23 research outputs found
High aspect ratio silicon dioxide-coated single-walled carbon nanotube scanning probe nanoelectrodes
We have fabricated high aspect ratio, hydrophilic nanoelectrodes from individual single-walled carbon nanotubes (SWNTs) mounted on conductive atomic force microscope (AFM) tips for use as electrochemical probes. Individual SWNTs with an average diameter of 5 nm and up to 1.5 ÎŒm in length were passivated with nanometer-thick SiO_2 films, deposited conformally in an inductively coupled plasma reactor. The electrically insulating SiO_2 films improved the nanotube rigidity and stabilized the nanotubeâAFM tip contact to enable use in aqueous environments. The nanotube tip was successfully exposed by subjecting the probe to nanosecond electrical pulse etching but only after electron beam irradiation in a transmission electron microscope (TEM). Probe functionality was verified by electrodepositing gold nanoparticles from aqueous solution only at the exposed tip
Nanopencil as a wear-tolerant probe for ultrahigh density data storage
A dielectric-sheathed carbon nanotube probe, resembling a ânanopencil,â has been fabricated by conformal deposition of silicon-oxide on a carbon nanotube and subsequent âsharpeningâ to expose its tip. The high aspect-ratio nanopencil probe takes advantage of the small nanotube electrode size, while avoiding bending and buckling issues encountered with naked or polymer-coated carbon nanotube probes. Since the effective electrode diameter of the probe would not change even after significant wear, it is capable of long-lasting read/write operations in contact mode with a bit size of several nanometers
Fully inverted single-digit nanometer domains in ferroelectric films
Achieving stable single-digit nanometer inverted domains in ferroelectric thin films is a fundamental issue that has remained a bottleneck for the development of ultrahigh density (>1 Tbit/in.^2) probe-based memory devices using ferroelectric media. Here, we demonstrate that such domains remain stable only if they are fully inverted through the entire ferroelectric film thickness, which is dependent on a critical ratio of electrode size to the film thickness. This understanding enables the formation of stable domains as small as 4 nm in diameter, corresponding to 10 unit cells in size. Such domain size corresponds to 40 Tbit/in.^2 data storage densitie
Prospective cohort study of febrile neutropenia in breast cancer patients administered with neoadjuvant and adjuvant chemotherapies: CSPOR-BC FN study
Background
As Asians are more vulnerable to febrile neutropenia (FN) than Caucasians, evaluations of FN incidence and risk factors in Asians are important for the appropriate use of primary pegfilgrastim (PEG-G).
Patients and methods
Japanese breast cancer patients receiving standard adjuvant chemotherapies were prospectively enrolled in multicenter institutions from August 2015 to July 2017. FN was evaluated from 2 treatment policies: true FN (T-FN): â„37.5 °C, grade 4 neutropenia, mandatory hospital visit (visiting); surrogate FN (S-FN): â„37.5 °C, oral antibiotic, no mandatory visit (non-visiting). PEG-G was used at the physiciansâ discretion. The primary endpoint was FN incidence during all cycles. Multivariate logistic regression analysis was performed to identify T-FN risk factors.
Results
Of 1005 enrolled patients, 980 women treated with FEC, E(A)C, and TC were analyzed. The FN incidence proportions in all patients were 22.5%, 27.5%, and 33.9% for FEC, E(A)C, and TC, respectively. Those of T-FN were 27.7%, 22.4%, and 36.6%; those of S-FN were 17.3%, 32.4%, and 31.5% with more frequent primary PEG-G usage. The relative dose intensity (RDI) of the 3 regimens was â„0.85 in both groups. In the analysis of risk factors, TC (odds ratio = 2.67), age â„ 65 years (2.24), and pretreatment absolute neutrophil count (ANC)/1000 Όl (0.8) remained significant.
Conclusions
FN incidences were above 20% in the 3 regimens, with TC showing the highest. RDI was maintained at a high level in both visiting and non-visiting groups. Patient-related risk factors were age and pretreatment ANC
Tuning Inner-Ear Tip-Link Affinity Through Alternatively Spliced Variants of Protocadherin-15
Human
hearing relies upon the tip-to-tip interaction of two nonclassical
cadherins, protocadherin-15 (PCDH15) and cadherin-23 (CDH23). Together,
these proteins form a filament called the tip link that connects neighboring
stereocilia of mechanosensitive hair cells. As sound waves enter the
cochlea, the stereocilia deflect and tension is applied to the tip
link, opening nearby transduction channels. Disruption of the tip
link by loud sound or calcium chelators eliminates transduction currents
and illustrates that tip-link integrity is critical for mechanosensing.
Tip-link remodeling after disruption is a dynamic process, which can
lead to the formation of atypical complexes that incorporate alternatively
spliced variants of PCDH15. These variants are categorized into six
groups (N1âN6) based upon differences in the first two extracellular
cadherin (EC) repeats. Here, we characterized the two N-terminal EC
repeats of all PCDH15 variants (pcdh15Â(N1) to pcdh15Â(N6)) and combined
these variants to test complex formation. We solved the crystal structure
of a new complex composed of CDH23 EC1-2 (cdh23) and pcdh15Â(N2) at
2.3 Ă
resolution and compared it to the canonical cdh23âpcdh15Â(N1)
complex. While there were subtle structural differences, the binding
affinity between cdh23 and pcdh15Â(N2) is âŒ6 times weaker than
cdh23 and pcdh15Â(N1) as determined by surface plasmon resonance analysis.
Steered molecular dynamics simulations predict that the unbinding
force of the cdh23âpcdh15Â(N2) complex can be lower than the
canonical tip link. Our results demonstrate that alternative heterophilic
tip-link structures form stable proteinâprotein interactions <i>in vitro</i> and suggest that homophilic PCDH15âPCDH15
tip links form through the interaction of additional EC repeats
Tension Sensing Nanoparticles for Mechano-Imaging at the Living/Nonliving Interface
A review of Rachel Bowditch, On The Edge of Utopia: Performance and Ritual at Burning Man and Graham St John (ed.), The Local Scenes and Global Culture of Psytrance