Creation of silicon vacancy color centers with a narrow emission line in nanodiamonds by ion implantation

Nanodiamonds containing silicon-vacancy (SiV) centers with high brightness, high photo-stability, and a narrow zero phonon line (ZPL) have attracted attention for bioimaging, nanoscale thermometry, and quantum technologies. One method to create such nanodiamonds is the milling of diamond films synthesized by chemical vapor deposition (CVD). However, this requires post-processing such as acid treatment and centrifugation after the milling process. Therefore, the number of SiV center-containing nanodiamonds made from an initial CVD diamond is small. An alternative method without these problems is the implantation of Si ions into preselected nanodiamonds. This method, however, has an issue regarding the ZPL linewidths, which are more than twice as broad as those in nanodiamonds synthesized by CVD. In order to reduce the linewidth, we employed annealing treatment at high temperatures (up to 1100°C) and high vacuum after the implantation. For an ion fluence of 1013 ions/cm2, a ZPL with a linewidth of about 7 nm at room temperature was observed for a nanodiamond with a median size of 29.9 ± 16.0 nm. This was close to the linewidth for nanodiamonds created by CVD

Detection of adenovirus hepatitis and acute liver failure in allogeneic hematopoietic stem cell transplant patients

Human adenovirus (HAdV) is an important cause of the common cold and epidemic keratoconjunctivitis in immunocompetent individuals. In immunocompromised patients, HAdV can sometimes cause severe infection such as cystitis, gastroenteritis, pneumonia, encephalitis, hepatitis, or disseminated disease, resulting in significant morbidity and also mortality. In particular, severe cases have been reported in patients after allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Indeed HAdV has been recognized as a pathogen that requires careful monitoring in allo‐HSCT patients. While HAdV hepatitis leading to severe acute liver failure is rare, such liver failure progresses rapidly and is often fatal. Unfortunately, HAdV hepatitis has few characteristic symptoms and physical findings, which makes it difficult to promptly confirm and start treatment. We report here four cases of HAdV hepatitis after allo‐HSCT and their autopsy findings

Electrophysiological features of familial amyloid polyneuropathy in endemic area

The process of deterioration of peripheral nerve function in familial amyloid polyneuropathy (FAP) with amyloidogenic transthyretin (ATTR) Val30Met has not been systematically evaluated hitherto. We performed nerve conduction studies in 69 patients with FAP with ATTR Val30Met from one of the endemic areas in Japan. Sensory conduction velocity (SCV), motor conduction velocity (MCV), the size of the compound muscle action potential (CMAP) and distal latency (DL) were measured in the ulnar and tibial nerves. SCV was evaluated using the orthodromic method with needle recording electrodes. These electrophysiological parameters were compared with clinical stage of FAP and duration of neuropathy. When subjects noted minimal neuropathic symptoms only in the feet, motor and sensory nerve function in both the hands and feet had already been disturbed. Sensory nerve action potential on the foot disappeared more rapidly than CMAP. CMAP on foot muscle rapidly decreased during the initial 2 years and completely disappeared within 10 years. The duration of illness and deterioration parameters (CMAP of the abductor digiti minimi muscle, MCV and SCV of the ulnar nerve and DL of both ulnar and tibial nerves) were linearly correlated. CMAP was the most sensitive and reliable parameter to evaluate motor nerve degeneration in FAP.</.ArticleAMYLOID-JOURNAL OF PROTEIN FOLDING DISORDERS. 18(1):10-18 (2011)journal articl

EGR and Emulsified Fuel Combination Effects on the Combustion, Performance, and NOx Emissions in Marine Diesel Engines

Techniques such as exhaust gas recirculation (EGR) and water-in-fuel emulsions (WFEs) can significantly decrease NOx emissions in diesel engines. As a disadvantage of adopting EGR, the afterburning period lengthens owing to a shortage of oxygen, lowering thermal efficiency. Meanwhile, WFEs can slightly reduce NOx emissions and reduce the afterburning phase without severely compromising thermal efficiency. Therefore, the EGR–WFE combination was modeled utilizing the KIVA-3V code along with GT power and experimental results. The findings indicated that combining EGR with WFEs is an efficient technique to reduce afterburning and enhance thermal efficiency. Under the EGR state, the NO product was evenly lowered. In the WFE, a considerable NO amount was created near the front edge of the combustion flame. Additionally, squish flow from the piston’s up–down movement improved fuel–air mixing, and NO production was increased as a result, particularly at high injection pressure. Using WFEs with EGR at a low oxygen concentration significantly reduced NO emissions while increasing thermal efficiency. For instance, using 16% of the oxygen concentration and a 40% water emulsion, a 94% drop in NO and a 4% improvement in the Indicated Mean Effective Pressure were obtained concurrently. This research proposes using the EGR–WFE combination to minimize NO emissions while maintaining thermal efficiency

A proposal of helmet-PET with jaw detector enabling high sensitivity measurement for brain imaging

Objectives:The advanced depth-of-interaction PET detectors improved up to three-dimensionally uniform detector resolution. These detectors enable to make a geometry having detectors very close to imaging subjects, because they can maintain high spatial resolution even in peripheral region in the field of view (FOV) without loss of sensitivity. In this study, we propose helmet-PET geometry consisted of a hemisphere detector and a jaw detector. The key points of the geometry were the closely positioned detectors and the detector covering jaw. The hemisphere geometry was expected to have high sensitivity for cerebrum region. In addition, the jaw detector was expected to significantly improve the sensitivity at center region of the hemisphere, where the cerebellum positioned. Highly sensitive and quantitatively accurate measurement for the cerebellum is important especially for functional brain imaging because it is used as a reference region. To show the effectiveness of the proposed geometry, we analyzed the sensitivity at the center region with different size of the jaw detector.Methods:As a geometrical sensitivity, we calculated relative coverage of the solid angle in that coincidence measurement was available for each point in the FOV. The effect of the size of the jaw detector to the sensitivity at the center region was studied by changing its width and length.Results:We compared average sensitivities in a region of interest with a shape of hemisphere with a diameter of 10 cm at the center in the hemisphere detector with a diameter of 40 cm. We calculated surface area and the relative coverage of the solid angle for various size of jaw detector. As a result, we found that adding the jaw detector equivalent to 12 % of the hemisphere detector doubles the geometrical sensitivity at the center region.Conclusions:We proposed the helmet-PET geometry having a jaw detector. Geometrical analysis showed that the proposed geometry has potential for high-sensitivity and accurate measurement of the brain functions.SNMMI 2013 Annual Meetin

Influences of the pre-chamber orifices on the combustion behavior in a constant volume chamber simulating pre-chamber type medium-speed gas engines

The study aims to clarify the influence of pre-chamber (PC) configurations on the combustion process in the main chamber (MC) of medium-speed spark-ignition gas engines equipped with an active PC. A constant volume combustion chamber was prepared to simulate the chamber configurations of the gas engines. A high-speed shadowgraph was applied to visualize the torch flame development and the combustion process in the MC. Experiments were done by changing the charged gas in the MC, the number, and the diameter of the PC orifices. Combustion was most accelerated when the PC orifice configuration was set appropriately so that the adjacent torch flames would combine with each other. It was also found that the unburned mixture in the PC, which ejected prior to the torch flame, supported the penetration of the torch flame