Longitudinal spin-relaxation in nitrogen-vacancy centers in electron irradiated diamond

We present systematic measurements of longitudinal relaxation rates ($1/T_1$) of spin polarization in the ground state of the nitrogen-vacancy (NV$^-$) color center in synthetic diamond as a function of NV$^-$ concentration and magnetic field $B$. NV$^-$ centers were created by irradiating a Type 1b single-crystal diamond along the [100] axis with 200 keV electrons from a transmission electron microscope with varying doses to achieve spots of different NV$^-$ center concentrations. Values of ($1/T_1$) were measured for each spot as a function of $B$.Comment: 4 pages, 8 figure

Photoconductive properties of Bi2S3 nanowires

The photoconductive properties of Bi2S3 nanowires synthesized inside anodized alumina (AAO) membrane have been characterized as a function of illuminating photon energy between the wavelengths of 500 to 900 nm and at constant illumination intensity of 1–4 μW·cm−2. Photoconductivity spectra, photocurrent values, photocurrent onset/decay times of individual Bi2S3 nanowires liberated from the AAO membrane were determined and compared with those of arrays of as-produced Bi2S3 nanowires templated inside pores of AAO membrane. The alumina membrane was found to significantly influence the photoconductive properties of the AAO-hosted Bi2S3 nanowires, when compared to liberated from the AAO membrane individual Bi2S3 nanowires, possibly due to charge carrier trapping at the interface between the nanowire surface and the pore walls

Photoconductive properties of Bi2S3 nanowires

The photoconductive properties of Bi2S3 nanowires synthesized inside anodized alumina (AAO) membrane have been characterized as a function of illuminating photon energy between the wavelengths of 500 to 900 nm and at constant illumination intensity of 1–4 μW·cm−2. Photoconductivity spectra, photocurrent values, photocurrent onset/decay times of individual Bi2S3 nanowires liberated from the AAO membrane were determined and compared with those of arrays of as-produced Bi2S3 nanowires templated inside pores of AAO membrane. The alumina membrane was found to significantly influence the photoconductive properties of the AAO-hosted Bi2S3 nanowires, when compared to liberated from the AAO membrane individual Bi2S3 nanowires, possibly due to charge carrier trapping at the interface between the nanowire surface and the pore walls

Characterization of resistivity of Sb2S3 semiconductor nanowires by conductive AFM and in-situ methods

Conductive AFM and in situ methods were used to determine contact resistance and resistivity of individual Sb2S3 nanowires. Nanowires were deposited on oxidized Si surface for in situ measurements and on Si surface with macroelectrodes for conductive AFM (C-AFM) measurements. Contact resistance was determined by measurement of I(V) characteristics at different distances from the nanowire contact with the macroelectrode and resistivity of nanowires was determined. Sb2S3 is a soft material with low adhesion force to the surface and therefore special precautions were taken during measurements

Application of electrochemical impedance for characterising arrays of Bi2S3 nanowires

Electrochemical Impedance Spectroscopy (EIS) was used to characterise the electrical properties of bismuth sulphide (Bi2S3) nanowires (NWs) templated within anodic aluminium oxide (AAO) membranes. A specially engineered cell, with a nominal electrolyte volume of 0.1–0.2 ml, was used to hold and measure the electrochemical impedance of the fragile NW/AAO samples. An equivalent circuit model was developed to determine the filling density of nanowires within the porous templates. The EIS method can be utilised to probe the nanowire filling density in porous membranes over large sample areas, which is often unobtainable using electron microscopy and conductive atomic force microscopy techniques

Bistable nanoelectromechanical devices

A combined transmission electron microscopy-scanning tunneling microscopy (TEM-STM) technique has been used to investigate the force interactions of silicon and germanium nanowires with gold electrodes. The I(V) data obtained typically show linear behavior between the gold electrode and silicon nanowires at all contact points, whereas the linearity of I(V) curves obtained for germanium nanowires were dependent on the point of contact. Bistable silicon and germanium nanowire-based nanoelectromechanical programmable read-only memory (NEMPROM) devices were demonstrated by TEM-STM. These nonvolatile NEMPROM devices have switching potentials as low as 1 V and are highly stable making them ideal candidates for low-leakage electronic devices. (C) 2004 American Institute of Physics. (DOI:10.1063/1.1751622

Application of electrochemical impedance for characterising arrays of Bi2S3 nanowires

Electrochemical Impedance Spectroscopy (EIS) was used to characterise the electrical properties of bismuth sulphide (Bi2S3) nanowires (NWs) templated within anodic aluminium oxide (AAO) membranes. A specially engineered cell, with a nominal electrolyte volume of 0.1–0.2 ml, was used to hold and measure the electrochemical impedance of the fragile NW/AAO samples. An equivalent circuit model was developed to determine the filling density of nanowires within the porous templates. The EIS method can be utilised to probe the nanowire filling density in porous membranes over large sample areas, which is often unobtainable using electron microscopy and conductive atomic force microscopy techniques

Space charge limited current mechanism in Bi2S3 nanowires

We report on the charge transport properties of individual Bi2S3 nanowires grown within the pores of anodized aluminum oxide templates. The mean pore diameter was 80 nm. Space charge limited current is the dominating conduction mechanism at temperatures below 160 K. Characteristic parameters of nanowires, such as trap concentration and trap characteristic energy, were estimated from current–voltage characteristics at several temperatures

Prognostic value of the bone turnover markers in multiple myeloma

Background: Multiple myeloma (MM) is characterized by osteolytic bone disease resulting from increased osteoclast activity and reduced osteoblast function. Aim: The aim of our research was to determine connection between bone turnover markers and presence of bone lesions, their degree of severity, to monitor MM bone disease and to assess effectiveness of anti-myeloma treatment. Materials and Methods: Serum samples and clinical data from 123 patients with newly diagnosed MM were collected at Riga East Clinical University Hospital (Riga, Latvia) from June 2014 to June 2016. Bone lesions detected by radiography, CT scans, MRI, and PET/CT were divided into degrees from 0 to 3 (0 - no bone involvement, 1 - ≤ 3 bone lesions, 2 - ≥ 3 bone lesions, 3 - fracture). Staging was performed applying Durie/Salmon (DS) and International Staging System classifications. Progressive disease was defined as development of one or more new bone lesions. The levels of bone metabolic markers β-isomerized C-terminal telopeptide of collagen type I (β-CTX) and bone-specific alkaline phosphatase (bALP) were monitored regularly in the year. Results: Bone lesions were found in 86 (69%) patients. From these 6 (4%) patients had 1st degree, 11 (9%) had 2nd degree and 69 (56%) had 3rd degree bone lesions. Level of the bone resorption marker β-CTX in the control group was 0.41 ng/ml, which is lower than in MM patients (p 0.05). However, β-CTX was found to be an excellent diagnostic marker for MM (AUC 0.91; 95% confidence interval, 0.88-0.94; p < 0.001). Conclusions: Patients with MM and bone lesions have increased value of bone resorption marker β-CTX. There is a correlation between bone resorption marker and degree of bone lesions. Changes in β-CTX levels may be used to monitor the effectiveness of myeloma treatment.publishersversionPeer reviewe