkalinity and electric conductivity of the bottom-most water and is responsible for a small rise of pH between 205 m and 209.5 m, the bottom. The other dissolved species, e.g., Na+, K+, Ca2+, Mg2+, SiO 2(aq) etc., result from the CO 2 -water-basalt interaction at low temperatures (25°∼30 °C) in the sub-lacustrine fluid reservoir that is believed to exist in the diatreme beneath the lake bottom, and they seep into the bottom layer. Highlights • High enrichment of Fe2+ and HCO3− in Lake Nyos bottom water. • This enrichment was caused by anaerobic microbial reduction of Fe(OH)3 at the water-sediment interface. [ABSTRACT FROM AUTHOR]

Abstract A combined study of major ions, δ18O, δD, 13C, 87Sr/86Sr isotopes, X-ray diffraction, scanning electron microscopy, and electron probe microanalyses on springs and spring mineral precipitates along the Cameroon Volcanic Line (CVL) was undertaken to understand water chemistry, and infer the type and origin of the precipitates. The waters are of evaporated Na + K Cl and non-evaporated Ca + Mg HCO 3 types, with the more mineralized (electrical conductivity-EC of 13130 μS/cm) Lobe spring inferred to result from interaction of circulating 49 °C waters with magmatic volatiles of the active Mt. Cameroon. Water mineralization in the other springs follows the order: Sabga A > Sabga B > Bambui B > Bambui A > Nyos Cave. But for the Nyos Cave spring, all other springs contain fluoride (up to 0.5–35.6 mg/l above WHO potable water upper limit). The Sabga spring contains arsenic (up to 1.3 mg/l above the WHO limits). The springs show low fractionation temperatures in the range of 19–43 ᵒC. The Lobe and Sabga A springs are precipitating dolomite (CaMg(CO 3) 2), while the Nyos Cave, Bambui A, Bambui B and Sabga B springs precipitate trona ((Na 3 H(CO 3) 2.H 2 O). Our data suggest a marine provenance for the carbonates, and point to a volcanic input for the Lobe, Nyos, Sabga A, and Bambui A springs. The latter springs are therefore proposed as proxies for monitoring volcanic activity for hazard mitigation along the CVL. [ABSTRACT FROM AUTHOR]

The hydrodynamic fragmentation that formed Lake Nyos in northwest Cameroon did not only make it the most unpopular lake in the world from a gas disaster perspective, it also opened a rare and formidable window through which much of the geology of Cameroon can be studied in a single locality. The Cambrian quartz monzonite cliff excavated by the maar-forming explosion and exposed in its northeastern shore is intruded by mafic dykes, two of which we dated. Even though close to one another, the dykes are different in composition. The alkaline dyke yields a slightly older (Carnian) K-Ar fedspar age of 231.1 ± 4.8 Ma, while the sub alkaline dyke yields an age of 224.8 ± 4.7 Ma (Norian). Based on radioisotopic age data available over the last 48 years (347 data) for the Cameroon Line magmatism comprising eruptives and volcano-plutonic complexes, the Nyos dykes are way older than the Cameroon Line, and even pre-date the Lower Cretaceous initiation of west Gondwana fragmentation in Equatorial Atlantic domain. They would therefore not have been directly linked to the formation of the Cameroon Line. Alternatively, they might be associated with the development of intra-continental rift systems in West Central Africa that pre-dated west Gondwana breakup to form the Atlantic Ocean. [ABSTRACT FROM AUTHOR]

This study clarifies the hydrothermal system of Jigokudani Valley near Mt. Tateyama volcano in Japan by using a combination of audio-frequency magnetotelluric (AMT) survey and hot-spring water analysis in order to assess the potential of future phreatic eruptions in the area. Repeated phreatic eruptions in the area about 40,000 years ago produced the current valley morphology, which is now an active solfatara field dotted with hot springs and fumaroles indicative of a well-developed hydrothermal system. The three-dimensional (3D) resistivity structure of the hydrothermal system was modeled by using the results of an AMT survey conducted at 25 locations across the valley in 2013–2014. The model suggests the presence of a near-surface highly conductive layer of < 50 m in thickness across the entire valley, which is interpreted as a cap rock layer. Immediately below the cap rock is a relatively resistive body interpreted as a gas reservoir. Field measurements of temperature, pH, and electrical conductivity (EC) were taken at various hot springs across the valley, and 12 samples of hot-spring waters were analyzed for major ion chemistry and H 2 O isotopic ratios. All hot-spring waters had low pH and could be categorized into three types on the basis of the Cl − /SO 4 2 − concentration ratio, with all falling largely on a mixing line between magmatic fluids and local meteoric water (LMW). The geochemical analysis suggests that the hydrothermal system includes a two-phase zone of vapor–liquid. A comparison of the resistivity structure and the geochemically inferred structure suggests that a hydrothermal reservoir is present at a depth of approximately 500 m, from which hot-spring water differentiates into the three observed types. The two-phase zone appears to be located immediately beneath the cap rock structure. These findings suggest that the hydrothermal system of Jigokudani Valley exhibits a number of factors that could trigger a future phreatic eruption. [ABSTRACT FROM AUTHOR]

Lake Nyos is located at the summit of a stratovolcano in the Oku Volcanic Group (OVG) along the Cameroon Volcanic Line. The sudden release of magmatic CO 2 trapped at the bottom of Lake Nyos in August 1986 caused historical casualties of 1750 people and over 3000 cattle. New geochemical data of volcanic rocks from the Nyos volcano and the first available data for volcanic rocks from other maar-bearing volcanoes (Lakes Elum, Wum and Oku) in the OVG are presented and compared. Lavas from the Nyos, Elum and Wum volcanoes show similarities in major and trace elements and Sr–Nd–Pb isotopes, suggestive of a similar mantle source. However, this source is slightly different from that of the Oku volcano. The samples from Lake Oku have lower alkali, higher TiO 2 and more depletion and enrichment in most incompatible trace elements than those from the Nyos, Elum and Wum volcanoes. These differences and those observed in the Sr–Nd–Pb results are consistent with a heterogeneous source for lavas in the OVG. Trace element compositions suggested the presence of garnet in the source (< 6% garnet) and modelled melting results indicate < 2% partial melting of the source material. Isotope data plot within the focal zone, extending towards enriched mantle 1 (EM1; e.g. Lakes Oku and Nyos samples). This indicates the involvement of at least three mantle components: depleted mid-ocean ridge basalt mantle, high-μ and EM1 components in the magmatism of the lavas studied. The contributions of these components in different proportions, originating from asthenospheric and subcontinental lithospheric mantle sources, can account for the observed variations in geochemical characteristics. The geochemical characteristics of the studied lavas indicate that the magma source need not necessarily have an abnormal CO 2 concentration to pose a potential threat. Degassing of an ordinary magma chamber and the migration of gas to the bottom of the lakes through cracks and faults can lead to the accumulation of CO 2 in lake bottoms. This is controlled by tectonic parameters (fractures and faults) that enhance degassing from the magma chamber to the lake bottom and physical parameters of the lake (e.g. size, depth, temperature and solubility) that control CO 2 stability. [ABSTRACT FROM AUTHOR]

Summary The shallow aquifer in the vicinity of Lake Nyos (Northwest, Cameroon) is one of the main water supply sources to meet the water needs of the inhabitants to be resettled after 1986s tragedy. Unfortunately, there is a lack of knowledge on the groundwater recharge and flow systems in the area. Multiple environmental tracers (δ 18 O, δD, Cl − , CFCs and SF 6 ) and a yearly record of rainfall, surface waters and groundwater were employed to characterize the recharge mechanism of the shallow groundwater seeping in the fractured rock of the Lake Nyos catchment (LNC). The δ 18 O–δD relationship of the rainfall events gave the Nyos Meteoric Water Line: δD = 8.28 δ 18 O + 11.87. Inland moisture vapor may have impacted the isotopic composition of original vapor masses from Gulf of Guinea prior to precipitation. Shallow groundwater in the LNC shows a similar trend of enrichment in 18 O and D as surface waters indicating a well-mixed aquifer. The proportions of surface waters and rainfall in the groundwater reservoir were 87% and 13%, respectively. The high annual recharge rate (941 mm/yr) and the seasonal variability in the isotopic signatures of groundwater indicate a renewable aquifer system. CFCs apparent ages-based piston flow model revealed a young age (average of 24 a.) of the groundwater in the LNC. SF 6 -based ages were biased young as compared to relatively younger than CFCs-based ages, implying an additional terrigenic production of SF 6 . The conceptual model for groundwater flow suggests that three main flow regimes, mainly controlled by the physical properties of the rock heterogeneities govern the movement of water in the aquifer. The piston flow model appears, however, to be the better model to explain the flow regime in the highly faulted and fissured area where recharge occurs (∼1200–1600 masl). The rapid circulation and the low solubility lead to low mineralization. In the middle-lower area where waters circulate more in the weathered layer, exponential mixing model dominates, yielding more mineralized water. Downward to the valley, with prevailing gentle slope, interaction between surface and recently infiltrated groundwater better explain the observed similarity in the isotopic compositions and the mineralization of water. [ABSTRACT FROM AUTHOR]

Rainwater characteristics can reveal emissions from various anthropogenic and natural sources into the atmosphere. The physico-chemical characteristics of 44 monthly rainfall events (collected between January and December 2012) from 4 weather stations (Bamenda, Ndop plain, Ndawara and Kumbo) in the Bamenda Highlands (BH) were investigated. The purpose was to determine the sources of chemical species, their seasonal inputs and suitability of the rainwater for drinking. The mean pH of 5 indicated the slightly acidic nature of the rainwater. Average total dissolved solids (TDS) were low (6.7 mg/L), characteristic of unpolluted atmospheric moisture/air. Major ion concentrations (mg/L) were low and in the order K(+) > Ca(2+) > Mg(2+) > Na(+) for cations and NO3(-)≫HCO3(-)>SO4(2-)>Cl(-)>PO4(3-)>F(-) for anions. The average rainwater in the area was mixed Ca-Mg-SO4-Cl water type. The Cl(-)/Na(+) ratio (1.04) was comparable to that of seawater (1.16), an indication that Na(+) and Cl(-) originated mainly from marine (Atlantic Ocean) aerosols. High enrichments of Ca(2+), Mg(2+) and SO(2-)4 to Na(+) ratios relative to seawater ratios (constituting 44% of the total ions) demonstrated their terrigenous origin, mainly from Saharan and Sahelian arid dusts. The K(+)/Na(+) ratio (2.24), which was similar to tropical vegetation ash (2.38), and NO3(-) was essentially from biomass burning. Light (< 100 mm) pre-monsoon and post-monsoon convective rains were enriched in major ions than the heavy (> 100 mm) monsoon rains, indicating a high contribution of major ions during the low convective showers. Despite the acidic nature, the TDS and major ion concentrations classified the rainwater as potable based on the WHO guidelines., (Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.)

Objectives: To evaluate the incidence among 80-year-olds of periapical lesions as detected on panoramic radiographs and to determine the relationship between sclerotic bone around the periapical lesions to heel bone density, body height, and hand-grip strength., Study Design: Six hundred fifty-nine panoramic radiographs (262 males, 397 females), obtained from 80-year-old residents of Fukuoka Prefecture, Japan, were used for evaluation of periapical lesions. These findings were correlated with physical examination results to determine the relationship to general health., Results: Of 659 panoramic radiographs, 31 (5%) were noted to have periapical lesions. Average size of the 31 periapical lesions was 6.1 +/- 2.2 mm. Of the 31 periapical lesions, 21 (68%) were accompanied by linear or diffuse types of sclerotic bone. Of the 21 sclerotic bones, 10 (48%) were of a linear type of sclerotic bone and 11 (52%) of a diffuse type of sclerotic bone. Of the 11 diffuse types of sclerotic bone, 10 (91%) were in the mandible and 1 (9%) in the maxilla. Periapical lesions in the mandible were more frequently accompanied by a diffuse type of sclerotic bone than those in the maxilla (P < .01). The hand-grip strength of those having periapical lesions, accompanied by a diffuse type of sclerotic bone, was stronger than those having no periapical lesions (P < .01) and those accompanied by a linear type of sclerotic bone (P < .03). However, there was no relationship between presence of sclerotic bone and heel bone density or body height., Conclusions: Periapical lesions accompanied by a diffuse type of sclerotic bone were more frequently seen in the mandible of 80-year-olds. To evaluate the clinical significance of sclerotic bone around periapical lesions in 80-year-olds, further study to evaluate the significance of endodontic treatment needs to be done.

Objective: In a previous study, we named the magnetic resonance imaging (MRI) signal that is characteristic of mandibular condyles in growing children the "double contour-like structure" (DCLS). In the current study, we evaluated the alternating appearance and disappearance of the DCLS in children as they grow to elucidate the significance of the DCLS., Study Design: In 11 subjects who were 9-14 years old at the time of the first examination, MRI characteristics of mandibular condyles were sought from fast spin-echo intermediate-weighted images; 2 or 3 years later, repeat MRI were obtained from the same subjects., Results: At the second examination, 10 of the 16 DCLSs detected at the first examination had disappeared. A significant relationship was found between the alternation of the DCLS and the bone marrow conversion from red to yellow in mandibular condyles. Alternation of the DCLS tended to coincide with eruption of the permanent maxillary second molars. The DCLS was also shown to appear as a hypersignal on T2-weighted images., Conclusions: Double contour-like structure signals in mandibular condyles appeared and disappeared as children grew, and these signal alternations may be useful as a criterion for the staging of mandibular condyle development in children. Possible constituents of the DCLS may be hypervascular loose fibrous tissue and a proliferation of cartilage.

Objective: We sought to determine the magnetic resonance imaging (MRI) characteristics of mandibular condyles in still-growing children. In addition, we also evaluated the significance of the double-contour-like structure and the conversion from red to yellow marrow characteristic of this age., Methods: The MRI characteristics of mandibular condyles were determined by means of fast spin-echo intermediate-weighted images in subjects 9 to 14 years old. In 1 subject who developed temporomandibular joint-related clinical symptoms 1 year later, MRI was re-performed at that time., Results: With the use of MRI, a total of 17 double-contour-like structures were detected in 42 temporomandibular joints of 9- to 14-year-olds, but neither 50 healthy joints of youths nor adults. In terms of bone marrow signal changes, the turning point was found to be 11 years old. In 1 subject, the double-contour-like structures were not visible on the MR images obtained 1 year after the first examination., Conclusion: The double-contour-like structure and the periods of conversion from red to yellow marrow may be able to be used as part of the criteria for the staging of mandibular condyle development in children.

Objectives: We investigated the occurrence of inflammatory paradental cysts (IPC) in the mandibular premolar, and demonstrated the points of difference with regard to diagnostic features between IPC and dentigerous cysts (DC)., Material and Methods: We analyzed the radiographs and histology of 60 cases with a cystic lesion associated with inflammation in the mandibular premolar region based on diagnostic criteria as IPC., Results: In 4 out of 60 cases, we diagnosed the 4 cysts as IPCs in the mandibular premolar region, and recognized that one form of IPC was similar to a mandibular infected buccal cyst. The other 56 non-IPC cases were diagnosed as DC. On the IPCs, the permanent tooth normally erupted in all 4 cases after treatment, but in one case, the IPC recurred., Conclusions: The present investigation suggested that we might have misdiagnosed IPCs in the mandibular premolar region as DC to date. It is important to consider the differences between IPC and DC with regard to the causes of recurrence during treatment of IPC.

Objective: To evaluate the incidence among 80-year-olds of calcified carotid artery atheromas (CCAAs) as detected on panoramic radiographs. The relationship between CCAAs and general and oral health was also evaluated., Study Design: Six hundred and fifty-nine panoramic radiographs (262 males, 397 females), obtained from 80-year-old residents of Fukuoka Prefecture, Japan, were used for evaluation of CCAAs., Results: Of 659 panoramic radiographs, 33 (5%) were noted to have CCAAs. These appeared as a radiopaque nodular mass or masses adjacent to or just below the intervertebral space between C3 and C4. CCAAs were found in 8 males and 25 females. There were marginally significant differences between males and females in CCAAs (P = 0.06). Seventy-four percent of CCAAs were detected in the right side. There appeared to be very little relationship between CCAAs and general and oral health., Conclusions: The results of this study gives further support to the idea of using panoramic radiographs to detect CCAAs. Therefore, we feel that panoramic radiographs should be evaluated not only for pathosis of the teeth and jaws, but also for other incidental findings, especially in the soft-tissue region of the neck. The findings from this study provide potentially life-saving information especially for those elderly people who are at risk for stroke.