Non-destructive low-temperature contacts to MoS2\textrm{MoS}_2 nanoribbon and nanotube quantum dots

Molybdenum disulfide nanoribbons and nanotubes are near-one dimensional semiconductors with strong spin-orbit interaction, a nanomaterial highly promising for quantum electronic applications. Here, we demonstrate that a bismuth semimetal layer between the contact metal and this nanomaterial strongly improves the properties of the contacts. Two-point resistances on the order of $100\textrm{k}\Omega$ are observed at room temperature. At cryogenic temperature, Coulomb blockade is visible. The resulting stability diagrams indicate a marked absence of trap states at the contacts and the corresponding disorder, compared to previous devices using low-work function metals as contacts. Single level quantum transport is observed at temperatures below 100mK.Comment: 7 pages, 5 figure

Coulomb Blockade Spectroscopy of a MoS2 Nanotube

Low-temperature transport spectroscopy measurements on a quantum dot lithographically defined in a multiwall MoS2 nanotube are demonstrated. At T = 300 mK, clear Coulomb blockade is observed, with charging energies in the range of 1 meV. In single-electron tunneling, discrete conductance resonances are visible at finite bias. Additionally, a magnetic field perpendicular to the nanotube axis reveals clear indications of quantum state transitions, with effective g factors consistent with published theoretical predictions

Twisted Nanotubes of Transition Metal Dichalcogenides with Split Optical Modes for Tunable Radiated Light Resonators

Synthesized micro- and nanotubes composed of transition metal dichalcogenides (TMDCs) such as MoS$_2$ are promising for many applications in nanophotonics, because they combine the abilities to emit strong exciton luminescence and to act as whispering gallery microcavities even at room temperature. In addition to tubes in the form of hollow cylinders, there is an insufficiently-studied class of twisted tubes, the flattened cross section of which rotates along the tube axis. As shown by theoretical analysis, in such nanotubes the interaction of electromagnetic waves excited at opposite sides of the cross section can cause splitting of the whispering gallery modes. By studying micro-photoluminescence spectra measured along individual MoS$_2$ tubes, it has been established that the splitting value, which controls the energies of the split modes, depends exponentially on the aspect ratio of the cross section, which varies in "breathing" tubes, while the relative intensity of the modes in a pair is determined by the angle of rotation of the cross section. These results open up the possibility of creating multifunctional tubular TMDC nanodevices that provide resonant amplification of self-emitting light at adjustable frequencies

Familitary with assistive devices for performing daily activities of the elderly in the municipality of Zagorje ob Savi

Uvod: Staranje prebivalstva predstavlja velik izziv za sodobno družbo in tudi posameznika. Človek se skozi različna življenjska obdobja spoprijema s spremembami, ki se jim mora prilagajati, v starosti pa so te spremembe največje. Starostniki si želijo obdobje starosti preživljati v domačem okolju, dokler je to mogoče. Zaradi starostnega upada različnih funkcij, lahko daljšo samostojnost v domačem okolju omogočamo tudi z uporabo podporne tehnologije. Namen: Namen diplomskega dela je ugotoviti, v kolikšni meri so starostniki, ki živijo v domačem okolju in koristijo storitev patronažne službe ali pomoč na domu v občini Zagorje ob Savi, seznanjeni s pripomočki za izvedbo ožjih dnevnih aktivnosti. Metode dela: Oblikovali smo anketni vprašalnik, sestavljen iz dveh sklopov. Prvi sklop je bil namenjen pridobivanju demografskih podatkov, drugi sklop pa je bil sestavljen iz sedemnajstih vprašanj o poznavanju pripomočkov iz priloženih fotografij. Zanimalo nas je tudi, kje so anketiranci informacije o pripomočkih prejeli. Poznavanje pripomočkov smo preverjali z vprašanjem o tem, čemu je pripomoček namenjen. Vzorčenje je bilo namensko, anketirani so bile osebe, stare 65 let ali več, ki so vključene v storitev patronažne službe Zdravstvenega doma Zagorje ob Savi ali storitev pomoči na domu Doma starejših občanov Polde Eberl - Jamski Izlake. Zbrali smo 42 veljavnih vprašalnikov. Rezultati: Anketiranci so skupno prepoznali 36,6 % vseh pripomočkov v anketnem vprašalniku. Poznavanje se glede na posamezne pripomočke razlikuje. Največ informacij o pripomočkih so prejeli od osebja v zdravstvenem domu ali bolnišnici (31,5 %). S pripomočki so v največji meri seznanjeni posamezniki v starostni skupini od 75 do 84 let (29,4 %). Razprava in zaključek: Poznavanje enostavnejših pripomočkov za izvedbo ožjih dnevnih aktivnosti med anketiranci je nizko, kar je bilo pričakovano. Največkrat so bili prepoznani tisti pripomočki, ki se ne navezujejo izključno na obdobje starosti in s tem povezanega funkcionalnega upada. Anketiranci so največ informacij prejeli v zdravstvenem domu ali bolnišnici od osebja, ne vemo pa, ali so jim pripomočke predstavili delovni terapevti in ali jih je kdo poučil o njihovi neposredni uporabi. V največji meri so pripomočke prepoznali posamezniki v obdobju srednje starosti. Na ravni preventive bi bilo smiselno s pripomočki seznaniti posameznike v obdobju poznih srednjih let do zgodnje starosti. Vključevanje delovnega terapevta kot člana multidisciplinarnega tima v skupnostno obravnavo bi bilo smiselno, saj bi s tem preko aktivnosti, adaptacij in uporabe pripomočkov ohranjal samostojnost in varnost posameznikov v njihovem okolju. Skupnostna obravnava bi pomembno vplivala na kakovost življenja vključenih.Introduction: The aging process of the population represents a great challenge for modern society and the individual himself. Every human being has to face changes throughout different stages of their life, to which they have to adapt. These changes are most pronounced in old age. The elderly want to spend their remaining years in a home environment for as long as possible. Due to the age decline of various functions of the individual, we can enable longer independence in the home environment by using assistive technology. Purpose: The purpose of this dissertation is to determine the extent to which elderly people who are aging in the home environment and use the home care services or home help in the municipality of Zagorje ob Savi are familiar with low- technology assistive devices for performing daily activities. Methods of work: We designed a questionnaire consisting of two sets. The first set was intended for obtaining demographic data, and the second set consisted of seventeen questions based on the knowledge of tools for basic activities of daily living, completed with photos. We were also interested in respondents’ source of infrormation about gadgets. We tested the participants’ knowledge of the gadgets by asking them what the gadget is used for. The sampling was purposeful, and people aged 65 or over who were included in the home care service of the Zagorje ob Savi Health Center or the home help service of the Elderly home Polde Eberl Jamski Izlake were interviewed. We collected 42 valid questionnaires. Results: Respondents identified a total of 36.6% of all devices in the questionnaire. Their knowledge varied from device to device. Most information on devices was received from staff at the health center or hospital (31.5%). Individuals in the age group of 75 to 84 years were most familiar with assistive devices (29.4%). Discussion and conclusion: Knowledge of low technology assistive devices for performing basic daily activities among respondents is low, as expected. Most often, the identified devices do not relate exclusively to old age, and the correlated functional decline was identified, but to various types of decline in functional abilities in previous periods of life. As expected, the respondents received most of the information in the health center or hospital from the staff, but we do not know whether the devices were presented to them by occupational therapists and whether anyone taught them about their direct use. The gadgets were largely recognized by middle-aged individuals. At the level of prevention, it would make sense to focus on knowledge of the devices in early and late middle-aged individuals. The inclusion of an occupational therapist, as a member of a multidisciplinary team in the home environment of the elderly in the municipality of Zagorje ob Savi would be beneficial, as this would encourage the independence and safe aging of individuals in their environment through activity, adaptations and the introduction of assistive technology, thus significantly influencing their satisfaction and quality of lif

Genome mining in myxobacteria and actinobacteria : studies of natural products and their biosynthetic pathways

Bacterial resistance to antibiotics drives the need for incessant research efforts to discover substitutes for ineffective antibiotics. Soil-dwelling Myxobacteria and Actinobacteria provide many biologically active natural products that can be developed into new treatment options. In postgenomic era, the natural product discovery is often based on the genome mining approach combined with genetic engineering used also in this work. This thesis presents two novel natural products, myxopentacin and myxoglucamide, produced by Cystobacterineae sp. MCy9003, a representative of a novel myxobacterial genus. The nonribosomal peptide myxopentacin features rare cispentacin and pseudoarginine moieties, incorporated by a unique assembly mechanism. The glycolipopeptide myxoglucamide contains an unusual vinyl moiety and its biosynthesis involves multiple biochemical transfomations. In addition, this thesis describes the identification of the biosynthetic gene cluster in Streptomyces hagronensis, responsible for the production of the known antibiotic globomycin, a signal peptidase II inhibitor. Furthermore, the genome of the antibiotic fidaxomicin producer Actinoplanes deccanensis was genetically engineered to acquire desired shunt products for further semi-synthesis. Finally, the biosynthetic pathway of the atypical tetracycline chelocardin, regarding cyclization and C6- methylation, was characterized via gene knockout and site-directed mutagenesis in Amycolatopsis sulphurea.Aufgrund der zunehmenden Resistenz von Bakterien gegen die bekannten Antibiotika, besteht ein ständiger Bedarf an neuen Wirkstoffen. Im Boden lebende Mikroorganismen wie Myxobakterien und Actinobakterien produzieren viele biologisch aktive Naturstoffe, die zu neuen Behandlungsoptionen entwickelt werden können. Um dieser Problematik entgegen zuwirken, wurde in dieser Arbeit der "genome-mining" Ansatz in Kombination mit gentechnischer Manipulationen von Cystobacterineae sp. MCy9003, einem Vertreter einer neuartigen myxobakteriellen Gattung, verwendet. Das nichtribosomale Peptid Myxopentacin mit den seltenen Cispentacin- und Pseudoarginin-Einheiten, weist einen einzigartigen Assemblierungsmechanismus auf. Das Lipoglykopeptide Myxoglucamid enthält eine ungewöhnliche Vinyleinheit und die Biosynthese umfasst viele biochemische Prozesse. . Zusätzlich wurde in dieser Arbeit der Biosyntheseweg des bekannten Antibiotikums Globomycin, ein Signalpeptidase II-Inhibitor, nach Identifizierung des entsprechenden Biosynthesegenclusters in Streptomyces hagronensis analysiert. Darüber hinaus wurde das Genom des Fidaxomicin-Produzenten Actinoplanes deccanensis gentechnisch verändert, um spezielle Shunt-Produkte für weitere semisynthetische Studien zu erhalten. Des weiteren wurde der Biosyntheseweg des atypischen Tetracyclin Antibiotikums Chelocardin hinsichtlich Zyklisierung und C6-Methylierung in Amycolatopsis sulphurea charakterisiert

Liquid crystal elastomer–nanoparticle systems for actuation

Liquid crystal elastomers (LCE) are currently of great interest due to conjoining of mesogenic ordering and rubber elasticity, exhibited in their large spontaneous thermally stimulated changes in shape. It has been shown that nanoparticles (nanotubes, photo-isomerisable dyes, magnetic nanoparticles) can be incorporated into these LCE networks to create a more sensitive network to external stimuli (i.e. strain or stress, optical, electrical, electro-thermal, magnetic). Here, we briefly summarise the current state of LCE–nanoparticle systems and explain in detail one system utilising carbon nanoparticles integrated at surfaces that may be used for electro-thermal heating of LCE systems

Size- and time-dependent aerosol removal from a protective box during simulated intubation and extubation procedures

Because the SARS-CoV-2 virus primarily spreads through droplets and aerosols, a protective box could provide adequate protection by shielding medical professionals during the intubation and extubation procedures from generated droplets and aerosols. In this study, size- and timedependent aerosol concentrations were measured inside and outside the protective box in the particle size ranging from 14 nm to 20 µm during simulated intubation and extubation procedures. An improved protective box with active ventilation was designed based on a plastic bag with armholes covered with latex sheets that utilizes a supportive frame. Coughing during the intubation and extubation procedure was simulated using an aerosol generator which dispersed the aerosol powder into the protective box. During the intubation and extubation procedure, the concentration of particles increased inside the protective box but, due to the high negative airflow, quickly dropped to background levels. The particle concentration of all measured particle sizes decreased within the same time frame. No leakage of particles was observed through the armhole openings. The presented protective box design provides excellent protection against generated droplets and aerosols. The decrease in concentration does not depend on the particle size. Outside the box, particle concentration did not change with time

Single-layer and double-layer filtration materials based on polyvinylidene fluoride-co-hexafluoropropylene nanofibers coated on melamine microfibers

In this work, we demonstrate selected optimization changes in the simple design of filtration masks to increase particle removal efficiency (PRE) and filter quality factor by combining experiments and numerical modeling. In particular, we focus on single-layer filters fabricated from uniform thickness fibers and double-layer filters consisting of a layer of highly permeable thick fibers as a support and a thin layer of filtering electrospun nanofibers. For single-layer filters, we demonstrate performance improvement in terms of the quality factor by optimizing the geometry of the composition. We show significantly better PRE performance for filters composed of micrometer-sized fibers covered by a thin layer of electrospun nanofibers. This work is motivated and carried out in collaboration with a targeted industrial development of selected melamine-based filter nano- and micromaterials