Design and Applications of In-Situ Differential Scanning Electron Microscopy

Contrast enhancement in the scanning electron microscope (SEM) is usually achieved by either of the two techniques of black level suppression, and differential imaging. This paper is mainly concerned with the latter method. Differential imaging of SEM images is commonly accomplished by either using a selective electronic filtering circuit (time sensitive) on the video signals, or the post processing of a collected digitized image (application of special kernel operatives). A technique is described that is capable of generating true in-situ SEM differential video signals of local sample features. Characteristics of this method are enhanced sample feature-boundary sensitivity, suppression of large background signals, and the ability to perform critical pattern alignments prior to feature measurements. Results are presented on the application of the technique to the general field of electron microscopy, as well as to integrated circuit micro-metrology

Uptake and distribution of lead in tobacco (Nicotiana tabacum L.)

Six Nicotiana tabacum varieties were in vitro cultured and experimentally exposed to lead in order to estimate lead uptake and distribution in tobacco plantlets and to observe possible differences depending on variety. Fifty-day-old plantlets were exposed to four Pb rates ranging from 0 to 200 mg dm-3. No statistically significant effect of lead on dry matter weight was observed for any variety or plant part. Tissue lead concentration was determined on upper leaves, lower leaves, stems and roots. Lead accumulation in the plant positively correlated with lead exposure level. Lead concentration in the different plant parts decreased as follows: root, lower leaves, stem and upper leaves. All tobacco varieties showed similar behaviour with respect to lead treatment level and revealed the same distribution pattern of lead concentration in the different plant part. The highest values of tissue lead concentration were found in tobacco variety Pr61, while the lowest in G94-2

Isothiourea-catalysed enantioselective radical conjugate addition under batch and flow conditions

Financial support was provided by the Spanish Government (RTI2018-095038-B-I00), “Comunidad de Madrid” for European Structural Funds (S2018/NMT-4367) and proyectos sinergicos I+D (Y2020/NMT-6469). J. A. F.-S. thanks the Spanish Government for a Ramón y Cajal contract. The research leading to these results has received funding from the EaSI-CAT centre for Doctoral Training (M.T.W) and Carlsberg Foundation (M.J.).The photocatalytic generation of α-amino radicals is combined with chiral isothiourea derived α,β-unsaturated acyl ammonium intermediates. The reaction proceeds via a [3+2] radical-polar crossover mechanism to generate γ-lactams in good yields and enantioselectivities. The enantioselective radical conjugate addition was carried out under batch and flow conditions.Publisher PDFPeer reviewe

Dose-volumerelated dysphagia after constrictor muscles definition in head and neck cancer intensitymodulated radiation treatment

OBJECTIVE: Dysphagia remains a side effect influencing the quality of life of patients with head and neck cancer (HNC) after radiotherapy. We evaluated the relationship between planned dose involvement and acute and late dysphagia in patients with HNC treated with intensity-modulated radiation therapy (IMRT), after a recontouring of constrictor muscles (PCs) and the cricopharyngeal muscle (CM). METHODS: Between December 2011 and December 2013, 56 patients with histologically proven HNC were treated with IMRT or volumetric-modulated arc therapy. The PCs and CM were recontoured. Correlations between acute and late toxicity and dosimetric parameters were evaluated. End points were analysed using univariate logistic regression. RESULTS: An increasing risk to develop acute dysphagia was observed when constraints to the middle PCs were not respected [mean dose (D(mean)) ≥50 Gy, maximum dose (D(max)) >60 Gy, V50 >70% with a p = 0.05]. The superior PC was not correlated with acute toxicity but only with late dysphagia. The inferior PC was not correlated with dysphagia; for the CM only, D(max) >60 Gy was correlated with acute dysphagia ≥ grade 2. CONCLUSION: According to our analysis, the superior PC has a major role, being correlated with dysphagia at 3 and 6 months after treatments; the middle PC maintains this correlation only at 3 months from the beginning of radiotherapy, but it does not have influence on late dysphagia. The inferior PC and CM have a minimum impact on swallowing symptoms. ADVANCES IN KNOWLEDGE: We used recent guidelines to define dose constraints of the PCs and CM. Two results emerge in the present analysis: the superior PC influences late dysphagia, while the middle PC influences acute dysphagia

First spectroscopic investigation of Anomalous Cepheid variables

Anomalous Cepheids (ACEPs) are intermediate mass metal-poor pulsators mostly discovered in dwarf galaxies of the Local Group. However, recent Galactic surveys, including the Gaia DR3, found a few hundreds of ACEPs in the Milky Way. Their origin is not well understood. We aim to investigate the origin and evolution of Galactic ACEPs by studying for the first time the chemical composition of their atmospheres. We used UVES@VLT to obtain high-resolution spectra for a sample of 9 ACEPs belonging to the Galactic halo. We derived the abundances of 12 elements, including C, Na, Mg, Si, Ca, Sc, Ti, Cr, Fe, Ni, Y, and Ba. We complemented these data with literature abundances for an additional three ACEPs that were previously incorrectly classified as type II Cepheids, thus increasing the sample to a total of 12 stars. All the investigated ACEPs have an iron abundance [Fe/H]$<-1.5$ dex as expected from theoretical predictions for these pulsators. The abundance ratios of the different elements to iron show that the ACEP's chemical composition is generally consistent with that of the Galactic halo field stars, except the Sodium, which is found overabundant in 9 out of the 11 ACEPs where it was measured, in close similarity with second-generation stars in the Galactic Globular Clusters. The same comparison with dwarf and ultra-faint satellites of the Milky Way reveals more differences than similarities so it is unlikely that the bulk of Galactic ACEPs originated in such a kind of galaxies which subsequently dissolved in the Galactic halo. The principal finding of this work is the unexpected overabundance of Sodium in ACEPs. We explored several hypotheses to explain this feature, finding that the most promising scenario is the evolution of low-mass stars in a binary system with either mass transfer or merging. Detailed modelling is needed to confirm this hypothesis.Comment: 15 Figures, 4 Tables, Accepted for publication on Astronomy & Astrophysic

A Comparative Study of the Triglycerides/HDL Ratio and Pseudocholinesterase Levels in Patients with Bladder Cancer

Background: Lipid alterations may serve as potential tumour biomarkers. The ratio of triglycerides to HDL cholesterol (TG/HDL ratio) is associated with various cancers. Pseudocholinesterase (PChE) activity, involved in TG hydrolysis, plays an important role in the metabolism of lipoprotein. There is scarce data assessing the reliability of both the TG/HDL ratio and PChE levels in correctly classifying patients suffering from bladder cancer. Methods: Three hundred and ninety-six patients undergoing cystoscopy or transurethral resection of the bladder (TURB), broken into two major groups, i.e., patients with histologically confirmed, non-metastatic bladder cancer (n = 208) and without bladder cancer (no bladder cancer, n = 188), formed the study population. The last group was split into two subgroups consisting of a cohort of patients never suffering from bladder cancer but with other bladder diseases (no CaBD, n = 100) and another cohort formed by patients characterised by eradicated bladder cancer after TURB with no recurrence during a three-month follow-up (previous bladder cancer, n = 88). Pieces of information by both metabolic derangement (the presence of type 2 diabetes mellitus), hypertension and lipid profile were retrieved from patient records upon entry to the study. Sensitivity, specificity, areas under the ROC (AUROC) of the TG/HDL ratio, and PChE levels were used in diagnostic decision making. Results: The TG/HDL ratio as well as PChE concentrations of bladder cancer patients were significantly different when compared to those with previous bladder cancer and the no CaBD patients (p = 0.023 and 0.0004, respectively). There was an independent role of both the TG/HDL ratio and PChE levels in predicting the presence of bladder cancer (OR: 1.22 and 0.99, respectively), but the reliability of the TG/HDL ratio (AUROC: 0.587) was superior to that of PChE levels (AUROC: 0.374). The AUROC of a new parameter resulting from the combination of the TG/HDL ratio with PChE levels showed a further increment in the discriminant power of the bladder cancer presence (0.6298), interestingly with a negative predictive value (89%) according to the Bayesian approach. The cut-off of the TG/HDL ratio, the main marker of the present study that better distinguishes bladder cancer from no bladder cancer patients, was 2.147. Discussion and Conclusions: The reliability of the TG/HDL ratio is based on the fact that this parameter likely mirrors the insulin resistance (IR) underlying bladder cancer patients. Furthermore, PChE levels evidence both IR and the associated non-alcoholic fatty liver disease. The TG/HDL ratio and PChE levels as well as their combined use could help physicians to assess/confirm the presence of this very common cancer, where early detection is important to ensure the best therapeutical approach

The Impact of Meat Intake on Bladder Cancer Incidence: Is It Really a Relevant Risk?

Bladder cancer (BC) represents the second most common genitourinary malignancy. The major risk factors for BC include age, gender, smoking, occupational exposure, and infections. The BC etiology and pathogenesis have not been fully defined yet. Since catabolites are excreted through the urinary tract, the diet may play a pivotal role in bladder carcinogenesis. Meat, conventionally classified as "red", "white" or "processed", represents a significant risk factor for chronic diseases like cardiovascular disease, obesity, type 2 diabetes, and cancer. In particular, red and processed meat consumption seems to increase the risk of BC onset. The most accepted mechanism proposed for explaining the correlation between meat intake and BC involves the generation of carcinogens, such as heterocyclic amines and polycyclic aromatic hydrocarbons by high-temperature cooking. This evidence claims the consumption limitation of meat. We reviewed the current literature on potential biological mechanisms underlying the impact of meat (red, white, and processed) intake on the increased risk of BC development and progression. Toward this purpose, we performed an online search on PubMed using the term "bladder cancer" in combination with "meat", "red meat", "white meat" or "processed meat". Although some studies did not report any association between BC and meat intake, several reports highlighted a positive correlation between red or processed meat intake, especially salami, pastrami, corned beef and bacon, and BC risk. We speculate that a reduction or rather a weighting of the consumption of red and processed meat can reduce the risk of developing BC. Obviously, this remark claims future indications regarding food education (type of meat to be preferred, quantity of red meat to be eaten and how to cook it) to reduce the risk of developing BC. Further well-designed prospective studies are needed to corroborate these findings

The Role of Testosterone in the Elderly: What Do We Know?

Testosterone is the most important hormone in male health. Aging is characterized by testosterone deficiency due to decreasing testosterone levels associated with low testicular production, genetic factors, adiposity, and illness. Low testosterone levels in men are associated with sexual dysfunction (low sexual desire, erectile dysfunction), reduced skeletal muscle mass and strength, decreased bone mineral density, increased cardiovascular risk and alterations of the glycometabolic profile. Testosterone replacement therapy (TRT) shows several therapeutic effects while maintaining a good safety profile in hypogonadal men. TRT restores normal levels of serum testosterone in men, increasing libido and energy level and producing beneficial effects on bone density, strength and muscle as well as yielding cardioprotective effects. Nevertheless, TRT could be contraindicated in men with untreated prostate cancer, although poor findings are reported in the literature. In addition, different potential side effects, such as polycythemia, cardiac events and obstructive sleep apnea, should be monitored. The aim of our review is to provide an updated background regarding the pros and cons of TRT, evaluating its role and its clinical applicability in different domains

Nutrition and IBD: Malnutrition and/or Sarcopenia? A Practical Guide

Malnutrition is a major complication of inflammatory bowel disease (IBD). This mini review is focusing on main determinants of malnutrition in IBD, the most important components of malnutrition, including lean mass loss and sarcopenia, as an emerging problem. Each one of these components needs to be well considered in a correct nutritional evaluation of an IBD patient in order to build a correct multidisciplinary approach. The review is then focusing on possible instrumental and clinical armamentarium for the nutritional evaluation