Randomized clinical trial of postoperative hernia prophylaxis in open bariatric surgery

Background

Postoperative hernia following bariatric procedures is more common than in other groups of surgical patients, and remains a serious problem. Gastric bypass is the most often performed bariatric procedure and, despite the increasing popularity of a laparoscopic approach, many morbidly obese patients are still offered open procedures. The aim of this study was to assess the effects of prophylactic polypropylene mesh in morbidly obese patients undergoing gastric by-pass surgery.

Methods

The study randomized 74 patients undergoing open Roux-en-Y gastric bypass into two groups: wound closure with (n = 36) or without (n = 38) a polypropylene mesh. Mean(s.d.) body mass and body mass index in the mesh group were 137·3(24·5) kg and 46·2(7·1) kg/m2 and in the non-mesh group were 139·0(24·9) kg and 46·8(7·6) kg/m2 respectively. In the non-mesh group, the wound was closed with a polypropylene suture. Patients in the mesh group had in addition a polypropylene mesh inserted in a sublay manner.

Results

Patients were followed up for at least 6 (range 6–38) months. Hernia developed in eight patients in the non-mesh group but in none in the mesh group. The duration of hospital stay was similar in both groups: mean(s.d.) 8·4(3·2) and 10·3(5·9) days (P = 0·092). There were no serious complications in either group.

Conclusion

The use of a mesh prevented hernia development and did not lengthen hospital stay.

Thermal and Electronic Transport Properties of the Half-Heusler Phase ScNiSb

Thermoelectric properties of the half-Heusler phase ScNiSb (space group F 4 ¯ 3m) were studied on a polycrystalline single-phase sample obtained by arc-melting and spark-plasma-sintering techniques. Measurements of the thermopower, electrical resistivity, and thermal conductivity were performed in the wide temperature range 2-950 K. The material appeared as a p-type conductor, with a fairly large, positive Seebeck coefficient of about 240 μV K^-1 near 450 K. Nevertheless, the measured electrical resistivity values were relatively high (83 μΩm at 350 K), resulting in a rather small magnitude of the power factor (less than 1 × 10^-3 W m^-1 K^-2) in the temperature range examined. Furthermore, the thermal conductivity was high, with a local minimum of about 6 W m^-1 K^-1 occurring near 600 K. As a result, the dimensionless thermoelectric figure of merit showed a maximum of 0.1 at 810 K. This work suggests that ScNiSb could be a promising base compound for obtaining thermoelectric materials for energy conversion at high temperatures.

Upconversion Luminescence of Silica-Calcia Nanoparticles Co-doped with Tm3+ and Yb3+ Ions

Looking for upconverting biocompatible nanoparticles, we have prepared by the sol-gel method, silica-calcia glass nanopowders doped with different concentration of Tm³⁺ and Yb³⁺ ions (Tm³⁺ from 0.15 mol% up to 0.5 mol% and Yb³⁺ from 1 mol% up to 4 mol%) and characterized their structure, morphology, and optical properties. X-ray diffraction patterns indicated an amorphous phase of the silica-based glass with partial crystallization of samples with a higher content of lanthanides ions. Transmission electron microscopy images showed that the average size of particles decreased with increasing lanthanides content. The upconversion (UC) emission spectra and fluorescence lifetimes were registered under near infrared excitation (980 nm) at room temperature to study the energy transfer between Yb³⁺ and Tm³⁺ at various active ions concentrations. Characteristic emission bands of Tm³⁺ ions in the range of 350 nm to 850 nm were observed. To understand the mechanism of Yb³⁺-Tm³⁺ UC energy transfer in the SiO₂-CaO powders, the kinetics of luminescence decays were studied.

On the Sensitivity of the Ni-rich Layered Cathode Materials for Li-ion Batteries to the Different Calcination Conditions

Ni-rich layered oxides, i.e., LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622) and LiNiO₂ (LNO), were prepared using the two-step calcination procedure. The samples obtained at different calcination temperatures (750–950 °C for the NMC622 and 650–850 °C for the LNO cathode materials) were characterized using nitrogen physisorption, PXRD, SEM and DLS methods. The correlation of the calcination temperature, structural properties and electrochemical performance of the studied Ni-rich layered cathode materials was thoroughly investigated and discussed. It was determined that the optimal calcination temperature is dependent on the chemical composition of the cathode materials. With increasing nickel content, the optimal calcination temperature shifts towards lower temperatures. The NMC-900 calcined at 900 °C and the LNO-700 calcined at 700 °C showed the most favorable electrochemical performances. Despite their well-ordered structure, the materials calcined at higher temperatures were characterized by a stronger sintering effect, adverse particle growth, and higher Ni²⁺/Li⁺ cation mixing, thus deteriorating their electrochemical properties. The importance of a careful selection of the heat treatment (calcination) temperature for each individual cathode material was emphasized.

A high performance barium-promoted cobalt catalyst supported on magnesium-lanthanum mixed oxide for ammonia synthesis

Ammonia synthesis was performed over a barium-promoted cobalt catalyst supported on magnesium-lanthanum mixed oxide. The rate of NH3 formation over this catalyst was about 3.5 times higher than that over the unpromoted catalyst at 9 MPa and 400 °C. Furthermore, no sign of thermal deactivation was observed during long-term overheating at 600 °C for 360 h. The results of physicochemical studies, including XRPD, DRIFTS, H2-TPD, CO2-TPD, Nads + H2 TPSR and kinetic analysis, revealed that the addition of Ba promoter increased the surface basicity of the catalyst and modified the adsorption properties of the Co surface towards H2 and NH3. The decreased adsorption strength of the corresponding sites towards hydrogen and ammonia resulted in greater availability of active sites in the Ba-promoted cobalt catalyst. These characteristics are considered to have a profound effect on the performance of this catalyst in NH3 synthesis.

Sublay or onlay incisional hernia repair along with abdominoplasty: which is better? Long-term results

PURPOSE

Estimation and comparison of results after incisional hernia repair (IHR) modo onlay or sublay with abdominoplasty in patients who lost the weight following Roux-en-Y Gastric Bypass (RYGB). Analysis and comparison of changes in quality of life (QL) of these patients prior to RYGB, before and after simultaneous IHR and abdominoplasty.

METHODS

Clinical analysis involved 40 patients with abdominal disfigurement (following RYGB and massive weight loss) after one-time IHR sublay method with abdominoplasty-group 1 or IHR onlay method with abdominoplasty-group 2. We evaluated postoperative results and long-term QL changes (DAS24, SF-36 scales).

RESULTS

We noted abnormal wound healing (2), pneumonia (3) and dysesthesia (3) in patients from group 1, and abnormal wound healing (2), seroma (2), pneumonia (2), and dysesthesia (4) in group 2. Quality of life was improved in the functional, esthetic and psychological aspects.

CONCLUSIONS

One stage incisional hernia repair by onlay as well as sublay method with abdominoplasty are safe surgical methods improving the functioning of patients after major weight loss following RYGB. Sublay hernia repair and abdominoplasty was connected with longer time of the: operation, drainage, analgesic agents use, time to mobilization and to full oral diet than the onlay method. Significant improvement of the quality of life was noted after every subsequent step of surgical treatment in both groups. Reduction of the risk of BMI re-growth after bariatric surgery is related to the need for constant, specialized care for these patients at every stage of follow-up after bariatric surgery.

Modification of insulin amyloid aggregation by Zr phthalocyanines functionalized with dehydroacetic acid derivatives

Amyloid fibrils are widely studied both as target in conformational disorders and as basis for the development of protein-based functional materials. The three Zr phthalocyanines bearing dehydroacetic acid residue (PcZr(L1)2) and its condensed derivatives (PcZr(L2)2 and PcZr(L3)2) as out-of-plane ligands were synthesized and their influence on insulin fibril formation was studied by amyloid-sensitive fluorescent dye based assay, scanning electron microscopy, fluorescent and absorption spectroscopies. The presence of Zr phthalocyanines was shown to modify the fibril formation. The morphology of fibrils formed in the presence of the Zr phthalocyanines differs from that of free insulin and depends on the structure of out-of-plane ligands. It is shown that free insulin mostly forms fibril clusters with the length of about 0.3-2.1 μm. The presence of Zr phthalocyanines leads to the formation of individual 0.4-2.8 μm-long fibrils with a reduced tendency to lateral aggregation and cluster formation (PcZr(L1)2), shorter 0.2-1.5 μm-long fibrils with the tendency to lateral aggregation without clusters (PcZr(L2)2), and fibril-like 0.2-1.0 μm-long structures (PcZr(L3)2). The strongest influence on fibrils morphology made by PcZr(L3)2 could be explained by the additional stacking of phenyl moiety of the ligand with aromatic amino acids in protein. The evidences of binding of studied Zr phthalocyanines to mature fibrils were shown by absorption spectroscopy (for PcZr(L1)2 and PcZr(L2)2) and fluorescent spectroscopy (for PcZr(L3)2). These complexes could be potentially used as external tools allowing the development of functional materials on protein fibrils basis.

Spectroscopic properties of GdxLa1−xAlO3 nanocrystals doped with Pr3+ ions

The spectroscopic and structural properties of Gd_xLa_1−xAlO₃ nanocrystals doped with praseodymium(iii) ions have been investigated.

Mechanism of Action and Efficiency of Ag3PO4-Based Photocatalysts for the Control of Hazardous Gram-Positive Pathogens

Silver phosphate and its composites have been attracting extensive interest as photocatalysts potentially effective against pathogenic microorganisms. The purpose of the present study was to investigate the mechanism of bactericidal action on cells of opportunistic pathogens. The Ag3PO4/P25 (AGP/P25) and Ag3PO4/HA (HA/AGP) powders were prepared via a co-precipitation method. Thereafter, their antimicrobial properties against Enterococcus faecalis, Staphylococcus epidermidis, and Staphylococcus aureus (clinical and reference strains) were analyzed in the dark and after exposure to visible light (VIS). The mechanism leading to cell death was investigated by the leakage of metabolites and potassium ions, oxidative stress, and ROS production. Morphological changes of the bacterial cells were visualized by transmission electron microscopy (TEM) and scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (SEM EDS) analysis. It has been shown that Ag3PO4-based composites are highly effective agents that can eradicate 100% of bacterial populations during the 60 min photocatalytic inactivation. Their action is mainly due to the production of hydroxyl radicals and photogenerated holes which lead to oxidative stress in cells. The strong affinity to the bacterial cell wall, as well as the well-known biocidal properties of silver itself, increase undoubtedly the antimicrobial potential of the Ag3PO4-based composites.

Mechanical and Antimicrobial Properties of the Graphene-Polyamide 6 Composite

This paper presents the synthesis and characterization of graphene-polymer composites, focusing on their mechanical and antibacterial properties. Graphene flakes were obtained via an electrochemical method and integrated into polyamide 6 (PA6) matrices using melt intercalation. Various characterization techniques confirmed the quality of the graphene flakes, including X-ray diffraction (XRD), Raman spectroscopy, and infrared (IR) spectroscopy, as well as scanning and transmission electron microscopy (SEM and TEM) imaging. Mechanical tests showed an increase in the elastic modulus with graphene incorporation, while the impact strength decreased. The SEM analysis highlighted the dispersion of the graphene flakes within the composites and their impact on fracture behavior. Antimicrobial tests demonstrated significant antibacterial properties of the composites, attributed to both oxidative stress and mechanical damage induced by the graphene flakes. The results suggest promising applications for graphene-polymer composites in advanced antimicrobial materials.

Horizontal flux growth as an efficient preparation method of CeRh2As2 single crystals

We report an efficient method to obtain CeRh2As2 single crystals with the use of a bismuth flux growth method in a horizontal configuration. Based on our numerous attempts, we found this technique to be scalable and repeatable. The crystals thus obtained are characterized by much sharper phase transitions and distinctly higher characteristic temperatures Tc and T0, compared to previous reports. Moreover, based on our specific heat studies of the obtained single crystals, we also indicate a clear connection between both transition temperatures.

Effect of the Addition of Graphene Flakes on the Physical and Biological Properties of Composite Paints

In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices. The mechanical properties were evaluated using micro-hardness testing, while wettability and antimicrobial activity against three pathogens (Staphylococcus aureus 33591, Pseudomonas aeruginosa 15442, Candida albicans 10231) were also examined. The results indicate that the addition of graphene flakes significantly enhances both the mechanical and antimicrobial properties of the coatings.

Hippocampal vasopressin release evoked by N-methyl D-aspartate (NMDA) microdialysis

Hippocampus is a brain structure containing vasopressin (AVP) fibers and specific binding sites for this peptide. There is growing evidence that AVP and its metabolites participate in glutamate-mediated plasticity of the hippocampus. The aim of the present study was to evaluate the influence of NMDA on AVP release in the rabbit hippocampus. Caudate nucleus was chosen as the reference structure. The mentioned brain structures were simultaneously microdialyzed with 0.9 % NaCl solution. AVP was determined in the outflowing fluid by radioimmunoassay. The mean basal AVP content in the fluid outflowing from the hippocampus was significantly greater than that from the caudate nucleus. The addition of K(+) into the fluid perfusing the probes implanted into the hippocampus and caudate nucleus significantly increased AVP release into the extracellular fluid of both brain structures. NMDA applied into the mentioned brain structures increased AVP release only from the hippocampus but not from the caudate nucleus. Our findings indicate a role which NMDA receptors play in AVP release into the extracellular fluid of the hippocampus.

Micro-Inclusion Engineering via Sc Incompatibility for Luminescence and Photoconversion Control in Ce3+-Doped Tb3Al5-xScxO12 Garnet

Aluminum garnets display exceptional adaptability in incorporating mismatching elements, thereby facilitating the synthesis of novel materials with tailored properties. This study explored Ce3+-doped Tb3Al5-xScxO12 crystals (where x ranges from 0.5 to 3.0), revealing a novel approach to control luminescence and photoconversion through atomic size mismatch engineering. Raman spectroscopy confirmed the coexistence of garnet and perovskite phases, with Sc substitution significantly influencing the garnet lattice and induced A1g mode softening up to Sc concentration x = 2.0. The Sc atoms controlled sub-eutectic inclusion formation, creating efficient light scattering centers and unveiling a compositional threshold for octahedral site saturation. This modulation enabled the control of energy transfer dynamics between Ce3+ and Tb3+ ions, enhancing luminescence and mitigating quenching. The Sc admixing process regulated luminous efficacy (LE), color rendering index (CRI), and correlated color temperature (CCT), with adjustments in CRI from 68 to 84 and CCT from 3545 K to 12,958 K. The Ce3+-doped Tb3Al5-xScxO12 crystal (where x = 2.0) achieved the highest LE of 114.6 lm/W and emitted light at a CCT of 4942 K, similar to daylight white. This approach enables the design and development of functional materials with tailored optical properties applicable to lighting technology, persistent phosphors, scintillators, and storage phosphors.