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1.
Article in English | MEDLINE | ID: mdl-37379757

ABSTRACT

Recent scientific studies in the field of health and nutrition have unanimously affirmed the importance of consuming the omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), because of their cardioprotective properties. Fatty acid profiling in erythrocyte membranes allows the omega-3 index, which is a recognized indicator of the risk of developing cardiovascular disease, to be calculated. One consequence of the upward trend in healthy lifestyles and longevity is an increase in the number of studies into the omega-3 index, which requires a reliable method for the quantitative analysis of fatty acids. This article describes the development and validation of a sensitive and reproducible liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for the quantitative analysis of 23 fatty acids (in the form of fatty acid methyl esters, FAMEs) in 40 µl of whole blood and erythrocytes. The list of acids includes saturated, omega-9 unsaturated, omega-6 unsaturated and omega-3 unsaturated fatty acids as well as their trans-isomers. The limit of quantitation was 250 ng ml-1 for C12:0, C16:0 and C18:0; and 62.5 ng ml-1 for other FAMEs, including EPA, DHA and trans-isomers of FAME C16:1, C18:1 and C18:2 n-6. Sample preparation for fatty acid (FA) esterification/methylation with boron trifluoride-methanol (BF3) has been optimized. Chromatographic separation has been carried out on a C8 column in gradient mode using a mixture of acetonitrile, isopropanol and water with the addition of 0.1% formic acid and 5 mM ammonium formate. As a result, the problem of separating the cis- and trans-isomers of FAME C16:1, C18:1 and C18:2 n-6 has been solved. The electrospray ionization mass spectrometry (ESI-MS) detection of FAMEs, in the form of ammonium adducts, has been optimized for the first time, which has made the method more sensitive that when the protonated species are used. This method has been applied to 12 samples from healthy subjects that consumed omega-3 supplements and has proven to be a reliable tool for determining the omega-3 index.


Subject(s)
Fatty Acids, Omega-3 , Tandem Mass Spectrometry , Humans , Tandem Mass Spectrometry/methods , Fatty Acids/analysis , Chromatography, High Pressure Liquid/methods , Docosahexaenoic Acids/analysis , Erythrocytes/chemistry
2.
J Phys Condens Matter ; 34(16)2022 Feb 23.
Article in English | MEDLINE | ID: mdl-35120339

ABSTRACT

The neutron diffraction, magnetic and heat capacity measurements have been carried out to study the polycrystalline sample LiNi0.5Co0.5PO4prepared by the glycerol-nitrate synthesis method. Models of Ni- and Co-ion occupation the 4coctahedral position in a crystal structure LiNi0.5Co0.5PO4are calculated for a paramagnetic state. The best model is the Ni- and Co-ions occupy the 4csite inPnmapatent space-group in sequence Ni-Co-Ni-Co or Co-Ni-Co-Ni. It is shown that nickel ions formabplanes alternating with the planes of cobalt ions in the direction of theccrystallographic axis. At 7 K, an average magnetic moment of 3d-ions is equal to 1.90 (9)µB. The moments are ordering antiferromagnetically and parallel to thebcplane decreasing to zero at 15 K. In the high-spin state a temperature dependence of the Ni2+/Co2+ion-magnetic moment is well described within the 2D Ising model with order parameterß= 0.198 and Néel temperatureTN= 14.1 (1) K, obtained from heat capacity data. This temperature agrees well withTcr= 14.3 (2) K, determined with magnetic measurement. Maybe the short-range magnetic order exists in LiNi0.5Co0.5PO4over temperature region (14-16) K, that is confirmed by the maximum on a temperature dependence of the magnetization at 16.1 (5) K.

3.
Ter Arkh ; 91(3): 31-35, 2019 Mar 30.
Article in English | MEDLINE | ID: mdl-31094456

ABSTRACT

AIM: The aim of the research was to study the state of the bronchial mucosa epi-thelium in relation to the severity of clinical manifestations in severe uncon-trolled asthma depending on the pattern of inflammation and the presence of cold airway hyperresponsiveness. MATERIALS AND METHODS: In 48 patients with severe uncontrolled asthma, there were assessed asthma symptoms, clinical signs of cold airway hyperre-sponsiveness, and lung function; the samples of slides were analyzed in the cytological examination of the sputum; the degree of damage to epithelial cells and granulocytes was estimated using the total cell destruction index (CDI). RESULTS: According to the analysis of sputum cytograms, the patients were divided into two groups: group I (22 patients) included persons with eosin-ophilic inflammation pattern (31.0±3.1% of eosinophils and 22.0±2.2% of neutrophils), group II (26 patients) was with mixed inflammation pattern (7.2±1.4 and 71.8±4.2%, respectively). The patients of group II had lower disease control according to Asthma Control Test (ACT; 12.1±0.7 and 17.8±0.2 points, respectively; р<0.05), a greater frequency of exacerbations (4.1±0.3 and 3.2±0.2 per year, respectively; р<0.05), greater incidence of clinical signs of cold airway hyperresponsiveness (79 and 19%, respectively; χ2=14.18; р<0.001); lower lung function (midexpiratory flow rate MEF25-75 was 14.6±1.6 and 20.7±1.9%, respectively; р<0.05); they received a higher dose of the combined medications of inhaled glucocorticosteroid in controller anti-inflammatory therapy (salmeterol/fluticasone at a dose of 705.3±19.7 and 650.7±14.8 µg/day for fluticasone propionate; р<0.05) In patients of group II the correlations of epithelial CDI with neutrophil CDI (r=0.61; p<0.01) and eosinophil CDI (r=0.48; p<0.05), as well as correlation of ACT with neutrophil CDI (r=-0.71; p<0.01) and eosinophil CDI (r=-0.53; p<0.05) were found. CONCLUSION: The degree of destruction of the epithelium and granulocytes in the inflammatory patterns has diagnostic relevance for the assessment of the severity of the disease, clinical manifestations of the airway response to the cold trigger, and the inertia of achieving control in patients with severe un-controlled asthma.


Subject(s)
Asthma/physiopathology , Bronchial Hyperreactivity/physiopathology , Cryopyrin-Associated Periodic Syndromes , Bronchi , Bronchial Hyperreactivity/immunology , Cold Temperature/adverse effects , Eosinophils , Humans , Inflammation/immunology , Inflammation/physiopathology , Severity of Illness Index , Sputum/cytology
4.
Urologiia ; (5): 69-74, 2017 Oct.
Article in Russian | MEDLINE | ID: mdl-29135146

ABSTRACT

INTRODUCTION: Duplication of the upper urinary tract is one of the most common congenital urological anomalies. In patients with critically decreased or lost function of one of the renal segments, heminephrureterectomy is usually the treatment of choice. Until recently, this was an open surgery; in cases of complete removal of the ureter, an additional incision in the iliac region was required. Currently, heminephrureterectomy is increasingly performed laparoscopically. We report the experience in laparoscopic heminephrureterectomy (LHNUE) in 10 clinics in Russia and Belarus. Some of them have already used this technique for 10 years. AIM: The study aimed to to improve the treatment results in children with urodynamic dysfunction due to duplicated upper urinary tract. MATERIALS AND METHODS: We retrospectively analyzed medical records of 111 children treated from 2007 to 2016. There were 26 (23.4%) boys and 85 (76.6%) girls with mean age 44.6 months (from 2 to 170) at the time of surgery. All children included in the study had complete duplex kidneys, including 51 (45.9%) right-sided and 60 (54.1%) left-sided. All the children underwent LHNUE for a critical decrease or absence of function of the upper or lower segment of the duplex kidney caused by the following pathology: obstruction of the ureterovesical junction with the development of the megaureter of the upper ureteral segment in 57 (51.4%) patients; ureterocele in 28 (25.2%); extra-vesical ectopic ureter with urinary incontinence in 10 (9.0%) girls; high-grade UVR in 16 (14.4%) patients. RESULTS: There were no conversions in this series of patients. The mean operative time was 135 minutes (60-240 min.). All children included in the study were followed for 1 to 9 years after surgery. Complications occurred in 17 (15.3%) patients, of whom 12 (10.8%) required repeat surgery. In one patient with the loss of lower pole function, the treatment result was considered unsatisfactory. CONCLUSION: LHNUE for duplex kidney is performed by a few clinics and is still at the stage of development and accumulation of experience. Nevertheless, LHNUE, though an effective treatment modality, carries the risk of reducing or losing the function of the retained segment.


Subject(s)
Kidney/abnormalities , Kidney/surgery , Laparoscopy/methods , Nephroureterectomy/methods , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Laparoscopy/adverse effects , Male , Nephroureterectomy/adverse effects , Republic of Belarus , Retrospective Studies , Russia
5.
Urologiia ; (6): 59-64, 2017 Dec.
Article in Russian | MEDLINE | ID: mdl-29376597

ABSTRACT

AIM: Recent advances in the field of minimally invasive surgical technologies in children and adolescents have led to the development of vesicoscopic (transvesical, pneumoscopic) access (VA). Current limitations in using VA emphasize the need for further studies investigating surgical options for the management of various pathological conditions of the bladder and ureterovesical junction, the features of surgical techniques and the course of the early postoperative period when used in pediatric urological practice. MATERIALS AND METHODS: From 2013 to 2017, 157 patients (79 girls and 78 boys) aged between 2 months and 18 years (mean age 4.9-8.7 years) underwent surgery using VD. Unilateral and bilateral vesicoscopic ureterocystoneoimplantation was performed in 110 (70%) and 44 (28%) patients, respectively. A total of 198 ureters was implanted. Three (1.9%) children underwent vesicoscopic excision of the bladder diverticulum. Transvesicoscopic Cohen ureteric reimplantation, pneumovesical Glenn-Anderson procedure, and Chumakov ureterocystoneoimplantation were performed in 151 (96.1%), 2 (1.3%) and 1 (0.6%) patients, respectively. RESULTS: The mean operative time when using VA was 126.8+/-46.7 min. In patients younger than one year, 1-3 years, 4-17 years, it was 136.0+/-43.8 min, 130.1+/-43.5 min and 122.4+/-65.8 min, respectively. The mean length of postoperative hospital stay was 6.2+/-2.3 days. In 3 (1.9%) cases we had to convert to open surgery. Gas migration into the abdominal cavity occurred in 6 (3.8%) patients. Fourteen (9%) patients had early postoperative complications. Transient obstruction of ureterovesical junction occurred in 6 (3.8%) patients. Acute complete obstruction of the distal ureter developed in 3 (1.9%) patients aged three months who did not undergo drainage of the upper urinary tract intraoperatively. A paravesical urine leak occurred in 1 (0.6%) patient. In one (0.6%) of the boys, the distal end of the urinary drainage inserted through the trocar into the ureter migrated in the bladder. The urine leakage from the trocar puncture occurred once (0.6%) and was stopped by indwelling urethral catheterization for seven days. In 2 (1.3%) patients, exacerbation of pyelonephritis required a modification in antibacterial therapy. DISCUSSION: Despite the accumulated experience, vesicoscopic surgery remains a laborious and complicated surgical intervention, requiring long learning curves even for surgeons who have good manual skills in laparoscopic surgery. CONCLUSION: In our opinion, vesicoscopic access allows the entire range of surgical interventions on the vesicoureteral junction and bladder in children to be performed. It is effective, significantly less traumatic than traditional open cystotomy access, and associated with an excellent cosmetic result.


Subject(s)
Cystostomy/methods , Minimally Invasive Surgical Procedures/methods , Ureter/surgery , Urinary Bladder Diseases/surgery , Urinary Bladder/surgery , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Male , Ureter/pathology , Urinary Bladder/physiology , Urinary Bladder Diseases/pathology
6.
Bull Exp Biol Med ; 161(4): 550-3, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27591875

ABSTRACT

Positive reaction of the bronchi to distilled water inhalation in asthmatics is associated with significant stimulation of the respiratory epithelium desquamation against the background of increased content of eosinophilic and neutrophilic leukocytes in induced sputum, predomination of eosinophil and neutrophil cytolysis, and lower activity of myeloperoxidase in leukocyte granules (in comparison with the parameter in patients with a negative response to bronchostimulation). Enhanced cytolysis and destruction of leukocytes and high myeloperoxidase concentration in the extracellular space are essential for the development of bronchial hyperresponsiveness to hypoosmotic stimulus in asthma.


Subject(s)
Asthma/immunology , Bronchial Hyperreactivity/immunology , Inflammation/immunology , Adult , Asthma/metabolism , Asthma/physiopathology , Bronchi/immunology , Bronchi/physiopathology , Bronchial Hyperreactivity/metabolism , Bronchial Hyperreactivity/physiopathology , Eosinophils/immunology , Female , Humans , Inflammation/metabolism , Macrophages/immunology , Male , Neutrophils/immunology , Peroxidase/metabolism , Young Adult
7.
Article in English | MEDLINE | ID: mdl-26830791

ABSTRACT

Some comments on the review by Sim et al. [(2016). Acta Cryst. B72, 3-19] are given. The review is devoted to hexagonal multiferroics RMnO3, in which there are ferroelectric and magnetic orders. Strong interaction between these orders causes a series of interesting properties of multiferroics.

8.
Klin Med (Mosk) ; 93(9): 30-5, 2015.
Article in Russian | MEDLINE | ID: mdl-27008740

ABSTRACT

AIM: To study effectiveness of the use of the anti-leukotriene drug montelukast in combination with inhalation glucocorticoid and long-acting beta-agonist in patients with bronchial asthma (BA) and cold-induced bronchial hyperactivity (CBHA) with a view to optimizing control of the disease. MATERIALS AND METHODS: We carried out an open comparative prospective study of patients with persistent BA in a cold season under conditions of real clinical practice. The patients were divided into 2 groups. Group 1 included patients with CBHA, group 2 consisted of subjects with constant bronchial reactivity in response to cold in the standard provocative test. The patients were followed up for 24 weeks. During the first 12 weeks of the treatment, the patients of group I were given sodium montelukast with budesonide/formoterol. In the next 12 weeks they received only budesonide/formoterol at the same dose. Patients of group 2 were treated with budesonide/formoterol during the entire study period. Efficacy of therapy was assessed by asthma control test (ACT). RESULTS: Control of BA in group 1 (20-25 scores in A CT) was achieved in 83% of the patients within the first 12 week period The result was comparable (87%) with that in group 2. Impairment of control (to 52%) was documented in group I during the last 12 weeks although it was preserved (20-25 scores) in group 2 (81%). CONCLUSION: The use of sodium montelukast in combination with budesonide/formoterol for the treatment of BA with CBHA in winter season ensured control of the disease in most patients during 12 weeks. Withdrawal of montelukast in the subsequent period leads to the loss of control and a rise in the frequency of exacerbation.


Subject(s)
Acetates/administration & dosage , Asthma/drug therapy , Bronchial Hyperreactivity/complications , Cold Temperature/adverse effects , Quinolines/administration & dosage , Administration, Inhalation , Adolescent , Adult , Anti-Asthmatic Agents/administration & dosage , Asthma/complications , Bronchial Hyperreactivity/drug therapy , Cyclopropanes , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prospective Studies , Sulfides , Treatment Outcome , Young Adult
9.
Ter Arkh ; 86(3): 40-4, 2014.
Article in Russian | MEDLINE | ID: mdl-24779069

ABSTRACT

AIM: To evaluate the clinical efficiency of tactics to widen the scope of monotherapy with inhaled glucocorticosteroids (IGCS) in asthmatic patients with bronchial cold hyperreactivity (BCHR) during winter to achieve control of the disease in real clinical practice. SUBJECTS AND METHODS: An open-label longitudinal study was conducted in a cold period in 106 asthmatics divided into 2 groups: 1) those with BCHR and 2) those with unchanged bronchial reactivity to a cold stimulus. The study involved monitoring the symptoms by the asthma control test, peak expiratory flow rate (PEFR), and spirometry results before and after cold bronchoprovocation testing; assessment of the pattern of bronchial inflammation from the ratios of induced sputum (IS) cell populations; and estimation of the number of asthma exacerbations and emergency care recourses. Group 1 used a stepwise increase of the scope of basic therapy with beclomethasone dipropionate 1000 microg/day until asthma control was achieved, which was followed by the therapy with the stable dose. Group 2 received monotherapy with beclomethasone dipropionate as the stable dosage of < or = 500 microg/day. RESULTS: After the first 12 weeks of a follow-up, Group 1 showed the most marked positive changes in the intensity of clinical symptoms, forced expiratory volume in one second, and PEFR that remained within the following 12 weeks during the continued therapy with the stable dose of the drug. A preponderance of the eosinophilic and neutrophilic pattern of inflammation was seen in the patients of this group. By the end of the study, there was a decline in the number of IS inflammatory cells. A discriminant model was developed as a tool to predict asthma control achievement in patients with BCHR. CONCLUSION: A stepwise increase in the scope of IGCS monotherapy in asthmatic patients with BCHR during winter can yield the results of disease control and the incidence of exacerbations, which are similar to those seen in asthmatics with no signs of BCHR (53 and 49%, respectively).


Subject(s)
Asthma , Beclomethasone/therapeutic use , Bronchial Hyperreactivity , Cold Temperature/adverse effects , Adult , Anti-Asthmatic Agents/therapeutic use , Asthma/diagnosis , Asthma/epidemiology , Asthma/physiopathology , Bronchial Hyperreactivity/diagnosis , Bronchial Hyperreactivity/epidemiology , Bronchial Hyperreactivity/etiology , Discriminant Analysis , Disease Management , Disease Progression , Emergency Medical Services/methods , Emergency Medical Services/statistics & numerical data , Female , Humans , Longitudinal Studies , Male , Middle Aged , Respiratory Function Tests/methods , Russia/epidemiology , Seasons
10.
Sci Rep ; 4: 4280, 2014 Mar 05.
Article in English | MEDLINE | ID: mdl-24594587

ABSTRACT

Current interest in nanomaterials is focused mostly on artificial materials fabricated for various applications. However, naturally occurring nanocrystal arrays, like those recently found in the meteorite that fell near Chelyabinsk in Russia on 15 February, 2013, can provide some new insights into the nature of nanomaterials, including the conditions for their natural occurrence. Here we report the results of our spectroscopic investigation of a fragment of the Chelyabinsk meteorite. The atomic structure of a fragment of the Chelyabinsk meteorite was studied using high-resolution transmission electron microscopy. Elemental and phase analysis of the object that was carried out by energy dispersive X-ray spectroscopy and electron diffraction revealed the presence of crystalline phases of different chemical compounds specific to meteorites of the LL group. In addition to single-crystal inclusions, extensive areas with ferropericlase nanocrystals having characteristic sizes from 3 to 15 nm were found in the structure of the meteorite. The study of the meteorite employing combination scattering of light (Raman) and photoluminescence spectroscopy methods has revealed quantum effects of ferropericlase nanoparticles and related photoluminescence with a maximum in the range of 675-800 nm.

11.
J Chromatogr A ; 1323: 104-14, 2014 Jan 03.
Article in English | MEDLINE | ID: mdl-24309716

ABSTRACT

Novel poly(styrene-divinylbenzene) (PS-DVB) based anion exchangers having one and two (2,3-dihydroxypropyl) substitutes in the quaternary ammonium functional groups are prepared and characterised by ion chromatography (IC). The introduction of bulky and hydrophilic substitutes to the anion-exchange groups allows the elimination of non-ionic interactions between the polarisable anions and the aromatic rings from the matrix and the improvement of separation selectivity as compared with the traditional trimethylammonium (TMA) functionalised ion exchangers. The synthesis of the ion exchangers includes acylation of PS-DVB particles with acetic anhydride followed by reductive amination either with methylamine hydrochloride or dimethylamine and further alkylation with oxiranes under varied conditions. The ion exchange selectivity and separation efficiency of nine adsorbents having different structure of bonded groups, ion exchange capacity (9-98µequiv.g(-1)) or particle size is studied for model mixture of inorganic anions (F(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) using carbonate and hydroxide eluents. The adsorbents with more hydrophilic substitutes provided superior columns efficiencies and better peak symmetry as compared with analogues having hydrophobic functional groups. The calculated values of column efficiencies for polarisable NO3(-) and HPO4(2-) are 18,500 and 29,000N/m, respectively, for anion-exchanger, having N-methyl-N',N″-di-(2,3-dihydroxypropyl)ammonium groups which is significantly higher than 1800 and 12,000N/m obtained for these anions with anion exchanger bearing TMA functional groups.


Subject(s)
Anion Exchange Resins/chemistry , Anion Exchange Resins/chemical synthesis , Chromatography, Ion Exchange/methods , Polystyrenes/chemistry , Polystyrenes/chemical synthesis , Quaternary Ammonium Compounds/chemistry , Hydrophobic and Hydrophilic Interactions , Particle Size
12.
Adv Gerontol ; 22(2): 356-63, 2009.
Article in Russian | MEDLINE | ID: mdl-19947404

ABSTRACT

The pleiotropic effects of simvastatin in a daily doze of 20 mg in persons of senile age with chronic heart failure were studied in the submitted work. The practical opportunity to reduce the risk of acute vascular events, improvement of vascular endothelium function and relative safety of application of the preparation in the specified dosage at persons of senile age is shown.


Subject(s)
Endothelium, Vascular/drug effects , Heart Failure/drug therapy , Hypolipidemic Agents/therapeutic use , Lipids/blood , Simvastatin/therapeutic use , Vasodilation/drug effects , Aged, 80 and over , Chronic Disease , Dose-Response Relationship, Drug , Drug Therapy, Combination , Endothelium, Vascular/diagnostic imaging , Female , Heart Failure/blood , Heart Failure/diagnostic imaging , Heart Failure/physiopathology , Humans , Hypolipidemic Agents/administration & dosage , Male , Simvastatin/administration & dosage , Treatment Outcome , Ultrasonography
13.
J Pharm Biomed Anal ; 50(4): 671-4, 2009 Nov 01.
Article in English | MEDLINE | ID: mdl-19264438

ABSTRACT

A simple, rapid and sensitive high-performance liquid chromatography method with electrochemical detection was developed for the determination of glucosamine in human plasma. Plasma samples were analyzed after a simple two-step procedure of protein precipitation with subsequent dilution. The chromatographic separation was performed on a Carbopack column (3 mm x 150 mm) with a mobile phase consisting of water and 200 mM sodium hydroxide. Detection was performed electrochemically in a pulsed voltammetry mode. The limit of detection was 2.0 ng/ml, inter- and intra-day precision were less than 10%. The method was successfully applied to the investigation of the pharmacokinetics of glucosamine in healthy man volunteers.


Subject(s)
Chromatography, High Pressure Liquid/methods , Glucosamine/blood , Dietary Supplements , Electrochemical Techniques/methods , Humans , Male , Reproducibility of Results
14.
Vestn Khir Im I I Grek ; 167(3): 49-53, 2008.
Article in Russian | MEDLINE | ID: mdl-18652214

ABSTRACT

An experience with treatment of 58 patients operated upon for carcinoma of the colon complicated by acute intestinal obstruction and diastatic perforation has been analyzed, 13 patients had incomplete diastatic ruptures (tears) of the colon. In 23 patients the IV stage of the tumor process (remote metastases) were found and the other 35 patients had the III stage. In early terms after operation 37 (63.8%) patients out of 58 patients died. Lethality after incomplete diastatic ruptures of the colon made up 53.8%, and after diastatic perforation - 67.7%. The main cause of lethal outcomes was polyorganic insufficiency against the background of intoxication of mixed genesis (cancerous + endogenous). Ablation of colonic tumor is justified in cases of local peritonitis. Hemicolectomy with ablation of the diastatic rupture is indicated for the right-side localization of the tumor Obstructive resection is expedient for left-side localization of the tumor and rupture, the diastatic ruptures should be sutured or extraperitonized with application of cecostoma. Subtotal colectomy is possible for left-side localization of the tumor and diastatic ruptures of the right half of the colon. Symptomatic operations are indicated for canceromatosis of the peritoneum, terminal phase of peritonitis or infectious-toxic shock.


Subject(s)
Colonic Neoplasms , Aged , Aged, 80 and over , Colectomy , Colonic Neoplasms/pathology , Colonic Neoplasms/surgery , Female , Humans , Male , Middle Aged , Postoperative Complications/mortality , Rupture, Spontaneous/pathology , Rupture, Spontaneous/surgery , Survival Rate
15.
Nature ; 451(7180): 805-8, 2008 Feb 14.
Article in English | MEDLINE | ID: mdl-18273014

ABSTRACT

The motion of atoms in a solid always responds to cooling or heating in a way that is consistent with the symmetry of the given space group of the solid to which they belong. When the atoms move, the electronic structure of the solid changes, leading to different physical properties. Therefore, the determination of where atoms are and what atoms do is a cornerstone of modern solid-state physics. However, experimental observations of atomic displacements measured as a function of temperature are very rare, because those displacements are, in almost all cases, exceedingly small. Here we show, using a combination of diffraction techniques, that the hexagonal manganites RMnO3 (where R is a rare-earth element) undergo an isostructural transition with exceptionally large atomic displacements: two orders of magnitude larger than those seen in any other magnetic material, resulting in an unusually strong magneto-elastic coupling. We follow the exact atomic displacements of all the atoms in the unit cell as a function of temperature and find consistency with theoretical predictions based on group theories. We argue that this gigantic magneto-elastic coupling in RMnO3 holds the key to the recently observed magneto-electric phenomenon in this intriguing class of materials.

16.
Morfologiia ; 132(4): 81-6, 2007.
Article in Russian | MEDLINE | ID: mdl-17969436

ABSTRACT

Comparative study of cytokeratin-positive (CK+) cells, isolated from bone marrow and lymph node micrometastases in patients with lung and esophageal cancer, was performed using the methods of immunocytochemistry and immunomagnetic separation. It was found that immunocytochemical analysis permitted the detection of CK+ cells in the smears of bone marrow of oncologic patients. All the samples of bone marrow with immunocytochemically demonstrated CK+ cells, contained also the cellular complexes marked by magnetic spheres. The method of positive immunomagnetic separation has some advantages for the intraoperative diagnosis. However, when either method was applied, among CK+ cells in bone marrow and lymph nodes some false-positive, questionable cellular forms and hemopoietic cells expressing epithelial markers were found. Theses results suggest that for verification of micrometastases in these organs, an additional study using the standard staining of the slides, is required.


Subject(s)
Bone Marrow Cells/chemistry , Bone Marrow Neoplasms/diagnosis , Immunohistochemistry/methods , Immunomagnetic Separation/methods , Keratins/analysis , Lymph Nodes/chemistry , Bone Marrow Cells/pathology , Bone Marrow Neoplasms/pathology , Bone Marrow Neoplasms/secondary , Humans , Lymph Nodes/pathology , Lymphatic Metastasis
17.
Talanta ; 68(5): 1474-81, 2006 Feb 28.
Article in English | MEDLINE | ID: mdl-18970488

ABSTRACT

Thermal-lens spectrometry was used for the investigation of the adsorption of ionene to quartz surfaces. The thermooptical analysis of the surface makes it possible to distinguish the modified surface from a clean quartz surface and to provide sensitive direct concentration measurements of the light absorbing co-adsorbed substance. The co-adsorption of chromate ions and 2,10-ionene from aqueous solutions to quartz surfaces was investigated and the desorption procedure proposed.

18.
Anal Bioanal Chem ; 375(8): 1204-11, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12733040

ABSTRACT

A mode-mismatched parallel dual-beam thermal lens spectrometer with a far-field single-channel detector system was used as a detector in HPLC. An expert estimation of the measurement results was applied to optimize the optical-scheme configuration of the spectrometer to achieve the longest linear calibration range and highest repeatability under chromatographic flow conditions. Chelates with 4-(2-pyridylazo)resorcinol were separated and determined with the limits of detection of n x 10(-8)- n x 10(-7) mol L(-1); the relative standard deviation of measurements was 46%. Xylenol Orange, 4-(2-thiazolylazo)resorcinol, and dithizone were studied as post-column reagents in thermal lens detection in ion chromatography. The limits of detection were n x 10(-8)- n x 10(-7) mol L(-1); the linear calibration ranges were about three orders; the relative standard deviation of measurements was 3-7%. A combined photothermal-refractometric detector for HPLC based on a polarization interferometer is proposed. Metal complexes as 4-(pyridylazo)resorcinol chelates (limits of detection of n x 10(-8)- n x 10(-7) mol L(-1)) and sugars (limits of detection of 10-20 ng L(-1)) were investigated as model substances. Obtained results were compared with results for traditional detectors, which show that photothermal detection has higher sensitivity than photometric and other absorption detectors.

19.
Anal Bioanal Chem ; 375(8): 1199-203, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12733039

ABSTRACT

Polyacrylic acid (PAA) and polymethacrylic acid (PMAA) with carboxyl groups partially blocked by dodecyltrimethylammonium bromide (DTAB) and tetrabutylammonium bromide (TBAB) were tested as new pseudo-stationary phases in micellar electrokinetic chromatography (MEKC). The separation of was examined using PAA and PMAA. Excellent resolution of the substituted phenols and derivatized amino acids was demonstrated using additives of PAA-DTAB polyelectrolyte complex in the running phosphate buffer. It was found that the capacity factors were proportional to the concentration of the complex PAA/DTAB. Critical micelle concentration was effectively zero. It was found that the migration times and efficiency of separation of phenols and derivatives of amino acids depended on the type of polymers and alkyltrimethylammonium salts used.

20.
J Chromatogr A ; 979(1-2): 191-9, 2002 Dec 06.
Article in English | MEDLINE | ID: mdl-12498248

ABSTRACT

This study demonstrates that an amino-beta-cyclodextrin-bonded phase column exhibits enantioselectivity for various amino acid derivatives. Mixtures of methanol, acetonitrile, tetrahydrofuran or dioxan and triethylamine buffers (pH 4.0-7.0) were used as mobile phases. The effect of the mobile phase on the resolution process was studied by varying the mobile phase composition (type and percentage of organic modifiers, pH, and ionic strength of the buffer solution). The 1-octanol-water partition coefficients are calculated and tabulated for 16 derivatized amino acids. The chromatographic data for 42 pairs of derivatized amino acids resolved on the amino-beta-cyclodextrin-bonded phase are summarised. The separation of adrenaline, noradrenaline and amphetamine on a novel vancomycin stationary phase is demonstrated.


Subject(s)
Amino Acids/isolation & purification , Biogenic Monoamines/isolation & purification , Chromatography, High Pressure Liquid/methods , Amino Acids/chemistry , Biogenic Monoamines/chemistry , Chromatography, High Pressure Liquid/instrumentation , Stereoisomerism
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