[The application of negative pressure wound therapy (NPWT) in potentially lethal conditions]

Bemutatásra kerülő esetünkben egy 47 éves, generalizált septicus állapotú férfi beteg komplex terápiás megoldást igénylő kezelését ismertetjük, negatív nyomásterápia segítségével (NPWT). A páciens kezeletlen diabéteszes láb szindróma talaján kialakult szepszis, fasciitis necrotisans klinikai-radiomorfológiai képével került osztályunkra, akinél sürgősséggel feltárást, az alsó végtag valamennyi kompartmentjét érintő fasciotomiát végeztünk, NPWT-kezelést indítottunk. Kezelése során a beteg állapotát súlyosbító szövődmények léptek fel: Curling-fekély, toxicus epidermalis necrolysis (TEN). A fascitis kapcsán kialakult kb. 6% TBSA (total body surface area) kiterjedésű hámhiányt a TEN-szindróma további epidermális állományvesztéssel tovább súlyosbította. Állapotstabilizálást, kezdeti lokalis kontroll biztosítását követően a hámhiányos felület csökkentése érdekében a sebeket szűkítettük, a feltisztult sebalapok fedése 1:3 arányban hálósított félvastag bőr transzplantációjával történt. Az NPWT-kezelést a transzplantációt követően is folytattuk. A beteg három hónapos intenzív osztályos és sebészeti kezelést követően sebészi szempontból meggyógyult. A negatív nyomásterápia korai - a kórlefolyásnak megfelelő - adekvát üzemmódban és fedési technikával történő alkalmazása a végtagvesztéssel és életveszéllyel járó nagy fokú hámhiány esetében hatékony eszköznek bizonyult. A multidiszciplináris terápiának köszönhetően betegünk sebészeti alapbetegségét sikeresen gyógyítottuk, azonban az évtizedes tartamú kezeletlen cukorbetegsége, SARS-Covid peumoniája, a relabáló septicus állapota során fellépő szövődmények következtében felépülni már nem tudott.

Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes

Fruiting bodies (sporocarps, sporophores or basidiomata) of mushroom-forming fungi (Agaricomycetes) are among the most complex structures produced by fungi. Unlike vegetative hyphae, fruiting bodies grow determinately and follow a genetically encoded developmental program that orchestrates their growth, tissue differentiation and sexual sporulation. In spite of more than a century of research, our understanding of the molecular details of fruiting body morphogenesis is still limited and a general synthesis on the genetics of this complex process is lacking. In this paper, we aim at a comprehensive identification of conserved genes related to fruiting body morphogenesis and distil novel functional hypotheses for functionally poorly characterised ones. As a result of this analysis, we report 921 conserved developmentally expressed gene families, only a few dozens of which have previously been reported to be involved in fruiting body development. Based on literature data, conserved expression patterns and functional annotations, we provide hypotheses on the potential role of these gene families in fruiting body development, yielding the most complete description of molecular processes in fruiting body morphogenesis to date. We discuss genes related to the initiation of fruiting, differentiation, growth, cell surface and cell wall, defence, transcriptional regulation as well as signal transduction. Based on these data we derive a general model of fruiting body development, which includes an early, proliferative phase that is mostly concerned with laying out the mushroom body plan (via cell division and differentiation), and a second phase of growth via cell expansion as well as meiotic events and sporulation. Altogether, our discussions cover 1 480 genes of Coprinopsis cinerea, and their orthologs in Agaricus bisporus, Cyclocybe aegerita, Armillaria ostoyae, Auriculariopsis ampla, Laccaria bicolor, Lentinula edodes, Lentinus tigrinus, Mycena kentingensis, Phanerochaete chrysosporium, Pleurotus ostreatus, and Schizophyllum commune, providing functional hypotheses for ~10 % of genes in the genomes of these species. Although experimental evidence for the role of these genes will need to be established in the future, our data provide a roadmap for guiding functional analyses of fruiting related genes in the Agaricomycetes. We anticipate that the gene compendium presented here, combined with developments in functional genomics approaches will contribute to uncovering the genetic bases of one of the most spectacular multicellular developmental processes in fungi. Citation: Nagy LG, Vonk PJ, Künzler M, Földi C, Virágh M, Ohm RA, Hennicke F, Bálint B, Csernetics Á, Hegedüs B, Hou Z, Liu XB, Nan S, M. Pareek M, Sahu N, Szathmári B, Varga T, Wu W, Yang X, Merényi Z (2023). Lessons on fruiting body morphogenesis from genomes and transcriptomes of Agaricomycetes. Studies in Mycology 104: 1-85. doi: 10.3114/sim.2022.104.01.

A Multi-Omics Approach Reveals Features That Permit Robust and Widespread Regulation of IFN-Inducible Antiviral Effectors

The antiviral state, an initial line of defense against viral infection, is established by a set of IFN-stimulated genes (ISGs) encoding antiviral effector proteins. The effector ISGs are transcriptionally regulated by type I IFNs mainly via activation of IFN-stimulated gene factor 3 (ISGF3). In this study, the regulatory elements of effector ISGs were characterized to determine the (epi)genetic features that enable their robust induction by type I IFNs in multiple cell types. We determined the location of regulatory elements, the DNA motifs, the occupancy of ISGF3 subunits (IRF9, STAT1, and STAT2) and other transcription factors, and the chromatin accessibility of 37 effector ISGs in murine dendritic cells. The IFN-stimulated response element (ISRE) and its tripartite version occurred most frequently in the regulatory elements of effector ISGs than in any other tested ISG subsets. Chromatin accessibility at their promoter regions was similar to most other ISGs but higher than at the promoters of inflammation-related cytokines, which were used as a reference gene set. Most effector ISGs (81.1%) had at least one ISGF3 binding region proximal to the transcription start site (TSS), and only a subset of effector ISGs (24.3%) was associated with three or more ISGF3 binding regions. The IRF9 signals were typically higher, and ISRE motifs were "stronger" (more similar to the canonical sequence) in TSS-proximal versus TSS-distal regulatory regions. Moreover, most TSS-proximal regulatory regions were accessible before stimulation in multiple cell types. Our results indicate that "strong" ISRE motifs and universally accessible promoter regions that permit robust, widespread induction are characteristic features of effector ISGs.

First DNA sequence proof for the occurrence of bovine adenovirus types 10 and 11 in continental Europe

Bovine adenoviruses (BAdV) are known to cause respiratory and/or intestinal disease in calves. Infection can manifest as acute outbreaks, but more often only sporadic cases occur. Here we describe the PCR detection and partial sequence characterization of several BAdVs found in sick or dead calves on different farms in Western Hungary. Intermittent diarrhoeal illnesses occurred after weaning among calves on several farms located up to 40 km apart. A high-sensitivity, broad-spectrum nested PCR, developed for the general detection of adenoviruses, gave positive results in four independent cases. Direct sequencing of PCR products showed clear results from only two samples, whereas sequences from the other two amplicons were mixed. Molecular cloning of these heterogeneous PCR products was performed to separate each DNA fragment therein. By sequencing several plasmid clones from both mixed samples, we were able to detect the simultaneous presence of two different BAdV types, namely types 6 and 10 classified into two separate (Atadenovirus and Mastadenovirus) genera. The sequence of one homogenous sample was identified as being derived also from BAdV-10, whereas the other sample contained a novel type, proposed to be BAdV-11. We demonstrated, for the very first time, the occurrence of the two latter virus types in continental Europe. Their appearance in Hungary marks a significant shift in the types of BAdVs actually circulating in the country. Considering the similarity of the pathological findings to those, attributed to BAdV-10 infections reported to date, the causative role of the viruses in these cases seems to be plausible. Phylogeny reconstruction further confirmed that BAdVs represent multiple genetic lineages.

Kinetic Model Development of the Oligomerization of High Olefin Containing Hydrocarbon By-products to Clean Engine Fuels on Amberlyst Catalyst

Nowadays, since the demand for engine fuels is continuously changing, in petroleum refineries, increasing the flexibility of gasoline/middle distillate is still an important issue, e.g. by oligomerizing light olefins (3–6 carbon atoms). The aim of our work was to develop a valid kinetic model based on the extended Eley-Rideal mechanism to describe the oligomerization of the olefin content of light naphtha by fluidized catalytic cracking (FCC) on an ion-exchange resin. Experiments were carried out in a fixed-bed tubular reactor at temperatures of between 80 and 130 °C with liquid hourly space velocities (LHSV) of between 0.5 and 2.0 1/h using Amberlyst® 15 as a catalyst. The oligomerization process was characterized based on the composition of products determined by gas chromatography. The conversion of olefins and the selectivity of the oligomerization reactions forming C8-11 and C12+ hydrocarbons (C8-11 and C12+ selectivity; unit: relative %) were dependent on factors that determine the reactor performance in order to identify the kinetic model parameters. Given that the developed reactor model described the measured data reasonably accurately, it can be used in terms of the optimal design of an industrial oligomerization reactor.

Rape, sunflower and forest honeys for long-term environmental monitoring: Presence of indicator elements and non-photosynthetic carbon in old Hungarian samples

In this paper, we present the time-dependent elemental composition and AMS radiocarbon dating results of 36 rape, sunflower and forest honey samples, collected between 1985 and 2018 in geographically close locations. Based on the elemental information, we conclude that bee products regardless the type provide useful environmental information of the previous decades, such as the decreasing trend of airborne Pb emission can be traced. However, radiocarbon results agree less with the atmospheric bomb peak. Random offsets were observed in the specific radiocarbon activity of the honey samples indicating that rape, sunflower and forest honey samples are not as reliable materials for radiocarbon dating as acacia honeys. The radiocarbon results show that the rape, sunflower and forest honey samples can contain non-photosynthetic carbon, presumably derived from the soil. Thus, the complex application of honey samples for environmental reconstruction requires the species-separated investigation of bee products to reveal their adaptability for assessment approaches.

Semi-supervised Clustering Algorithm for Retention Time Alignment of Gas Chromatographic Data

Gas chromatography (GC) is an effective tool for the analysis of complex mixtures with a huge number of components. To keep tracking the chemical changes during the processes like plastic waste pyrolysis usually different sample states are profiled, but retention time drifts between the chromatograms make the comparability difficult. The aim of this study is to develop a fast and simple method to eliminate the time drifts between the chromatograms using easily accessible priori information. The proposed method is tested on GC chromatograms obtained by analysis of pyrolysis product (Mg/Y catalyst) of shredded real waste HDPE/PP/LDPE mixture. A modified k-means algorithm was developed to account the retention time drifts between samples (different sample states). The outcome of the retention time alignment is an averaged retention time for each peak from all the chromatograms which makes the comparison and further analysis (such as "fingerprinting") easier or possible.

Radiocarbon in the atmospheric gases and PM10 aerosol around the Paks Nuclear Power Plant, Hungary

Our study shows a one-year-long, monthly integrated continuous monitoring campaign of gaseous radiocarbon emission and ambient air compared with 4 event-like, weekly (168 h) atmospheric aerosol radiocarbon data in every season of 2019, at 4 locations (n = 16 aerosol sample) around the Paks Nuclear Power Plant, Hungary. The study shows the first aerosol radiocarbon results around a nuclear power plant measured by accelerator mass spectrometry in Hungary. There was no dominant contribution detected in the atmospheric CO₂ gas fraction, but we could detect excess radiocarbon in the total gaseous carbon fraction at almost every sampling point around the Paks Nuclear Power Plant. The highest Δ¹⁴C value in the total gaseous carbon form was 157.9 ± 4.6‰ in November and the highest Δ ¹⁴C value in the CO₂ fraction was 86.1 ± 4.0‰ in December during 2019. Observed ¹⁴C activity excess is not higher than previously published values around the Paks Nuclear Power plant at the same sampling points (Molnár et al., 2007; Varga et al., 2020). Our aerosol radiocarbon measurements show that there is no significant contribution from the nuclear power plant to the atmospheric PM₁₀ fraction. We could not detect a Δ ¹⁴C value higher than 0‰ in any season. The results show that the simple aerosol sampling, without pre-treatment of the filters, is appropriate for the measurement of excess radiocarbon at the vicinity of nuclear power plants. The applied preparation and measurement method can be applicable for detection of hot (¹⁴C) particles and early identification of radiocarbon emission from nuclear power plants in the PM₁₀ fraction.

Analysing the genomes of two tick-borne encephalitis viruses isolated in Hungary in 1952 and 2019

The genomes of two Tick-borne encephalitis virus (TBEV) strains were fully sequenced and compared to those of known Hungarian strains. One was a laboratory strain (KEM-1) isolated in 1952, which had gone through hundreds of passages both on Vero cell cultures and in laboratory mice, while the other was a recent isolate (2019) from questing female ticks. The laboratory strain formed a monophyletic group with the already published 4 Hungarian strains on the evolutionary tree, located relatively close to Finnish (Kumlinge) and Russian (Absettarov) strains. This KEM-1 strain was phylogenetically distantly related both to the geographically close reference strain Neudörfl and the chronologically close Czech isolates from 1953. The 2019 isolate, KEM-195 was related to TBEV isolates from Southern Slovakia and Styria, and had the longest (328 nucleotides) deletion in its 3'-non-coding region among published sequences of strains of European subtype. Our results show that decades of laboratory passage have not altered the viral genome too much and that at least two distinct branches of TBEV strains circulate in Hungary.

Pseudoaneurysm of the ascending aorta: case report of a donor-derived Pseudomonas infection in a heart transplant recipient

Background

Mycotic aortic pseudoaneurysm is a rare complication after heart transplantation (HTX) with remarkable mortality. Intrathoracic infection is a well-documented predisposing factor for this disease. Staphylococcus aureus, Pseudomonas aeruginosa or Candida species are commonly isolated from resected specimens of the pseudoaneurysms. We demonstrate a unique case of mycotic pseudoaneurysm caused by presumably donor-derived Pseudomonas infection in a heart transplant recipient.

Case presentation

Our 67-year-old male patient treated with diabetes mellitus underwent HTX. The donor suffered from epiglottic abscess and pneumonia with known microorganisms including Pseudomonas, therefore both the donor and recipient received targeted antimicrobial therapy and prophylaxis. Five months after the uneventful HTX, lab test of the asymptomatic patient showed moderate, increasing C-reactive protein level without obviuos source of infection. Chest computed tomography showed a large (90 mm) saccular dilatation of the tubular portion of ascending aorta. Urgent surgical intervention identified a pseudoaneurysm, histological examinations and cultures of the resected aorta verified Pseudomonas aeruginosa aortitis, while all blood cultures remained negative. Retrospective interrogation of other transplanted organs of the donor supported donor-derived infection as the transport fluid of the right kidney grew Pseudomonas. The patient received 3 weeks of ceftazidime followed by 7 months of oral ciprofloxacin therapy. One year after the operation the patient was asymptomatic with normal inflammatory markers.

Conclusions

Donor-derived infection is a rare but potential cause of aortitis. Early diagnosis, surgical intervention and adjuvant antibiotic therapy seem to be the keys to successful management of mycotic pseudoaneurysms after HTX.

Unexpected radical mechanism in a [4+1] cycloaddition reaction

The mechanism of the cheletropic reaction of monoimines with PPh₃via unexpected radical intermediates resulting in oxazaphospholes has been discussed based on EPR, UV-vis and DFT calculations.

Honey as an indicator of long-term environmental changes: MP-AES analysis coupled with 14C-based age determination of Hungarian honey samples

Several studies show that the elemental content of honey entirely depends on the botanical and geographical origin, but the information is incomplete regarding its time-dependent composition changes. Twenty-six acacia and three honey samples with unknown botanical origin were collected between 1958 and 2018 and analysed for elemental composition by Microwave Plasma Atomic Emission Spectrometry (MP-AES). The elemental analysis was coupled with independent dating method by Accelerator Mass Spectrometry (AMS) to confirm the calendar age of the honey samples and test the possibility of radiocarbon based dating of bee products, which has not been applied before. According to the analytical measurements and statistical analysis, we can conclude that the elemental composition shows change with time in the acacia honey during the last five decades. We have proven that honey preserves carbon isotopic and elemental information of its production time and thus can be applied as an environmental indicator (e.g. trace urban pollutants, precipitation, local industrial or agricultural emission) in reconstruction studies by analysing the non-degradable mineral content. Our results further show that acacia honey is a suitable material for radiocarbon dating, proved by the results compared to the atmospheric radiocarbon bomb-peak. The new approach presented for investigation of honey by radiocarbon-based age determination coupled with elemental analysis can be used in biological, dietary, archaeological or other multidisciplinary studies as well. Some samples show slightly depleted radiocarbon content. This could be an indication of local fossil CO₂ emission. Based on these depleted ¹⁴C results, honey could be used for atmospheric monitoring of fossil CO₂ urban or industrial hot-spots.

Right ventricular mechanical pattern in patients undergoing mitral valve surgery: a predictor of post-operative dysfunction?

Aims

The PREPARE‐MVR study (PRediction of Early PostoperAtive Right vEntricular failure in Mitral Valve Replacement/Repair patients) sought to investigate the alterations of right ventricular (RV) contraction pattern in patients undergoing mitral valve replacement/repair (MVR) and to explore the associations between pre‐operative RV mechanics and early post‐operative RV dysfunction (RVD).

Methods and results

We prospectively enrolled 42 patients (63 ± 11 years, 69% men) undergoing open‐heart MVR. Transthoracic three‐dimensional (3D) echocardiography was performed pre‐operatively, at intensive care unit discharge, and 6 months after surgery. The 3D model of the RV was reconstructed, and RV ejection fraction (RVEF) was calculated. We decomposed the motion of the ventricle to compute longitudinal ejection fraction (LEF) and radial ejection fraction (REF). Pulmonary artery catheterization was performed to monitor RV stroke work index (RVSWi). RVEF was slightly decreased after MVR [52 (50–55) vs. 51 (46–54)%; P = 0.001], whereas RV contraction pattern changed notably. Before MVR, the longitudinal shortening was the main contributor to global systolic RV function [LEF/RVEF vs. REF/RVEF; 0.53 (0.47–0.58) vs. 0.33 (0.22–0.42); P < 0.001]. Post‐operatively, the radial motion became dominant [0.33 (0.28–0.43) vs. 0.46 (0.37–0.51); P = 0.004]. However, this shift was temporary as 6 months later the two components contributed equally to global RV function [0.44 (0.38–0.50) vs. 0.41 (0.36–0.49); P = 0.775]. Pre‐operative LEF was an independent predictor of post‐operative RVD defined as RVSWi < 300 mmHg⋅mL/m² [OR = 1.33 (95% CI: 1.08–1.77), P < 0.05].

Conclusions

MVR induces a significant shift in the RV mechanical pattern. Advanced indices of RV mechanics are associated with invasively measured parameters of RV contractility and may predict post‐operative RVD.

Advanced atmospheric 14C monitoring around the Paks Nuclear Power Plant, Hungary

Atmospheric air samples were collected at 9 monitoring stations (A1 to A9) less than 2 km from the Paks Nuclear Power Plant (Paks NPP) and a background station (B24). The monthly integrated CO₂ and total carbon (CO₂+hydrocarbons (C_nH_m)) samples were collected to determine the excess ¹⁴C activity at the vicinity of the NPP. The measurements providing the ¹⁴C/¹²C ratio of the monthly integrated samples were carried out on a MICADAS type AMS at HEKAL. Due to the relatively low ¹⁴CO₂ emission of PWR type Paks reactors and the local Suess effect, there was negligible excess ¹⁴C activity at the investigated stations in the pure CO₂ fraction during the investigated 2 years period (2015-2016). On the contrary, there was a detectable (although minor) excess at every station in the C_nH_m fraction. In case of CO₂, the average Δ¹⁴C excess was 3.8‰ and the highest measured value was 91.2‰ at the A3 station in February 2015. In case of C_nH_m, the average excess was 31.1‰ and the highest measured value was 319.1‰ at the A4 station in February 2016. We applied PC-CREAM 08 modelling to investigate the observed excess ¹⁴C activity at the environmental sampling stations, which depends on the distance from the NPP and the meteorological conditions, such as wind direction and wind speed. Meteorology data was collected at the operating area of the Paks NPP in a meteorology tower. The direct C-14 emission through the 120 m high stacks was measured in the NPP by liquid scintillation counting. These emission data and our model calculations explain the excess activity in the C_nH_m fraction at the A4 station, which is located only 915 m far from the NPP's stacks in the prevailing wind direction. The excess activity at A3 station (the farthest unit) probably came from the nearby NPP wastewater discharge point. The recently observed average excess and highest excess data is similar to the published data in former studies (Molnár et al., 2007; Veres et al., 1995) on Paks NPP, the highest ¹⁴CO₂ and ¹⁴C_nH_m excess are just a little higher than it was in the earlier studies, but in these former studies, the A3 station was not equipped with a radiocarbon monitoring unit and the level of radiocarbon emission was almost invisible from the wastewater discharge point.

429 Right ventricular longitudinal and radial fiber contractility in patients undergoing mitral valve surgery: a PREPARE-MVR substudy

Severe mitral regurgitation results in significant hemodynamic demands of not only the left, but the right ventricle (RV) as well. Increased pulmonary pressures and consequential pressure overload of the RV induces complex remodeling, which can be partially restored by mitral valve repair/replacement (MVR). MVR is associated with marked changes of RV deformation, however, the clinical significance of these changes is not well estabilished. The PREPARE-MVR study (PRediction of Early PostoperAtive Right vEntricular failure in Mitral Valve Replacement/Repair patients) aims to determine parameters, which may predict the perioperative risk of acute RV failure.

In this current substudy, our aim was to determine the changes of RV global, longitudinal and radial fiber contractility before and following MVR.

Our study group consisted of 27 MVR patients (mean age: 64 ± 12 years, m/f: 19/8). Transthoracic 3D echocardiography was performed before the operation and following intensive care unit discharge. 3D beutel model of the RV was created and RV end-diastolic volume index (EDVi) among with RV ejection fraction (RVEF) were calculated using commercially available software. For in-depth analysis of RV mechanics, we have decomposed the motion of the RV using our custom software (ReVISION) to determine longitudinal (LEF) and radial ejection fraction (REF). Right heart catheterization was also performed before MVR and 24 hours after MVR as well to measure pulmonary arterial mean systolic pressure (mPAP), pulmonary arterial wedge pressure (PAWP) and RV stroke work index (RVSWi). Using the aforementioned parameters, we have calculated RV longitudinal (longRVSWi) and RV radial stroke work index (radRVSWi), which represent RV longitudinal and radial fiber contractility.

RV morphology did not change significantly according to RVEDVi (preop vs. postop: 71 ± 17 vs. 72 ± 20 mL/m², p = NS). RVEF slightly decreased after MVR (50 ± 6 vs. 48 ± 7 %, p &lt; 0.05), however, RV motion pattern markedly changed. Postoperative LEF was significantly lower compared to preoperative values (25 ± 6 vs. 16 ± 6%, p &lt; 0.0001), among with an increase in REF (21 ± 7 vs. 27 ± 7%, p &lt; 0.01). As expected, mPAP and PAWP decreased in response to MVR (mPAP: 30 ± 10 vs. 25 ± 7 mmHg; PAWP: 19 ± 7 vs. 13 ± 3 mmHg, both p &lt; 0.01). Global RV contractility decreased after surgery (RVSWi: 603 ± 355 vs. 474 ± 251 mmHg*mL/m², p &lt; 0.05). While RV longitudinal contractility also significantly reduced (longRVSWi: 289 ± 179 vs. 166 ± 122 mmHg*mL/m², p &lt; 0.001), radial contractility was maintained following MVR (radRVSWi: 240 ± 141 vs. 261 ± 144 mmHg*mL/m², p = NS).

MVR is associated with marked changes of RV function and hemodynamics. RV longitudinal and radial contractility have distinct response to surgery, which may be important in postoperative patient management. The PREPARE-MVR study aims to examine the role of preoperative RV mechanics in clinical outcome.

Optimization of the Production Process and Product Quality of Titanate Nanotube-Drug Composites

Recently, there has been an increasing interest in the application of nanotubular structures for drug delivery. There are several promising results with carbon nanotubes; however, in light of some toxicity issues, the search for alternative materials has come into focus. The objective of the present study was to investigate the influence of the applied solvent on the composite formation of titanate nanotubes (TNTs) with various drugs in order to improve their pharmacokinetics, such as solubility, stability, and bioavailability. Composites were formed by the dissolution of atenolol (ATN) and hydrochlorothiazide (HCT) in ethanol, methanol, 0.01 M hydrochloric acid or in ethanol, 1M sodium hydroxide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), respectively, and then they were mixed with a suspension of TNTs under sonication for 30 min and vacuum-dried for 24 h. The structural properties of composites were characterized by SEM, TEM, FT-IR, differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, and optical contact angle (OCA) measurements. Drug release was determined from the fast disintegrating tablets using a dissolution tester coupled with a UV-Vis spectrometer. The results revealed that not only the good solubility of the drug in the applied solvent, but also the high volatility of the solvent, is necessary for an optimal composite-formation process.

Noble-Metal-Free Iron Nitride/Nitrogen-Doped Graphene Composite for the Oxygen Reduction Reaction

Considerable effort has been devoted recently to replace platinum-based catalysts with their non-noble-metal counterparts in the oxygen reduction reaction (ORR) in fuel cells. Nitrogen-doped carbon structures emerged as possible candidates for this role, and their earth-abundant metal-decorated composites showed great promise. Here, we report on the simultaneous formation of nitrogen-doped graphene and iron nitride from the lyophilized mixture of graphene oxide and iron salt by high-temperature annealing in ammonia atmosphere. A mixture of FeN and Fe2N particles was formed with average particle size increasing from 23.4 to 127.0 nm and iron content ranging from 5 to 50 wt %. The electrocatalytic oxygen reduction activity was investigated via the rotating disk electrode method in alkaline media. The highest current density of 3.65 mA cm-2 at 1500 rpm rotation rate was achieved in the 20 wt % catalyst via the four-electrode reduction pathway, exceeding the activity of both the pristine iron nitride and the undecorated nitrogen-doped graphene. Since our catalysts showed improved methanol tolerance compared to the platinum-based ones, the formed non-noble-metal system offers a viable alternative to the platinum-decorated carbon black (Pt/CB) ORR catalysts in direct methanol fuel cells.

Green synthesis and in situ immobilization of gold nanoparticles and their application for the reduction of p-nitrophenol in continuous-flow mode

A green and facile method has been developed for the preparation of in situ immobilized gold nanoparticles (AuNPs) using agarose as a reducing and stabilizing agent. The size of the synthesized AuNPs ranges between 10 and 100 nm, and their average size can be controlled by the concentrations of the agarose and gold salt. The agarose matrix as a mild and green reaction medium can provide a good dispersion environment for forming AuNPs, and the hydrogel can be well homogenized with polyacrylic macroporous microbeads as well, which can adsorb and stabilize the particles leading to the simultaneous synthesis and immobilization of AuNPs avoiding harmful inorganic compounds or organic solvents. The supported gold nanocatalyst was successfully applied as a catalyst in packed bed reactors for efficient NaBH₄-mediated reduction of p-nitrophenol in continuous-flow mode.

Gold nanoparticles synthesized using agarose and supported in macroporous polymer beads were used in continuous-flow mode in reduction of p-nitrophenol by sodium borohydride.

Comparison of Particle Size Distribution Models for Polymer Swelling

In polymer technologies, various particle shapes and size distributions can be found. One of these are heterodisperse polymer beads. The capabilities of polymer swelling can be used in industries, e.g in the production of ion-exchange resins, to intensify specific technological steps such as sulphonation in the manufacturing process of ion-exchange resins. According to the literature different approaches can be used to create models for describing the behavior of disperse systems, of which the simplest models are the particle size distribution models for a given state of the solid phase. The aim of our examination was to compare and evaluate these simple models in terms of modeling polymer swelling. Hence, most of these models examine how each of the investigated models can be applied to approximately describe growth in a heterodisperse polymer system and how the identified model parameters in each time step could be interpreted. All the models were fitted to generate particle size distributions based on a swelling rate constant. The swelling of a styrene divinylbenzene-based copolymer was chosen as the basis of our examination. A model is proposed that is capable of describing the changes in the size of beads over time in this system.

Development and Application of Carbon-Layer-Stabilized, Nitrogen-Doped, Bamboo-Like Carbon Nanotube Catalysts in CO2 Hydrogenation

Nitrogen-doped, bamboo-like carbon nanotubes (BCNTs) were synthesized from butylamine by catalytic chemical vapor deposition (CCVD method). The nanotubes were oxidized by H2SO4/HNO3 treatment and used to prepare calcium alginate gelled BCNT spheres. These beads were first carbonized and then Pd, Rh and Ni nanoparticles were anchored on the surface of the spheres. These systems were then applied as catalysts in CO2 hydrogenation. The BCNT support was examined by Raman spectroscopy, dynamic light scattering (DLS) and X-ray photoelectron spectroscopy (XPS). The prepared catalysts were characterized by HRTEM and SEM. The oxidation pretreatment of BCNTs was successful, with the electrokinetic potential of the water-based dispersion of BCNTs measuring -59.9 mV, meaning the nanotube dispersion is stable. Pyridinic and graphitic types of incorporated nitrogen centers were identified in the structure of the nanotubes, according to the XPS measurements. The Pd-containing BCNT sphere catalyst was the most efficient in the catalytic studies. The highest conversion was reached on the Pd catalyst at 723 K, as well as at 873 K. The difference in the formation rate of CO was much less at 873 K between the Pd and Rh compared to the 723 K values. Accordingly, the application of Pd-containing BCNT/carbon-supported catalyst favored the generation of CO. However, the Ni-BCNT/carbon catalyst leads to the formation of CH4 as the major product.

CFD Based Qualification of Mixing Efficiency of Stirred Vessels

In this work, we focus on the most crucial units in a chemical technology, the chemical reactors. Using a commercially available CFD software package, COMSOL Multiphysics, 3D mathematical models of a batch reactor with different impeller geometries have been investigated. The reasonable agreement between the experimental and simulation results indicates the validity of the developed CFD model. The effect of the impeller design, e. g. number of blades on the mixing efficiency is evaluated based on the simulation studies. The proposed measure to determine the energy efficiency of mixing (i. e. mixing index) is based on the calculated velocity field and energy usage. The information about the homogeneity of the mixed phase in the system can be extracted from the developed velocity field. Hence, we proposed histograms of velocity fluctuations on a logarithmic scale as an efficient tool to measure the achieved homogeneity of the phase in case of different impellers and rotational speeds.

Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture Part 2: Image sequence analysis based evaluation and biological application

As a continuation of our previously published work, this paper presents a detailed evaluation of a microfabricated cell capture device utilizing a doubly tilted micropillar array. The device was fabricated using a novel hybrid technology based on the combination of proton beam writing and conventional lithography techniques. Tilted pillars offer unique flow characteristics and support enhanced fluidic interaction for improved immunoaffinity based cell capture. The performance of the microdevice was evaluated by an image sequence analysis based in-house developed single-cell tracking system. Individual cell tracking allowed in-depth analysis of the cell-chip surface interaction mechanism from hydrodynamic point of view. Simulation results were validated by using the hybrid device and the optimized surface functionalization procedure. Finally, the cell capture capability of this new generation microdevice was demonstrated by efficiently arresting cells from a HT29 cell-line suspension.