Application of thermal lens microscopy (TLM) for measurement of Cr(VI) traces in wastewater.

In this work, we demonstrate for the first time that Thermal Lens Microscopy technique (TLM) can be applied to monitor the dynamics of a photocatalytic process in-situ. The photocatalytic reduction of hexavalent chromium -Cr(VI)- in aqueous solution using CdS and irradiated with visible light is monitored by TLM. Since the values of Cr(VI) concentration obtained after the photocatalytic process were close to those imposed by the international regulations for drinking water, the use of TLM allowed its measurement with a better reliability than with UV spectroscopy, usually used in this kind of analysis.

Diffusional limitations explain the lower photosynthetic capacity of ferns as compared with angiosperms in a common garden study.

Ferns are thought to have lower photosynthetic rates than angiosperms and they lack fine stomatal regulation. However, no study has directly compared photosynthesis in plants of both groups grown under optimal conditions in a common environment. We present a common garden comparison of seven angiosperms and seven ferns paired by habitat preference, with the aims of (1) confirming that ferns do have lower photosynthesis capacity than angiosperms and quantifying these differences; (2) determining the importance of diffusional versus biochemical limitations; and (3) analysing the potential implication of leaf anatomical traits in setting the photosynthesis capacity in both groups. On average, the photosynthetic rate of ferns was about half that of angiosperms, and they exhibited lower stomatal and mesophyll conductance to CO2 (gm ), maximum velocity of carboxylation and electron transport rate. A quantitative limitation analysis revealed that stomatal and mesophyll conductances were co-responsible for the lower photosynthesis of ferns as compared with angiosperms. However, gm alone was the most constraining factor for photosynthesis in ferns. Consistently, leaf anatomy showed important differences between angiosperms and ferns, especially in cell wall thickness and the surface of chloroplasts exposed to intercellular air spaces.

Dynamic Fracture Resistance under Plane Strain Conditions of High-Density Polyethylene Nanoclay Composites.

Polymer nanoclay composites have received significant attention due to their substantially enhanced mechanical, thermal and barrier properties. However, the effect of these nanoclays on the dynamic fracture resistance of a polymer matrix during fast fracture events has not been documented. In this study, the effect of nanoclay addition on the rapid crack propagation (RCP) resistance of high-density polyethylene (HDPE) was investigated through the high-speed double torsion test. Results showed that the addition of 1, 3, and 5% of nanoclays improved the dynamic fracture resistance under the plane strain conditions (Gd1) of HDPE up to 65%. An increase in the storage and loss modulus, and a decrease in crystallinity and melt flow index with nanoclay content was also found. Although the presence of agglomerates can hinder the enhancement of Gd1 as it promotes agglomerate fracture and debonding, the increase in energy consumption through fibrillation and crazing promoted by the nanoclay prevails, suggesting that the nanoclay's toughening effect that has been extensively reported under quasi-static and impact tests, is also present under RCP conditions, and that the HDPE nanocomposites could be used in applications in which RCP must be prevented.

Non-topographic current contrast in scanning field emission microscopy.

In scanning field emission microscopy (SFEM), a tip (the source) is approached to few (or a few tens of) nanometres distance from a surface (the collector) and biased to field-emit electrons. In a previous study (Zanin et al. 2016 Proc. R. Soc. A 472, 20160475. (doi:10.1098/rspa.2016.0475)), the field-emitted current was found to change by approximately 1% at a monatomic surface step (approx. 200 pm thick). Here we prepare surface domains of adjacent different materials that, in some instances, have a topographic contrast smaller than 15 pm. Nevertheless, we observe a contrast in the field-emitted current as high as 10%. This non-topographic collector material dependence is a yet unexplored degree of freedom calling for a new understanding of the quantum mechanical tunnelling barrier at the source site that takes into account the properties of the material at the collector site.

Pleomorphic malignant fibrous histiocytoma in bladder diverticulum.

The Malignant Fibrous Histiocytoma is a very rare cancer and rather exceptional when located in bladder diverticulum. it occurs in men in their sixties, manifests itself through haematuria and/or irritative micturition. There is not a causal association. An immunohistochemical analysis is necessary to establish a differential diagnosis. It is aggressive, with a high rate of local recurrence and remote progression, thereby requiring early treatment that consists of radical cystectomy with pelvic lymph node dissection followed by adjuvant therapy, predominantly radiotherapy on the surgical wound. Close follow-up is crucially important. Poor survival rate even when patients undergo multimodal therapy.

Comprehensive clinical, molecular and histopathological analysis of bone marrow in chronic myeloproliferative neoplasia. / Análisis integrado clínico, molecular e histopatológico de la médula ósea en las neoplasias mieloproliferativas crónicas.

OBJECTIVES: To analyse the possible correlation between molecular changes in the JAK2, MPL and CALR genes, the morphological pattern of bone marrow and the clinical-haematologic profile of patients. PATIENTS AND METHODS: We conducted a retrospective study that included 140 patients diagnosed with Philadelphia-negative myeloproliferative neoplasia (Ph-MPN) in a single centre. RESULTS: In essential thrombocythaemia (ET), the patients with the JAK2 V617F mutation presented more leucocytes and neutrophils than patients who presented the CALR mutation, who had more platelets and a greater need for cytoreductive therapy. These findings support the fact that the mutational state in ET appears to define subtypes of patients with substantially different clinical courses and prognoses. In myelofibrosis, the mutational state appears to influence the histopathological changes found in the bone marrow biopsy, which did not occur in polycythaemia vera or ET.

Multimodal therapy in urachal carcinoma with oligometastatic bone disease.

A 35-year-old male patient was admitted to our hospital for urachal carcinoma with oligometastatic bone disease. He received a surgical resection through the umbilical area, urachal ligament and bladder dome (partial cystectomy) and adjuvant chemotherapy based on cisplatin-gemcitabine regimens together zoledronic acid with a good tolerance, no toxicity. Nine months after surgery, our patient presented no symptoms and the metastasis had been brought under control with no apparent signs of recurrence as assessed in a follow-up CT. To our knowledge, is the first case report of a urachal carcinoma with oligometastatic bone disease who received multimodal therapy, including surgery resection.

[Usefulness of urine cytology for bladder carcinoma diagnosis: comparative study with biopsy]. / Utilidad de la citología de orina para el diagnóstico del carcinoma vesical: estudio comparativo con biopsia.

OBJECTIVES: Traditionally, urine cytology has been considered as the gold standard for bladder cancer screening. However, new methods are playing new roles in these cases. In order to assess the value of cytology of voided urine we performed one comparative study between cytology and biopsy. METHODS: We retrospectively analyzed the results of urine cytology and biopsy follow-up in 109 patients. All cytologies were from voided urine. They were cytocentrifuged and stained with Papanicolaou stain. RESULTS: We found 70 true positive cases and 24 true negative cases. Sensitivity was calculated to be 97% and specifity 96-100%. 12 cases had the first cystoscopy test and biopsy negative, as the cancer was diagnosed in the second biopsy. CONCLUSIONS: Patients with clearly positive urine cytology, which was not confirmed in a first cystoscopic study, should be carefully followed up to identify a possible bladder or upper urinary tract cancer. The urine cytology still has a significant role as the gold standard for bladder cancer screening.

Thermal diffusivity measurement in thin metallic filaments using the mirage method with multiple probe beams and a digital camera.

Photothermal beam deflection is a well-established technique for measuring thermal diffusivity. In this technique, a pump laser beam generates temperature variations on the surface of the sample to be studied. These variations transfer heat to the surrounding medium, which may be air or any other fluid. The medium in turn experiences a change in the refractive index, which will be proportional to the temperature field on the sample surface when the distance to this surface is small. A probe laser beam will suffer a deflection due to the refractive index periodical changes, which is usually monitored by means of a quadrant photodetector or a similar device aided by lock-in amplification. A linear relationship that arises in this technique is that given by the phase lag of the thermal wave as a function of the distance to a punctual heat source when unidimensional heat diffusion can be guaranteed. This relationship is useful in the calculation of the sample's thermal diffusivity, which can be obtained straightforwardly by the so-called slope method, if the pump beam modulation frequency is well-known. The measurement procedure requires the experimenter to displace the probe beam at a given distance from the heat source, measure the phase lag at that offset, and repeat this for as many points as desired. This process can be quite lengthy in dependence of the number points. In this paper, we propose a detection scheme, which overcomes this limitation and simplifies the experimental setup using a digital camera that substitutes all detection hardware utilizing motion detection techniques and software digital signal lock-in post-processing. In this work, the method is demonstrated using thin metallic filaments as samples.

Measurement of nonlinear absorption coefficients of organic materials by mode-mismatched Z-scan thermal lensing technique.

We evaluate a new pump-probe mode-mismatched thermal lens (TL) scheme for the measurement of nonlinear absorption in nitrobenzene, benzene, and chloroform. In this new scheme the pump beam is focused in the presence of a collimated probe beam. Values of the nonlinear absorption coefficients of the materials studied for the wavelength of 532 nm are reported, and we compare the proposed technique with the well-known open Z-scan method.

High sensitivity thermal lens microscopy: Cr-VI trace detection in water.

In this work, a low detection limit for hexavalent chromium in water of parts per trillions (21ng/L) was achieved using a micro-spatial thermal lens spectroscopy setup with coaxial counter-propagating pump and probe laser beams and an integrated passive optical Fabry-Perot resonator, aided with a well-established diphenyl carbazide colorimetric method. Cr-VI concentrations in the range of µg/L, i.e. well-below the toxicity thresholds in humans and animals (26 and 190mg/L respectively) and below those delimited by international regulations for drink water (~0.05-0.5mg/L), have been obtained by measurements in bottled and tap water samples. The developed thermal lens microscope is also capable to detect Cr-VI directly in potassium dichromate solutions using pump beam wavelengths within the very low optical absorption region in the visible part of the spectrum, i.e., without the use of any colorimetric method.

Spin-polarised electrons in a one-magnet-only Mott spin junction.

The current flowing through a Mott spin junction depends on the relative spin orientation of the two ferromagnetic layers comprising the "source" and "drain" sides of the junction. The resulting current asymmetry is detected as giant or tunnelling magnetoresistance depending on whether the two ferromagnets are separated by a metal or an insulator. Based on the fundamental principles of reciprocity for spin-dependent electron scattering, one can envisage a one-magnet-only spin junction in which the source is non-magnetic, and the spin information is encoded by the spin polarisation of the electrons that have crossed or are backscattered from the drain magnetic layer. The practical significance of using an unpolarised source is that the state of the magnetic layer can be modified without affecting the process of probing it. Whether this reciprocity is realised in the actual junctions is not yet known. Here, we demonstrate a nano-sized, one-magnet-only Mott spin junction by measuring the finite spin polarisation of the backscattered electrons. Based on this finding, we conclude that since the junction acts as a spin filter, the magnetic layer must experience a spin transfer that could become detectable in view of the high current densities achievable in this technology.

Ovarian Leydig cells (OLC): A histomorphological and immunohistochemical study.

Testicular Leydig cells (LC) regulate the proper development of male individuals, both during fetal life (fetal LC) and puberty (adult LC). In the ovaries of adult women, there are cells that are very similar to Leydig cells, the ovarian hilus cells (OHC), which also produce testosterone. The origin of these cells, in both sexes, remains unknown and is still a matter of debate. We have studied the location, characteristics and relationships of the OHC in 90 patients. The indications for oophorectomy were: metrorrhagia (n=9), prolapse (n=8), endometrial hyperplasia (n=14), cancer (endometrial, myometrial, or cervical) (n=35), uterine leiomyomata (n=14), and various ovarian tumors (cysts and benign tumors, borderline and malignant) (n=10). In addition to the hilus, occasionally the nodules, nests and clusters of OHC were located in the mesovarium, the mesosalpinx, and in the medullar and cortical regions of the ovaries. The morphological (including crystalloids of Reinke) and immunohistochemical (positivity for calretinin and alpha-inhibin) findings were similar to those described for testicular LC. Therefore, OHC can be considered ovarian Leydig cells (OLC). LC are usually found in small numbers in the ovaries, but if one looks for them intentionally, one always finds them. Close relationships were observed between the OLC with nerves and vessels. Moreover, an intraneural location of the OLC was demonstrated in all cases, and these intraneural cells showed similar characteristics to extraneural OLC, suggesting that they derive from endoneural cells which are present in the vegetative nerves of the ovaries.

Chondroma of the Bladder: An Atypical Localization.

Chondroma is a benign tumour of mesenchymal origin that is composed of cartilage and rarely located in soft tissues, being described so far only in four cases, as located in the bladder, according to our knowledge. We describe the fifth case of a 67-year-old woman who consulted for microscopic haematuria, with an endoscopic finding of submucosal nodular image in the anterior wall of the bladder, which after resection and the histologic study shows cartilage and fibroconnective tissue, in part hyalinised, and positive immunohistochemical staining of cells with vimentin and S-100; this fact can support the diagnosis of bladder chondroma.

Thirty per cent contrast in secondary-electron imaging by scanning field-emission microscopy.

We perform scanning tunnelling microscopy (STM) in a regime where primary electrons are field-emitted from the tip and excite secondary electrons out of the target-the scanning field-emission microscopy regime (SFM). In the SFM mode, a secondary-electron contrast as high as 30% is observed when imaging a monoatomic step between a clean W(110)- and an Fe-covered W(110)-terrace. This is a figure of contrast comparable to STM. The apparent width of the monoatomic step attains the 1 nm mark, i.e. it is only marginally worse than the corresponding width observed in STM. The origin of the unexpected strong contrast in SFM is the material dependence of the secondary-electron yield and not the dependence of the transported current on the tip-target distance, typical of STM: accordingly, we expect that a technology combining STM and SFM will highlight complementary aspects of a surface while simultaneously making electrons, selected with nanometre spatial precision, available to a macroscopic environment for further processing.

An epidemic in a coronary care unit caused by Pseudomonas species.

Five patients in a coronary care unit were involved in an epidemic caused by a nonfermenting Gram-negative bacillus, presumptively identified by our laboratory as Pseudomonas cepacia. All medications administered intravenously to these patients were cultured. Because morphine was the only such medication common to the treatment of all the patients involved, a vial used in the unit at that time was cultured, as were two previously-entered vials of saline solution and several sterile vials of distilled water used in the preparation of injectable medication. The Pseudomonas cepacia organism was recovered from one of the vials of saline solution. The epidemic ended as soon as the practice of re-entering the vials of sterile saline solution was discontinued.

The growth of micro-organisms in intravenous fluids.

The growth of four micro-organisms in 12 different intravenous fluids at room temperature was studied. Gram-negative organisms grew better than Gram-positive, and lipid solutions were most favourable to microbial growth. Microbial growth was inhibited in solutions with osmolalities over 500 mosmol/l; Staphylococcus epidermidis was inhibited by inocula with Gram-negative bacilli, while the growth of Gram-negative bacilli generally was not affected. Candida albicans was inhibited by Gram-negative bacilli in lipid and 5% dextrose solutions.

Effects of temperature on photosynthesis of two morphologically contrasting plant species along an altitudinal gradient in the tropical high Andes.

The effects of temperature on photosynthesis of a rosette plant growing at ground level, Acaena cylindrostachya R. et P., and an herb that grows 20-50 cm above ground level, Senecio formosus H.B.K., were studied along an altitudinal gradient in the Venezuelan Andes. These species were chosen in order to determine - in the field and in the laboratory - how differences in leaf temperature, determined by plant form and microenvironmental conditions, affect their photosynthetic capacity. CO2 assimilation rates (A) for both species decreased with increasing altitude. For Acaena leaves at 2900 m, A reached maximum values above 9 µmol m-2 s-1, nearly twice as high as maximum A found at 3550 m (5.2) or at 4200 m (3.9). For Senecio leaves, maximum rates of CO2 uptake were 7.5, 5.8 and 3.6 µmol m-2 s-1 for plants at 2900, 3550 and 4200 m, respectively. Net photosynthesis-leaf temperature relations showed differences in optimum temperature for photosynthesis (A o.t.) for both species along the altitudinal gradient. Acaena showed similar A o.t. for the two lower altitudes, with 19.1°C at 2900 m and 19.6°C at 3550 m, while it increased to 21.7°C at 4200 m. Maximum A for this species at each altitude was similar, between 5.5 and 6.0 µmol m-2 s-1. For the taller Senecio, A o.t. was more closely related to air temperatures and decreased from 21.7°C at 2900 m, to 19.7°C at 3550 m and 15.5°C at 4200 m. In this species, maximum A was lower with increasing altitude (from 6.0 at 2900 m to 3.5 µmol m-2 s-1 at 4200 m). High temperature compensation points for Acaena were similar at the three altitudes, c. 35°C, but varied in Senecio from 37°C at 2900 m, to 39°C at 3550 m and 28°C at 4200 m. Our results show how photosynthetic characteristics change along the altitudinal gradient for two morphologically contrasting species influenced by soil or air temperatures.

Evaluation of residual levels of benomyl, methyl parathion, diuron, and vamidothion in pineapple pulp and bagasse (Smooth cayenne).

The objective of this research was to study the residual levels of benomyl, methyl parathion, diuron, and vamidothion in pineapple bagasse and pulp. Benomyl (benlate), methyl parathion (Folidol 600), diuron (Krovar), and Vamidothion (Kilval 300) were applied pre-harvest to pineapples (smooth cayenne). After harvesting, the fruits were washed (100 ppm sodium hypochlorite) and the pulp was separated from the sub-products (peel, core, tops, and tails). The pulp was not submitted to any heat treatment. The sub-products and the juice expressed from them, were submitted to a blanching process (95 degrees C for 1 min). After separating the juice, the bagasse and pulp were analyzed for residues of diuron and benomyl by high performance liquid chromatography, and for residues of vamidothion and methyl parathion by gas chromatography using a TSD detector. No residues of benomyl, diuron, vamidothion, or methyl parathion were detected in the pulp within the quantification limits of the methods (0.1 mg/kg, 0.1 mg/kg, 0.005 mg/kg, and 0.005 mg/kg, respectively). Only methyl parathion (0.052 mg/kg) and vamidothion (0.021 mg/kg) were detected in the bagasse. The presence of these residues in the bagasse was probably due to the action of the wax found in the peel, which prevented the methyl parathion and vamidothion from dissolving in the juice. According to these results, the pulp was fit for human consumption, as far as pesticide residues were concerned, and the bagasse was fit for animal feed and similar applications, because the residual levels found were below the limits established for these compounds.