Application of LiMgPO4 crystal for proton beam quality control in radiotherapy.

The radioluminescence (RL) emitted by LiMgPO4 detector under proton beam irradiation was investigated in real time at the radiotherapy facility in the Institute of Nuclear Physics Polish Academy of Sciences in Krakow. The facility uses protons accelerated by the AIC-144 isochronous cyclotron up to the energy of 60 MeV. The measurements of RL were carried out using a remote optical fiber device with a luminophore detector and photomultiplier located at opposite ends of the optical fiber. A thin slice of LiMgPO4 doped with Tm (1.2 mol%) crystal was exposed to the proton beam. The tested detector allowed for the measurement of proton beam current, flux fluence and determination of proton beam time structure parameters. The investigation of LiMgPO4 crystal showed its high sensitivity, fast reaction time to irradiation and possibility of application as the detector for control of proton beam parameters.

Pathways for the Formation of Formamide, a Prebiotic Biomonomer: Metal-Ions in Interstellar Gas-Phase Chemistry.

The chemistry occurring in the interstellar medium (ISM) is an active area of contemporary research. New aspects of interstellar chemistry are getting unraveled regularly. In this context, the role of metal-ions in the chemistry occurring in the ISM is not well-studied so far. Herein, we highlight the role of metal-ions in interstellar chemistry. For this purpose, we choose the problem of gas-phase formamide formation in interstellar molecular clouds. Formamide is a key biomonomer and contains the simplest peptide [-(C═O)-NH-] linkage. With its two electronegative atoms ("O" and "N"), it provides an excellent platform to probe the role of the metal-ions. The metal-ions chosen are Na+, K+, Al+, Mg+, and Mg2+-all of them present in the ISM. The metal-ions are studied in three different forms as bare positively charged ions, as hydrated metal-ions co-ordinated with a molecule of water, and when the metal-ions are part of a neutral covalent molecule. With the aid of electronic structure calculations [CCSD(T) and DFT methods], we study different gas-phase pathways which result in the generation of interstellar formamide. Throughout our study, we find that metal-ions lower the barriers (with Mg+, Mg++, and Al+ offering maximal stabilization of the transition states) and facilitate the reactions. The chemical factors influencing the reactions, how we consider the putative conditions in the ISM, the astrochemical implications of this study, and its connection with terrestrial prebiotic chemistry and refractory astrochemistry are subsequently presented. Based on our results, we also recommend the detection of two new closed-shell molecules, NH2CH2OH (aminomethanol) and CH2NH2+ (iminium ion), and two open-shell molecules, CONH2 (carbamyl radical) and HCONH (an isomer of carbamyl radical), in the ISM.

ESIPT-based fluorescent probe for bioimaging and identification of group IIIA ions in live cells and zebrafish.

Aluminum (Al), gallium (Ga), indium (In) are three essential elements in group IIIA of the periodic table, which all share similar chemical properties and are also vital in many aspects of bio- and environmental systems. Proper control of their levels is thus necessary as overexposure to them has been linked to onsets of many diseases. Fluorescence based molecular probes have always been the driving horse for detecting vital ions including group IIIA ions. However, only a few such probes have been reported so far and all of them are faced with one or more shortcomings such as not very high sensitivity, incapability to detect multiple ions simultaneously, and poor cell penetration abilities due to emitted fluorescence at shorter wavelengths. To meet those challenges, we herein presented the successful development and application of a novel group IIIA ions fluorescent probe, NBD-hnap, in live RAW264.7 cell and zebrafish models, especially the imaging of ocular tumor cell OCM-1 (human choroid melanoma cells). NBD-hnap was synthesized by a simple conjugation of NBD and hnap molecules under suitable conditions. Subsequent experimental analysis and theoretical calculations confirmed that NBD-hnap forms a 1:1 chelate with each of three selected group IIIA ions. Further evaluation proved that NBD-hnap can realize highly sensitive [LODs of 113, 82 and 150 nM for Al(III), Ga(III), and In(III) respectively in aqueous solutions] and highly selective (over a dozen of interfering cations) through an ESIPT-based fluorescent sensing mechanism with strong far-red emission around 640 nm. Those value merits make NBD-hnap superior to other group IIIA ion probes reported before and NBD-hnap is thus expected to find wider and greater applications in the near future.

Application of Group I Metal Adduction to the Separation of Steroids by Traveling Wave Ion Mobility Spectrometry.

Steroids represent an interesting class of small biomolecules due to their use as biomarkers and their status as scheduled drugs. Although the analysis of steroids is complicated by the potential for many isomers, ion mobility spectrometry (IMS) has previously shown promise for the rapid separation of steroid isomers. This work is aimed at the further development of IMS separation for the analysis of steroids. Here, traveling wave ion mobility spectrometry (TWIMS) was applied to the study of group I metal adducted steroids and their corresponding multimers for five sets of isomers. Each set of isomers had a minimum of one dimeric metal ion adduct that exhibited a resolution greater than one (i.e., approaching baseline resolution). Additionally, ion-neutral collision cross sections (CCSs) were measured using polyalanine as a calibrant, which may provide an additional metric contributing to analyte identification. Where possible, measured CCSs were compared to previously reported values. When measuring CCSs of steroid isomers using polyalanine as the calibrant, nitrogen CCS values were within 1.0% error for monomeric sodiated adducts and slightly higher for the dimeric sodiated adducts. Overall, TWIMS was found to successfully separate steroids as dimeric adducts of group I metals. Graphical Abstract ᅟ.

Quantitative chemical imaging of the intracellular spatial distribution of fundamental elements and light metals in single cells.

We report a method that allows a complete quantitative characterization of whole single cells, assessing the total amount of carbon, nitrogen, oxygen, sodium, and magnesium and providing submicrometer maps of element molar concentration, cell density, mass, and volume. This approach allows quantifying elements down to 10(6) atoms/µm(3). This result was obtained by applying a multimodal fusion approach that combines synchrotron radiation microscopy techniques with off-line atomic force microscopy. The method proposed permits us to find the element concentration in addition to the mass fraction and provides a deeper and more complete knowledge of cell composition. We performed measurements on LoVo human colon cancer cells sensitive (LoVo-S) and resistant (LoVo-R) to doxorubicin. The comparison of LoVo-S and LoVo-R revealed different patterns in the maps of Mg concentration with higher values within the nucleus in LoVo-R and in the perinuclear region in LoVo-S cells. This feature was not so evident for the other elements, suggesting that Mg compartmentalization could be a significant trait of the drug-resistant cells.

Un método para evaluar el enriquecimiento de metales en sedimentos marinos en Costa Rica / A method to evaluate metal enrichment in marine sediments

A method to evaluate metal enrichment in marine sediments. In order to evaluate metal enrichment in sediments , a method is proposed and tested in Bahia Culebra and the Golfo de Nicoya, Costa Rica through the normalization of the elements against aluminum, and by linear regression of the logarithm of the concentrations of different elements respect to aluminum. The distributions of the elements manganese, and strontium of Bahía Culebra did not satisfy the tests of normalization and linear regression, indicating a nonnatural distribution or enrichment of these elements in this region. In the Golfo de Nicoya the elements copper , zinc , rubidium and the strontium did not satisfy the test of normality or the linear regression with respect to aluminum, indicating a possible enrichment of these elements. The majority of the concentrations of the elements in two sample sites, with the exception of chromium, are within the natural ranges in rocks or clays of marine sediments, and within the concentration ranges of other studies done in these same regions. Chromium has average values beyond the natural concentrations, the values of some samples in the Golfo de Nicoya are up to 10 times greater than the concentration value of a typical bay with high contamination of this element.

Se propone un método para evaluar enriquecimiento de metales en sedimentos de Bahía Culebra y en el Golfo de Nicoya de Costa Rica a través de la normalización de los elementos y el aluminio usando la regresión lineal de las concentraciones de los elementos y el Aluminio. Las distribuciones de los elementos manganeso y el estroncio de Bahía Culebra no cumplen con las pruebas de normalización y de regresión lineal, indicando una distribución no natural o enriquecimiento de estos elementos en esta región. En el Golfo de Nicoya los elementos cobre, zinc, rubidio y el estroncio no cumplen ya sea con la hipótesis de normalidad o con la regresión lineal respecto al aluminio, indicando un posible enriquecimiento de estos elementos en esta región. La mayoría de las concentraciones de los elementos tanto en ambos sitios de muestreo, con excepción del cromo, se encuentran dentro de los ámbitos naturales encontrados en las rocas o en las arcillas de sedimentos marinos a nivel mundial, y dentro de los ámbitos de las concentraciones de otros estudios realizados en estas mismas regiones. El cromo muestra valores promedio más allá de las concentraciones naturales, siendo la concentración de algunas muestras en el Golfo de Nicoya hasta diez veces mayores que el valor de una bahía con alta contaminación de este elemento.

The potential role of metal ion release as a marker of loosening in patients with total knee replacement: a cohort study.

We investigated the role of ion release in the assessment of fixation of the implant after total knee replacement and hypothesised that ion monitoring could be a useful parameter in the diagnosis of prosthetic loosening. We enrolled 59 patients with unilateral procedures and measured their serum aluminium, titanium, chromium and cobalt ion levels, blinded to the clinical and radiological outcome which was considered to be the reference standard. The cut-off levels for detection of the ions were obtained by measuring the levels in 41 healthy blood donors who had no implants. Based on the clinical and radiological evaluation the patients were divided into two groups with either stable (n = 24) or loosened (n = 35) implants. A significant increase in the mean level of Cr ions was seen in the group with failed implants (p = 0.001). The diagnostic accuracy was 71% providing strong evidence of failure when the level of Cr ions exceeded the cut-off value. The possibility of distinguishing loosening from other causes of failure was demonstrated by the higher diagnostic accuracy of 83%, when considering only patients with failure attributable to loosening. Measurement of the serum level of Cr ions may be of value for detecting failure due to loosening when the diagnosis is in doubt. The other metal ions studies did not have any diagnostic value.

[Metallic elements in 31st updating of 67/548/EEC directive]. / Gli elementi metallici nel trentunesimo adeguamento della Direttiva 67/548/CEE.

In this paper the update of directive 67/548/EEC published in Official Journal of the European Union on 16 January 2009 proposes about carcinogenicity of metallic elements is reported and discussed. The main change is represented by the classification R49 and R40 of many species of nickel, organic and inorganic, respectively for their water solubility and particles size. Titanium oxide and 3 tin species are in addition classified as R40. Sodium dichromate moved from R49 (in the 22nd update) to R45 (classified as carcinogen, without restriction on the route of exposure). The list of the 31st updates, if combined with previous list, provides detailed and more precise information on the carcinogenicity of metallic elements in relation to different species, suggesting once again the importance of metallic element speciation.

Urinary level of nickel and acute leukaemia in Chinese children.

The 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidized nucleoside of DNA, not only is a widely used biomarker for the measurement of endogenous oxidative DNA damage but might also be a risk factor for many diseases including cancer. Metal exposure may play an important role in oxidative DNA damage among children. However, few studies on urinary 8-OHdG and metals have been conducted in children with acute leukemia. In the present study, urinary Ni and 8-OHdG were examined in 116 children with acute leukaemia (94 acute lymphoid leukaemia [ALL] and 22 acute myeloid leukaemia [AML]) and 51 healthy child controls. Our result showed that urinary Ni in acute leukaemia patients (ALL: 68.40 +/- 133.98, AML: 41.48 +/- 76.31 ng/mg creatinine) was significantly higher than that in controls (62.47 +/- 124.90 vs 17.63 +/- 46.17 ng/mg creatinine, P < 0.05). Similarly, the pretherapy level of urinary 8-OHdG in patients (ALL: 11.83 +/- 16.23, AML: 12.36 +/- 11.36 ng/mg creatinine) was significantly elevated compared with controls (11.92 +/- 15.42 vs 4.03 +/- 4.70 ng/mg creatinine, P < 0.05). Moreover, urinary 8-OHdG and urinary Ni showed a weak but significant association with increased risk of childhood leukaemia. The present study suggests that Ni may be an etiologic factor for childhood acute leukaemia by oxidative DNA damage.

Carcinogenic metal compounds: recent insight into molecular and cellular mechanisms.

Mechanisms of carcinogenicity are discussed for metals and their compounds, classified as carcinogenic to humans or considered to be carcinogenic to humans: arsenic, antimony, beryllium, cadmium, chromium, cobalt, lead, nickel and vanadium. Physicochemical properties govern uptake, intracellular distribution and binding of metal compounds. Interactions with proteins (e.g., with zinc finger structures) appear to be more relevant for metal carcinogenicity than binding to DNA. In general, metal genotoxicity is caused by indirect mechanisms. In spite of diverse physicochemical properties of metal compounds, three predominant mechanisms emerge: (1) interference with cellular redox regulation and induction of oxidative stress, which may cause oxidative DNA damage or trigger signaling cascades leading to stimulation of cell growth; (2) inhibition of major DNA repair systems resulting in genomic instability and accumulation of critical mutations; (3) deregulation of cell proliferation by induction of signaling pathways or inactivation of growth controls such as tumor suppressor genes. In addition, specific metal compounds exhibit unique mechanisms such as interruption of cell-cell adhesion by cadmium, direct DNA binding of trivalent chromium, and interaction of vanadate with phosphate binding sites of protein phosphatases.

[Mechanisms of action for metallic elements and their species classified carcinogen R 45 and R 49 by EU]. / Meccanismi di azione per gli elementi metallici e loro specie classificati cancerogeni R45 ed R49 dall'UE--parte 2.

In this paper we will deal with mechanism of carcinogenic action of metallic elements and their species (arsenic, beryllium, cadmium, cobalt, chromium, nickel) identified by EU as carcinogen R 45 or R 49. The carcinogenic effect depended on the ability of to penetrate the cell and interacted with the target sites, therefore the state of oxidation, charging, the solubility, type of binding, stereochemistry and the ability to interact with other xenobiotics were crucial. The carcinogenic metallic elements classified R45 or R49 are essentially weak mutagen and do not form adducts with the DNA as initial step of their carcinogenicity In spite of the wide range of metallic elements physicochemical properties, some common general mechanisms of carcinogenesis emerge:from the induction of oxidative stress, to inhibition of DNA repair, from activation of mitogenic signalling, to epigenetic modification of gene expression. However, each species lead to specific molecular interactions and were subject to different bioavailability. It has been also strongly supported the hypothesis that the metallic elements may act as a co-carcinogen with other organic compounds, for example with PAH.

Monte Carlo investigation of breast intraoperative radiation therapy with metal attenuator plates.

In intraoperative electron radiation therapy for breast cancer, attenuation plates are commonly used to protect organs at risk. These plates can be made of different materials, and the correct material (or combination of materials) has to be chosen in order to achieve the desired attenuation, while avoiding excessive backscattered radiation. The Monte Carlo method (BEAMnrcMP and DOSXYZnrcMP) has been used to characterize the electron beam generated by the setup (composed of a nondedicated linac and an applicator), and to simulate the percent depth dose (PDD) for plates of different materials. The beam has been characterized for nominal energies of 9 and 12 MeV. Several differently composed plates have been investigated: it was found, as expected, that the use of a plate presenting to the electron beam a high-Z material (i.e., lead) has to be avoided because of excessive backscatter (up to 52% compared to the PDD without plate). On the other hand, the use of a single low-Z material (i.e., aluminum) in the plate can lead to an insufficient attenuation of the beam. The two-layer plate (6 mm of Al plus 3 mm of Cu) used in S. Chiara Hospital has been found to attenuate the beam almost completely for both considered energies, causing negligible backscatter radiation. The spectrum at various depth and at the tissue-plate interface has also been investigated.

Sources of fine particulate matter in personal exposures and residential indoor, residential outdoor and workplace microenvironments in the Helsinki phase of the EXPOLIS study.

OBJECTIVES: This study assessed the source contributions to the mass concentrations of fine particles (PM2.5) in personal exposures and in residential indoor, residential outdoor, and workplace indoor microenvironments of the nonsmoking adult population unexposed to environmental tobacco smoke in Helsinki, Finland. METHODS: The elemental composition of 48-hour personal exposure and residential indoor, residential outdoor, and workplace indoor PM2.5 was analyzed by energy-dispersive X-ray fluorescence spectrometry for 76 participants not exposed to environmental tobacco smoke and 102 participating residences with no smoking in Helsinki as a part of the EXPOLIS study. Subsequently, a principal component analysis was used to identify the emission sources of PM2.5-bound elements and black smoke in each microenvironment, and this information was used to identify the corresponding sources in personal exposures. Finally, source reconstruction was done to determine the relative contributions of each source type to the total PM2.5 mass concentrations. RESULTS: Inorganic secondary particles, primary combustion, and soil were the dominant source types for the PM2.5 mass concentration in all the microenvironments and personal exposures. The ratio of the residential indoor-to-outdoor PM2.5 concentration was close to unity, but the corresponding elemental ratios and source contributions varied. Resuspension of soil dust tracked indoors was a much larger contributor to residential and workplace indoor PM2.5 than soil dust to residential outdoor PM2.5. Source contributions to personal PM2.5 exposures were best approximated by data from residential and workplace indoor microenvironments. CONCLUSIONS: Population exposure assessment of PM2.5, based on outdoor fixed-site monitoring, overestimates exposures to outdoor sources like traffic and long-range transport and does not account for the contribution of significant indoor sources.

Titanium elastic nail--a useful instrument for the treatment of simple bone cyst.

A simple bone cyst is a common benign lytic lesion in the pediatric population. Successful methods of treatment include injections with bone marrow and curettage of the cyst and filling with bone graft or bone graft substitute. Opening the cyst walls and creating a connection with the medullary canal promote healing. We describe a simple method of opening the cyst walls without creating a large cortical defect, using the AO Titanium Elastic Nail. This flexible nail allows creation of connections to the medullary canal in several directions through one cortical hole.

Release of toxic metals from button batteries retained in the stomach: An in vitro study.

BACKGROUND: Ingestion of button batteries by children is a rapidly growing problem, and opinions differ on how button batteries distal to the gastroesophageal junction should be managed. The authors therefore performed an experimental study to determine the cumulative load of various toxic elements released from retained button cells in simulated gastric juice. METHODS: Eight different groups of button cells were immersed in simulated gastric juice. Analyzed elements included Al, Ba, Cd, Cr, Cu, Fe, Hg, Li, Mg, Mn, Ni, Pb, Sb, Sn, Sr, Te, TI, V, W; and Zn. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate the residual amounts of elements after 4, 24, 72, and 120 hours. RESULTS: At 4 hours, leakage was seen with almost all batteries, with the levels increasing in a time-dependent manner. The highest detected levels at 4 hours were 1.20 microgram for Cd, 280.51 ng for Hg, and 2.63 microgram for Pb. Dissolution, holes, and defragmentation were seen within 24 to 72 hours. Battery weight loss varied between 22 and 104 mg over the course of the study. CONCLUSIONS: Toxic elements contained in button cells are released quickly in gastric juice. This finding might change the current policy of watchful waiting or conservative management of batteries lodged in the stomach.

1997 UK Total Diet Study--dietary exposures to aluminium, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, tin and zinc.

Concentrations of aluminium, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, tin and zinc were determined in samples from the 1997 UK Total Diet Study and used to estimate dietary exposures of the general UK population. Population average dietary exposures to aluminium (3.4 mg/day), arsenic (0.065 mg/day), cadmium (0.012 mg/day), chromium (0.10 mg/day), copper (1.2 mg/day), mercury (0.003 mg/day), nickel (0.13 mg/day), tin (1.8 mg/day) and zinc (8.4 mg/day) are similar to those from previous UK Total Diet Studies and are below the appropriate PTWIs, PMTDIs and TDIs. Dietary exposure of the UK population (0.026 mg/day) to lead is falling as a result of measures taken to reduce lead contamination of the environment and food and is well below the PTWI. There has been little change in UK estimates of selenium exposure since the 1994 Total Diet Study but current-estimates (0.039 mg/day) are lower than those derived from earlier Total Diet Studies.

Concentration of metal elements in the blood and urine in the patients with cementless total knee arthroplasty.

Titanium (Ti), cobalt (Co) and chromium (Cr) element concentrations in the whole blood and urine specimen in 40 patients with cementless total knee arthroplasty were determined by the electrothermal atomic absorption spectrophotometry. Their ages ranged from 55 to 78 years (mean, 65 years). Twenty of them had loosening of prosthesis and underwent revision surgery, including 4 subjects with Ti-6Al-4V alloy prosthesis and 16 subjects with Co-Cr-Mo alloy prosthesis. The other 20 patients had well-functioning stable prosthesis, including 5 subjects with Ti-6Al-4V alloy prosthesis and 15 subjects with Co-Cr-Mo alloy prosthesis. The mean duration of prostheses implantation in patients with loosened or well-functioning prostheses were 6.5 and 4.0 years, respectively. The control group consisted of 20 age-matched normal subjects who did not undergo any metal implant surgery. Analysis of variance showed that the metal element concentrations in the whole blood, either Co, Cr or Ti, was statistically higher in the patients with loosened prosthesis than the other two groups. However, the metal element concentrations in the urine did not show any difference. The linear regression analysis showed a moderate positive relationship between the metal element concentrations, either Co or Cr elements, in whole blood and urine only in the patients with loosened prostheses. In conclusion, elevated concentration of metal elements may indicate a loosening of prosthesis while the clinical significance of the metal element concentration in the urine needs further investigation.

The interaction of melatonin and its precursors with aluminium, cadmium, copper, iron, lead, and zinc: an adsorptive voltammetric study.

Melatonin, a pineal secretory product, and its precursors, tryptophan and serotonin, were examined for their metal binding affinities for both essential and toxic metals: aluminium, cadmium, copper, iron, lead, and zinc. An electrochemical technique, adsorptive stripping voltammetry, showed the varying abilities of melatonin and its precursors to bind the metals in situ. The results show that the following metal complexes were formed: aluminium with melatonin, tryptophan, and serotonin; cadmium with melatonin and tryptophan; copper with melatonin and serotonin; iron(III) with melatonin and serotonin; lead with melatonin, tryptophan, and serotonin; and zinc with melatonin and tryptophan. Iron(II) showed the formation of an in situ complex with tryptophan only. These studies suggest a further role for melatonin in the reduction of free radical generation and metal detoxification, and they may explain the accumulation of aluminium in Alzheimer's disease.

Pulmonary metal distribution in urban dwellers.

To clarify the factors influencing the concentrations and distribution of metal elements in the lung, we analyzed the following 8 metals in the 5 lung lobes of 17 autopsied urban dwellers by flame or flameless atomic absorption spectrometry: aluminum (Al), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), manganese (Mn), copper (Cu), and Zinc (Zn). The arithmetic mean value (in micrograms of metal per gram of dry weight) calculated for five lobar metal concentrations in each subject ranged from 80 to 681 for Al, from 0.34 to 3.41 for Cd, from 0.41 to 12.7 for Cr, from 0.22 to 1.93 for Ni, from 0.15 to 1.47 for Pb, from 0.64 to 2.36 for Mn, from 2.84 to 7.24 for Cu, and from 40.7 to 77.6 for Zn. The eight metals were classifiable into two groups on the basis of the interindividual and interlobar concentration variations. The first group, consisting of Cu and Zn, was characterized by smaller interindividual variations (co-efficient of variation, CV < 30%) and smaller inter lobar variations (mean CV < 15%). Their levels were not affected significantly by sex, smoking habits, or possible occupational exposure to metal-containing dust. In contrast, the second group, consisting of Al, Cd, Cr, Ni, Pb, and Mn, exhibited larger interindividual variations (CV > 45%) and larger interlobar variations (mean CV > 25%). Concentrations of these metals, except for Cd, tended to be higher in the upper lobes than in the lower lobes. The concentrations of Al and Cr were significantly higher in men than in women. Smoking significantly elevated the levels of Cr, Cd, Ni, and Pb, and the concentrations of Al, Cr, Ni, and Mn were higher in subjects with possible occupational exposure to metal-containing dust than in those without such exposure. However, the interlobar distribution patterns of the metals did not seem to be influenced by sex, smoking habits, or occupational exposure to metal-containing dust.