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In recent years, the control of volatile N-nitrosamines (NAs) has been of interest in the pharmaceutical and food industries, as many of these compounds are probable human carcinogens. Thus, rapid and trace-level quantitative determination methods are in urgent demand. In this work, ambient pressure ammonium-adduct ionization mass spectrometry was proposed for the sensitive detection of volatile nitrosamines in various pharmaceutical headspaces. The ammonium ions produced through electrospray ionization acted as reactant ions for NAs to generate ammonium-NA adduct ions and underwent in-source collision-induced dissociation to produce protonated NAs, which were detected by mass spectrometry. The ionization selectivity and sensitivity for various volatile NAs were improved significantly using the developed method, which was demonstrated by the limit of quantification (LOQ) below 52 ng L^-1 for all NAs, and the quantitative performance was consequently improved. Different NAs exhibited almost equimolar response using NH₄⁺ as the reactant ion, with at least a twofold enhancement in intensity for the individual compounds relative to when using H⁺ as the reactant ion. The proposed method is a rapid, sensitive, and environmentally economical approach that uses few reagents.

Bladder cancer (BC) is an epidemiological urologic malignancy that continues to increase each year. Early diagnosis and prognosis monitoring is always significant in clinical practice, especially in distinguishing non-muscle-invasive bladder cancer (NMIBC) from muscle-invasive bladder cancer (MIBC), due to the various depths of tumor invasion related to different therapeutic schedules and recurrence rates. Common diagnostic approaches are too invasive or generally inefficient in accuracy and specificity. In this work, a totally non-invasive and cost-effective method is established by investigating urine samples using surface-enhanced Raman spectroscopy (SERS) and multivariate statistical analysis. The comparison of urine SERS spectra shows the intensities of characteristic peaks for DNA/RNA, hypoxanthine, albumin, D-( +)-galactosamine, fatty acids, and some amino acids are distinguishable in BC occurrence and invasion progression. A PLS-LDA-based two-step binary classification scheme is performed on urine SERS spectra and the diagnostic accuracies were 97.7% and 96.3% for healthy individuals versus BC patients and NMIBC versus MIBC patients, respectively. Moreover, the impact of urine SERS spectral lengths in reaching high-precision recognition of BC is investigated. The results show that the Raman peaks at 803, 893, 1139, 1375, and 1466 cm^-1 play an essential role in correctly categorizing healthy control, NMIBC, and MIBC patients, and SERS spectra ranges from 400 to 1600 cm^-1 are enough for this identification task. These findings provide a sensitive, label-free, rapid, and totally non-invasive way for assessment of invasion depth of BC to its early diagnosis and prognosis monitoring, as well as valuable insights for selecting reasonable spectral range to enhance the measurement efficiency especially in large-scale sample datasets.

An analytical method for the determination of imatinib (IMA, the primary treatment for chronic myeloid leukemia), based on the fluorescence properties of graphene quantum dots (GQDs), is reported in this work. The method is addressed to the analytical control of IMA in biological and pharmaceutical samples, due to the present interest in the control of the doses of this anticancer drug, as well as the therapeutic monitoring. The whole method involves the use of a solid-phase extraction (SPE) procedure, followed by an evaporation step, for the treatment of biological samples. For that, tC18 sorbent cartridges were used. After the sample treatment, the solution containing the analyte was mixed with an aqueous solution of GQDs at pH 7.2, and the fluorescent quenching of GQDs was measured. IMA was determined in the 10-250 µg L^-1 range, with a limit of detection of 21 µg L^-1 and a precision of 1.5% as relative standard deviation, measured in terms of reproducibility. The recovery for biological samples was in the 84-113% range.

Periodontal disease affects supporting dental structures and ranks among one of the top most expensive conditions to treat in the world. Moreover, in recent years, the disease has also been linked to cardiovascular and Alzheimer's diseases. At present, there is a serious lack of accurate diagnostic tools to identify people at severe risk of periodontal disease progression. Porphyromonas gingivalis is often considered one of the most contributing factors towards disease progression. It produces the Arg- and Lys-specific proteases Rgp and Kgp, respectively. Within this work, a short epitope sequence of these proteases is immobilised onto a magnetic nanoparticle platform. These are then used as a template to produce high-affinity, selective molecularly imprinted nanogels, using the common monomers N-tert-butylacrylamide (TBAM), N-isopropyl acrylamide (NIPAM), and N-(3-aminopropyl) methacrylamide hydrochloride (APMA). N,N-Methylene bis(acrylamide) (BIS) was used as a crosslinking monomer to form the interconnected polymeric network. The produced nanogels were immobilised onto a planar gold surface and characterised using the optical technique of surface plasmon resonance. They showed high selectivity and affinity towards their template, with affinity constants of 79.4 and 89.7 nM for the Rgp and Kgp epitope nanogels, respectively. From their calibration curves, the theoretical limit of detection was determined to be 1.27 nM for the Rgp nanogels and 2.00 nM for the Kgp nanogels. Furthermore, they also showed excellent selectivity against bacterial culture supernatants E8 (Rgp knockout), K1A (Kgp knockout), and W50-d (wild-type) strains in complex medium of brain heart infusion (BHI).

The presence of antibiotic residues in cow's milk entails high risk for consumers, the dairy industry, and the environment. Therefore, the development of highly specific and sensitive screening tools for the rapid and cost-effective identification of traces of these compounds is urgently needed. A multiplexed screening platform utilizing DNA-directed immobilization (DDI) was developed aiming to detect three classes of antibiotic residues (fluoroquinolones, sulfonamides, and tylosin) prevalently found in milk. Throughout this work, each oligonucleotide sequence was conjugated to a different hapten molecule, while the three complementary strands were immobilized in 24 independent microarray chips on a single glass slide. First, the array was incubated with the pool of hapten-oligonucleotide conjugate site encoded the signal through DNA hybridization. Next, commercial milk samples were incubated with the cocktail of monoclonal antibodies following a secondary fluorophore-labeled antibody which was required for fluorescent readout. Direct sample detection was achieved in milk diluting 20 times in assay buffer. The limits of detection (LODs) reached were 1.43 µg kg^-1, 1.67 µg kg^-1, and 0.89 µg kg^-1 for TYLA, STZ, and CIP, respectively, which represented in raw milk 7.15 µg kg^-1, 8.35 µg kg^-1, and 4.45 µg kg^-1 for TYLA, STZ, and CIP, respectively, that are below the EU regulatory limits. Cross-reactivity profiles were evaluated against the family of structurally related antibiotics in order to demonstrate the capability to detect antibiotics from the same family of compounds. A pre-validation study was performed by spiking 20 blind samples above and below the maximum residue limits established by the EU guidelines. The system was successfully implemented towards randomized sample classification as compliant or non-compliant. The proposed DDI-based immunoarray provides a fast and cost-effective alternative to obtain semi-quantitative information about the presence of three veterinary residues simultaneously in milk samples.

This paper proposes a new approach to improving image quality in pulsed X-raytomography. The method is based on establishing a functional dependence of the reconstructedimages on the duration of the probing pulses and applying an extrapolation procedure. Thenumerical experiments demonstrated that the developed algorithm effectively suppresses theinfluence of scattered radiation and significantly increases image contrast. The proposedalternative approach allows substantially increasing the stability of the method even for mediacontaining strong scattering inhomogeneities and with a significant level of noise in the projectiondata. In addition, the algorithm has greater stability to errors in the source data caused by anincrease in the duration of the probing pulses. The numerical experiments confirmed the highefficiency of the extrapolation tomography algorithm for recovering the internal structure of thetest object.

We consider an initial–boundary value problem for a semilinear parabolic differentialequation with a time-nonlocal term. This term contains the integral of the solution over the entiretime interval on which the problem is considered. The solvability of the problem inHölder classes is proved. The uniqueness of the solution is established under a constrainton the length of the time interval over which the solution is integrated in the nonlocal term.

A three-vertex subset is called an open triangle (OT) if it induces a subgraph with exactlytwo edges. The problem of finding graphs with maximum number of OTs is considered. It isproved that, in case of sufficiently many vertices, such a graph is unique in the class of graphswith constant difference between the numbers of edges and vertices.

We consider the problem of minimizing the weighted average execution time ofequal-length jobs performance on one machine at the specified time of job arrival and thepossibility of their interruption. The computational complexity of this problem is currentlyunknown. The article proposes an algorithm for preprocessing input data that allows reducing theproblem to a narrower and more regular class of examples. The properties of optimal solutions aresubstantiated. Based on them, an algorithm for constructing a finite subset of solutions containingan optimal schedule has been developed. A parametric analysis of the schedules in this subset hasbeen carried out that makes it possible to form a subclass of schedules that are optimal at somevalues of weights. A polynomially solvable case of the problem is isolated.

Ulcerative colitis (UC) is an idiopathic inflammatory disease. We intend to explore the mechanism of Rutin in the therapy of UC. Disease activity index (DAI) and hematoxylin-eosin staining were employed to assess therapeutic effect of Rutin on dextran sulfate sodium-stimulated mice. The proliferation was detected by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay. Oxidative stress (OS) was assessed by measuring reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD). Inflammatory factors were detected using enzyme-linked immunosorbent assay and immunofluorescence staining. mRNA and protein expressions were detected by real-time quantitative polymerase chain reaction and immunoblotting assay. Rutin decreased DAI scores and ameliorated pathological damage in UC mice with decreased levels of inflammatory factors. Rutin recovered the inhibited proliferation of fetal human colon cells caused by lipopolysaccharide. Rutin inhibited OS by reducing ROS and MDA, while enhancing SOD activity in LPS-induced fetal human colon cells. Rutin inhibited NLRP3 inflammasome in UC mice and cell model. Silencing NLRP3 enhanced the inhibitory effect of Rutin on OS in lipopolysaccharide-induced fetal human colon cells. Conversely, NLRP3 overexpression reversed the restraining role of Rutin in OS. Rutin ameliorates UC by inhibiting inflammation and OS through suppressing NLRP3 inflammasome.