Search

A new, rapid method for isolating no-carrier-added 197m,gHg from proton irradiated Au foils has been developed based on a commercially available crown ether-containing extraction chromatography resin, Eichrom Pb resin. The separation procedure allows for loading Au dissolved in Aqua Regia directly onto a pre-packed Pb resin column. Under these conditions Hg passes through the column and is isolated with a high separation factor from the Au target material, which is strongly retained on the resin.

Formation of Sc radioisotopes under the irradiation of titanium of natural isotopic composition by bremsstrahlung photons with energies up to 55 MeV was studied. The yield of 47Sc is 5·105 Bq/μA h (g/cm2). Inevitable impurities are 46Sc and 48Sc (1.5% and 9.1% of 47Sc radioactivity at EOB, respectively). 47Sc was separated by extraction chromatography on a DGA resin in HNO3 and HCl media. The separation procedure takes about 2 h, the radiochemical efficiency was > 97%. The result was compared with other photonuclear experiments on titanium nuclei. It is shown that the photonuclear method can be used for the production of therapeutic amounts of 47Sc.

Bivariant multiple development thin-layer chromatography technique (BMD–TLC) along with high-performance liquid chromatography–diode array detection–electrospray ionization–mass spectrometry (HPLC–DAD–ESI–MS) analysis was used in determination of lutein or lutein mixed with zeaxanthin in eight dietary supplements. The developed two-step TLC separation procedure combined purification, compaction of samples and separation of the analyzed compounds what significantly shortened and simplified samples preparation. Qualitative analysis was based on co-chromatography with reference substances and HPLC–DAD–ESI–MS analysis. It was revealed that three of eight dietary supplements did not contain lutein. In turn, quantitative analysis with the use of developed TLC conditions along with densitometry showed that the amount of lutein or its mixture with zeaxanthin in the others differed from that claimed by producers.

Synthesis and purification of metal clusters without strong binding agents by wet chemical methods are very attractive for their potential applications in many research areas. However, especially challenging is the separation of uncharged clusters with only a few number of atoms, which renders the usual techniques very difficult to apply. Herein, we report the first efficient separation of Ag2 and Ag3 clusters using the different entropic driving forces when such clusters interact with DNA, into which Ag3 selectively intercalates. After sequential dialysis of the samples and denaturalizing the DNA‐Ag3 complex, pure Ag2 can be found in the dialysate after extensive dialysis. Free Ag3 is recovered after DNA denaturation., Uncharged Ag2 and Ag3 clusters synthesized by a wet chemical procedure based on kinetics control, without using strong binding ligands, are separated by a simple procedure due to their very different chemical properties, namely, the different interaction with DNA. Using the specific intercalation ability of Ag3 with DNA, and the corresponding large entropy created in the surrounding water, we report a sequential dialysis/washing procedure allowing the complete separation of both type of clusters.

The aim of the work was the removal of diclofenac (DCF) and amoxicillin (AMX) pharmaceuticals by integrated methods of advanced oxidation and membrane filtration. The advanced oxidation process was carried out using UV/H2O2. Two polymer membranes, HL and NF270, were applied for the separation procedure. The effectiveness of the UV/H2O2 treatment, nanofiltration and the integrated processes was comparatively evaluated by monitoring the concentration of DCF/AMX and the removal of chemical oxygen demand (COD) and total organic carbon (TOC). It was found that despite the complete disappearance of the tested compounds during advanced oxidation process the slight reduction of COD and TOC was observed. Moreover, the solution after UV/H2O2 treatment exhibited higher toxicity towards Vibrio fischeri than the initial solution, proving that the transformation by-products of DCF and AMX are more toxic than the parent compound. The nanofiltration process led to an almost complete removal of DCF and AMX from the solution. The integration of the two methods enabled both the chemical modification of tested compounds and the removal of their toxic oxidation products from the solution.

Age dating of Cs-137 sources requires the accurate and precise quantification of the isotope Ba-137. In previous efforts to determine the age of Cs-137 source material, variation in Ba recovery was the largest source of uncertainty. This work investigates the use of several common chelating agents (EDTA, CDTA, DTPA, and NTA) to strip barium from Sr Resin columns quantitatively in an effort to improve the reproducibility of the separation. Batch studies showed conditions in which CDTA, EDTA, and NTA may suppress the retention of Ba on the column. Follow-up column studies showed excellent removal of barium from the column with quantitative recovery in the appropriate elution fraction. This work builds upon previous studies and establishes additional chelating agents that could be used in an age dating separation procedure.

This study evaluated the effect of the wheat gluten (WG) separation process and transglutaminase (TG) microbial source on WG dough quality, and opportunities to use these factors to tailor dough quality. Two types of gluten (harshly and mildly separated), two types of TG (commercial and novel SB6), and three TG concentrations were evaluated for effects on dough mixing properties, protein structure and solubility. Mildly separated gluten improved dough development parameters, resulting into higher values of most compared with harshly separated gluten. Despite more strongly cross-linked proteins being found in the harshly separated gluten, both gluten types showed similar levels of cross-linking at optimum mixing time, although differences in the secondary protein structure were indicated. Thus, disulfide-sulfhydryl exchange reactions were found to be promoted by mixing, although restrictions on establishment of new bonds because of prior cross-links in the material were clearly indicated. Degree of polymerization in doughs made from mildly separated gluten increased to varying extents with TG addition depending on TG source and concentration. Thus, for the first time, we show that an appropriate combination of WG separation procedure and TG source can be used to tailor gluten dough end-use properties.

A separation procedure was developed and implemented for the isolation of gold (Au) and platinum (Pt) radionuclides from deuteron irradiated Pt using tri-butyl phosphate (TBP) resin. Computational modeling and experimental results of the Au and Pt radionuclide production were reported and compared to literature values. Results of the separation procedure demonstrated a Pt recovery of 98 ± 2% and a Au recovery of 92 ± 7%, in their respective fractions (n = 4 ± 1σ) The decontamination factors were 2900 ± 500 for Au removal from the Pt fraction and 830 ± 30 for Pt removal from the Au fraction (n = 4 ± 1σ).

Purpose We demonstrate cyclotron production of high-quality 225Ac using an electroplated 226Ra target. Methods 226Ra was extracted from legacy Ra sources using a chelating resin. Subsequent ion-exchange purification gave pure 226Ra with a certain amount of carrier Ba. The radium target was prepared by electroplating. We successfully deposited about 37 MBq of 226Ra on a target box. Maximum activation was achieved using 15.6 MeV protons on the target at 20 µA for 5 h. Two functional resins with various concentrations of nitric acid purified 225Ac and recovered 226Ra. Cooling the intermediate 225Ac for 2–3 weeks decayed the major byproduct of 226Ac and increased the radionuclidic purity of 225Ac. Repeating the same separation protocol provided high-quality 225Ac. Results We obtained 225Ac at a yield of about 2.4 MBq at the end of bombardment (EOB), and the subsequent initial purification gave 1.7 MBq of 225Ac with 226Ac/225Ac ratio of 225Ac (4n + 1 series) radionuclidic purity up to 99 + %. The recovered 225Ac had a similar identification to commercially available 225Ac originating from a 229Th/225Ac generator. Conclusion This procedure, which involves the 226Ra(p,2n)225Ac reaction and the appropriate purification, has the potential to be a major alternative pathway for 225Ac production because it can be performed in any facility with a compact cyclotron to address the increasing demand for 225Ac.

A procedure for the determination of Pb isotope ratios by coupling liquid chromatography to a multicollector ICP-MS has been developed. The procedure allows the direct injection of samples after dissolution without resorting to time-consuming off-line separation procedures. The separation of Pb from concomitant elements is carried out by anionic exchange as ethylenediamine tetraacetic acid (EDTA) chelates using EDTA and ammonium nitrate as a mobile phase. A flow injection system allows the injection of NIST 981 Pb isotopic standard, before and after the Pb peak from the sample, and the on-line addition of Tl for mass bias correction and bracketing. The procedure was validated by injecting NIST 981 into the chromatographic system and by comparing the results for real samples with the classical off-line separation procedure using Pb spec resins. The optimised procedure was applied to archaeological samples containing different concentrations of Pb. It was observed that the only limitation to the accuracy of the procedure was the concentration of Pb in the samples as no preconcentration is performed. Solid archaeological samples containing at least 500 μg g−1 of Pb can be studied using the proposed procedure.

A simple, common-sense, three-component procedure—the Carrier Separation Plan (CSP)—can immediately halt the transmission of SARS-CoV-2 or a comparable pathogen, allow the safe reopening of an entire economy without the need for social distancing, and quickly eradicate the pathogen from the population (assuming the pathogen can be killed by the immune systems of the carriers). The three components are (a) nearly simultaneous self-testing for the pathogen by an entire population, followed rapidly by (b) nearly simultaneous self-isolation of carriers, and (c) secondary screening at entrances to facilities where people congregate. After a period of preparation lasting roughly 5–10 weeks, these steps could and probably should be taken in a single day. The power of this methodology has already been demonstrated in varying degrees with groups ranging in size from 1,000 to 11 million. Although this plan might seem daunting, its costs are minimal compared to the losses we have incurred by relying on half measures, and the US and other countries have the technological, logistical, and industrial capacities to implement this plan in a matter of weeks. With proper messaging during the weeks leading up to the testing, compliance in such a program is likely to be high given the potential benefits, and because participation is voluntary and testing is noninvasive, the legal and ethical issues associated with such a program are minimal – trivial, in fact, compared to those associated with imposing a months-long lockdown on an entire population. A SIRD/CSP model suggests that the single-day testing and separation procedure will substantially lower the number of infections, even if compliance with the procedure is modest. Modeling also suggests that when long-term secondary screening is added to the 1-day procedure, over time, the pathogen is eradicated from the population. This can occur even when compliance with secondary screening is itself relatively low.

Conjoined twins are suggested to result from aberrant embryogenesis. The two main theories proposedto explain the phenomena are fission and fusion. The incidence rate is 1 in 50,000 births; however, sinceabout 60% of the cases are stillborn, the true incidence is approximated at 1 in 200,000. There is a higherpredisposition towards female than male gender with a ratio of 3:1. Conjoined twins are classified basedupon the site of attachment. The extent of organ sharing, especially the heart, determines the possibility andprognosis of a separation procedure. Meticulous preoperative evaluation, planning, and preparedness of theteam are crucial for a successful separation. Separation of conjoined twins poses several technical, legal,and ethical issues. With the aid of diagnostic imaging techniques, such as ultrasonography (US) and threedimensionalmagnetic resonance imaging (3D-MRI), physicians are able to make prenatal diagnoses.

A novel method for simultaneous determination of sucrose and sunset yellow in retail soft drink without separation by combination of retro-reflected beam interference-based refractive index (RBI) and thermal lens (TL) detections was developed. The method proposed here successfully realized individual measurements of sucrose and sunset yellow in one single sample, while their concentrations were thousands of times different in the sample. Under optimized conditions, a separation-free process was carried out so that sucrose and sunset yellow were quantified at the same time. Limits of detection (LODs) of sucrose and sunset yellow were 0. 21 mg ml−1 and 0.23 μg ml−1 and the relative standard deviation (RSDs) were 3.9% and 3.07%. The developed method was successfully applied for the simultaneous analysis of sucrose and sunset yellow in retail soft drink. The soft drink containing 123.6 ± 2.6 mg ml−1 sucrose and 46.6 ± 1.8 μg ml−1 sunset yellow have been simultaneously measured without any separation procedure.

The likelihood of an attack by a terrorist organization using a radiological dispersal device (RDD) is much higher than that of an attack with an improvised nuclear device or true nuclear weapon, as much less technical expertise is required to build an RDD. Consequently, there has been an effort to develop methods for age-dating radiological sealed sources in recent years. One such procedure, described by Steeb et al., is used for determining the age of 90Sr sources. That procedure utilized a rather expensive extraction chromatography resin and was based on an uncommon apparatus with limited sample capacity for the separation step. The procedure also left the Zr fraction contaminated with the radioactive 90Y daughter nuclide. The present work investigates using an alternative separation scheme that utilizes a less costly resin in a widely available column configuration and results in the isolation of 90Sr’s stable granddaughter, 90Zr, without 90Y contamination. This allows the zirconium quantification to be done with a mass spectrometer outside the radiological environment and increases the number of instruments capable of making the measurement, which could allow measurements to be made more quickly.

The 63Zn was produced by16.8 MeV proton irradiation of natural copper. Thick target yield for 63Zn in the energy range of 16.8 →12.2 MeV was 2.47 ± 0.12 GBq/μA.h. Reasonable agreement between achieved experimental data and theoretical value of thick target yield for 63Zn was observed. A simple separation procedure of 63Zn from copper target was developed using cation exchange chromatography. About 88 ± 5% of the loaded activity was recovered. The performance of FLUKA to reproduce experimental data of thick target yield of 63Zn is validated. The achieved results from this code were compared with the corresponding experimental data. This comparison demonstrated that FLUKA provides a suitable tool for the simulation of radionuclide production using proton irradiation.

The interest in DNA–protein-based diagnostics has recently been growing enormously, which makes the separation process of DNA or protein from a cell extract extremely important. Unlike the traditional separation process, a novel approach is in demand which can nondestructively isolate the target biomolecules without sacrificing the other components in the mixture. In this study, we have demonstrated a new and simple separation technique by using well-established bifunctional Au–Fe3O4 nanocomposites as the separation nanoprobes to efficiently isolate the specifically targeted nanomolar concentrated DNA over 70% from its associate DNA–protein mixture in the presence of a magnetic field. The sensing accuracy of both as-separated DNA and protein are quantitatively examined by UV–vis spectroscopy, and then qualitatively validated by gel analysis. Results obtained in this study clearly demonstrated that this newly developed separation procedure not only provides the efficient separation for the targeted DNA but...

We propose a novel general approximation to transform and simplify the description of a complex fully quantized system describing the interacting light and matter. The method has some similarities to the time-dependent Born-Oppenheimer approach: we consider a quantum description of light rather than of nuclei and follow a similar separation procedure. Our approximation allows us to obtain a decoupled system for the light-excited matter and "dressed" light connected parametrically. With these equations at hand, we study how intense light as a quantum state is affected due to the back-action of the interacting matter. We discuss and demonstrate the possibility of the light-mode entanglement and nonclassical light generation during the interaction.

The reported experimental data for the separation of aromatic from aliphatic compounds using green solvents is growing exponentially. This paper surveys the existing data and presents a critical review that helps clarifying the major findings, identifies shortcomings and provides some recommendations. The comparison between deep eutectic solvents (DESs) and both ionic liquids (ILs) and classical organic solvents for this challenging separation is also presented based on experimental selectivity and distribution ratio data. This comparison confirms the capability of DESs to effectively extract aromatic compounds and shows that DESs can compete with ILs and even outclass them in some cases. Moreover, our comprehensive literature survey has revealed that in many cases the use of DESs yields to a minimum cross-contamination between the two phases. This will undeniably facilitate the separation procedure and thus reduce the cost of the separation process. On the other hand, the performance of COSMO-RS to predict ternary liquid-liquid equilibrium diagrams for systems including DESs is also evaluated in this work for all available data. COSMO-RS was able to reproduce the experimental tie-lines with a good accuracy in many cases. Therefore, it represents a cost-effective and time-saving screening tool to evaluate the extraction performance of the unlimited number of possible salt/complexing agents' combinations.

Radioactive waste generated in decommissioning activities need be classified according to their radioactive content. The radiological information required by national authorities includes diverse alpha and beta emitters, which can only be determined after a radiochemical separation process. This paper presents the work on the development of radiochemical methods for the simultaneous separation of several radionuclides in concrete, steel and graphite samples, on the basis of individual sample treatments which merge in a common radiochemical separation procedure based on extraction chromatography.

Conjoined twins are suggested to result from aberrant embryogenesis. The two main theories proposed to explain the phenomena are fission and fusion. The incidence rate is 1 in 50,000 births; however, since about 60% of the cases are stillborn, the true incidence is approximated at 1 in 200,000. There is a higher predisposition towards female than male gender with a ratio of 3:1. Conjoined twins are classified based upon the site of attachment. The extent of organ sharing, especially the heart, determines the possibility and prognosis of a separation procedure. Meticulous preoperative evaluation, planning, and preparedness of the team are crucial for a successful separation. Separation of conjoined twins poses several technical, legal, and ethical issues. Clin. Anat. 30:385-396, 2017. © 2017 Wiley Periodicals, Inc.

A new method was developed for the purification of Nd in geological samples using a single column containing TODGA extraction resin and the precise determination of Nd isotope ratios by multicollector inductively coupled plasma-mass spectrometry (MC-ICPMS). The samples were digested with HF–HNO3 and then transferred to a solution of 3 M HNO3. After loading the solutions onto the TODGA resin column, the column was first eluted with 12 ml of 2.3 M HCl, followed by 8 ml of 1.2 M HCl. The Nd isotope ratios of the latter eluate were measured by MC-ICPMS. This separation procedure was validated by measuring the 143Nd/144Nd ratios (mean ± 2σ) of certified reference materials, BHVO-2, BCR-2 and AGV-2, which were determined to be 0.512989 ± 0.000012, 0.512635 ± 0.000012 and 0.512790 ± 0.000018, respectively, in good agreement with the certified and literature values.

This paper presents a systematic investigation of the effects of Ca on the matrix separation of Sr and Pb and subsequent isotope-amount ratio measurements using a variety of synthetic solutions and reference materials with varying Ca content during the application of an automated analyte/matrix separation approach. The separation method based on the DGA resin was optimized by using increased column bed volumes, comparing two different column sizes (1-mL and 3-mL-bed volume). Certified reference materials (synthetic calcium carbonate – MACS-3, basalt – BCR-2, saggital otolith – FEBS-1, bone meal – NIST SRM 1486, bone ash – NIST SRM 1400, and skim milk powder – BCR-063R) with varying Ca content, Ca/Sr and Ca/Pb mass fraction ratios were separated using the optimized method and analyzed for the Sr and Pb isotopic composition by multi collector inductively coupled plasma mass spectrometry (MC ICP-MS). The developed separation method based on the 3-mL-bed volume column provides quantitative recoveries (84% to 105% for Sr, 77 % to 96% for Pb), while maintaining a quantitative separation of Sr and Pb. Procedural blank levels were

210Po is naturally occurring alpha emitter and exists in the environmental as a result of the 210Pb decay within the 238U decay chain. Radioactivity in drinking-water is principally derived from two sources: the leaching of radionuclides from rocks and soils and the deposition of radionuclides from the atmosphere. In the paper, a study of the 210Po radioactive content of drinking water in Albania was carried out. According to Albanian legislation the total alpha/beta screening was first carried out since it is a simple radioanalytical procedure, without regard to the identity of specific radionuclides. For total alpha and total beta radioactivity concentration exceeding the screening levels of 0.1 Bq/L and 1 Bq/L respectively, the determination of 210Po activity concentrations were determined by alpha-spectrometry with low-level-activity silicon detectors. The radiochemical separation procedure on large volume of water samples (10 L) was applied. The chemical yield (efficiency) of this procedure was controlled using a standard source of 209Po. The screening of total alpha and beta showed the activity concentrations ranging from 60 ± 6 mBq/L to 210 ± 24mBq/L and from 250 ± 23 mBq/L to 9400 ± 95 mBq/L respectively. The results obtained for 210Po activity concentration range from 3.2 ± 0.25 mBq/L to 9.6 ± 0.8 mBq/L.210Po is naturally occurring alpha emitter and exists in the environmental as a result of the 210Pb decay within the 238U decay chain. Radioactivity in drinking-water is principally derived from two sources: the leaching of radionuclides from rocks and soils and the deposition of radionuclides from the atmosphere. In the paper, a study of the 210Po radioactive content of drinking water in Albania was carried out. According to Albanian legislation the total alpha/beta screening was first carried out since it is a simple radioanalytical procedure, without regard to the identity of specific radionuclides. For total alpha and total beta radioactivity concentration exceeding the screening levels of 0.1 Bq/L and 1 Bq/L respectively, the determination of 210Po activity concentrations were determined by alpha-spectrometry with low-level-activity silicon detectors. The radiochemical separation procedure on large volume of water samples (10 L) was applied. The chemical yield (efficiency) of this procedure was contr...

In this paper selection of maximal precipitation amounts for Polish Atlas of Rains Intensities (PANDa) has been presented. PANDa supposes to be the source of actual and indisputable information about reliable rainfall intensities for designing of storm water drainage and retention systems in Poland. During the realization of the maximum amounts separation procedure, for chosen 100 meteorological stations with the use of peak over threshold (POT) method, a number of problems has been found, for which proceeding algorithms have been described.

A simplified method using a single column of N,N,N',N'-tetraoctyl diglycolamide (TODGA) resin is developed for the separation of Sr, Nd and Hf with matrix and interference elements from geological samples, and for subsequent determination of their isotopic ratios by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The analytes of Sr, Nd and Hf are absorbed by the TODGA resin and eluted with 6 mol/L HNO3, 1.2 mol/L HCl and 1 mol/L HNO3-1.6 mol/L HF, respectively. The separation procedure is validated by the certified reference materials (CRMs) of BHVO-2, BCR-2 and AGV-2 with analyte recovery greater than 97%. The ratios are measured for 87Sr/86Sr, 143Nd/144Nd and 176Hf/177Hf and the mean values (2σ) are 0.703455 (16), 0.512977 (12) and 0.283108 (8) for BHVO-2, 0.705008 (18), 0.512633 (10) and 0.282878 (4) for BCR-2, and 0.703989 (20), 0.512791 (8) and 0.282982 (8) for AGV-2, which are consistent with the certified values.

We investigate a variant of the standard Capacitated Vehicle Routing Problem (CVRP), where each vehicle is powered exclusively by electricity stored in its rechargeable battery. Consequently, each vehicle should visit not only customer nodes but also (possibly) some charging stations before the battery got depleted. The importance of this problem stems from the fact that logistics companies are increasingly relying on electric vehicles in urban distribution. We propose three exact approaches. The first one requires solving a compact polynomial-sized formulation. The second approach is a branch-and-cut algorithm. An original feature of this algorithm is that it embeds the first exact separation of the well-known rounded capacity constraints. Finally, the third approach is a hybrid algorithm that requires solving an augmented variant of the compact formulation. We report the results of a computational study that was carried out on a set of 125 instances, providing evidence that the polynomial-sized formulation can consistently solve instances having up to 30 customer nodes and 21 charging stations, and that the hybrid algorithm solves some instances having up to 100 customer nodes and 21 charging stations while requiring moderate CPU times. Furthermore, the proposed approach was shown to exhibit limitations in solving some large-scale tightly-constrained instances. 2020 Elsevier Ltd Scopus

Microbial metabolites represent an important source of bioactive natural products, but always exhibit diverse of chemical structures or complicated chemical composition with low active ingredients content. Traditional separation methods rely mainly on off-line combination of open-column chromatography and preparative high performance liquid chromatography (HPLC). However, the multi-step and prolonged separation procedure might lead to exposure to oxygen and structural transformation of metabolites. In the present work, a new two-dimensional separation workflow for fast isolation and analysis of microbial metabolites from Chaetomium globosum SNSHI-5, a cytotoxic fungus derived from extreme environment. The advantage of this analytical comprehensive two-dimensional liquid chromatography (2D-LC) lies on its ability to analyze the composition of the metabolites, and to optimize the separation conditions for the preparative 2D-LC. Furthermore, gram scale preparative 2D-LC separation of the crude fungus extract could be performed on a medium-pressure liquid chromatograph×preparative high-performance liquid chromatography system, under the optimized condition. Interestingly, 12 cytochalasan derivatives, including two new compounds named cytoglobosin Ab (3) and isochaetoglobosin Db (8), were successfully obtained with high purity in a short period of time. The structures of the isolated metabolites were comprehensively characterized by HR ESI-MS and NMR. To be highlighted, this is the first report on the combination of analytical and preparative 2D-LC for the separation of microbial metabolites. The new workflow exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods.

Purpose – Most systems have a non-linear (NL) behavior and measured signals reflect this non-linearity such that in general they are composed with more than one sinusoidal component. NL analysis methods represent an option for analyzing such signals, however these methods have been developed for single frequency signals, this forces to implement a components separation procedure before performing the signal analysis. The purpose of this paper is to present a new method for analyzing multi-component signals that allows calculating amplitude, frequency and damping constants of the contained sinusoidal components. The method is able to simultaneously identify the different components within a detection bandwidth without previous separation of mono-components, as needed for most methods in used today. Design/methodology/approach – The method proposed in this work characterizes sinusoidal signals determining their amplitude, frequency and damping constant. This method is based on transforming from the time domain to the z-domain an oscillatory signal that may or may not possess damping. Since frequency and damping of a signal can be determined knowing its z-domain poles, using the signal in z-transform domain an equations system to find the signal poles can be written. Findings – From the results it can be concluded that the proposed method is reliable and consistent. One quality of the method is its short delay, when the procedure starts there is a delay equal to the time needed to accumulate four samples for each detectable frequency in order to perform the first calculation, after this, the algorithm can deliver a result at each sampling instant. This short delay and the low complexity of the algorithm can permit using the method in real time applications. Originality/value – The proposed method is able to determine frequencies, damping constants and amplitudes of the components of a signal without a previous separation of mono-components, in contrast with other methods that require filter banks tuned using a previous knowledge of the signal. Moreover unlike techniques such as the Hilbert-Huang Transform the proposed method can be applied to signals with components having very close frequencies.

Microdialysis is a separation technique widely used for sampling and monitoring purposes. Microdialysis requires a (microdialysis) probe to be inserted to the designated area of study. Separation procedure is completed by using a selective semi-permeable membrane attached to the microdialysis proe. Despite being a well-established technique, there are still issues regarding the performance of the microdialysis probe. The biggest issue is arguably that the concentration of solutes collected via microdialysis sampling represents only 20-30% of the original concentration from the sampling site. This issue can be resolved by understanding mass transport phenomena within the microdialysis probe and its surroundings. One straightforward, yet sustainable way to analyze mass transport is through the use of computational modelling. In this paper, a mathematical framework, representing glucose recovery from a quiescent media using a microdialysis probe of linear design was described. Governing equations, boundary conditions and operational parameters were justifiably selected. Different diffusion coefficients were used to describe the mass transport through the quiescent media, semi-permeable membrane and the probe's lumen. Subsequently, the influence of some identified parameters, on the overall recovery is examined. Scanning electron microscopy imaging was used to study the physical characteristics of the microdialysis membrane, thus being utilized to estimate the diffusion coefficient values. The impact of using different diffusion coefficient values on the overall recovery was also discussed.

Radioisotopes of arsenic are of considerable interest to the field of nuclear medicine with unique nuclear and chemical properties making them well-suited for use in novel theranostic radiopharmaceuticals. However, progress must still be made in the production of isotopically pure radioarsenic and in its stable conjugation to biological targeting vectors. This work presents the production and irradiation of isotopically enriched (72)Ge(m) discs in an irrigation-cooled target system allowing for the production of isotopically pure (72)As with capability on the order of 10 GBq. A radiochemical separation procedure isolated the reactive trivalent radioarsenic in a small volume buffered aqueous solution, while reclaiming (72)Ge target material. The direct thiol-labeling of a monoclonal antibody resulted in a conjugate exhibiting exceptionally poor in vivo stability in a mouse model. This prompted further investigations to alternative radioarsenic labeling strategies, including the labeling of the dithiol-containing chelator dihydrolipoic acid, and thiol-modified mesoporous silica nanoparticles (MSN-SH). Radioarsenic-labeled MSN-SH showed exceptional in vivo stability toward dearsenylation.

Separation possibilities of 126Sn with a new extraction-chromatographic material TBP Resin were studied. Suitable conditions for tin separation were determined in hydrochloric acid medium. 126Sn was concentrated on TBP resin from 6 mol L−1 HCl and was eluted with 0.1 mol L−1 HCl. A purification step to remove 137Cs with AMP-PAN column was necessary to obtain sufficiently purified samples which were directly measured with gamma spectrometry for 126Sn activity. Separation of 126Sn from a raw sludge sample was done according to proposed procedure, 126Sn was detected and its activity was determined.

Conjoined twins are identical twins that have incompletely separated in utero. The prognosis for conjoined twins is poor and management in a skilled tertiary care centre is paramount for definitive care. We describe our experience with a telemedical consultation on conjoined twins in The Dominican Republic from our eHealth centre in Valhalla, NY. The patients were two month old, female, pygopagus conjoined twins. A multidisciplinary teleconference was initiated with the patients, their family, the referring paediatrician and our team. Based on this teleconsultation, the team felt as though the twins may be amenable to a surgical separation. They presented to our centre in Valhalla, NY, for a detailed physical examination and series of imaging studies. Soon after, the patients underwent a successful 21 h separation procedure and were discharged 12 weeks later. To our knowledge, this is one of the first reports of an international teleconsultation leading to a successful conjoined twin separation procedure.

A facile strategy for dehulling of six Canadian flaxseed cultivars using ethanol wash in combination with wet-screening was reported. Quantitative determinations of nutritional components including oil, sterol, protein, carbon and cyclolinopide in each separated fraction were also performed. Results showed that an efficient separation of hull, kernel and oil from the whole seed is achieved, because ethanol wash can eliminate the stubborn interference of flaxseed oil, thus facilitating the shell and kernel separation procedure. Among six flaxseed cultivars, the separated hull, kernel and oil account for 20.52–26.66%, 36.02–43.23% and 29.82–32.00% of whole seed, respectively. Triglyceride and sterol contents in separated hull, kernel, oil, whole seed are 2.13–3.34%, 24.68–27.46%, 97.26–98.84%, 37.70–45.82% and 0.02–0.11%, 0.04–0.08%, 0.28–0.53%, 0.11–0.23%, respectively. Besides, flaxseed oil is rich in cyclolinopepides, including new orbitides Q, R and S that have never been reported in these flaxseed varieties. Protein and carbon contents in separated hull, kernel and whole seed are 19.01–26.46%, 34.91–43.80%, 20.15–24.65% and 55.39–56.59%, 45.11–45.93%, 49.61–50.94%, respectively. In addition, the milled flaxseed hull shows a concentration-dependent intrinsic viscosity. This study presents a convenient method for flaxseed dehulling and preliminarily reveals the distribution of different nutrient elements in different parts of flaxseed.

A novel approach based on the use of desirability functions is presented for the robustness assessment of liquid chromatographic separations as derived from computer-assisted methods development processes. The approach is based on generally accepted hypothesis that a robust separation procedure will be inert to small random variations of the operational variables, typically encountered in the day-to-day routine analytical practice. This means that peak positions along the chromatograms must keep standstill or move insignificantly when operational variables are not intentionally changed. Thus, the degree of peak positions variation as evaluated from mathematical retention models can be used to assess the robustness of the developed procedures before testing the actual performance experimentally. In the approach proposed, this assessment is obtained by fixing a bilateral partial desirability window around each peak in the simulated chromatogram. The whole chromatogram robustness is characterized by an overall desirability value calculated as the geometric mean of the partial desirability windows evaluation. An added advantage of this approach is that the robustness value calculated is normalized between zero and one and thus, easy to interpret. Thus, when chromatograms are simulated and small random variations are introduced into the operational factors of the model, values for the overall desirability close to one means that the procedure performs robustly. On the contrary, low values for the overall desirability clearly indicated a serious lack of robustness. When used in conjunction with the Pareto optimality approach, as shown here, this robustness assessment strategy allows testing several Pareto front solutions before the final experimental testing which is always needed. In this way, a dramatical reduction of the experimental effort is obtained. Although the approach is theoretically applicable to any chromatographic separation, examples of reversed phase liquid chromatographic procedures are used to show the performance of the proposed methodology.

A method to optimize a high-speed countercurrent chromatography solvent system from many possible solvent systems was guided by average polarity and K values of crude samples, which was successfully applied in separation of the naphtho-γ-pyrones. This method expanded the scope of spectrophotometer application in the solvent systems selection, and showed the merits of simplicity, rapidity, and low reagent consumption. As a consequence of utilizing the method, an efficient separation procedure was established, and two groups of naphtho-γ-pyrone isomers (fonsecinone B and asperpyrone F; asperpyrone C, fonsecinone A, and aurasperone A) were obtained from Pleurotus ostreatus by high-speed countercurrent chromatography with a solvent system composed of petroleum ether/ethyl acetate/methanol/water (5:5:5:5, v/v). The results indicate that high-speed countercurrent chromatography could be a powerful technology for separation isomers and analogues, and the method guided by average polarity and K values of crude samples is feasible to optimize solvent system.

2,5-Diketopiperazines (DKPs) are widely recognized as chiral molecules with great potential in medicinal chemistry. Complete separation of DKP stereoisomers is very important for efficiently investigating the chemical characteristics of DKPs. The combination of esterification and acylation caused the enantiomers of cyclo(d-Ala-d-Ala) and cyclo(l-Ala-l-Ala) to ring-open and generate their dipeptide derivatives. These derivatives were completely separated by chiral gas chromatography (GC), and the determined isomer ratios were the same as the original isomer ratios. The derivatization also caused the ring-opening of cyclo(l-Asp-l-Phe) and cyclo(l-Met-l-Pro), and their derivatives were determined by the chiral GC method. The present study is the first report of the complete separation of cis-DKPs using chiral GC. This separation procedure can substantially contribute to the development of the chemistry of chiral DKPs.

Conjoined twins are uncommon with reported incidences of 1 in 30,000-200,000 births. They represent a heterogeneous population in regard to location of joint body parts and presence/extent of internal organ fusion. Positioning, airway management, possible presence of cross-circulation, and the fact that 2 patients require anesthesia for each procedure present significant challenges to the anesthesiologist. We report the anesthetic care of a conjoined twin set in which one of the patients presented with tricuspid atresia, d-transposition of the great arteries, and both atrial and ventricular septal defect. A balloon atrial septostomy was performed to allow survival after a separation procedure.

A procedure for the rapid separation of 99Tc, 90Sr, 55Fe, 94Nb, and 59,63Ni in radioactive waste samples was developed for measuring their activity. After separating 99Tc on an anion-exchange resin column, 90Sr was separated as 90Sr(CaC2O4) co-precipitates, and 59,63Ni, 55Fe, and 94Nb were sequentially separated on an anion-exchange resin column in the presence of oxalate. The separated 90Sr and 59,63Ni were further purified on extraction chromatographic resin columns, respectively. The chemical yields of the separation procedure for Re, Sr, Fe, Nb, and Ni, which were added as chemical carriers, are 99.3 ± 0.3 %, 94.8 ± 0.6 %, 93.3 ± 1.2 %, 95.3 ± 1.9 %, and 92.6 ± 0.6 %, respectively. The separation of these radionuclides from sixteen radioactive waste samples required only seven person-days.

Despite the increasing production of wheat gluten (WG) for industrial use, minor attention has been given to the impact of the separation procedure on the gluten quality. The purpose of the present ...

The various stages of the separation are carefully planned but despite this, variations which will change the schedule of the procedure may exist. In general the operation commences on the opposite side from the main procedure and then the twins are turned for the remainder of the operation. Each type of conjoined twin is different but basically thoracopagus involves the hearts, omphalopagus involves the liver and small intestine and ischiopagus involves the large intestine and genito-urinary system. Our results are presented together with interesting cases from which lessons have been learned.