Cancer Marker Immunosensing through Surface-Enhanced Photoluminescence on Nanostructured Silver Substrates

Nanostructured noble metal surfaces enhance the photoluminescence emitted by fluorescent molecules, permitting the development of highly sensitive fluorescence immunoassays. To this end, surfaces with silicon nanowires decorated with silver nanoparticles in the form of dendrites or aggregates were evaluated as substrates for the immunochemical detection of two ovarian cancer indicators, carbohydrate antigen 125 (CA125) and human epididymis protein 4 (HE4). The substrates were prepared by metal-enhanced chemical etching of silicon wafers to create, in one step, silicon nanowires and silver nanoparticles on top of them. For both analytes, non-competitive immunoassays were developed using pairs of highly specific monoclonal antibodies, one for analyte capture on the substrate and the other for detection. In order to facilitate the identification of the immunocomplexes through a reaction with streptavidin labeled with Rhodamine Red-X, the detection antibodies were biotinylated. An in-house-developed optical set-up was used for photoluminescence signal measurements after assay completion. The detection limits achieved were 2.5 U/mL and 3.12 pM for CA125 and HE4, respectively, with linear dynamic ranges extending up to 500 U/mL for CA125 and up to 500 pM for HE4, covering the concentration ranges of both healthy and ovarian cancer patients. Thus, the proposed method could be implemented for the early diagnosis and/or prognosis and monitoring of ovarian cancer.

SERS Determination of Oxidative Stress Markers in Saliva Using Substrates with Silver Nanoparticle-Decorated Silicon Nanowires

Glutathione and malondialdehyde are two compounds commonly used to evaluate the oxidative stress status of an organism. Although their determination is usually performed in blood serum, saliva is gaining ground as the biological fluid of choice for oxidative stress determination at the point of need. For this purpose, surface-enhanced Raman spectroscopy (SERS), which is a highly sensitive method for the detection of biomolecules, could offer additional advantages regarding the analysis of biological fluids at the point of need. In this work, silicon nanowires decorated with silver nanoparticles made by metal-assisted chemical etching were evaluated as substrates for the SERS determination of glutathione and malondialdehyde in water and saliva. In particular, glutathione was determined by monitoring the reduction in the Raman signal obtained from substrates modified with crystal violet upon incubation with aqueous glutathione solutions. On the other hand, malondialdehyde was detected after a reaction with thiobarbituric acid to produce a derivative with a strong Raman signal. The detection limits achieved after optimization of several assay parameters were 50 and 3.2 nM for aqueous solutions of glutathione and malondialdehyde, respectively. In artificial saliva, however, the detection limits were 2.0 and 0.32 μM for glutathione and malondialdehyde, respectively, which are, nonetheless, adequate for the determination of these two markers in saliva.

Enhanced Photoluminescence of R6G Dyes from Metal Decorated Silicon Nanowires Fabricated through Metal Assisted Chemical Etching

In this study, we developed active substrates consisting of Ag-decorated silicon nanowires on a Si substrate using a single-step Metal Assisted Chemical Etching (MACE) process, and evaluated their performance in the identification of low concentrations of Rhodamine 6G using surface-enhanced photoluminescence spectroscopy. Different structures with Ag-aggregates as well as Ag-dendrites were fabricated and studied depending on the etching parameters. Moreover, the addition of Au nanoparticles by simple drop-casting on the MACE-treated surfaces can enhance the photoluminescence significantly, and the structures have shown a Limit of Detection of Rhodamine 6G down to 10-12 M for the case of the Ag-dendrites enriched with Au nanoparticles.

Control of Electron Wave Packets Close to the Continuum Threshold Using Near-Single-Cycle THz Waveforms

The control of low-energy electrons by carrier-envelope-phase-stable near-single-cycle THz pulses is demonstrated. A femtosecond laser pulse is used to create a temporally localized wave packet through multiphoton absorption at a well defined phase of a synchronized THz field. By recording the photoelectron momentum distributions as a function of the time delay, we observe signatures of various regimes of dynamics, ranging from recollision-free acceleration to coherent electron-ion scattering induced by the THz field. The measurements are confirmed by three-dimensional time-dependent Schrödinger equation simulations. A classical trajectory model allows us to identify scattering phenomena analogous to strong-field photoelectron holography and high-order above-threshold ionization.

[What rheumatologists can learn from ophthalmologists]

Intraocular inflammation with the imprecise and broad umbrella term "uveitis" is a diagnostic and therapeutic challenge in ophthalmology. Uveitis is one of the most common causes of blindness worldwide and due to the associated costs is comparable to diabetic retinopathy. Patients can be affected by uveitis at any age. Any part of the eye may be affected. The symptoms range from complete absence of symptoms, through all types of vision deterioration up to a red and even very painful eye. Uveitis can be strictly unilateral (also alternating from the left to the right eye) or bilateral with a relapsing or chronic course. The transitions are smooth and the differential diagnoses are very broad. In addition to infectious forms and ocular syndromes restricted to the eye, it also includes those with extraocular systemic diseases, such as ankylosing spondylitis or sarcoidosis. All commonly administered immunosuppressive treatment strategies in rheumatology can be used for non-infectious forms in addition to local and regional forms of treatment. The diagnostic and therapeutic impulses of this interdisciplinary interface between rheumatology and ophthalmology is discussed in more detail in this article.

Electronic decay of core-excited HCl molecules probed by THz streaking

The ultrafast electronic decay of HCl molecules in the time domain after resonant core excitation was measured. Here, a Cl-2p core electron was promoted to the antibonding σ^* orbital initiating molecular dissociation, and simultaneously, the electronic excitation relaxes via an Auger decay. For HCl, both processes compete on similar ultrashort femtosecond time scales. In order to measure the lifetime of the core hole excitation, we collinearly superimposed 40 fs soft x-ray pulses with intense terahertz (THz) radiation from the free-electron laser in Hamburg (FLASH). Electrons emitted from the molecules are accelerated (streaked) by the THz electric field where the resulting momentum change depends on the field's phase at the instant of ionization. Evaluation of a time-shift between the delay-dependent streaking spectra of photo- and Auger electrons yields a decay constant of (11 ± 2) fs for LMM Auger electrons. For further validation, the method was also applied to the MNN Auger decay of krypton. Reproduction of the value already published in the literature confirms that a temporal resolution much below the duration of the exciting x-ray pulses can be reached.

Epidemiological Study Between Greek People and Immigrants with Regard to Diagnosis in a Greek Hospital in Athens

Introduction

Differences between the most frequently reported diagnoses of Greek people and immigrants in Greece are expected due to the different underlying factors which are associated with mental health issues.

Objectives

Examine differences in diagnoses between Greek people and immigrants.

Aims

To investigate whether Greek people and immigrants had significant differences with regard to reported diagnoses in a Greek hospital.

Methods

The patients who participated in this study are 5551, among them 2760 (49.7%) were males and 2791 (50.3%) were females. The mean age of the sample was 45.54. The sample consisted of 455 (8.3%) immigrants and 5,042 (91.7%) Greek people. Convenience sampling method was used and the sample was collected at the General Hospital of Nikaia, “Ag. Panteleimon” in Athens, Greece, between 01/01/2012 and 31/12/2015.

Results

There were significant differences between Greek people and immigrant with regard to diagnosis as χ2 (20): 136.875, P < 0.001. More specifically, among Greek people, the most frequently reported diagnosis was psychotic disorder (26.2%), followed by depression (24.7%), general anxiety disorder (9.9%) and substance abuse (8.4%). Among immigrants, the most frequently reported diagnosis was psychotic disorder (22.9%), followed by substance abuse (21.3%), depression (17.4%) and general anxiety disorder (12.1%).

Conclusions

The differences between Greek people and immigrants with regard to diagnoses showcase the different needs between the two populations with regard to mental health. Especially, the higher prevalence of anxiety disorders and substance abuse problems among immigrants highlight the need for protective measures to improve their well-being and reduce their risk of mental health issues.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Determination of the solid angle and response function of a hemispherical spectrograph with injection lens for Auger electrons emitted from long lived projectile states

We present SIMION 8.1 Monte Carlo type simulations of the response function and detection solid angle for long lived Auger states (lifetime τ ∼ 10(-9) - 10(-5) s) recorded by a hemispherical spectrograph with injection lens and position sensitive detector used for high resolution Auger spectroscopy of ion beams. Also included in these simulations for the first time are kinematic effects particular to Auger emission from fast moving projectile ions such as line broadening and solid angle limitations allowing for a more accurate and realistic line shape modeling. Our results are found to be in excellent agreement with measured electron line shapes of both long lived 1s2s2p(4)P and prompt Auger projectile states formed by electron capture in collisions of 25.3 MeV F(7+) with H2 and 12.0 MeV C(4+) with Ne recorded at 0° to the beam direction. These results are important for the accurate evaluation of the 1s2s2p (4)P/(2)P ratio of K-Auger cross sections whose observed non-statistical production by electron capture into He-like ions, recently a field of interesting interpretations, awaits further resolution.

Allergic reactions during allergy skin testing with food allergens

Skin testing is a reliable and safe way to diagnose IgE-mediated allergies, with rare side-effects. Two cases of systemic allergic reactions during skin testing to food allergens are hereby reported. A 28-year-old male reported allergic reactions, mild to moderate in severity, each time he tasted fish in the frame of his professional duties. During SPT and prick-to-prick to raw and cooked fishes, he presented urticaria and tachycardia. A 59-year-old male had a long history of urticaria-angioedema and asthma attacks, following the consumption of mammalian meat. He was skin-tested to various meats and during the 5 last minutes of the test he developed generalized urticaria, allergic rhinitis and conjunctivitis. They were both advised to completely avoid the relative allergens. In conclusion, skin testing, particularly prick-to-prick, may cause anaphylaxis. Tests should be performed only by physicians with proper training in allergy, experienced in treating promptly and properly episodes of anaphylaxis.

Peritoneal membrane transport for low molecular weight substances with the use of one bag dialysate collection

The 24-hour collection of dialysate provides an accurate method for evaluation of both adequacy of dialysis and peritoneal membrane transport characteristics in patients on chronic ambulatory peritoneal dialysis. However, this test requires 24 hours to complete and therefore it is inconvenient for both patients and nurses in the every day practice. We determined the peritoneal membrane transport characteristics for low molecular weight substances of ten patients by using the dialysate collection of only one bag. Dialysate/plasma creatinine ratios were calculated for each of the 4 bags (DATT1, DATT2, DATT3, DATT4) as well as for the 24 hour dialysate (DATTo). We found a very good correlation between DATTo and the four DATTs. We therefore propose that the evaluation of the peritoneal membrane transport, at least for creatinine could be determined with the use of one bag dialysate collection.

Personal and environmental air sampling of methyl bromide during experimental greenhouse fumigation

In this investigation methyl bromide, a widely used soil fumigant, was investigated with respect to workers exposure and environmental fortification at the greenhouses of Thessaloniki area, Northern Greece. By means of personal and environmental air sampling through charcoal, methyl bromide concentration was measured by gas chromatography using a capillary OV-1 column at 45 degrees C and flame ionization detector (FID). Personal air sampling for two workers showed that the levels of exposure to methyl bromide were 89 and 92 mg/m3 respectively. These values exceeded the safety limits. The mean maximum and mean minimum concentrations in the environmental air samples inside the greenhouse, for 8 hours duration, were 142 mg/m3 and 4 mg/m3, respectively. These concentrations were determined within four and eleven days after the application of methyl bromide.

Death during deliberate propane inhalation

Propane gas is used as a fuel and very rarely it is abused by young people in Greece. In this paper, we report a case of abuse of propane inhalation that resulted in accidental death. The determination of propane in autopsy samples was done by headspace gas chromatography and semiquantitation in liver, blood and the contents of the plastic bag through which the gas was diffused, which proved to be lethal.

Immunohistochemical detection of the melanocortin 1 receptor in human testis, ovary and placenta using specific monoclonal antibody

We describe the immunohistochemical detection of the melanocortin 1 receptor (MC1R) protein in human gonadal tissues using a specific monoclonal antibody. The MC1R was found to be present in Leydig's cells in testis, in lutein cells in the corpus luteum and in the nucleus of the trophoblastic cells of the placenta. Though it has been speculated earlier that MC1R is present in gonadal tissues, this is the first report demonstrating the presence of MC1R protein in these cells.

Moisture sorption profiles and tensile strength of tableted phenobarbitone formulations

The tensile strength of tablets made from phenobarbitone and sodium phenobarbitone formulations after storage at increasing ambient relative humidity has been investigated. The moisture sorption and desorption profiles of the formulations were analysed for three locations of moisture: monolayer adsorbed moisture, normally condensed moisture and absorbed moisture. Maxima in tensile strength occur at moisture distributions determined by the disintegrant used. The changes in tensile strength have been explained in terms of changes produced in the interparticle separation, the range of the interparticle forces and changes in the ratio of the binding to diffusional forces, acting on the water molecules which are on the particles' surface.