Lifting the Concentration Limit of Mass Photometry by PEG Nanopatterning.

Mass photometry (MP) is a rapidly growing optical technique for label-free mass measurement of single biomolecules in solution. The underlying measurement principle provides numerous advantages over ensemble-based methods but has been limited to low analyte concentrations due to the need to uniquely and accurately quantify the binding of individual molecules to the measurement surface, which results in diffraction-limited spots. Here, we combine nanoparticle lithography with surface PEGylation to substantially lower surface binding, resulting in a 2 orders of magnitude improvement in the upper concentration limit associated with mass photometry. We demonstrate the facile tunability of degree of passivation, enabling measurements at increased analyte concentrations. These advances provide access to protein-protein interactions in the high nanomolar to low micromolar range, substantially expanding the application space of mass photometry.

Gas-aggregated Ag nanoparticles for detection of small molecules using LDI MS.

Several reports demonstrate that silver nanomaterials can serve as surface-assisted laser desorption ionization mass spectrometry (SALDI MS) substrates for low molecular weight analytes. Substrate with tailored silver nanostructures, primarily representing the upmost layer of the bulk, i.e., occurring beneath the analyzed medium, limits the use of silver only for desorption enhancement; the charge transfer progresses through atoms from the absorbing analyte or an additional matrix (resulting in the formation of analyte/hydrogen, sodium, or potassium adducts in the most cases). In the presented approach, we utilize a homogeneous layer of silver nanoparticles, prepared under low-pressure conditions, deposited onto a dried analyte. We demonstrate that the nanoparticle layer can fully replace a matrix typically used for the detection of small molecules by laser desorption/ionization mass spectrometry-based technique (LDI MS) and can be applied to the already prepared samples. Various chemical species were detected as [M + Ag]+ adduct ions employing the proposed technique. The normalized signal of the analyte/silver adduct can be utilized to characterize a quantitative presence of analytes on the surface similar to signal-to-noise value, here demonstrated by the detection of trimethoprim molecule. This study also includes a detailed description of additional features one needs to take into account, such as a formation of [Mx + Agy]+ adducts, presence of silver ions (can be used for m/z calibration), analyte fragmentation, and influence of deposited nanoparticles quantity on the signal intensity. Graphical abstract.

A New Insight into the Stereoelectronic Control of the Pd0 -Catalyzed Allylic Substitution: Application for the Synthesis of Multisubstituted Pyran-2-ones via an Unusual 1,3-Transposition.

Pyran-2-ones 3 undergo a novel Pd0 -catalyzed 1,3-rearrangement to afford isomers 6. The reaction proceeds via an η2 -Pd complex, the pyramidalization of which (confirmed by quantum chemistry calculations) offers a favorable antiperiplanar alignment of the Pd-C and allylic C-O bonds (C), thus allowing the formation of an η3 -Pd intermediate. Subsequent rotation and rate-limiting recombination with the carboxylate arm then gives isomeric pyran-2-ones 6. The calculated free energies reproduce the observed kinetics semi-quantitatively.

Compliance with ethical rules for scientific publishing in biomedical Open Access journals indexed in Journal Citation Reports.

This study examined compliance with the criteria of transparency and best practice in scholarly publishing defined by COPE, DOAJ, OASPA and WAME in Biomedical Open Access journals indexed in Journal Citation Reports (JCR). 259 Open Access journals were drawn from the JCR database and on the basis of their websites their compliance with 14 criteria for transparency and best practice in scholarly publishing was verified. Journals received penalty points for each unfulfilled criterion when they failed to comply with the criteria defined by COPE, DOAJ, OASPA and WAME. The average number of obtained penalty points was 6, where 149 (57.5%) journals received 6 points and 110 (42.5%) journals 7 points. Only 4 journals met all criteria and did not receive any penalty points. Most of the journals did not comply with the criteria declaration of Creative Commons license (164 journals), affiliation of editorial board members (116), unambiguity of article processing charges (115), anti-plagiarism policy (113) and the number of editorial board members from developing countries (99). The research shows that JCR cannot be used as a whitelist of journals that comply with the criteria of transparency and best practice in scholarly publishing.

[Predatory journals: how their publishers operate and how to avoid them]. / Predátorské casopisy: praktiky jejich vydavatelu a jak se jim bránit.

Authors who publish in scientific or scholarly journals today face the risk of publishing in so-called predatory journals. These journals exploit the noble idea of the Open Access movement, whose goal is to make the latest scientific findings available for free. Predatory journals, unlike the reputable ones working on an Open Access basis, neglect the review process and publish low-quality submissions. The basic attributes of predatory journals are a very quick review process or even none at all, failure to be transparent about author fees for publishing an article, misleading potential authors by imitating the names of well-established journals, and false information on indexing in renowned databases or assigned impact factor. Some preventive measures against publishing in predatory journals or drawing information from them are: a thorough credibility check of the journals webpages, verification of the journals indexing on Bealls List and in the following databases: Web of Science Core Collection, Scopus, ERIH PLUS and DOAJ. Asking other scientists or scholars about their experience with a given journal can also be helpful. Without these necessary steps authors face an increased risk of publishing in a journal of poor quality, which will prevent them from obtaining Research and Development Council points (awarded based on the Information Register of Research & Development results); even more importantly, it may damage their reputation as well as the good name of their home institution in the professional community.Key words: academic writing - medical journals - Open Access - predatory journals - predatory publishers - scientific publications.

Finite Element Analysis of Silver Nanorods, Spheres, Ellipsoids and Core-Shell Structures for Hyperthermia Treatment of Cancer.

The finite element analysis technique was used to investigate the suitability of silver nanorods, spheres, ellipsoids and core−shell structures for the hyperthermia treatment of cancer. The temperature of the silver nanostructures was raised from 42 to 46 °C, in order to kill the cancerous cells. The time taken by the nanostructures to attain this temperature, with external source heating, was also estimated. The heat transfer module in COMSOL Multiphysics was used for the finite element analysis of hyperthermia, based on silver nanostructures. The thermal response of different shapes of silver nanostructures was evaluated by placing them inside the spherical domain of the tumor tissue. The proposed geometries were heated at different time intervals. Optimization of the geometries was performed to achieve the best treatment temperature. It was observed that silver nanorods quickly attain the desired temperature, as compared to other shapes. The silver nanorods achieved the highest temperature of 44.3 °C among all the analyzed geometries. Moreover, the central volume, used to identify the thermal response, was the maximum for the silver nano-ellipsoids. Thermal equilibrium in the treatment region was attained after 0.5 µs of heating, which made these structures suitable for hyperthermia treatment.

Experimental and Numerical Investigation of Effect of Static and Fatigue Loading on Behavior of Different Double Strap Adhesive Joint Configurations in Fiber Metal Laminates.

Double strap lap adhesive joints between metal (AA 6061-T6) and composite (carbon/epoxy) laminates were fabricated and characterized based on strength. Hand layup methods were used to fabricate double strap match lap joints and double strap mismatch lap joints. These joints were compared for their strength under static and fatigue loadings. Fracture toughness (GIIC) was measured experimentally using tensile testing and validated with numerical simulations using the cohesive zone model (CZM) in ABAQUS/Standard. Fatigue life under tension-tension fluctuating sinusoidal loading was determined experimentally. Failure loads for both joints were in close relation, whereas the fatigue life of the double strap mismatch lap joint was longer than that of the double strap match lap joint. A cohesive dominating failure pattern was identified in tensile testing. During fatigue testing, it was observed that inhomogeneity (air bubble) in adhesive plays a negative role while the long time duration between two consecutive cycle spans has a positive effect on the life of joints.

Physicochemical and Mechanical Performance of Freestanding Boron-Doped Diamond Nanosheets Coated with C:H:N:O Plasma Polymer.

The physicochemical and mechanical properties of thin and freestanding heavy boron-doped diamond (BDD) nanosheets coated with a thin C:H:N:O plasma polymer were studied. First, diamond nanosheets were grown and doped with boron on a Ta substrate using the microwave plasma-enhanced chemical vapor deposition technique (MPECVD). Next, the BDD/Ta samples were covered with nylon 6.6 to improve their stability in harsh environments and flexibility during elastic deformations. Plasma polymer films with a thickness of the 500-1000 nm were obtained by magnetron sputtering of a bulk target of nylon 6.6. Hydrophilic nitrogen-rich C:H:N:O was prepared by the sputtering of nylon 6.6. C:H:N:O as a film with high surface energy improves adhesion in ambient conditions. The nylon-diamond interface was perfectly formed, and hence, the adhesion behavior could be attributed to the dissipation of viscoelastic energy originating from irreversible energy loss in soft polymer structure. Diamond surface heterogeneities have been shown to pin the contact edge, indicating that the retraction process causes instantaneous fluctuations on the surface in specified microscale regions. The observed Raman bands at 390, 275, and 220 cm-1 were weak; therefore, the obtained films exhibited a low level of nylon 6 polymerization and short-distance arrangement, indicating crystal symmetry and interchain interactions. The mechanical properties of the nylon-on-diamond were determined by a nanoindentation test in multiload mode. Increasing the maximum load during the nanoindentation test resulted in a decreased hardness of the fabricated structure. The integration of freestanding diamond nanosheets will make it possible to design flexible chemical multielectrode sensors.

State-of-the-Art, and Perspectives of, Silver/Plasma Polymer Antibacterial Nanocomposites.

Urgent need for innovative and effective antibacterial coatings in different fields seems to have triggered the development of numerous strategies for the production of such materials. As shown in this short overview, plasma based techniques arouse considerable attention that is connected with the possibility to use these techniques for the production of advanced antibacterial Ag/plasma polymer coatings with tailor-made functional properties. In addition, the plasma-based deposition is believed to be well-suited for the production of novel multi-functional or stimuli-responsive antibacterial films.

Fully substituted pyranones via quasi-heterogeneous genuinely ligand-free Migita-Stille coupling of iodoacrylates.

Migita-Stille coupling of (Z)-ß-iodoacrylates with (E)-α-stannyl allylic alcohols to furnish 5-alkylidene-4-substituted-5,6-dihydro-2H-pyran-2-ones is efficiently catalyzed by 2% Pd black in DMF, while Pd(PPh3)4 is inactive. Heterogeneous Pd released in solution is most likely responsible for the catalysis. The reaction is applicable to other substrates, without having to resort to ligands, additives, and/or solid support for Pd. The resulting pyranones can be rearranged to fully functionalized pyranones in another single step.