On the impact of side methyl groups on the structure and vibrational properties of β-carotenoids. The case of butadiene and isoprene

Theoretical consideration about the impact of methyl groups on the structure and vibrational properties of β-carotenoids, using medium size molecules of trans-butadiene and trans-isoprene, are reported. Density functional theory (DFT) calculations with correlation-consistent and polarization-consistent basis sets were applied to trans-1,3-butadiene and trans-isoprene as the smallest building bricks of β-carotenoids. Their structure and harmonic vibrations were estimated in the complete basis set limit (CBS) using the non-linear least square fit. Optimized geometries and harmonic frequencies, obtained with B3LYP and BLYP density functionals and large basis sets, were favorably reproduced by a significantly faster approach, using a recently modified STO(1M)-3G Slater-type basis set. Selected density functionals with STO(1M)-3G and 6-311++G** basis sets were also successful in predicting β-carotene structures and harmonic vibrations. This work demonstrates the potential applicability of the proposed level of theory for larger molecules, including β-carotenoids, present in numerous natural food sources. The proposed scheme of molecular modeling, applied to biologically active compounds in food, could provide a deeper insight into their function in vivo, which is directly related to their structure and spectroscopic properties. It could also support the experimental qualitative analysis, based on peak assignment of β-carotenoids in various food sources.

Change of Mechanical Properties of Repair Mortars after Frost Resistance Rests

The use of repair mortars for concrete structures repair with no or limited resistance to the impact caused by freeze and thaw cycles is often the primary repair failure cause. This is particularly important in Poland. Due to the geographical location of the country, there is a large temperature difference between summer and winter. The number of passes through the threshold temperature of 0 °C throughout the year in the winter season exceeds 100. The article presents a comparison of the frost resistance results of tests of repair mortars. The first method was performed according to the Polish Guidelines (without the use of de-icing salts) and the second method according to PN-EN 1504-3 (with the use of de-icing salts). The results obtained were inconsistent in many areas. In particular, significant differences in the results for the change in compressive strength and the change in bending strength were observed. In the case of the frost resistance testing without the use of de-icing salts, a decrease in compressive strength was usually accompanied by a decrease in bending strength. In the case of frost resistance tests with the use of de-icing salts, an increase in the bending strength of mortars was observed (even by a dozen or so percent) with a decrease in the compressive strength of mortars (even by several dozen percent).

Sleepwalking episodes are preceded by arousal-related activation in the cingulate motor area: EEG current density imaging

OBJECTIVE

To investigate local arousal fluctuations in adults who received ICSD-2 diagnosis of somnambulism.

METHODS

EEG neuroimaging (eLORETA) was utilized to compare current density distribution for 4s epochs immediately preceding sleepwalking episode (from -4.0 s to 0 s) to the distribution during earlier 4s epochs (from -8.0 s to -4.0 s) in 20 EEG segments from 15 patients.

RESULTS

Comparisons between eLORETA images revealed significant (t>4.52; p<0.05) brain activations before onset of sleepwalking, with greater current density within beta 3 frequency range (24-30 Hz) in Brodmann areas 33 and 24.

CONCLUSIONS

Sleepwalking motor events are associated with arousal-related activation of cingulate motor area.

SIGNIFICANCE

These results support the notion of blurred boundaries between wakefulness and NREM sleep in sleepwalking.

The Stability and Structure of Complex Species Formed in Equilibrium Reactions of Diethyltin(IV) with N-D-Gluconylamino Acids in Aqueous Solution

Complex formation equilibria of diethyltin(IV) with five N-D-gluconylamino acids in aqueous solution (I = 0.1 M, NaClO4) were studied and the stabilities of the species were determined by potentiometric titrations. Diethyltin(IV) complexes of α-amino acid derivatives are water-soluble in the physiological pH range, while in the presence of N-D-gluconyl-β-alanine a precipitate is formed, which dissolves with increasing pH. 13C NMR measurements showed that in the N-D-gluconyl-α-amino acid complexes the ligand is coordinated through its deprotonated carboxylate oxygen, amide nitrogen and C(2)-hydroxy group, while for the soluble N-D-gluconyl-β-alanine complex the ligand is coordinated via the deprotonated carboxylate and C(3)-, C(4)-, C(5)-hydroxy groups. Mössbauer measurements reflected the geometry of the complexes formed.

Bone mineral density changes after total knee arthroplasty: one-year follow-up

The study involved analysis of differences in bone mineral density (BMD) in the region of knee arthroplasty in 106 female patients. BMD was assessed using dual-energy X-ray absorptiometry in a follow-up time schedule: before surgery and 2 weeks postoperatively (baseline), 5, 12, 24, and 48 weeks after knee joint arthroplasty. Four assessment regions A, B, C, and D were determined in immediate proximity to the arthroplasty site. A year after surgery, a decrease in BMD was observed in all determined regions-(9.9%, 13.8%, 9.9%, and 7.6% respectively) in comparison with the baseline value. The most significant BMD decrease was observed in the period between 5 and 12 weeks after the knee joint arthroplasty. In our opinion, the decrease in BMD at the knee joint arthroplasty site is a result of the postoperative increased bone resorption and decreased patient motor activity.

Intramedullary nailing in treatment of complications of long bone union following fracture - case studies

Open osteosynthesis of long bones fractures carries high risk of complications, the most common of which are plate breakage, slow union, delayed union and non-union. The paper analysis of 3 cases of bone union complications treated by locked intramedullary nailing. The aim was to show differences in the therapeutic management of different bones and non-unions following different types of osteosynthesis. Although bone union took longer to complete than in acute fractures, a good functional result was obtained in each case. Locked intramedullary nailing permits stable bone fixation. Intramedullary canal reaming stimulates bone consolidation since it is the source of autologous bone graft. Similar to its use in the treatment of acute fractures, the method permits early, active and efficient patient rehabilitation.

Use of densitometric examination after cemented total knee arthroplasty

Background. Dual energy X-ray absorptiometry (DXA, DEXA) is one of many ways of measuring bone mineral density (BMD). Considering the fact that it is possible using DXA analysis to distinguish metal elements from bone, this method seems to be optimal in the assessment of bone mineral density in the area of an inserted implant. The aim of our study was to examine the usefulness of DXA examination of the knee joint area after cement arthroplasty. Material and methods. A BMD analysis of four areas surrounding the knee prosthesis was performed using the author's own method. Results. After a series of densitometry analyses, the coefficient of variation (CV) and the least significant difference (LSD) were determined. Conclusions. DXA analysis of the knee joint after arthroplasty using the method described here shows high repeatability. Periodic DXA analysis of the vicinity of the knee prosthesis may be useful in assessing the dynamics of change occurring around the implant.

[Revision hip arthroplasty management tactics--own experience]

INTRODUCTION

Aseptic loosening of hip prosthesis is one of the most serious complications after primary joint arthroplasty. Due to the aging of societies, lengthening of the average life span and increasing number of primary arthroplasty procedures, it can be assumed that the number of revision procedures will be continuously increasing by the year.

THE AIM OF THE STUDY

presentation of own experience in operative management tactics and early results of treatment after the revision hip arthroplasty. MATERIALS AND THE METHOD: The analysis included 182 patients at the average age of 68, who underwent the revision hip arthroplasty procedure. The procedures of this type were performed most often after cement arthroplasty performed using the Weller's method (45%). The average observation period was 2.3 years. A clinical evaluation of the patients was performed using the Harris scale. A preoperative radiological evaluation was performed using Paprosky classification (for an acetabulum) and Mallory classification (for a femoral bone shaft). Bone defects were evaluated using AAOS classification. A postoperative radiological evaluation was performed on the basis of: radiolucent lines of the acetabulum area in DeLee-Charnley zones and in the area of the endoprosthesis stem in Gruen zones, acetabulum migration and settling of the endoprosthesis stem.

RESULTS

During the 2-year observation there were 88.5% of good results reported. According to the Harris scale an improvement was achieved from the average of 46 points before the operation to 85 points after the procedure. 11.5% of bad radiological and functional results were reported including: 11 cases (6.0%) with bad radiological results, and 10 cases (5.5%) with bad clinical results.

CONCLUSIONS

Revision hip arthroplasty procedures require individual planning, selection of implants and additional implants. Intraoperative evaluation is required due to lack of an objective image analysis of prosthesis element loosening and a level of bone stock damage determining the scope of the procedure, selection of implants and number of allogenic grafts. Our management tactics is an effective method of aseptic loosening of acetabulum and stem treatment after primary hip arthroplasty.

An integrated system for the management of decubitus ulcers

Background. The purpose of this article is to draw closer attention to a particularly important orthopedic problem: the prevention and early treatment of decubitus ulcers (bedsores). Material and methods. We retrospectively analyzed medical documentation for all orthopedic patients seen in our clinic during the period 1997-2003 (a total of 13,710 patients), and treated in accordance with an in-house protocol. Results. There were 3,061 patients (22.3% of all hospitalized) classified as high risk for decubitus ulcers. During the 7-year observation period, decubitus ulcers began to form in 103 patients, which comes to 0.42-1.49% of all orthopedic patients hospitalized each year. We observed a decreased incidence during the period in question; in the last year, 2003, 4.7% of the high-risk patients developed decubitus ulcers. Conclusions. Therapeutic success depends on effective cooperation between physicians and nurses.

Solution chemical properties and catecholase-like activity of the copper(ii)–Ac-His-His-Gly-His-OH system, a relevant functional model for copper containing oxidases

The solution chemical properties, superoxide dismutase and catecholase activity of the copper(ii)-Ac-His-His-Gly-His-OH (hhgh) complexes were studied to identify functional and structural models of copper-containing oxidases. The solution speciation was determined in the pH range 3-11 by two independent methods (potentiometry and pH-dependent EPR measurements). The results obtained by the two methods agree very well with each other and show the formation of differently protonated CuH(x)L complexes (where x= 2 ,1, 0, -1, -2, -3) in aqueous solution. The spectroscopic (UV-Vis, CD, EPR) data indicate that the coordination of the imidazole rings is a determinant factor in all these complexes. Amide coordinated complexes are dominant only above pH 8. This offers excellent possibilities for structural/functional modelling of copper(ii) containing metalloenzymes. Indeed, the {3N(im)} coordinated CuL species (pH = 6-7) has efficient superoxide dismutase-like activity. The {3N(im),OH(-)} coordinated CuH(-1)L possesses outstanding activity to catalyze the oxidation of 3,5-di-tert-butylcatechol (H(2)dtbc) by dioxygen in 86 wt% methanol-water, providing the first example that copper(ii)-peptide complexes are able to mimic copper containing oxidases.

[Locked intramedullary nailing in treatment of femur and tibia delayed union and pseudoarthrosis]

Five patients treated operatively on account of tibia and femur shaft delayed union and pseudoarthrosis were re-operated by locked intramedullary nailing. The method permits stable bone fixation. Intramedullary canal reaming stimulates bone union, as it refreshes fracture site and is a source of bone graft. Intramedullary nail covers anatomical axis of bone and, in the case of femur, is close to its mechanical axis. It diminishes the risk of implant breakage. The method permits active and efficient rehabilitation. Some fractures stabilised with external fixator or operated by Zespol or Polfix method can be re-operated by close technic. It shortens time of operation and diminishes its aggressiveness. In our opinion locked intramedullary nailing is an efficient method in treatment of tibia and femur shaft delayed union and pseudoarthrosis.

[Infections of the male urogenital tract and the problem of infertility in the couple]

The retrospective analysis of group of 164 men from sterile couples was made. Authors compared spermiograms with bacteriological investigations' results (sperm bacteriology and blots from urethra for present of Chlamydia, Mycoplasma and Ureaplasma). The statistical signification of coincidence of leucospermia and one-species bacterial infection and dependence between leucospermia and pathological spermiogram were found. The positive results of sperm bacteriological investigations were found in normospermic patients too.

Highly efficient phosphodiester hydrolysis promoted by a dinuclear copper(II) complex

The interaction of Cu(II) with the ligand tdci (1,3,5-trideoxy-1,3,5-tris(dimethylamino)-cis-inositol) was studied both in the solid state and in solution. The complexes that were formed were also tested for phosphoesterase activity. The pentanuclear complex [Cu(5)(tdciH(-2))(tdci)(2)(OH)(2)(NO(3))(2)](NO(3))(4).6H(2)O consists of two dinuclear units and one trinuclear unit, having two shared copper(II) ions. The metal centers within the pentanuclear structure have three distinct coordination environments. All five copper(II) ions are linked by hydroxo/alkoxo bridges forming a Cu(5)O(6) cage. The Cu-Cu separations of the bridged centers are between 2.916 and 3.782 A, while those of the nonbridged metal ions are 5.455-5.712 A. The solution equilibria in the Cu(II)-tdci system proved to be extremely complicated. Depending on the pH and metal-to-ligand ratio, several differently deprotonated mono-, di-, and trinuclear complexes are formed. Their presence in solution was supported by mass, CW, and pulse EPR spectroscopic study, too. In these complexes, the metal ions are presumed to occupy tridentate [O(ax),N(eq),O(ax)] coordination sites and the O-donors of tdci may serve as bridging units between two metal ions. Additionally, deprotonation of the metal-bound water molecules may occur. The dinuclear Cu(2)LH(-3) species, formed around pH 8.5, provides outstanding rate acceleration for the hydrolysis of the activated phosphodiester bis(4-nitrophenyl)phosphate (BNPP). The second-order rate constant of BNPP hydrolysis promoted by the dinuclear complex (T = 298 K) is 0.95 M(-1) s(-1), which is ca. 47600-fold higher than that of the hydroxide ion catalyzed hydrolysis (k(OH)). Its activity is selective for the phosphodiester, and the hydrolysis was proved to be catalytic. The proposed bifunctional mechanism of the hydrolysis includes double Lewis acid activation and intramolecular nucleophilic catalysis.

Potentiometric and spectroscopic studies on the dimethyltin(IV) complexes of 2-hydroxyhippuric acid

Equilibrium and spectroscopic (1H, 13C NMR and 119Sn Mössbauer) studies in aqueous solution are reported for dimethyltin(IV) complexes of 2-hydroxyhippuric acid (Sal-Gly). Below pH 4, oxygen-coordinated complexes MLH and ML are formed. In the pH range 5-8.5, the species MLH(-1), predominates at any metal-to-ligand ratio. The ligand exchange of this species is slow on the NMR time scale, which allows its structural characterization by NMR spectroscopy: the coordination polyhedron around the tin atom is distorted trigonal bipyramidal, with tridentate [O-,N-,COO-] coordination of Sal-Gly, involving two equatorial methyl groups. The NMR results reveal that the main cause of the distortion of the polyhedron is the large CH3-Sn-CH3 angle of 136+/-4 degrees. The presented results supplement the data available on the dimethyltin(IV)-promoted amide deprotonation of peptides, and provide further arguments for the fundamental role of the carboxylate as an anchoring group in this process.

[Trends in functional mimicking of metallophosphatases]

The promising practical applications of the so called artificial nucleases have inspired widespreading research studies on the functional mimicking of phosphoesterases. This paper is a short summary of the strategies for the selection or design of suitable model compounds, which are derived largely from the mechanistic details of phosphoesterases.

[Unusual coordination behavior of D-fructose towards dimethyltin(IV)2+: metal-promoted deprotonation of alcoholic hydroxyl groups in aqueous solutions at low pH]

To study the effect of the conformation of sugar hydroxy groups on metal complexation processes, complex formation of eight saccharides (D-fructose, L-sorbose, L-arabinose, D-arabinose, D-glucose, D-sorbitol, 2-deoxy-D-glucose and D-saccharose) with dimethyltin(IV)2+ cations was investigated in aqueous solution by potentiometric equilibrium measurements, 13C NMR, polarimetric and Mössbauer spectroscopic methods. The experimental results proved that deprotonation of D-fructose and L-sorbose is caused by the coordination of dimethyltin(IV)2+ in the unusual low pH interval 4-6 in contrast to the other saccharides deprotonated in analogous way at pH > 8. Increasing the pH of the solution resulted in the formation of further complexes. Stability and composition of the species was determined by potentiometric studies. 13C NMR measurements led to the assignment of the sugar OH groups participating in the processes. Mössbauer investigations in the quick-frozen solutions permitted the determination of the stereochemistry of tin(IV) in the complexes.

pH-metric study of reaction centers from photosynthetic bacteria in micellular solutions: protonatable groups equilibrate with the aqueous bulk phase

Hydrogen ion equilibria of the reaction center protein from photosynthetic purple bacteria Rhodobacter sphaeroides and Rhodobacter capsulatus dissolved in micellular solution were studied by acid-base titration to estimate the water accessibility of protonatable residues of the protein determined from structural data. The ionizable amino acids of the reaction center underwent protonation-deprotonation with protons from the interfacial layer, which, however, exchanged protons from the aqueous bulk phase. The equilibrium was described in terms of the buffering capacity of the multiphase system. The detergents decreased the proton activity coefficient (increased the buffering capacity) of the aqueous solution by a factor of 0.33 (in 0.03% Triton X-100 and LDAO) and 0.12 (0.04% dodecyl beta-D-maltoside). The observed buffering capacities of the reaction center protein were large and detergent-dependent. However, corrections for proton activities made the pH dependence of buffering capacities in different detergents uniform and similar to that expected from the number and pK values of protonatable groups of the protein. The vast majority of protonatable amino acids of the reaction center are in protonation equilibria with the aqueous bulk phase on an extended time scale.

Questions employers should ask about managed care

Managed care may be the best way to control employee health plan costs, but employers should qualify any plan they are considering to ensure that it will deliver what it promises.

[Structural and equilibrium studies of the proton and copper(II) complexes of N-D-gluconylglycine]

N-D-Gluconylglycine, a pseudopeptide derivative glucono-delta-lactone and glycine, was prepared and the equilibrium constants of its protonation and copper(II) coordination and the structures of the copper complexes formed were studied in aqueous solution by potentiometry, spectrophotometry, CD, EPR and 13C-NMR relaxation. The parent complexes formed in acidic medium have low stabilities, characteristic of carboxylate coordination. In the pH range 5-9, the amide group and the 2-OH group of the ligand undergo deprotonation. In parallel with these processes, one ligand is replaced from the copper(II) coordination sphere. For the species MLH-2' we propose (30, 1N) coordination in the equatorial plane around the copper(II). EPR measurements indicate that dimeric species are also formed. At pH > 9, further base-consuming processes start as an indication of the deprotonation of other alcoholic hydroxy groups of the sugar moiety or the formation of mixed hydroxy complexes.