Residual Deposits Research Articles

Dinosaurs and rivers on the edge of a desert: A first recognition of fluvial deposits associated to the Botucatu Formation (Jurassic/Cretaceous), Brazil

This work aimed to investigate the ichnofossiliferous sites in Nioaque and surrounding region, Mato Grosso do Sul state, Brazil, analyzing their paleontological, stratigraphic and paleoenvironmental context, because dinosaur tracks were found in an area previously mapped as Permo–Carboniferous age. Some sedimentary facies previously assigned to the glacial Aquidauana Formation were herein reinterpreted as part of the basal section of the Botucatu Formation (Late Jurassic/Early Cretaceous) and include floodplain and residual channel deposits, possibly representing the lower half of this formation's sequence in the studied area. The ichnofossils that have been found include both isolated tracks of Theropoda and Ornithopoda, a trackway of Eubrontes isp., a vertebrate burrow and invertebrate traces (Palaeophycus) possibly related to the Entradichnus ichnofacies. Sedimentological interpretation suggests the existence of a river system just before the deposition of the typical Botucatu eolian facies in this region. This is the first documented record of fluvial deposits transitionally to the traditional eolian Botucatu Formation. Noteworthy, the dinosaur tracks have played a key role for the interpretation of these rocks as Botucatu Formation and for better understanding the whole system due to the impossible Paleozoic age (dinosaur tracks).

U‐Pb Zircon and Re‐Os Molybdenite Geochronology of the W‐Mo Mineralized Region of South Qinling, China, and their Tectonic Implications

AbstractA W‐Mo mineralized region is located along the northern margin of the South Qinling tectonic belt of China. W‐Mo mineralization occurs mainly in Cambrian–Ordovician clastic and carbonate rocks, and the ore bodies are structurally controlled by NW–SE‐ and NNE–SSW‐striking faults. Evidence for magmatism in the area is widespread and is dominated by intermediate–felsic intrusives or apophyses, such as the Dongjiangkou, Yanzhiba, Lanbandeng, and Sihaiping granitic bodies. Quartz‐vein‐type mineralization and fault‐controlled skarn‐type mineralization dominate the ore systems, with additional enrichment in residual deposits. At present, there are few or insufficient studies on (1) the age of mineralization, (2) the relationship between intermediate–felsic granite and W‐Mo mineralization, (3) the source of ore‐forming materials, and (4) the metallogenic and tectonic setting of the mineralized area. In this paper, we present geochronology results for numerous intrusive granitic bodies in the South Qinling tectonic belt. U‐Pb zircon geochronology of the Lanbandeng monzogranite and Wangjiaping biotite monzogranite yields ages of 222.7 ± 2.3 and 201.9 ± 1.8 Ma, respectively. In contrast to the Late Triassic age of the Lanbandeng monzogranite, the age of the newly discovered Wangjiaping biotite monzogranite places it at the Triassic–Jurassic boundary. Re‐Os molybdenite geochronology on the Qipangou W‐Mo deposit yielded a model age of 199.7 ± 3.9 Ma, indicating the deposit formed in the early Yanshanian period of the Early Jurassic. Granitoid intrusions in the mineralized area are characterized by composite granite bodies that crystallized at ca. 240–190 Ma. While there were multiple stages of intrusion, most occurred at 210–220 Ma, with waning magmatic activity at 200–190 Ma. The Re‐Os age of molybdenite in the region is ca. 200–190 Ma, which may represent a newly discovered period of W‐Mo metallogenesis that occurred during the final stages of magmatism. The heat associated with this magmatism drove ore formation and might have provided additional ore‐forming components for metallogenesis (represented by the Wangjiaping biotite monzogranite). Ore materials in the mineralized area were derived from mixed crustal and mantle sources. Enrichment of the region occurred during intracontinental orogenesis in the late Indosinian–Yanshanian, subsequent to the main Indosinian collision. At this time, the tectonic environment was dominated by extension and strike‐slip motion.

Judicious and non-judicious use of cephalexin antibiotic in indoor poultry experimentation and detection of cephalexin residues in edible poultry tissues

Antibiotics are the most widely injudiciously used drugs for therapeutic purposes throughout the world. This study aimed to detect cephalexin residue after discriminate and indiscriminate administration of cephalexin antibiotic in broiler. Eighteen broiler chicks, DOC (Cobb-500) were collected & reared for up to 31 days. The chicks were randomly divided into three groups namely control group (Group-A), discriminate cephalexin group (Group-B) and indiscriminate cephalexin group (Group-C). Each group consists of 6 birds. In this investigation, only a detectable level of antibiotic residues was found in indiscriminate group of poultry. A total of 72 samples were investigated by the TLC method. The overall residue of cephalexin found in indiscriminate group as in liver (100%), kidney (83.33%), thigh muscle (25.00%), breast muscle (8.33%), fat and spleen (66.67%) respectively. The final average body weight were recorded highest in indiscriminate antibiotic group (1804.17 ± 73.92gm) followed by discriminate group (1741.33 ± 63.63gm) and control group (1453.33 ± 26.39gm). The body weight was found significantly (p<0.05) higher in the antibiotic treated groups. The hematological parameters such as Hb, PCV and TEC values of treatment groups showed significantly (p<0.05) lower, while PCV did not show any significant difference compared to the control group. Overall, the present study documented the widespread abuse of cephalexin and failure to implement the recommended withdrawal period will undeniably lead to deposition of residues in broiler tissues.

Mining heritage and community identity in the social licence of proposed renewed mining

Mining legacies are manifest in multiple ways. One of these relates to heritage values of former mining places which may contribute to regional identity and potentially tourism. Changes in mining methods and technologies make it economically feasible to re-open some mines that previously closed due to market factors, ore grades or difficulties in accessing residual mineral deposits. In this paper, we consider the factors affecting the social licence for proposed renewed mining activity in a post-mining town (Kapunda, South Australia). We examined how residents of Kapunda view the mining sector in general and how it fits with town identity. Focus groups and interviews explored the extent to which a potential renewed mining industry would align to community values, considering the possible application of copper in-situ recovery (ISR) for an historic deposit in the town. The research found that participants were open to the prospect of a new copper ISR operation, provided it was well managed, environmentally responsible, and able to align with tourism. The paper concludes that an important dimension of social licence for re-opening mines is whether new mining could occur in a way that doesn't undermine the heritage values associated with a former mining legacy.

Effect on nanoscale damage precursors of fused silica with wet etching in KOH solutions

We investigate the nanoscale damage precursors that will cause laser damage initiation on fused silica surface during KOH-based wet etching. Some nanoscale damage precursors, like impurity contamination and chemical structure defects on different etched surface with a KOH solution, are explored through a variety of testing methods at nanoscale spatial resolution. The etched surface roughness and photothermal absorption level are also studied. The results show that KOH-based etching can keep a good surface roughness, reduce impurity contamination significantly, and thus decrease surface photothermal absorption level. However, it can mitigate little chemical structure defect and has a risk of secondary pollution induced by residual deposition such as K2SiO3. The work can be a reference on using KOH-based wet etching technology to mitigate nanoscale damage precursors of fused silica ultraviolet optics.

Impact of surface roughness on the deposition of saliva and fingerprint residue on non-porous substrates

A diverse range of non-porous substrate surfaces routinely encountered in crime scene settings were evaluated for their affinity towards deposited saliva and fingerprint residue. Raman spectroscopy, atomic force microscopy (AFM), field-emission scanning electron microscopy (FE-SEM) and water contact angle measurements were employed to quantitatively and qualitatively evaluate the physicochemical variables impacting the deposition of touch and salivary deposits. It was established that small changes in surface roughness and physicochemical interactions, including hydrophobicity, resulted in observable impacts on the spread of salivary deposits and deposition of fingerprint residue. It was further identified that not only did the surface free energy (SFE) available to the deposit, measured through water contact angles, influence the deposition and spread of the material on the surface, but that the nature of the deposit further impacted these dynamics. This preliminary study has developed a platform to gain a better understanding of the importance of surface roughness as a consideration, when interrogating how forensically relevant deposits such as saliva and fingerprint residue interact with non-porous surfaces. This better understanding is necessary when reflecting on the successfulness of recovering DNA, when considering means to improve recovery of trace samples from crime scenes, and when improving assessment of the likelihood of transfer of a deposit from one substrate to another upon contact.

The Mogangling giant landslide triggered by the 1786 Moxi M 7.75 earthquake, China

A good understanding of seismic giant landslides could provide favourable guidance for seismic stability evaluation of nearby slopes. Here, an excellent example of a catastrophic seismic landslide named the Mogangling giant landslide (MGL), located upstream along the Dadu River and triggered by the 1786 Moxi M 7.75 earthquake, is analysed for its deposit characteristics, failure mechanism and dammed lake. The MGL, with a volume of approximately 4500 × 104 m3, 450 m long and 1000 m wide, blocked the Dadu River completely and caused over 100 000 deaths when the landslide dam broke. The MGL occurred on the upper part of a narrow granite ridge; a potentially unstable wedge-shaped rock mass was separated from the remaining massif by unloading fissures and an active fault (Detuo fault) that just crossed the slope foot. The Moxi earthquake coupled with strong site amplification triggered the MGL, which blocked the Dadu River; the elevation of the dam crest was approximately 130 m higher than the present river level. The dammed lake had a volume of approximately 9.504 × 108 m3, an area of 19.91 km2 and a length of approximately 31 km; the peak flow of the outburst flood was larger than 7100 m3/s. After hundreds of years of concave bank erosion, the deposit is divided into the right bank deposit (main deposit) and left bank deposit (residual deposit).

Biochemical attributes and establishment of tree seedlings in soil after urochloa decumbens cultivation in soil with deposition of iron mining residues

background: the recovery of areas impacted by mining activities is a major challenge and requires knowledge of how the biological and biochemical processes of the soil as well as the establishment of plant species are affected by mining residue. in this work, the influence of deposition of iron mining mud and tailings on soil biochemical attributes and the initial development of tree seedlings was studied in a simulated event in the greenhouse. pots (n = 27) with natural soil (2.0 kg) received deposition (280 ml) of iron mining mud or tailings and by three-month was cultivated with urochloa decumbens. at the end of this period, part of the pots was sampled and the soil biochemical activities were evaluated. then tree seedlings (schinus terebinthifolius and eremanthus incanus) were planted and cultivated for a year, when then shoot (sdw) and roots (rdw) dry weight were evaluated. results: deposition of iron mining mud and tailings did not affect microbial biomass carbon or basal soil respiration, however both conditions reduced (p < 0.05) β-glucosidase activities by up to 30%, and the easy extractable glomalin by about 19%. in addition, the mud deposition reduced (p < 0.05) the sdw and rdw of s. terebinthifolius by about 21% and 24%, respectively. nevertheless, uruchloa decumbens and eremanthus incanus had no variation in dry weight production between treatments, so they have good ability to grow settle in soil affected by mining residue. conclusion: this study shows that the sequential planting of u. decumbens and e. incanus can be an alternative for use in environments with deposition of iron mining tailings.

细晶岩脉型瓷土(瓷石)与花岗岩风化壳残积型高岭土矿床地质特征差异性研究

细晶岩脉型瓷土(瓷石)与花岗岩风化壳残积型高岭土矿床地质特征差异性研究

Assessment of benzyl isothiocyanate as an adjunct to conventional periodontal therapy.

Background:Conventional nonsurgical periodontal therapy eliminates the pathogenic microbes, yet residual deposits promote the recurrence of the disease. As antimicrobials may pose undesirable effects, alternate therapies are probed.Aim:The aim of the study is to evaluate the efficacy of locally delivered benzyl isothiocyanate (BITC) as an adjunct to scaling and root planing to treat patients with chronic periodontitis.Materials and Methods:The study included 30 patients diagnosed with chronic periodontitis. Test (scaling and root planing along with BITC intervention) and control (scaling and root planing) sites were randomly assigned to each patient. These sites were in the contralateral quadrants, having a probing depth of 4–6 mm. The plaque index (PI), gingival index (GI), pocket probing depth (PPD), clinical attachment level (CAL), and microbial load (colony forming unit [CFU]) were assessed at baseline, 1-week, and 6-week time interval. Data were analyzed by ANOVA/Friedman test, Mann–Whitney U-test, pairwise paired t-test, and Wilcoxon test, with P ≤ 0.05 set as statistically significant.Results:The scores of PI, GI, PPD, and CAL from baseline to 6-week follow-up within both the test and control sites were noted to be statistically significant (P < 0.0001). The CFU showed a significant reduction (P = 0.0229) within the test site at varying time intervals. The change in the mean PI score from baseline to 6-week time interval between the test and control site was noted to be statistically significant (P = 0.0039).Conclusion:The local application of BITC chips effectively reduced the PI, GI, PPD, and CFU, subsequently with the gain in CAL, and improved the tissue integrity and thereby oral hygiene.

Soil chemical properties and yield of onion crops grown for eight years under no-tillage system with cover crops

The use of cover crops in no-tillage systems can change soil chemical properties and crop yield over time. Studies using cover crops without the application of pesticides and soluble mineral fertilizers in no-tillage systems are important to reduce production costs, the need for mechanization, and to improve nutrient cycling and crop yield. The study aimed to evaluate how the use of different cover crops and the amount of dry matter produced by such species affect soil chemical properties and onion yield. Onion crops were grown for eight years without the use of pesticides and soluble mineral fertilizers in no-tillage system. The experiment was conducted from 2009 to 2016 in Ituporanga, state of Santa Catarina (SC), Brazil. The following treatments were used: barley (2010)/black oat, rye, oilseed radish, oilseed radish + rye, and oilseed radish + barley or black oat, and a control (consisting of weed species). A randomized block experimental design was used with eight replications. Plants from each treatment were collected 100 days after sowing in plot areas of 0.75 m² to determine dry matter yield. The cover crops were desiccated and the onion seedlings were transplanted in July. The onion crops were harvested every November to evaluate yield. Soil samples were collected at depths of 0−10 and 10−20 cm after the onion harvest to evaluate soil chemical properties. The onion crop and residue deposition of single or intercropped black oat, rye, and oilseed radish improved and maintained soil chemical properties. The lower dry matter yield of cover crops found in the control treatment resulted in lower onion yields over the years. Cover crops combined with soil tillage limited to the planting rows increased total onion yields and yield of larger-sized onions as the system stabilized over time.

Research on dental plaque removal methods for efficient oral prophylaxis: With a focus on air polishing and rubber cup polishing.

This study was conducted to compare the plaque control effectiveness of rubber cup polishing with that of air polishing during oral prophylaxis procedures and to investigate the effect of the order of air-polishing application on the efficiency of oral prophylaxis. The study included adult patients (≥20years of age) who had visited the dental clinic for oral prophylaxis. A total of 173 subjects were divided into three groups (scaling followed by rubber cup polishing, SR; scaling followed by air polishing, SA; and air polishing followed by scaling, AS) based on sex, age, oral health status, oral hygiene status, and indications and contraindications according to the oral prophylaxis method. The analysis of variance (ANOVA) was used to determine the difference in oral prophylaxis time, residual deposits rate, subjects and dental hygienist satisfaction. The total scaling time was shorter in the AS group (15.4±6.9 minutes) than in the SA (18.7±5.5 minutes) and SR groups (19.9±6.2 minutes) (p<0.05). The rate of residual deposits was significantly higher in the SR group than in the AS or SA groups (p<0.05). The satisfaction level of dental hygienists was higher in the AS group (8.8±1.0 points) and the SA group (8.4±1.0 points) than in the SR group (6.2±1.3 points). During oral prophylaxis, dental plaque removal using air polishing requires a relatively longer time when compared to rubber cup polishing, but it can better eliminate dental plaque. In addition, we found that dental plaque removal using air polishing prior to scaling reduced the total scaling time.

Consequences of chemical residue formation during potentiation of final irrigation

Seeking to increase the efficiency of endodontic irrigation, the association of different solutions as final irrigant has been investigated, such as sodium hypochlorite with chlorhexidine. The literature shows that the combination of these substances leads to the formation of a brownish precipitate, but does not reveal measurements of the intensity of this precipitate and its consequences. Aim: The present study aimed to evaluate the change in dentin color and the obliteration of the dentinal tubules after the association of sodium hypochlorite (NaOCl) with chlorhexidine (CHX) in the final irrigation. Methods: Fifty sterile human lower premolars were prepared with a ProDesign R 35.05 files and divided into 6 groups. Four different NaOCl concentrations (0.5%; 1%, 2.5% and 5.25%) associated with 2% CHX were tested, in addition to 2 control groups, using only 2.5% NaOCl and 2% CHX, respectively. After the final irrigation protocol, the dentin color change was evaluated by spectrophotometry immediately and after 24 hours, and the dentinal tubule obliteration was assessed by scanning electron microscopy. Results: It was possible to verify that regardless the NaOCl concentration used when associated with CHX, a chemical residue was formed, with consequent dentin pigmentation and tubular obstruction. There was a trend towards increased dentin pigmentation and tubular obstruction due to the deposition of the chemical residue formed by this association. Conclusion: It can be concluded that all concentrations of NaOCl associated with CHX caused color changes and tubular obstruction, being proportional to the concentration of NaOCl used.

Constructions for the Protection of Underground Water against Pollution, in Warehouse Deposit Areas

Groundwater pollution can occur from the emission of a pollutant through the soil, which then interacts at biotic and abiotic levels entering the food chain and reaching directly or indirectly to humans. Such a pollutant can be represented by the deposition of household residues. The water infiltrated by these deposits and then by their sole and flanks is an important source of pollution of groundwater with the most serious effects. By virtue of this concept, for the protection of the groundwater in the area of household waste deposits, it is proposed to adopt a “clean technology” for the implementation of complex deposition improvements, which will prevent the appearance of pollutants, initially in the most important urban areas, and for the future generalization of these improvements in other localities. The essential elements of this complex arrangement of household waste depots refer to: the sealing system of the base layer which integrates a safety gallery from which checks and repairs are made; deep sealing walls that do not allow the circulation of the groundwater located below the deposit site so that in case of infiltration of some polluting substances in this area, their area of influence is limited; the sealing system that limits the flow of water infiltrating through the deposits and avoids air pollution with substances resulting from the anaerobic decomposition of household waste. Above the combined sealing system, it realizes a system of streams of granular material of φ 16-32 mm, casts the distance of about 20 m, to capture the infiltration water and to conduct it by gravitational flow spreading collector. For this purpose, the streams will have a minimum slope of 1%.

Experimental investigation on mechanical behavior and particle crushing of calcareous sand retrieved from South China Sea

Calcareous sand containing weak particles originated from the deposition of skeletal residue of marine organisms is susceptible to significant particle crushing under compression and shearing. The breakage of grains results in excessive deformation and foundation failure. This study focuses on the mechanical properties and particle crushing of calcareous sand retrieved from Nansha Island, South China Sea. A series of isotropically drained and undrained triaxial compression tests were performed on reconstituted calcareous sand samples at different initial densities and at a wide range of confining stresses. The amount of particle crushing for calcareous sand after shearing was measured and quantified. Experimental results demonstrate that the shear response of calcareous sand had been well interpreted within the critical state framework. The amount of particle crushing for calcareous sand increases with increasing density and confining stress. Compared with the undrained condition, a larger amount of particle crushing of calcareous sands is observed in the drained triaxial compression test. Stress-dilatancy curves exhibit similar varying tendency for calcareous sand. Multiple critical state lines for calcareous sands with different initial densities are identified in the void ratio and logarithm of the mean stress plane. Considering the variation in stress ratio at the critical state induced by particle crushing, all stress paths are normalized to determine the state bounding surface for calcareous sand at varying densities and stresses.

Geochemical and mineralogical characteristics of clay deposits at Ijesha–Ijebu and its environs, southwestern Nigeria

Two residual clay deposits and one transported clay deposit in Ijesha-Ijebu area were investigated for their mineralogical, chemical and industrial properties. The investigation was to evaluate their industrial applications and economic importance. The mineralogy of the clay samples was determined using X-ray Diffraction (XRD). The chemical composition of the clay samples was determined using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Physical tests which include; thermal properties, plasticity tests, density measurement, linear shrinkage and water absorption capacity were determined to determine their industrial potentials. The clay within the weathered profiles above banded gneiss and pegmatite at Ijesha-Ijebu is brownish with red spots, while the clays derived from sedimentary terrain is chocolate in colour. The X-ray diffraction results showed that kaolinite is the dominant mineral, while quartz, albite and muscovite are the major non clay minerals. Chemical data showed that the values of SiO2, Al2O3 and Fe2O3 are 66.11%, 20.53% and 3.07%, respectively in weathered banded gneiss, in sedimentary the values of SiO2, Al2O3 and Fe2O3 are 42.12%, 34.43% and 7.37%. In weathered pegmatite, the values of SiO2, Al2O3 and Fe2O3 are 53.17%, 32.7%, 1.44%, respectively. The average percentage of clay in the banded gneiss, pegmatite and sedimentary samples are 50%, 56% and 47% respectively. The clay mouldability ranged between moderate to high. Evaluation of the clay properties and characteristics shows the industrial application of the clay like production of ceramic, building bricks and other structural wares.&#x0D; Keywords: Clay, Mineralogy, Chemistry, Ceramics, Building bricks.

Interaction of gunshot residues (GSR) with natural and synthetic textiles having different structural features

This study relies on the ability of six different fabrics to retain gunshot residues on their surfaces, and their capability to let them pass through. The fabrics were cotton, linen, elastane, polyester, silk and viscose, each of them placed above a filter paper sheet. This last was used to retain residues passing through fabric. Microscopic structures of the chosen textiles were characterized by optical microscopy, and their surface morphology was characterized by stylus profilometry. A semi-automatic Sig Sauer P228 pistol, calibre 9 × 21 mm IMI, was exploited and two shooting distances were considered, 10 cm and 40 cm. Preliminary, inorganic residue (IGSR) deposition patterns were visualized by X-ray fluorescence spectroscopy. Scanning electron microscopy was also used to describe morphology and composition of IGSR generated by discharging the selected gun. Concentration of IGSR on targets was then quantitatively determined by inductively coupled plasma optical emission spectrometry, while nitrites and nitrates, originated by nitrocellulose content of smokeless powders, were identified by ion chromatography. As expected, the amount of metallic residues, nitrites and nitrates decreases inversely with the shooting distance. In addition, considering the same distance, concentration of these elements changes significantly depending on the analyzed cloth. Therefore, when evaluating shooting distance in a forensic case, the habit to use a cotton textile to construct a calibration curve, despite of the actual nature of the target, could not be quantitatively accurate. It was evidenced that a significant amount of GSR passed through target fabrics, making their identification possible even on underneath tissues.

The prevalence and mechanism of triclosan resistance in Escherichia coli isolated from urine samples in Wenzhou, China

BackgroundThe widespread application of triclosan contributes to its residual deposition in urine, which provides an environment of long-term exposure to triclosan for the intestinal Escherichia coli. We determined the triclosan and antibiotic resistance characteristics of E. coli strains isolated from urine samples and further investigated the resistance mechanism and molecular epidemic characteristics of triclosan-resistant E. coli isolates.MethodsA total of 200 non-repetitive E. coli strains were isolated from urine samples and then identified. The minimum inhibitory concentrations (MICs) of triclosan and antibiotics, fabI mutation, efflux pump activity, the expression of 14 efflux pump encoding genes, and epidemiological characteristics were determined by the agar dilution method, polymerase chain reaction (PCR), carbonyl cyanide 3-chlorophenylhydrazone (CCCP) inhibition test, quantitative real-time polymerase chain reaction (RT-qPCR), multilocus sequence typing (MLST), and pulse-field gel electrophoresis (PFGE) for all triclosan-resistant isolates. Furthermore, we also investigated the effect of triclosan exposure in vitro on antibiotic susceptibility and the efflux pump encoding gene expressions of triclosan-susceptible strains via serial passage experiments.ResultsOf the 200 E. coli isolates, 2.5% (n = 5) were found to be resistant to triclosan, and multidrug resistance (MDR) and cross-resistance phenotypes were noted for these triclosan-resistant strains. The triclosan-sensitive strains also exhibited MDR phenotypes, probably because of the high resistance rate to AMP, CIP, LVX, and GEN. Gly79Ala and Ala69Thr amino acid changes were observed in the triclosan-resistant strains, but these changes may not mediate resistance of E. coli to triclosan, because mutations of these two amino acids has also been detected in triclosan-susceptible strains. Moreover, except for DC8603, all other strains enhanced the efflux pumps activity. As compared with ATCC 25922, except for fabI, increased expressions were noted for all efflux pump encoding genes such as ydcV, ydcU, ydcS, ydcT, cysP, yihV, acrB, acrD, and mdfA among the studied strains with varying PFGE patterns and STs types. Unexpectedly, 5 susceptible E. coli isolates showed rapidly increasing triclosan resistance after exposure to triclosan in vitro for only 12 days, while MDR or cross-resistance phenotypes and the overexpression of efflux pump genes were recorded among these triclosan-induced resistant isolates.ConclusionsThis is the first study to report that short-term triclosan exposure in vitro increases triclosan resistance in susceptible E. coli isolates. After acquiring resistance, these strains may present MDR or cross-resistance phenotypes. Moreover, triclosan resistance mainly involves the overexpression of fabI and efflux pumps in E. coli isolates.

Residue Analysis of Insecticides in Potatoes by QuEChERS-dSPE/UHPLC-PDA.

Insecticides are broadly applied in agriculture to defend crops from illnesses and pest attacks, consequently guaranteeing high production. However, their residual deposits in food products are becoming a main concern with regard to human consumption. As such, sensitive analytical methods should be developed to assess, prevent and control insecticide residues. In this research, an accurate, fast and reliable residual analytical method, that is quick, easy, cheap, effective, rugged and safe, combined with dispersive solid phase extraction (QuEChERS-dSPE), was developed for the determination of the most common insecticides used in potatoes cultivation (chlorpyrifos, λ-cyhalothrin, deltamethrin and acrinathrin), using an ultra-high performance chromatography photodiode array detector (UHPLC-PDA). The most influential extraction and instrumentation parameters that affect the method’s performance, such as extraction solvent, ratio salts, sorbents, stationary phases, gradient conditions and eluents, were assessed. Under the ideal conditions, good linearity (0.992–0.998), limits of detection (0.02–0.47 µg/kg) and quantification (0.06–1.58 µg/kg), recovery (94.1 to 112%) and precision (relative standard deviation <18%) were achieved for spiked levels between 2.5 and 50 µg/kg. The obtained results revealed that the potatoes analyzed do not represent any concern for human healthy, as the insecticide residues detected were lower than the maximum residue limits set by the European Union, Codex Alimentarius, and other organizations.

The effect of heat on keratin and implications for the archaeological record

A horncore feature was encountered during excavations at Border Cave, in Member 2 BSL, dated 60–49 ka. The basal half of the horncore lay towards the centre of a combustion feature and was calcined. The tip half lay on a mat of burnt grass bedding towards the edge of the fireplace. It was covered with a black shiny residue, which was also present on nearby stone tools. The feature was jacketed and excavated later under a microscope in the laboratory. Raman spectroscopy identified the residue only as amorphous carbon, indicating the presence of a heated organic substance. Knowing that variation exists in modern and archaeological glue recipes, we wanted to know if the black residue was melted keratin, and if it was, whether it had been used as a substitute for beeswax or latex for hafting. We set out to test the hypothesis by conducting a heating experiment with a modern sheathed horncore. Experimental results showed that keratin does not transform into viable glue when heated. Instead, it reduces immediately to a glassy brittle residue. Our finding strongly supports a scenario of incidental deposition of residue on the archaeological stone tools. Previous combustion experiments have shown that the sediment below a fire can reach 300+ °C through vertical heat transfer. This implies that horn sheaths in archaeological deposits, separated from overlying combustion features by thousands of years, can transform into a black residue that may deposit on nearby stone and bone tools.