Charge sensitivity of radio frequency single-electron transistor (RF-SET)

A theoretical analysis of the charge sensitivity of the RF-SET is presented. We use the ``orthodox'' approach and consider the case when the carrier frequency is much less than $I/e$ where $I$ is the typical current through RF-SET. The optimized noise-limited sensitivity is determined by the temperature $T$, and at low $T$ it is only 1.4 times less than the sensitivity of conventional single-electron transistor.Comment: 3 pages, 4 figure

Setup for shot noise measurements in carbon nanotubes

We have constructed a noise measurement setup for high impedance carbon nanotube samples. Our setup, working in the frequency range of 600 - 900 MHz, takes advantage of the fact that the shot noise power is reasonably large for high impedance sources so that relatively large, fixed non-matching conditions can be tolerated.Comment: 2 pages, 2 figures, published on AIP conference proceedings 200

Multiwalled carbon nanotubes as single electron transistors

Single electron transistors (SET) are fabricated from multiwalled carbon nanotubes (MWNT) by manipulation with an atomic force microscope. The devices consist of either a single MWNT with Au contacts at the ends or of two crossing tubes. In the latter device, the lower nanotube acted as the central island of a single electron transistor while the upper one functioned as a gate electrode. Coulomb blockade oscillations were observed on the nanotube at low temperatures. The voltage noise of the nanotube-SET was gain dependent as in conventional SETs. The charge sensitivity at 10 Hz was 6x10 exp -4 e/√Hz. Furthermore, in another device where the MWNT is suspended above the substrate between the electrodes, we measure an extremely high charge sensitivity of 6x 10 exp -6 e/√Hz at 45 Hz, comparable to the best of the conventional SETs.Peer reviewe

Mesoscopic Josephson junction as a noise detector

Small Josephson junctions are known to be very susceptible to noise. We have utilized this property in developing methods to measure noise as well as environmental resonance modes in mesoscopic systems. We review recent results on tunnel junction systems and show also that higher order moments of shot noise can be addressed with the present method based on the noise-induced modification of incoherent tunneling of Cooper pairs.Peer reviewe

Low Noise Current Amplifier Based on Mesoscopic Josephson Junction

We utilize the band structure of a mesoscopic Josephson junction to construct low noise amplifiers. By taking advantage of the quantum dynamics of a Josephson junction, i.e. the interplay of interlevel transitions and the Coulomb blockade of Cooper pairs, we create transistor-like devices, Bloch oscillating transistors, with considerable current gain and high input impedance. In these transistors, correlated supercurrent of Cooper pairs is controlled by a small base current made of single electrons. Our devices reach current and power gains on the order of 30 and 5, respectively. The noise temperature is estimated to be around 1 Kelvin, but it is realistic to achieve TN < 0.1 Kelvin. These devices provide quantum-electronic building blocks that will be useful in low-noise, intermediate-impedance-level circuit applications at low temperatures.Non Peer reviewe

Single-electron transistor made of multiwalled carbon nanotube using scanning probe manipulation

We positioned semiconducting multiwalled carbon nanotube, using an atomic force microscope, between two gold electrodes at SiO2 surface. Transport measurements exhibit single-electron effects with a charging energy of 24 K. Using the Coulomb staircase model, the capacitances and resistances between the tube and the electrodes can be characterized in detail.Peer reviewe

Adult-Onset Anti-Citrullinated Peptide Antibody-Negative Destructive Rheumatoid Arthritis Is Characterized by a Disease-Specific CD8+T Lymphocyte Signature

Rheumatoid arthritis (RA) is a complex autoimmune disease targeting synovial joints. Traditionally, RA is divided into seropositive (SP) and seronegative (SN) disease forms, the latter consisting of an array of unrelated diseases with joint involvement. Recently, we described a severe form of SN-RA that associates with characteristic joint destruction. Here, we sought biological characteristics to differentiate this rare but aggressive anti-citrullinated peptide antibody-negative destructive RA (CND-RA) from early seropositive (SP-RA) and seronegative rheumatoid arthritis (SN-RA). We also aimed to study cytotoxic CD8+ lymphocytes in autoimmune arthritis. CND-RA, SP-RA and SN-RA were compared to healthy controls to reveal differences in T-cell receptor beta (TCR beta) repertoire, cytokine levels and autoantibody repertoires. Whole-exome sequencing (WES) followed by single-cell RNA-sequencing (sc-RNA-seq) was performed to study somatic mutations in a clonally expanded CD8+ lymphocyte population in an index patient. A unique TCR beta signature was detected in CND-RA patients. In addition, CND-RA patients expressed higher levels of the bone destruction-associated TNFSF14 cytokine. Blood IgG repertoire from CND-RA patients recognized fewer endogenous proteins than SP-RA patients' repertoires. Using WES, we detected a stable mutation profile in the clonally expanded CD8+ T-cell population characterized by cytotoxic gene expression signature discovered by sc-RNA-sequencing. Our results identify CND-RA as an independent RA subset and reveal a CND-RA specific TCR signature in the CD8+ lymphocytes. Improved classification of seronegative RA patients underlines the heterogeneity of RA and also, facilitates development of improved therapeutic options for the treatment resistant patients

Puulattian historiaa

Opinnäytetyössäni tutustun puulattian historiaan. Työn alussa perehdyn lattian merkitykseen asuinrakennuksissa. Tavoitteena on myös selvittää syyt, miksi lattiat on rakennettu sellaisiksi kuin ne ovat. Esittelen työssäni merkittävimmät lattiatyypit sekä niiden rakentamistekniikat historiasta aina näihin päiviin saakka. Puu on historiassa ollut käytetyimpiä materiaaleja lattian rakentamisessa. Tavoitteeni on selvittää opinnäytetyössäni, mitkä puulajit ovat parhaimpia lattian rakentamiseen sekä miten puutavaran valmistus on kehittynyt historiassa. Lähteinä olen käyttänyt kansatieteellisiä kertomuksia, rakennusoppikirjoja sekä puurakentamiseen erikoistunutta kirjallisuutta. Opinnäytetyöni osoittaa, että puulattian kehitys ei ole ollut yhtenäinen. Lattian rakentamista on pääsääntöisesti ohjannut asukkaan varallisuus.In my thesis I deal with the history of wooden floors. At first, I focus on the im-portance of floors in residential buildings. The objective is also to find out the rea-sons why floors have been built the way they have. I also present the most signifi-cant wooden floor types and their building techniques in history until the present day. Wood has been one of the most commonly used materials in floors. My target is to find out which species of trees are the best for the construction of floors and how the preparation of timber has evolved along the time. As literature sources, I have used are several different textbooks about building and ethnological literature. My thesis shows that the development of wooden floors has not been simultaneous. Construction of floors has mainly depended on the resident’s wealth