A new green approach to L-histidine and β-alanine analysis in dietary supplements using rapid and simple contactless conductivity detection integrated with high-resolution glass-microchip electrophoresis

The analysis of dietary supplements is far less regulated than pharmaceuticals, leading to potential quality issues. Considering their positive effect, many athletes consume supplements containing L-histidine and β-alanine. A new microfluidic method for the determination of L-histidine and β-alanine in dietary supplement formulations has been developed. For the first time, capacitively coupled contactless conductivity detection was employed for the microchip electrophoresis of amino acids in real samples. A linear relationship between detector response and concentration was observed in the range of 10-100 µmol L-1 for L-histidine (R2 = 0.9968) and β-alanine (R2 = 0.9954), while achieved limits of detection (3 × S/N ratio) were 4.2 µmol L-1 and 5.2 µmol L-1, respectively. The accuracy of the method was confirmed using recovery experiments as well as CE-UV-VIS and HPLC-UV-VIS techniques. The developed method allows unambiguous identification of amino acids in native form without chemical derivatization and with the possibility of simultaneous analysis of amino acids with metal cations.

Electrophoretic Determination of L-Carnosine in Health Supplements Using an Integrated Lab-on-a-Chip Platform with Contactless Conductivity Detection

The health supplement industry is one of the fastest growing industries in the world, but there is a lack of suitable analytical methods for the determination of active compounds in health supplements such as peptides. The present work describes an implementation of contactless conductivity detection on microchip technology as a new strategy for the electrophoretic determination of L-carnosine in complex health supplement formulations without pre-concentration and derivatization steps. The best results were obtained in the case of +1.00 kV applied for 20 s for injection and +2.75 kV applied for 260 s for the separation step. Under the selected conditions, a linear detector response of 5 × 10-6 to 5 × 10-5 M was achieved. L-carnosine retention time was 61 s. The excellent reproducibility of both migration time and detector response confirmed the high precision of the method. The applicability of the method was demonstrated by the determination of L-carnosine in three different samples of health supplements. The recoveries ranged from 91 to 105%. Subsequent analysis of the samples by CE-UV-VIS and HPLC-DAD confirmed the accuracy of the obtained results.

Study of zeolite clinoptilolite d-glucose adsorption properties in vitro and in vivo

Beneficial effects of a natural zeolite clinoptilolite in vivo on mammals, including humans, have been empirically observed and documented in literature. The positive biological activities have been associated to its detoxifying and antioxidative properties, and its immunostimulative and adsorption properties. Herein, we present the in vitro and in vivo study of clinoptilolite zeolite materials adsorption properties for d-glucose. In particular, we present data on the interaction of d-glucose on the tested zeolites' surface obtained by scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS) and quantification by ultra high-performance liquid chromatography (UHPLC). We also present results on the reduction of blood glucose levels in mice pre-treated with clinoptilolite in vivo upon feeding with d-glucose. In vivo results were in line with the in vitro adsorption and/or interaction properties of tested zeolite materials for d-glucose and were quantified by UHPLC as well (11.34% for TMAZ; 10.82% for PMA and 8.76% for PMAO2). In vivo experiments in mice showed that PMA zeolite reduces blood glucose levels upon 15 min for 13% (at p < 0.05) up to 19.11% upon 120 min (without statistical significance) in clinoptilolite pre-treated mice fed by addition of d-glucose. Due to lack of explicit mechanistic knowledge on zeolite clinoptilolite interactions or adsorption with sugars in vitro and in vivo, presented study provides novel insights into these aspects for researchers in the field. The presented data merit further investigations as the material clearly shows a potential in management of hyperglycemia, such as for example in obese people, people with diabetes and people with metabolic syndrome where it could help regulate blood glucose levels.

Study of Cationic Surfactants Raw Materials for COVID-19 Disinfecting Formulations by Potentiometric Surfactant Sensor

The behavior of a new 1,3-dioctadecyl-1H-imidazol-3-ium tetraphenylborate (DODI-TPB) surfactant sensor was studied in single and complex mixtures of technical grade QACs-benzalkonium chloride (BAC), N,N-didecyl-N,N-dimethylammonium chloride (DDAC), and N,N-dioctyl-N,N-dimethylammonium chloride (DOAC) usually used in COVID-19 disinfecting agents formulations. The results obtained with the new DODI-TPB sensor were in good agreement with data measured by a 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-tetraphenylborate (DMI-TPB) surfactant sensor, as well as two-phase titration used as a reference method. The quantitative titrations of a two-component mixture of the cationic homologs (a) DDAC and DOAC; and (b) BAC and DOAC showed that the new DODI-TPB surfactant sensor can clearly distinguish two separate mixture components in a single potentiometric titration curve with two characteristic inflexion points. The consumption of SDS (used as a titrant) in the end-point 1 (EP 1) corresponded to the content of DDAC (or BAC), whereas the consumption in the end-point 2 (EP 2) corresponded to the total content of both cationic surfactants in the mixture. DOAC content in both mixtures can be calculated from the difference of the titrant used to achieve EP1 and EP2. The addition of nonionic surfactants resulted in the signal change decrease from 333.2 mV (1:0; no nonionic surfactant added) to 243.0 mV (1:10, w/w). The sensor was successfully tested in ten two-component COVID-19 disinfecting formulations.

The 1,3-Dioctadecyl-1H-imidazol-3-ium Based Potentiometric Surfactant Sensor for Detecting Cationic Surfactants in Commercial Products

A low-cost and fast potentiometric surfactant sensor for cationic surfactants, based on the new ion-pair 1,3-dioctadecyl-1H-imidazol-3-ium-tetraphenylborate (DODI-TPB), is presented. The new cationic surfactant DODI-Br was synthesized and characterized by NMR, LC-MS, and elemental analysis, and was used for synthesis of the DODI-TPB ionophore. The DODI-TPB surfactant sensor was obtained by implementation of the ionophore in PVC. The sensor showed excellent response characteristics with near-Nernstian slopes to the cationic surfactants DMIC, CPC, CTAB, and Hyamine 1622. The highest voltage responses were obtained for DMIC and CPC (58.7 mV/decade of activity). DMIC had the lowest detection limit (0.9 × 10^-6 M) and the broadest useful linear concentration range (1.8 × 10^-6 to 1.0 × 10^-4 M). An interference study showed remarkable stability. Potentiometric titration curves for the titration of cationic surfactants (DMIC, CPC, CTAB, and Hyamine 1622), with DDS and TPB used as titrants, showed sigmoidal curves with well-defined inflexion points and a broad signal change. The standard addition method was successfully applied with recovery rates from 98.9 to 101.2 at two concentrations. The amount of cationic surfactant found in disinfectants and antiseptics was in good agreement with the referent two-phase titration method and the surfactant sensor on the market. This new surfactant sensor represents a low-cost alternative to existing methods for cationic surfactant detection.

Anticancer Activities of Marine-Derived Phenolic Compounds and Their Derivatives

Since the middle of the last century, marine organisms have been identified as producers of chemically and biologically diverse secondary metabolites which have exerted various biological activities including anticancer, anti-inflammatory, antioxidant, antimicrobial, antifouling and others. This review primarily focuses on the marine phenolic compounds and their derivatives with potent anticancer activity, isolated and/or modified in the last decade. Reports on the elucidation of their structures as well as biosynthetic studies and total synthesis are also covered. Presented phenolic compounds inhibited cancer cells proliferation or migration, at sub-micromolar or nanomolar concentrations (lamellarins D (37), M (38), K (39), aspergiolide B (41), fradimycin B (62), makulavamine J (66), mayamycin (69), N-acetyl-N-demethylmayamycin (70) or norhierridin B (75)). In addition, they exhibited anticancer properties by a diverse biological mechanism including induction of apoptosis or inhibition of cell migration and invasive potential. Finally, phlorotannins 1–7 and bromophenols 12–29 represent the most researched phenolic compounds, of which the former are recognized as protective agents against UVB or gamma radiation-induced skin damages. Finally, phenolic metabolites were assorted into six main classes: phlorotannins, bromophenols, flavonoids, coumarins, terpenophenolics, quinones and hydroquinones. The derivatives that could not be attributed to any of the above-mentioned classes were grouped in a separate class named miscellaneous compounds.

Chemical Evaluation, Antioxidant, Antiproliferative, Anti-Inflammatory and Antibacterial Activities of Organic Extract and Semi-Purified Fractions of the Adriatic Sea Fan, Eunicella cavolini

Due to sedentary lifestyle and harsh environmental conditions, gorgonian coral extracts are recognized as a rich source of novel compounds with various biological activities, of interest to the pharmaceutical and cosmetic industries. The presented study aimed to perform chemical screening of organic extracts and semi-purified fractions obtained from the common Adriatic gorgonian, sea fan, Eunicella cavolini (Koch, 1887) and explore its abilities to exert different biological effects in vitro. Qualitative chemical evaluation revealed the presence of several classes of secondary metabolites extended with mass spectrometry analysis and tentative dereplication by using Global Natural Product Social Molecular Networking online platform (GNPS). Furthermore, fractions F4 and F3 showed the highest phenolic (3.28 ± 0.04 mg GAE/g sample) and carotene (23.11 ± 2.48 mg β-CA/g sample) content, respectively. The fraction F3 inhibited 50% of DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and ABTS (2,2′-azino-bis (3-ethylbenzthiazolin-6-yl) sulfonic acid) radicals at the concentrations of 767.09 ± 11.57 and 157.16 ± 10.83 µg/mL, respectively. The highest anti-inflammatory potential was exhibited by F2 (IC₅₀ = 198.70 ± 28.77 µg/mL) regarding the inhibition of albumin denaturation and F1 (IC₅₀ = 254.49 ± 49.17 µg/mL) in terms of soybean lipoxygenase inhibition. In addition, the most pronounced antiproliferative effects were observed for all samples (IC₅₀ ranging from 0.82 ± 0.14–231.18 ± 46.13 µg/mL) against several carcinoma cell lines, but also towards non-transformed human fibroblasts pointing to a generally cytotoxic effect. In addition, the antibacterial activity was tested by broth microdilution assay against three human pathogenic bacteria: Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The latter was the most affected by fractions F2 and F3. Finally, further purification, isolation and characterization of pure compounds from the most active fractions are under investigation.

Potentiometric Surfactant Sensor Based on 1,3-Dihexadecyl-1H-benzo[d]imidazol-3-ium for Anionic Surfactants in Detergents and Household Care Products

A 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-tetraphenylborate (DHBI-TPB) ion-pair implemented in DHBI-TPB surfactant sensor was used for the potentiometric quantification of anionic surfactants in detergents and commercial household care products. The DHBI-TPB ion-pair was characterized by FTIR spectroscopy and computational analysis which revealed a crucial contribution of the C-H∙∙∙π contacts for the optimal complex formation. The DHBI-TPB sensor potentiometric response showed excellent analytical properties and Nernstian slope for SDS (60.1 mV/decade) with LOD 3.2 × 10^-7 M; and DBS (58.4 mV/decade) with LOD 6.1 × 10^-7 M was obtained. The sensor possesses exceptional resistance to different organic and inorganic interferences in broad pH (2-10) range. DMIC used as a titrant demonstrated superior analytical performances for potentiometric titrations of SDS, compared to other tested cationic surfactants (DMIC > CTAB > CPC > Hyamine 1622). The combination of DHBI-TPB sensor and DMIC was successfully employed to perform titrations of the highly soluble alkane sulfonate homologues. Nonionic surfactants (increased concentration and number of EO groups) had a negative impact on anionic surfactant titration curves and a signal change. The DHBI-TPB sensor was effectively employed for the determination of technical grade anionic surfactants presenting the recoveries from 99.5 to 101.3%. The sensor was applied on twelve powered samples as well as liquid-gel and handwashing home care detergents containing anionic surfactants. The obtained results showed good agreement compared to the outcomes measured by ISE surfactant sensor and a two-phase titration method. The developed DHBI-TPB surfactant sensor could be used for quality control in industry and has great potential in environmental monitoring.

Direct Potentiometric Study of Cationic and Nonionic Surfactants in Disinfectants and Personal Care Products by New Surfactant Sensor Based on 1,3-Dihexadecyl-1H-benzo[d]imidazol-3-ium

A novel, simple, low-cost, and user-friendly potentiometric surfactant sensor based on the new 1,3-dihexadecyl-1H-benzo[d]imidazol-3-ium-tetraphenylborate (DHBI-TPB) ion-pair for the detection of cationic surfactants in personal care products and disinfectants is presented here. The new cationic surfactant DHBI-Br was successfully synthesized and characterized by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectrometry, liquid chromatography-mass spectrometry (LC-MS) and elemental analysis and was further employed for DHBI-TPB ion-pair preparation. The sensor gave excellent response characteristics for CTAB, CPC and Hyamine with a Nernstian slope (57.1 to 59.1 mV/decade) whereas the lowest limit of detection (LOD) value was measured for CTAB (0.3 × 10-6 M). The sensor exhibited a fast dynamic response to dodecyl sulfate (DDS) and TPB. High sensor performances stayed intact regardless of the employment of inorganic and organic cations and in a broad pH range (2-11). Titration of cationic and etoxylated (EO)-nonionic surfactant (NSs) (in Ba2+) mixtures with TPB revealed the first inflexion point for a cationic surfactant and the second for an EO-nonionic surfactant. The increased concentration of EO-nonionic surfactants and the number of EO groups had a negative influence on titration curves and signal change. The sensor was successfully applied for the quantification of technical-grade cationic surfactants and in 12 personal care products and disinfectants. The results showed good agreement with the measurements obtained by a commercial surfactant sensor and by a two-phase titration. A good recovery for the standard addition method (98-102%) was observed.

Amide Synthesis by Transamidation of Primary Carboxamides

The amide functionality is one of the most important and widely used groups in nature and in medicinal and industrial chemistry. Because of its importance and as the actual synthetic methods suffer from major drawbacks, such as the use of a stoichiometric amount of an activating agent, epimerization and low atom economy, the development of new and efficient amide bond forming reactions is needed. A number of greener and more effective strategies have been studied and developed. The transamidation of primary amides is particularly attractive in terms of atom economy and as ammonia is the single byproduct. This review summarizes the advancements in metal-catalyzed and organocatalyzed transamidation methods. Lewis and Brønsted acid transamidation catalysts are reviewed as a separate group. The activation of primary amides by promoter, as well as catalyst- and promoter-free protocols, are also described. The proposed mechanisms and key intermediates of the depicted transamidation reactions are shown.

1 Introduction

2 Metal-Catalyzed Transamidations

3 Organocatalyzed Transamidations

4 Lewis and Brønsted Acid Catalysis

5 Promoted Transamidation of Primary Amides

6 Catalyst- and Promoter-Free Protocols

7 Conclusion

Marine Natural Products with High Anticancer Activities

This review covers recent literature from 2012-2019 concerning 170 marine natural products and their semisynthetic analogues with strong anticancer biological activities. Reports that shed light on cellular and molecular mechanisms and biological functions of these compounds, thus advancing the understanding in cancer biology are also included. Biosynthetic studies and total syntheses, which have provided access to derivatives and have contributed to the proper structure or stereochemistry elucidation or revision are mentioned. The natural compounds isolated from marine organisms are divided into nine groups, namely: alkaloids, sterols and steroids, glycosides, terpenes and terpenoids, macrolides, polypeptides, quinones, phenols and polyphenols, and miscellaneous products. An emphasis is placed on several drugs originating from marine natural products that have already been marketed or are currently in clinical trials.

Sequential Dispersive Measurement of a Superconducting Qubit

We present a superconducting device that realizes the sequential measurement of a transmon qubit. The device disables common limitations of dispersive readout such as Purcell effect or transients in the cavity mode by turning on and off the coupling to the measurement channel on demand. The qubit measurement begins by loading a readout resonator that is coupled to the qubit. After an optimal interaction time with negligible loss, a microwave pump releases the content of the readout mode by upconversion into a measurement line in a characteristic time as low as 10 ns, which is 400 times shorter than the lifetime of the readout resonator. A direct measurement of the released field quadratures demonstrates a readout fidelity of 97.5% in a total measurement time of 220 ns. The Wigner tomography of the readout mode allows us to characterize the non-Gaussian nature of the readout mode and its dynamics.

'Sandwich'-like hybrid ZnO thin films produced by a combination of atomic layer deposition and wet-chemistry using a mercapto silane as single organic precursor

This study describes a straightforward preparation of hybrid organic-inorganic thin films containing a stable 'sandwich'-like structure of two atomic layer deposited (ALD) ZnO layers separated by a thin organosilane phase, which is built from a single organic component (3-mercaptopropyl)trimethoxysilane (MPTMS). Grafting of MPTMS on the first ALD ZnO layer was performed in solution and driven by the strong affinity of the terminal thiol functionality (-SH) towards ZnO. We demonstrate that under different reaction conditions, either MPTMS monolayers are prepared or a 5 nm thick cross-linked polymeric network is formed due to the self-condensation of silane, which covers the ALD ZnO surface. This film served as a soft template for the nucleation of an ALD ZnO top layer by creation of S-Zn and Si-O-Zn bonds at the upper interface, as confirmed by XPS measurements. An increase in surface roughness, as compared to the initial ZnO film, is observed after removal of the organic layer from the hybrid structure by calcination, which is accompanied by an improvement in UVA photocatalytic activity towards the degradation of methyl orange dye. Thus, MPTMS can be used as a sacrificial agent in combination with low temperature ALD processes for building rougher and photocatalytically efficient ZnO coatings.

Secondary Metabolites from Gorgonian Corals of the Genus Eunicella: Structural Characterizations, Biological Activities, and Synthetic Approaches

Gorgonian corals, which belong to the genus Eunicella, are known as natural sources of diverse compounds with unique structural characteristics and interesting bioactivities both in vitro and in vivo. This review is focused primarily on the secondary metabolites isolated from various Eunicella species. The chemical structures of 64 compounds were divided into three main groups and comprehensively presented: a) terpenoids, b) sterols, and c) alkaloids and nucleosides. The observed biological activities of depicted metabolites with an impact on cytotoxic, anti-inflammatory, and antimicrobial activities were reviewed. The most promising biological activities of certain metabolites point to potential candidates for further development in pharmaceutical, cosmetic, and other industries, and are highlighted. Total synthesis or the synthetic approaches towards the desired skeletons or natural products are also summarized.

Demonstration of an Effective Ultrastrong Coupling between Two Oscillators

When the coupling rate between two quantum systems becomes as large as their characteristic frequencies, it induces dramatic effects on their dynamics and even on the nature of their ground state. The case of a qubit coupled to a harmonic oscillator in this ultrastrong coupling regime has been investigated theoretically and experimentally. Here, we explore the case of two harmonic oscillators in the ultrastrong coupling regime. Probing the properties of their ground state remains out of reach in natural implementations. Therefore, we have realized an analog quantum simulation of this coupled system by dual frequency pumping a nonlinear superconducting circuit. The pump amplitudes directly tune the effective coupling rate. We observe spectroscopic signature of a mode hybridization that is characteristic of the ultrastrong coupling. We experimentally demonstrate a key property of the ground state of this simulated ultrastrong coupling between modes by observing simultaneous single- and two-mode squeezing of the radiated field below vacuum fluctuations.

Evaluation of Ergonomic Risks during Dental Work

Aim: The purpose was to assess ergonomic risk level in dentistry, which may contribute to manifestation of musculoskeletal disorders (MSD).

Methods and Materials: The study included ten dentists, postgraduate students, mean age (33 ± 3.4). Participants were asked to perform typical dental examination in standing and sitting positions. The surface electromyography (EMG) was recorded during dental work from both left and right shoulder muscles: descendent trapezius muscle (T); back muscles: erector spinae muscle (ES); and neck muscles: sternocleidomastoid muscle (SCM) and splenius capitis muscle (SC).

Results: High muscles forces, greater than 21% of the maximal voluntary contraction (MVC), which could be indicative of high risk, particularly occurred in muscles SC on both sides of the body in the sitting position. The medium risk level occurred in the same muscles on both sides in standing position. Left and right T muscles were under medium ergonomic risk level in both, sitting and standing working positions. SCM muscles on the left and right side of the body in both working positions were under low risk level, lower than 10% of the MVC. In sitting position, medium risk level occurred in ES muscles on both body sides, while in standing position the risk was low.

Conclusion: Dentists are exposed to ergonomic risk. By combining both sitting and standing position the risk can be reduced.

The isolation and synthesis of neodolastane diterpenoids

This account summarises the progress in isolation, characterisation and synthesis of diterpenoids sharing a tricyclic neodolastane skeleton as well as their biogenetic origin and diverse biological activities.

Mild and chemoselective lactone ring-opening with (TMS)ONa. Mechanistic studies and application to sweroside derivatives

Mild and chemoselective opening of lactones with sodium trimethylsilanolate in high yields and aprotic solvents is described. Kinetic studies demonstrate that the B(Ac)2 mechanistic pathway is followed. Nucleophilic attack of silanolate onto the carbonyl of the lactone moiety is the rate-determining step. NaOH present as an impurity accelerates the reaction. The method was further applied to the base-sensitive and stable lactones derived from highly functionalized iridoid derivatives.

Amide formation in one pot from carboxylic acids and amines via carboxyl and sulfinyl mixed anhydrides

An efficient method has been developed for the preparation of yet unknown acyclic mixed anhydrides of carboxylic and sulfinic acids. Sterically hindered 2-methylbut-3-ene-2-sulfinyl carboxylates add primary and secondary amines preferentially onto the carbonyl moieties realizing a new method for the one-pot preparation of carboxamides. It uses 1:1 mixtures of carboxylic acids and amines without a base, requires no excess of reagents, and liberates only volatile coproducts. Protected di- and tripeptides have been prepared in solution without epimerization by application of this method.

Intermolecular insertion of ethylene and octene into a palladium-amide bond. Spectroscopic evidence for an ethylene amido intermediate

We report a series of palladium diarylamido complexes containing a cyclometalated phosphine ligand and a coordinated THF that form enamine products from migratory insertion of ethylene and octene into the metal-nitrogen bond. The reactions of these complexes were sensitive to the electronic properties of the diarylamido group. The complex with the more electron-donating amido ligand reacted nearly 2 orders of magnitude faster than the complex with the least electron-donating amido group. The mechanism of the reactions with alkenes involves exchange of olefin for THF, as revealed by the positive order of the reaction in alkene and inverse order in the concentration of THF. A syn-aminopalladation that would result from migratory insertion was revealed by the stereochemistry of the enamine product resulting from reaction with cis-ethylene-d(2). Finally, a three-coordinate THF-free species was isolated from a synthesis of the amido complex in aromatic solvents, and spectroscopic evidence for an ethylene amido species was gained, in part by the addition of H(2)(13)C=(13)CH(2) to the three-coordinate amido complex at -100 degrees C.

Direct, intermolecular, enantioselective, iridium-catalyzed allylation of carbamates to form carbamate-protected, branched allylic amines

The direct reaction between carbamates and achiral allylic carbonates to form branched, conveniently protected primary allylic amines with high regioselectivity and enantioselectivity is reported. This process occurs without base or with 0.5 equiv K(3)PO(4) in the presence of a metalacyclic iridium catalyst containing a labile ethylene ligand. The reactions of aryl-, heteroaryl-, and alkyl-substituted allylic carbonates with BocNH(2), FmocNH(2), CbzNH(2), TrocNH(2), TeocNH(2), and 2-oxazolidinone occur in good yields, with high selectivity for the branched isomer and high enantioselectivities (98% average ee).

[Assessment of perioperative fluid balance]

Careful assessment of the fluid balance is required in the perioperative period since appropriate fluid therapy is essential for successful patient's outcome. Haemodynamic monitoring allows understanding the physiology of the circulation and changes of fluid balance in the perioperative period. This is diagnostic aid and guide for fluid replacement therapy. Patient's volume status is frequently assessed by different haemodynamic variables that could be targeted as the endpoints for fluid therapy and resuscitation. Fluid balance is the crucial factor in the maintenance of haemodynamic stability, tissue oxygenation and organ function. When the haemodynamic monitoring is applied in a rigorous and consistent manner, it reduces mortality and length of stay as well as costs incurred. There are a number of tests which describe the effectiveness of the invasive haemodynamic monitoring procedures usage. Since the pulmonary artery catheter (PAC) had been introduced into clinical practice it was considered as a golden standard for cardiac output measurements, haemodynamic and fluid balance assessment. Nevertheless, in previous 10 years new minimally invasive and noninvasive simple techniques for haemodynamic monitoring and patient's hydroelectricity status evaluation have been developed. They can replace PAC under different clinical circumstances and some of these techniques

[A look into the larynx--two centuries along the path of laryngoscopy]

Both the design and purpose of the laryngoscope have been changed significantly since Alfred Kirstein invented his own "laryngeal mirror"--the autoscope. An initially straight, rigid oesophageal tube has been reshaped into a number of laryngeal blade modifications, suitable for use in various patient subpopulations. A tool initially intended to help otorhynolaryngologists diagnose and treat laryngeal diseases has been transformed into an instrument intended to help anesthesiologists intubate the trachea for the purpose of either anesthesia administration or airway maintenance. As direct laryngoscopy depends greatly upon individual manual skills, there has been almost no beginner who feels no proud of his first successful intubation. Thus, we should never forget the pioneers of laryngoscopy whose curiosity, creativity, and enthusiasm enabled us to give a clear and safe look into the larynx.

Simultaneous surgical treatment of ruptured abdominal aortic aneurysm and acute carotid occlusive disease

Combined rupture of abdominal aortic aneurysm and acute thrombosis of internal carotid artery is extremely rare but fatal combination resulting in high mortality rate. Presented case, shows successfully performed simultaneous surgery of ruptured abdominal aortic aneurysm and acute cerebrovascular insult caused by thrombosis of carotid artery in 81 year-old male. Post operative course was uneventfull. At 24 months follow up patient was in good condition, with full neurological recovery. Simultaneous surgical treatment of acute occlusive carotid disease and ruptured abdominal aortic aneurysm (RAAA) seems to be the only life saving procedure for this rare, but very complicated condition. To our knowledge, this is the first reported successful simultaneous surgical treatment of RAAA and acute thrombosis of internal carotid artery.

New organic chemistry of sulfur dioxide

Simple 1,3-dienes undergo highly stereoselective hetero-Diels-Alder additions with SO2 at low temperature giving sultines. These reactions that are faster than the more exothermic cheletropic additions of SO2-producing sulfolenes. This has led to the invention of a new C-C bond-forming reaction combining electron-rich dienes and alkenes with SO2. The reaction cascade has been exploited to develop combinatorial, one-pot, four-component syntheses of polyfunctional sulfones, sulfonamides, and sulfonic esters. It also allows us to generate, in one-pot operations, enantiomerically enriched polypropionate fragments containing up to three contiguous stereogenic centers and a (E)-alkene unit. These fragments can be used directly in further C-C bond-forming reactions, such as cross-aldol condensations, thus permitting the expeditious construction of complicated natural products of biological interest (e.g., Baconipyrones, Rifamycin S, Apoptolidinone) and analogues. New ene reactions of SO2 have also been discovered; they open new avenues to organic synthesis.

Mechanism of the diphenyldisulfone-catalyzed isomerization of alkenes. Origin of the chemoselectivity: experimental and quantum chemistry studies

Polysulfone- and diphenyldisulfone-catalyzed alkene isomerizations are much faster for 2-alkyl-1-alkenes than for linear, terminal alkenes. The mechanism of these reactions has been investigated experimentally for the isomerization of methylidenecyclopentane into 1-methylcyclopentene, and theoretically [CCSD(T)/6-311++G(d,p)//B3LYP/6-311++G(d,p) calculations] for the reactions of propene and 2-methylpropene with a methanesulfonyl radical, MeSO2*. On heating, polysulfones and (PhSO2)2 equilibrate with sulfonyl radicals, RSO2*. The latter abstract allylic hydrogen atoms in one-step processes giving allylic radical/RSO2H pairs that recombine within the solvent cage producing the corresponding isomerized alkene and RSO2*. The sulfinic acid, RSO2H, can diffuse out from the solvent cage (H/D exchange with MeOD,D2O) and reduce an allyl radical. Calculations did not support other possible mechanisms such as hydrogen exchange between alkenes, electron transfer, or addition/elimination process. Kinetic deuterium isotopic effects measured for the (PhSO2)2-catalyzed isomerization of methylidenecyclopentane and deuterated analogues and calculated for the H abstraction from 2-methylpropene and deuterated analogues by CH3SO2* are consistent also with the one-step hydrogen transfer mechanism. The high chemoselectivity for this reaction is not governed by an exothermicity difference but by a difference in ionization energies of the alkenes. Calculations for CH3SO2* + propene and CH3SO2* + 2-methylpropene show a charge transfer of 0.34 and 0.38 electron, respectively, from the alkenes to the sulfonyl radical in the transition states of these hydrogen abstractions.

A biased Gm haplotype and Gm paraprotein allotype in multiple myeloma suggests a role for the Gm system in myeloma development

The association between a particular Gm haplotype and susceptibility to multiple myeloma (MM) is not clear. The reason is probably because no investigations have so far been carried out on the relationship between the Gm haplotype, which represents the inherited combination of IgG Gm allotypes, and the Gm allotype expressed at the IgG paraprotein (M-component), which reflects the enhanced gene expression within the haplotype in MM. We studied the incidence of Gm allotypic markers present in IgG subclasses in the serum from 52 patients with MM and in parallel with the isolated IgG paraproteins. The results showed that 84.6% of the patients were heterozygous for haplotypes Gm(a; z; n-; g;)/Gm(f; n+/n-; b1; b0; b5) and 15.3% were homozygous for Gm(f; n/n-; b1; b0; b5), while no homozygous Gm(a; z; n-; g) individuals were found among the studied patients. The incidence of these combinations in the healthy population in Serbia is 34%, 66% and < 1%, respectively. Subjects with Gm(a; z; n-; g)/Gm(f; n+/n-; b1; b0; b5) combination are over 10 times [odds ratio (OR) = 10.69; 95% confidence interval 1.67-68] as likely to be affected by the disease as the subjects with homozygous Gm(f; n+/n-; b1; b0; b5) combination (OR = 0.35, 95% confidence interval 0.06-2.23). However, despite the Gm heterozygosity, most of the Gm(a; z; n-; g;)/Gm(f; n+/n-; b1; b0; b5) positive patients with MM (86.3%) had IgG paraprotein with the allotypic marker from the Gm(f; n+/n-; b1; b0; b5) haplotype. Together with patients homozygous for this haplotype, the relative number of patients with serum IgG paraprotein carrying allotypic marker from the Gm(f; n/n-; b1; b0; b5) haplotype was 88.5%. These results suggest that the development of an M-component could be related to a disturbance on chromosome 14q32 carrying the Gm (f; n+/n-; b1; b0; b5) set of genes.

[Perspective of mechanical ventilation of lungs]

Mechanical ventilation of lungs during the long history has gone through different phases, which have been associated with technological and scientific development of its time. This is the most complex process and in spite of many progress it does not solve all problems, maintained of respiratory homeostasis, especially in patients with difficult lungs damage. Therefore, there is an existing need for further development of mechanical ventilation of lungs. Over the past time, a number of innovative approaches or adjuncts to mechanical ventilation have been actively researched. Many of these have shown some promise in improving our ability to provide ventilatory support. Which of these innovations will outlast the future? Based on actual development at innovations of mechanical ventilation, it can be assumed that it will be: protective lung ventilation, special form of gas exchange, weaning from mechanical ventilation, noninvasive and home use ventilators, development in fallowing patient's condition and pharmacotherapy development.

Hydrothermal synthesis and nanostructure of carbonated calcium hydroxyapatite

The influence of precursor concentration, pressure, temperature and time of hydrothermal synthesis on the development of calcium hydroxyapatite structure has been analyzed. The obtained results show that it is possible to adjust the conditions of hydrothermal synthesis from solutions of relatively high concentrations to obtain calcium hydroxyapatite nanopowders of well-defined structure. The relationship between the synthesis and the lattice parameters, as well as the crystallite size and the microstructure of synthesized hydroxyapatite has been established. The synthesized powders are preferentially carbonated hydroxyapatite of the B type in the form of agglomerates that accommodate two-modal size pores of 1.5-10 and 50-200 nm. The structure of calcium hydroxyapatite particles consists of crystallites 8-22 nm in size, bound within prime particles, which size is between 10 and 63 nm, that in turn form bigger agglomerates 200 nm in size, which further cluster building up agglomerates 5-20 microm in size.

Allyl, Methallyl, Prenyl, and Methylprenyl Ethers as Protected Alcohols: Their Selective Cleavage with Diphenyldisulfone under Neutral Conditions

Diphenyldisulfone is a mild and efficient reagent for selective cleavage of methylprenyl (2,3-dimethylbut-2-en-1-yl), prenyl (3-methylbut-2-en1-yl), and methallyl (2-methylallyl) ethers. These reaction conditions are compatible with the presence of other protecting groups such as acetals, acetates, and allyl, benzyl, and TBDMS ethers. Exposure of 2,3-dimethylbut-2-en-1-yl and 3-methylbut-2-en1-yl ethers to diphenyldisulfone led to the formation of 2,3-dimethylbuta-1,3-diene and isoprene, respectively. 2-Methylallyl ethers undergo isomerization to 2-methylpropenyl ethers, which are easily hydrolyzed into the corresponding free alcohols and isobutyraldehyde. [reaction: see text]

The role of nitric oxide in treatment of acute lung injury after surgery with extracorporeal circulation

Postoperative acute lung injury (ALI) compromises oxygen transfer across alveolar-capillary membrane with consecutive hypoxia, one of its indicators being reduction of oxygenation index PaO2/FiO2 below 40 kPa (300 mm Hg). Management of ALI includes different procedures like mechanical lung ventilation (MLV), drugs and others. One of the new possibilities for treatment of ALI is nitric oxide (NO) inhalation. The aim of this prospective study was to examine the role of NO inhalation in treatment of ALI. 14 patients with ALI developed immediately after operation with extracorporeal circulation (ECC) were included in the study. Group A (n = 8) inhaled NO and group B (n = 6) did not inhale NO during treatment of ALI. All other therapeutic measures were the same in both groups. The groups were similar in relation to demographic data, type of surgery and duration of ECC. PaO2/FiO2 was calculated before operation (T1), immediately after surgery (T2) and after lung recovery, when the need for MLV stopped (T3). The duration of MLV was also registered. PaO2/FiO2 (kPa) in referent times was in group A 54,9 ? 1,6, 33,8 ? 1,2 and 46,2 ? 0,8 and in group B 52,2 ? 1,1, 33,5 ? 1,5 and 47,3 ? 0,9, respectively. There was a statistically significant decrease of PaO2/FiO2 in T2 and T3 vs T1 in both groups (p < 0,05), while the difference between the groups was not statistically significant. The duration of MLV (h) in group B (28,5 ? 1,6) was statistically significantly shorter than in group A (63,1 ? 8,7) (p < 0,01). According to the results of this study we conclude that NO inhalation during ALI after surgery with ECC significantly reduces the duration of MVL and improves pulmonary recovery .

A simple and rapid analysis of triplet repeat diseases by expand long PCR

It is now known that 15 monogenic, mostly neurological, disorders are caused by the same type of mutations that occur in trinucleotide repeat sequences in certain genes. Since they share a nonspecific and variable phenotype, the accurate diagnosis could be made only by DNA analysis. We developed an Expand Long PCR assay that provides more reliable molecular diagnosis of such disorders. Its main characteristics are robust amplification of expanded alleles, simplicity, low cost and speed. We suggest the use of Expand Long PCR for routine molecular diagnosis of triplet repeat diseases, and present such analysis of the fragile X syndrome, myotonic dystrophy and Huntington's disease.

[Periapical surgery of the molars]

INTRODUCTION

If loss of a great number of teeth occurs, one molar in the lateral segment is of great importance. Contemporary techniques and materials provide extremely successful conservative treatment of pulpal diseases and apical periodontitis. In some cases, however, surgery is indicated.

INDICATIONS

Indications for periapical surgery used to be a matter of double standards. If periapical surgery is indicated in incisors, it is performed without delay, but if it is indicated in molars, it is often exchanged for extraction. Surgical access in the region of upper and lower molars is specific in regard to much more frequently operated incisors due to anatomic structures at the surgical site. Canal filling techniques, implants, endodontic surgical procedures are of importance and can provide better healing. High quality canal filling is condition sine qua non in treatment of apical periodontitis. It is performed prior surgery, by conventional orthograde endodontic techniques, during surgery by orthograde technique and/or retrogradely. Implants provide better bone healing and are recommended in surgery of molar apex. Surgical packing has numerous advantages (better psychological and mechanical care).

CONCLUSION

Good knowledge of anatomy and surgical techniques is a pre-requisite for molar apicoectomy. Careful establishment of indications and good relations with the patient provide good prognosis of this therapeutic method.

[Specifics of mastication with complete dentures]

INTRODUCTION

Mastication is a process characterized by alternating phases of physiological inactivity, food intake, initial food crumbling, mouthful formation and deglutition. Although there is a so called human type of mastication, this process is individual for variety of reasons. Mastication is not an innate characteristic and it must be learned, but once it is learned, it gets a reflexive function, demanding maximal involvement of the highest nervous system centers.

DISCUSSION

Specificities of mastication in complete denture wearers are caused by specificities connected to changes of the oral cavity due to teeth loss, technical features of complete dentures and quality of their manufacture. Loss of teeth causes loss of periodontal receptors consequently damaging the source of information which, as long as teeth are present, travels from the oral cavity towards the central nervous system and regulates the masticatory muscles activity. As one of the consequences of periodontal receptors' loss, interocclusal perception decreases, because the number of receptors within the masticatory mucosa is negligible. Another problem is that loss of teeth causes loss of the occlusal surface. Occlusal surface is considered to be the only reference coordinate of the zero intermaxillary separation with precise spatial representation within the someostatic field cortex. Permanent loss of antagonistic contact causes disappearance of the memory pattern of the occlusal surface. Therefore completely edentulous mouths are characterized by disintegration of the free interocclusal space. Masticatory forces' value directly depends on the: size of muscles creating the forces, their position in the mandibula, shape of the edentulous alveolar ridge, type of chewing, the relationship between the height of the branch, length of the mandibular body, gonial angle, mandibular angle in relation to the anterior cranial base and posterior facial height and the degree of intermaxillary separation. Bite forces in complete denture wearers are significantly decreased in relation to persons with natural teeth. There is a fundamental difference in the distribution of the functional energy in complete denture wearers and subjects with intact teeth. Persons with natural teeth tend to generate energy through bolus, whereas in complete denture wearers most of the chewing energy is distributed outside bolus, directly through the denture base on the supporting tissues.

RESULTS

As the result of this specific dynamics stress of supporting tissues often occurs with consequential mucosal inflammation and rapid alveolar bone resorption. Reduction of masticatory efficacy in denture wearers may be caused by irregular activity of masticatory musculature or is the consequence of irregular flow of energy during mastication. In comparison with young examinees with healthy teeth, authors have registered that complete denture wearers need about seven times more masticatory movements to achieve equal number of sample parts.

CONCLUSION

It has been documented by experience and also scientifically proved, that the satisfaction of complete denture wearers is not often proportional with objective functional denture values. Comparison of subjective parameters with objective test results reveals that the percentage of complete denture wearers who consider their dentures to be good, although they objectively are not such, is significantly higher than the percentage of those who complain about their dentures, although they are functionally proper. Our study comprised patients (average age of 69) who wore complete dentures longer than five years.

[Current knowledge on resorption of the edentulous alveolar ridge]

INTRODUCTION

Due to inside physiological processes of the bone tissue of the residual ridge, the above is identical with the bone tissue in other parts of the body. All bones which contain a larger percentage of substance spongiosa are very sensitive to the changes in remodelation. In mandibula the arrangement of the bone trabeculas is in the same direction with the spongious bone traectoria. In maxillae, functional demands for transmitting the forces, are fulfilled by a larger number of trabeculas per square unit. The atrophia of the residual ridge was a result of teeth loss, which means that there was no working tension on the bone, affected by the periodontal ligament in a physiological way.

MATERIAL AND METHODS

The resent knowledge of the above problems indicates that inflammation and pressure which develop under the mobile denture cause an intensive process of resorption of edentulous arch. In periodontitis the connection between lymphocytes and other inflammatory cells on one side, and the residual bone resorption level on the other side, were proved by stereometrical methods. The ELISA method proved that cytokine interleukin-1 beta (IL-1 beta), IL-1 beta and the tumor necrosis factor alpha, were the major factors in the stimulation of bone resorption, and inhibitatory of the above, as well. Mononucleous blood cells under the influence of the Porphyromonas gingivalis were forming interleukin-1 which explains that the etiology of bone resorption can be affected by the infection, too.

DISCUSSION

It has been proved that there is a direct relation between the pressure under the mobile denture and the residual ridge resorption level on the other side. It seems that the frontal areas of the edentulous are more susceptible to resorption. It is considered that the orthopantomography is the most acceptable method in level measuring of the reduction of residual ridge. The advantages of the above method are simplicity, precision, repeating possibilities, and comparation of the radiographs in time interval which makes it possible to control the development of changes. Densitometric measuring of osteoporotic changes is also possible, due to above method.

CONCLUSION

The scientific contribution to research and prevention of negative consequences of the residual ridge resorption is the most valuable. Tere were many possibilities in using the indirect physiological role of piezoelectric field on the osteoclasts and activation by the AKMA. The effect of the fluor in drinking water as the element which has preventive role in reduction of the residual ridge, has been established. Due to the fact that the occlusal pressure which transmits itself through the mobile denture has an important role in resorption of the residual ridge, acts of terciare prevention include application of soft acrylates and reduction of occlusal surface.