Poled Research Articles

Neural net detection of seismic features related to gas hydrates and free gas accumulations on the northern U.S. Atlantic margin

Bottom-simulating reflections (BSRs) that sometimes mark the base of the gas hydrate stability zone in marine sediments are often identified based on the reverse polarity reflections that cut across stratigraphic layering in seismic amplitude data. On the northern U.S. Atlantic margin (USAM) between Cape Hatteras and Hudson Canyon, legacy seismic data have revealed pronounced BSRs south of the deepwater extension of Hudson Canyon and more subtle ones from offshore Delaware south to Cape Hatteras, where the reflections sometimes follow stratigraphic layering. Using high-resolution seismic data acquired during the 2018 Mid-Atlantic Resource Imaging Experiment and a supervised neural net, we identify seismic features associated with gas hydrates and/or the top of gas between Hudson Canyon and Cape Hatteras. Using seismic attributes especially sensitive to the presence of gas, we train a neural network algorithm on seismic data from an area with strong BSRs and then apply the model to the rest of the data set. The results indicate that gas hydrate and/or shallow free gas are significantly more widespread on the northern part of the USAM than previously known. Seismic indicators of gas extend landward from the 2000 m isobath to the upper continental slope in sectors with (offshore Virginia) and, to a lesser extent, without (offshore New Jersey) pervasive upper slope methane seeps. Higher sand content and intermediate sediment thickness, factors related to the container size and gas charge in a petroleum systems framework, are associated with more robust gas indicators.

Paleomagnetic study of impactites from the Karla impact structure suggests protracted postimpact hydrothermalism

AbstractWe present a paleomagnetic study of the ~10 km diameter Karla impact structure in Russia. We sampled the target carbonate rocks, and a yet undocumented fragmental melt‐bearing lithic breccia layer. This impact breccia, which contains carbonate melt, is enriched in stoichiometric magnetite by a factor of ~15 compared to the target lithologies, and carries a stable natural remanent magnetization. The weak remanent magnetization and the presence of both normal and reverse polarities down to the centimeter scale indicate that the breccia does not carry a thermoremanent magnetization (TRM), but rather a chemical remanent magnetization (CRM). The presence of stoichiometric magnetite and the absence of TRM suggest that the magnetite was formed during relatively low‐temperature postimpact hydrothermalism that affected the porous impact breccia layer. During this process, the breccia acquired a CRM. The paleomagnetic direction is compatible with a Cenozoic age for the impact event, but cannot bring more precise constraint on the age because of the stable position of the Eurasian plate over the last 60 Myr. However, the presence of both polarities indicates that mild hydrothermalism took place over a period of time long enough to span at least one reversal of the geomagnetic field, that is, over a time scale of the order of 100 kyr. This confirms that protracted hydrothermal systems associated with impact craters are long lived, even in relatively small craters such as Karla, and are key features of the geologic and environmental effects of impacts on Earth.

Long‐Term Field Screening by Mobile Ions in Thick Metal Halide Perovskites: Understanding Saturation Currents

Metal halide perovskite‐based semiconductor devices with micrometer‐to‐millimeter‐thick perovskite layers show a current response upon polarization which evolves up to several hours, transiting several regimes. This is the case of X‐ray detectors where the use of absorber perovskites produces instabilities in the dark reverse saturation current hindering the signal processing. Even though these phenomena are often attributed to the electronic–ionic conductivity and the interface phenomena in these perovskites, a proper theoretical description is missing. Herein, the numerical simulation study reproduces the main experimental trends and explains the origin of some of the apparently‐always‐increasing current transients in thick perovskite samples. The mobile ion concentration and mobility are correlated with three main transport regimes and interpretation and parameterization are provided to the current saturation time in terms of the ionic screening of the electric field toward the interfaces. The final steady‐state under reverse polarization is found as diffusion‐limited electronic current, which results from abrupt mobile ion depletion proportional to the Debye length in the vicinity of a contact. The conclusions suggest the material optimization of the contact interfaces as a pathway to reduce the long current saturation times in these devices.

Microwave photonic multiform microwave frequency shift keying signal generator.

A photonic approach to realizing multiform microwave frequency shift keying (FSK) signal generation is proposed and demonstrated. In the scheme, a commercial dual-polarization quadrature phase shift keying modulator (DP-QPSKM) is employed to generate two orthogonally-polarized signals containing specific optical sidebands, and a subsequent Sagnac loop structure govern the interference results of these two signals. From a theoretical analysis, when the modulators are properly biased, microwave FSK signal with fixed double relationship or flexibly tunable subcarrier frequencies can be obtained, and high frequency multiplication can be realized in the meantime. Furthermore, a photonic-optimized coherent demodulation structure is designed to recover the binary coding data, which can effectively avoid the electronic bottleneck. Simulation has been performed to investigate the mechanism and the discussions about the robustness to non-ideal parameters including DC bias, phase shift and polarization angle are also given. In the proof-of-concept experiment, microwave FSK signal with subcarrier frequencies of 2/4, 2.2/3.8, 2.4/3.6, 2.6/3.4, 2.8/3.2 GHz are generated, and the correct binary coding data is successfully recovered with the aid of simulation platform. The simulation and experimental results can verify the feasibility of the proposed multiform microwave FSK signal generator, which may find applications in modern radar and communication systems.

Acute multiple toxic effects of Trifloxystrobin fungicide on Allium cepa L.

Trifloxystrobin (TFS) is a strobilurin-type fungicide that should be investigated due to its risks to non-targeted organisms. The goal of this study was to assess the susceptibility of Allium cepa L. to TFS in a multi-pronged approach. For 72 h, 0.2 g/L, 0.4 g/L and 0.8 g/L doses of TFS were administered to A. cepa bulbs and the control group was treated with tap water. The toxic effects of TFS were tested, considering physiological, cytogenetic, biochemical and anatomical analyses. TFS delayed growth by reducing the rooting ratio, root elongation and weight increase. Following TFS treatments, mitotic index (MI) scores decreased, while the formation of micronucleus (MN) and chromosomal aberrations (CAs) ascended. CAs types induced by TFS were listed according to their frequency as fragment, vagrant chromosome, sticky chromosome, uneven distribution of chromatin, bridge, nucleus with vacuoles, reverse polarization and irregular mitosis. TFS provoked an increment in superoxide dismutase (SOD) and catalase (CAT) enzyme activities as well as an accumulation of malondialdehyde (MDA). Meristematic cells of A. cepa roots treated with TFS had various anatomical damages, including damaged epidermis, flattened cell nucleus, damaged cortex and thickness in the cortex cell wall. All damages arising from TFS treatments exhibited dose-dependency. The findings of the present study revealed the serious toxicity of TFS in a non-targeted plant. It should not be neglected to evaluate the potential hazards of TFS with different toxicity tests.

Recurrent KRAS mutations are early events in the development of papillary renal neoplasm with reverse polarity

AbstractWe evaluated the clinicopathologic and molecular characteristics of mostly incidentally detected, small, papillary renal neoplasms with reverse polarity (PRNRP). The cohort comprised 50 PRNRP from 46 patients, divided into 2 groups. The clinically undetected (<5 mm) neoplasms (n = 34; 68%) had a median size of 1.1 mm (range 0.2–4.3 mm; mean 1.4 mm), and the clinically detected (≥5 mm) neoplasms (n = 16; 32%) which had a median size of 13 mm (range 9–30 mm; mean 16 mm). Neoplasms were positive for GATA3 (n = 47; 100%) and L1CAM (n = 34/38; 89%) and were negative for vimentin (n = 0/44; 0%) and, to a lesser extent, AMACR [(n = 12/46; 26%; weak = 9, weak/moderate = 3)]. KRAS mutations were found in 44% (n = 15/34) of the clinically undetected PRNRP and 88% of the clinically detected PRNRP (n = 14/16). The two clinically detected PRNRP with wild-type KRAS gene were markedly cystic and contained microscopic intracystic tumors. In the clinically undetected PRNRP, the detected KRAS mutations rate was higher in those measuring ≥1 mm vs <1 mm [n = 14/19 (74%) vs n = 1/15 (7%)]. Overall, the KRAS mutations were present in exon 2—codon 12: c.35 G > T (n = 21), c.34 G > T (n = 3), c.35 G > A (n = 2), c.34 G > C (n = 2) resulting in p.Gly12Val, p. Gly12Asp, p.Gly12Cys and p.Gly12Arg, respectively. One PRNRP had a G12A/V/D complex mutation. Twenty-six PRNRP were concurrently present with other tumors of different histologic subtypes in the ipsilateral kidney; molecular testing of 8 of the latter showed wild-type KRAS gene despite the presence of KRAS mutations in 5 concurrent PRNRP. On follow up, no adverse pathologic events were seen (range 1–160 months; mean 44 months). In conclusion, the presence of KRAS mutations in small, clinically undetected PRNRP provides a unique finding to this entity and supports its being an early event in the development of these neoplasms.

The study of clinicopathologic features of cervical squamous carcinoma with invasive micropapillary like pattern and phenotype.

Invasive micropapillary carcinoma has been reported in the adenocarcinoma of many organs including cervix, and many studies have proved it has more invasive biological behavior. This study, for the first time, reports cervical squamous carcinoma with invasive micropapillary like pattern and phenotype (IMLPP) and further investigates its clinicopathologic features. Cervical squamous carcinoma with IMLPP was selected by histological characteristics and immunohistochemical staining. All patients' clinical information and pathological parameters were collected. Based on histological characteristics and immunohistochemical staining results, 24 cases, out of 104 cases of cervical squamous carcinoma, were identified as having invasive micropapillary like pattern. The staining of all 24 cases with EMA and MUC-1 showed the feature of "reverse polarity like". Meanwhile, patient age at diagnosis (P=0.011), maximum invasion depth (P=0.001), maximum diameter (P=0.015), lymphvascular space invasion (P<0.001), pelvic lymph node metastasis (P<0.001), metastasis (P=0.020), death (P=0.025) and FIGO stages (P=0.001) were related to the existence of IMLPP, independently of the proportion of IMLPP to the whole tumor in size. Univariate and multivariate disease-free survival analyses (follow-up time >12 months) showed significant statistical difference between cervical squamous carcinoma with or without IMLPP (P=0.016, P=0.043). Results from our study suggested that IMLPP may be associated with aggressive biological behavior in cervical squamous carcinoma. Therefore, pathologists should pay attention to the existence of it, no matter its proportion with relation to the whole tumor, and bring it to the attention of clinicians.

Surface Dielectric Characteristics of GFRP and PTFE in Cryogenic Environment Under the Switching Impulse Superimposed on DC Voltage

For insulation materials utilized in DC superconducting fault current limiter, surface discharge along the interface is more damaging to the insulation relative to penetration breakdown. Therefore, for the reliable and economical insulation design of DC superconducting fault current limiter, it is very important to investigate an insulation materials and study the surface dielectric characteristics. Additionally, DC superimposed switching impulse can cause critical stress to the insulation of DC superconducting fault current limiter and can potentially result in breakdown. Therefore, the insulation materials of DC superconducting fault current limiter must have sufficient surface distance to prevent surface discharge under DC superimposed switching impulse. In this paper, the surface breakdown tests were performed by applying DC superimposed switching impulse to glass fiber reinforced polymer (GFRP) and polytetrafluoroethylene (PTFE) specimen in cryogenic environment. Surface dielectric characteristics according to positive and negative polarities of DC and switching impulse were analyzed. In addition, the surface dielectric characteristics were analyzed by selecting the gap distance. From the experimental results, the surface dielectric strength of GFRP was higher than that of PTFE, but the difference in surface dielectric strength between GFRP and PTFE decreased as the gap distance increased. The surface breakdown voltage of PTFE was lowest at the superposition of positive DC and positive switching impulse. However, GFRP has the lowest surface breakdown voltage when negative DC superimposed positive switching impulse. Consequently, it is possible to design the optimal surface distance of solid insulation materials in DC superconducting current limiter by considering the superposition of DC and switching impulse polarity.

Papillary renal neoplasm with reverse polarity may be a novel renal cell tumor entity with low malignant potential

AimsThis study retrospectively investigated the morphological, immunohistochemical and molecular genetic features of papillary renal neoplasm with reverse polarity (PRNRP), a recently described renal tumor.Methods and resultsEleven cases of PRNRP were collected, and 16 cases of type I and 9 cases of type II papillary renal cell carcinoma were included as a control series. Pathological features were evaluated based on HE staining and immunohistochemistry. KRAS exon 2 and BRAF V600E mutations were detected by Real-time PCR and Sanger sequencing. Fluorescence in situ hybridization was conducted for identification of chromosomal abnormalities.Hemosiderin deposition was found in a small amount of tumor cells in 6 cases. Multifocal or patchy necrosis (5/11), small focal invasion of the pseudocapsules or renal parenchyma (6/11), and breakthrough of renal capsule with nerve invasion (1/11) were revealed, inconsistent with the previous view that the tumor lacks necrosis and intercellular hemosiderin. Immunohistochemical staining (diffusely positive for CK7 and GATA3, negative for CD117 and vimentin, and negative to weakly positive for P504S) and high frequency of KRAS mutations in exon 2 (9/10) supported the identification and inclusion of our cases. Chromosome 7 trisomy (1/7), chromosome 17 trisomy (0/7) and chromosome Y deletion (0/5 male patients) were seldom detected in this tumor.All patients were alive without metastasis or recurrence at the end of the follow-up.ConclusionOur findings may highlight the possibility of a low malignant potential of this emerging entity. We suggest that the tumor be classified as a novel renal cell tumor subtype independent of papillary renal cell carcinoma.

Effect of Welding Polarity on Mechanical Properties of Submerged Arc Welded Railway Vehicle Wheels

When a railway vehicle moves on a curved rail, sliding contact between the rail head side and wheel flange causes wear on the wheel flange. Traditionally, a wheel with thinned flange is machined to get a minimum flange thickness specified for structural safety. This operation reduces the rim thickness and shortens the life of the wheel. In the present study, the thinned flanges were hard-faced by submerged arc welding. A welding wire, which has good weldability to the base material of the wheel and does not generate thermal cracking, was developed. The effects of welding polarity on the microstructure, hardness, friction coefficient, and wear characteristics of the welded wheel were studied. The hardness of the wheel welded with reverse polarity was similar to that of welded with straight polarity. The wear rates of the wheel disc welded with reverse polarity and its counterpart rail disc were 11% and 27% lower than those welded with straight polarity. Delamination wear due to subsurface crack propagation and oxidation wear were mixed. The hardness of the rail before the wear test was in the range of 250–300 HV. After the wear test, it soared to 500 HV.

ADENOID AMELOBLASTOMA: A CASE REPORT

Adenoid ameloblastoma is a rare variant of ameloblastoma that exhibits adenoid characteristics, resembling an adenomatoid odontogenic tumor. Despite few studies, the clinical, histopathologic, and behavioral aspects of this lesion are still unknown. A 57-year-old White female patient presented with a well-defined unilocular radiolucency between the roots of the right mandibular premolars, without intraoral changes. After an excisional biopsy, microscopic examination revealed islands of odontogenic epithelium surrounded by fibrous stroma. The peripheral columnar cells showed ameloblast-like differentiation with nuclear palisading and reverse polarization. A cribriform pattern was observed, as well as large duct-like spaces lined by columnar or cuboid cells and filled with eosinophilic mucoid material. A diagnosis of adenoid ameloblastoma was made and the patient is currently being followed up. Adenoid ameloblastoma is a rare variant of ameloblastoma that exhibits adenoid characteristics, resembling an adenomatoid odontogenic tumor. Despite few studies, the clinical, histopathologic, and behavioral aspects of this lesion are still unknown. A 57-year-old White female patient presented with a well-defined unilocular radiolucency between the roots of the right mandibular premolars, without intraoral changes. After an excisional biopsy, microscopic examination revealed islands of odontogenic epithelium surrounded by fibrous stroma. The peripheral columnar cells showed ameloblast-like differentiation with nuclear palisading and reverse polarization. A cribriform pattern was observed, as well as large duct-like spaces lined by columnar or cuboid cells and filled with eosinophilic mucoid material. A diagnosis of adenoid ameloblastoma was made and the patient is currently being followed up.

MULTIDISCIPLINARY TREATMENT AND FOLLOW-UP OF AMELOBLASTOMA: CASE REPORT

Ameloblastoma is a benign epithelial odontogenic neoplasm with aggressive biological behavior and a tendency for local recurrence. A 21-year-old male patient was referred for treatment for an asymptomatic small intraoral swelling on the left posterior mandible. Clinical examination showed the absence of left molars and no extraoral asymmetry. Panoramic radiography revealed a unicystic radiolucent lesion. Previously, the patient was submitted to an incisional biopsy with a histopathologic diagnosis of ameloblastoma. The treatment was excision of the lesion followed by peripheral osteotomy and application of Carnoy's solution, and the surgical specimen was sent for histopathologic analysis. Microscopic examination confirmed the diagnosis of ameloblastoma presenting proliferation of islands and cords of odontogenic epithelium. Peripheral cells were arranged in a palisading pattern with reverse polarity and central cells were loosely arranged. The stroma consisted of fibrous connective tissue. The patient has been under follow-up for about 2 years without recurrence.

PERIPHERAL AMELOBLASTOMA IN THE MAXILLARY GINGIVA: A RARE CASE

A 51-year-old man was referred to the Oral Medicine Clinic with an asymptomatic slow-growing palatal injury with a 15-year evolution history. Extraoral examination showed no gross abnormalities. Intraoral examination revealed a firm sessile nodule of normal coloration in the palatal mucosa adjacent to teeth #13 and #14, measuring approximately 2 cm. Imaging exams did not show bone changes. As diagnostic hypotheses, peripheral ossifying fibroma and inflammatory fibrous hyperplasia were considered. Excisional biopsy of the lesion was performed, and microscopic sections stained with hematoxylin and eosin revealed odontogenic epithelial islands in the oral lamina propria, composed of hyperchromatic columnar cells showing peripheral palisading, reverse polarization, and central stellate reticulum-like changes immersed in a dense connective tissue. Following clinicopathologic correlation, the diagnosis of peripheral ameloblastoma was established. Follow-up is ongoing and no recurrence has been detected so far.

CLINICAL, RADIOGRAPHIC AND MORPHOLOGICAL FEATURES OF AMELOBLASTOMA: A CASE REPORT

Ameloblastoma is a benign epithelial odontogenic neoplasm with an aggressive biological behavior with a tendency of local recurrence. A 21-year-old male patient was referred for treatment for an asymptomatic small intraoral swelling on the left posterior mandible. Clinical examination showed the absence of left molars and no extraoral asymmetry. Panoramic radiography revealed an unicystic radiolucent lesion. Previously, the patient was submitted to an incisional biopsy with a histopathologic diagnosis of ameloblastoma. The treatment was excision of the lesion followed by peripheral osteotomy and application of Carnoy's solution, and the surgical specimen was sent for histopathologic analysis. Microscopic examination confirmed the diagnosis of ameloblastoma presenting proliferation of islands and cords of odontogenic epithelium. Peripheral cells were arranged in a palisading pattern with reverse polarity and central cells were loosely arranged. The stroma consisted of fibrous connective tissue. The patient has been under a follow-up for about 2 years without recurrence.

Papillary renal neoplasm with reverse polarity—a comparative study with CCPRCC, OPRCC, and PRCC1

Papillary renal neoplasm with reverse polarity (PRNRP) is a newly defined entity with distinct histomorphology and recurrent KRAS mutation. In this study, we aimed to identify and analyze the clinicopathological, immunohistochemical (IHC), and molecular features of PRNRP in our center and to evaluate its differential diagnosis with other tumors with which it is easily confused: clear cell papillary renal cell carcinoma (CCPRCC), oncocytic papillary renal cell carcinoma (OPRCC), and papillary renal cell carcinoma type 1 (PRCC1). Nephrectomy specimens of PRNRP (n=15), CCPRCC (n=11), and OPRCC (n=12) were retrieved from our pathology archives. We also selected typical cases of PRCC1 (n=15) as a control group. PRNRP accounted for 3.05% (15/492) of all PRCC cases at our center. The median follow-up period was 41.3 months. All PRNRP cases were pT1N0M0, and only one involved recurrence (1 year after surgery). IHC analysis showed diffuse staining of CK7, EMA, and GATA3 but weak or negative staining of CD10, CD117, p504s, and vimentin in the PRNRP samples and distinctive IHC features in the other three tumor types. KRAS mutation was detected in 4/10 PRNRP cases. Among the 40 most commonly mutated genes identified, 5 (BCLAF1, PDE4DIP, NCOR1, PARP4, and PABPC1) have actionable alterations. Our study supports the suggestion that PRNRP is an entity distinct from CCPRCC, OPRCC, and PRCC1.

Effects of electrolyte variation on ammonia sensing temperature for BiVO4 sensing electrode in mixed potential gas sensor

The aim of the present study is to investigate BiVO4 sensing electrode (SE) based electrochemical gas sensor for ammonia (NH3) sensing. Additionally, this study is also focused to reduce the operating temperature of sensor by applying different electrolytes i.e., yttria stabilized zirconia (YSZ) and gadolinia doped ceria (GDC). The maximum sensor response obtained for YSZ and GDC based cells towards 80 ppm NH3 were − 103.03 and − 78.81 mV at 600 ℃ and 550 ℃, respectively. Corresponding sensitivity of YSZ and GDC based cells for NH3 sensing were − 99.24 and − 42.66 mV/decade, respectively. Both the sensors demonstrate excellent selectivity as well as stability against 80 ppm NH3 (10 cycles) and humidity variation (pH2O = 0–0.12 atm.). Electrochemical impedance spectra (EIS) and dc polarization (I-V) curves confirms the mixed-potential sensing mechanism of the sensors. The systematic dependency of electrode’s resistance at a given frequency on the gas concentration reveals a novel pathway for prediction of sensors’ behavior. Additionally, the presence of GDC electrolyte decreases the response/recovery time (16/125 s) compared to YSZ-based cells (21/159 s) against 320 ppm NH3 at 550 ℃ which demonstrate its low temperature sensing capability. This 50 ℃ reduction in the operating temperature can be useful for extension of lifetime of sensor.

EP-276 Tall Cell Carcinoma with Reverse Polarity (TCCRP) of the breast; a rare form of breast cancer

Abstract Aim A case report on the diagnosis and treatment of this rare low grade triple negative breast cancer. Case Report A 41 year old female presented with a palpable left breast lump. Family history includes a sister with a rare myeloproliferative disorder. On examination, a left breast lower outer quadrant 2–3 cm hard irregular lump was palpable. Mammography and ultrasound revealed a 25 mm suspicious lesion (which was biopsied), with normal appearing lymph nodes. Results Biopsy revealed a grade 2 invasive apocrine carcinoma. Oestrogen and Herceptin receptors negative. Breast conserving surgery with sentinel lymph node biopsy was performed. Histology revealed a 22 mm well circumscribed tumour with nests of epithelial cells in micropapillary pattern with apocrine like appearance. The most striking feature was that the nuclei were at the apical rather than the basal poles of the epithelial cells (reverse polarity). No lymphovascular invasion present. Lymph nodes were negative (0/3). Diagnosis was then confirmed by molecular testing. Conclusion Tall cell carcinoma with reverse polarity (TCCRP)1, a rare cancer resembling tall cell variant of papillary thyroid carcinoma, was first reported by Eusebi et al in 20032. Although morphologically similar to metastatic papillary thyroid cancer, neither the immunohistochemical markers nor genetic profiles have established any connection3. Accurate diagnosis of TCCRP is important as it carries an excellent prognosis. Treatment is local regional radiotherapy. There is no indication for systemic therapy in this case, due to its indolent low metastatic potential.

Molecular docking and spectral shift supported toxicity profile of metaldehyde mollucide and the toxicity-reducing effects of bitter melon extract

Excessive use of metaldehyde to combat mollusks directly or indirectly endangers non-targeted organisms. The present study aimed to reveal the antitoxic potential of bitter melon (Momordica charantia L.) extract (BME) against metaldehyde-related toxicity in Allium cepa L. The experimental groups formed using A. cepa bulbs were exposed to aqueous solutions containing 350 mg/L BME, 700 mg/L BME, 200 mg/L metaldehyde, 200 mg/L metaldehyde +350 mg/L BME and 200 mg/L metaldehyde +700 mg/L BME, respectively. The bulbs in the control group dipped in tap water. Metaldehyde suppressed growth with respect to germination ratio, root elongation and weight gain parameters. In metaldehyde-administered group, mitotic index (MI) was reduced, while the frequencies of micronucleus (MN) and chromosomal aberrations (CAs) increased. Metaldehyde promoted CAs such as sticky chromosomes, vagrant chromosome, fragment, unequal distribution of chromatin, reverse polarization, bridge and multipolar anaphase in root tip meristem cells. Spectral shift and molecular docking confirmed the genotoxic effect of metaldehyde resulting from DNA-metaldehyde interaction. The DNA damage in root meristems was revealed using the Comet Assay. Metaldehyde stress provoked oxidative stress. Activities superoxide dismutase (SOD) and catalase (CAT) enzymes along with level of malondialdehyde (MDA) accumulation accelerated. In roots treated with metaldehyde, epidermis cell damage, flattened cell nucleus, cortex cell damage and cortex cell wall thickening were observed as meristematic cell damage. BME attenuated metaldehyde-induced toxicity in a dose-dependent manner. This study demonstrated the mitigative potential of plant derived BME with no-to-low side effects against hazardous chemicals including metaldehyde. Nature is the most valuable weapon against toxicity from pollutants. Therefore, the protective potential of BME against other harmful agents should be screened.

Dose-dependent toxicity profile and genotoxicity mechanism of lithium carbonate

The increasing widespread use of lithium, which is preferred as an energy source in batteries produced for electric vehicles and in many electronic vehicles such as computers and mobile phones, has made it an important environmental pollutant. In this study, the toxicity profile of lithium carbonate (Li2CO3) was investigated with the Allium test, which is a bio-indicator test. Dose-related toxic effects were investigated using Li2CO3 at doses of 25 mg/L, 50 mg/L, and 100 mg/L. The toxicity profile was determined by examining physiological, cytotoxic, genotoxic, biochemical and anatomical effects. Physiological effects of Li2CO3 were determined by root length, injury rate, germination percentage and weight gain while cytotoxic effects were determined by mitotic index (MI) ratio and genotoxic effects were determined by micronucleus (MN) and chromosomal aberrations (CAs). The effect of Li2CO3 on antioxidant and oxidant dynamics was determined by examining glutathione (GSH), malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD) levels, and anatomical changes were investigated in the sections of root meristematic tissues. As a result, Li2CO3 exhibited a dose-dependent regression in germination-related parameters. This regression is directly related to the MI and 100 mg/L Li2CO3 reduced MI by 38% compared to the control group. MN and CAs were observed at high rates in the groups treated with Li2CO3. Fragments were found with the highest rate among CAs. Other damages were bridge, unequal distribution of chromatin, sticky chromosome, vagrant chromosome, irregular mitosis, reverse polarization and multipolar anaphase. The genotoxic effects were associated with Li2CO3-DNA interactions determined by molecular docking. The toxic effects of Li2CO3 are directly related to the deterioration of the antioxidant/oxidant balance in the cells. While MDA, an indicator of lipid peroxidation, increased by 59.1% in the group administered 100 mg/L Li2CO3, GSH, which has an important role in cell defense, decreased by 60.8%. Significant changes were also detected in the activities of SOD and CAT, two important enzymes in antioxidant defense, compared to the control. These toxic effects, which developed in the cells belonging to the lithium-treated groups, were also reflected in the tissue anatomy, and anatomical changes such as epidermis cell damage, cortex cell damage, flattened cell nucleus, thickening of the cortex cell wall and unclear vascular tissue were observed in the anatomical sections. The frequency of these changes also increased depending on the Li2CO3 dose. As a result, Li2CO3, which is one of the lithium compounds, and has become an important contaminant in the environment with increasing technological developments, caused a combined and versatile toxicity in Allium cepa L. meristematic cells, especially by causing deterioration in antioxidant/oxidant dynamics.

Papillary renal cell neoplasm with reverse polarity: A new subtype of renal tumour with favorable prognosis

IntroductionPapillary renal cell neoplasm with reverse polarity (PRNRP) has recently been recognized as an entity separate from the traditional classification of papillary renal cell carcinomas, due to its specific histopathological, immunophenotypic and molecular characteristics, as well as its indolent behavior. Material and methodsWe provide 6 new cases and a review of the literature published until the present time, which comprises a total number of 104 cases. ResultsOur PRNRP cases correspond to 5 men and one woman aged between 47 and 91 years. In 5 of the 6 cases, the PRNRP was an incidental finding in nephrectomy specimens. Nephrectomy had been indicated due to the presence of another renal tumor, except for one case, in which surgical intervention was indicated due to PRNRP. Our cases present mass sizes between 2 and 13 mm, as well as papillary histology with a monolayered lining of eosinophilic cells with low-grade nuclei in apical location. Immunohistochemically, they show a constant positivity for GATA3 and negativity for vimentin. KRAS mutations were identified in 50% of our cases. After a follow-up ranging between one and 60 months, 5 of the cases were still alive without recurrences or metastases, and one died from urothelial carcinoma. ConclusionsOur cases agree with the clinical and pathological characteristics described in the PRNRP cases published to date. With the present study, we provide the first series of national cases corroborating the existence of well-defined and constant diagnostic criteria that allow PRNRP to be considered as a distinctive entity.