35 research outputs found
High-pressure xenon gas time projection chamber with scalable design and its performance at around the Q value of Xe double-beta decay
We have been developing a high-pressure xenon gas time projection chamber
(TPC) to search for neutrinoless double beta () decay of
Xe. The unique feature of this TPC is in the detection part of
ionization electrons, called ELCC. ELCC is composed of multiple units, and one
unit covers 48.5 . A 180 L size prototype detector with 12
units, 672 channels, of ELCC was constructed and operated with 7.6 bar natural
xenon gas to evaluate the performance of the detector at around the Q value of
Xe . The obtained FWHM energy resolution is (0.73
0.11) % at 1836 keV. This corresponds to (0.60 0.03) % to (0.70
0.21) % of energy resolution at the Q value of .
This result shows the scalability of the AXEL detector with ELCC while
maintaining high energy resolution. Factors determining the energy resolution
were quantitatively evaluated and the result indicates further improvement is
feasible. Reconstructed track images show distinctive structures at the
endpoint of electron tracks, which will be an important feature to distinguish
signals from gamma-ray backgrounds.Comment: 33 pages, 24 figures, preprint accepted by PTE
Unique characteristics of new complete blood count parameters, the Immature Platelet Fraction and the Immature Platelet Fraction Count, in dengue patients
The advanced platelet parameters Immature Platelet Fraction and Immature Platelet Fraction Count have been implemented in clinical practice as measures of thrombopoietic activity, mainly in hematologic disorders that cause thrombocytopenia. The purpose of this observational study was to examine thrombopoiesis as reflected by these 2 new CBC parameters in patients infected with dengue. The study was conducted in infectious disease referral hospital in Metro Manila, the Philippines. We enrolled hospitalized patients at admission who were diagnosed with acute dengue or community acquired bacterial infection (CABI). Immature Platelet Fraction (IPF) and Immature Platelet Fraction Count were evaluated at admission and during hospitalization. A total of 606 patients were enrolled from May 1, 2017 to June 1, 2018. The participants consisted of 152 patients with dengue infection, 180 confirmed CABI, and 274 suspected CABI patients. At admission, the percent IPF (IPF%) of the patients with dengue was significantly higher than that of the confirmed CABI patients (median 3.7% versus 1.9%; p <0.001). In a time course evaluation, there was no significant difference of IPF% between the patients with dengue infection and the confirmed CABI patients in the febrile phase (median 1.9% versus 2.4%; p = 0.488), however, the IPF% of the patients with dengue infection increased to be significantly higher than that of the confirmed CABI patients in the critical phase (median 5.2% versus 2.2%; p <0.001). Our study elucidated the unique characteristics and time-course trends of IPF percent and number (IPF#) in the patients with dengue infection. IPF% and IPF# are potentially valuable parameters in dengue and further investigation is required for the optimal use in clinical practice
A prospective observational study of community-acquired bacterial bloodstream infections in Metro Manila, the Philippines
Community-acquired bacterial bloodstream infections are caused by diverse pathogens with changing antimicrobial-resistance patterns. In low-middle income countries in Southeast Asia, where dengue fever is endemic and a leading cause of fever, limited information is available about bacterial bloodstream infections due to challenges of implementing a blood culture service. This study describes bacterial bloodstream pathogens and antimicrobial-resistance patterns in Metro Manila, the Philippines. We aimed to identify the proportion of patients with a positive blood culture, the bacteria isolated and their antimicrobial resistance patterns, and the clinical characteristics of these patients, in this dengue endemic area. We conducted a prospective observational study in a single hospital enrolling febrile patients clinically suspected of having a community-acquired bacterial bloodstream infection between 1st July 2015 and 30th June 2019. Each patient had a blood culture and additional diagnostic tests according to their clinical presentation. We enrolled 1315 patients and a significant positive blood culture was found in 77 (5.9%) including Staphylococcus aureus (n=20), Salmonella enterica Typhi (n=18), Escherichia coli (n=16), Streptococcus pneumoniae (n=3) and Burkholderia pseudomallei (n=2). Thirty-four patients had meningococcal disease diagnosed by culture (n=8) or blood PCR (n=26). Additional confirmed diagnoses included leptospirosis (n=177), dengue virus infection (n=159) and respiratory diphtheria (n=50). There were 79 (6.0%, 95%CI 4.8%−7.4%) patients who died within 28 days of enrollment. Patients with a positive blood culture were significantly more likely to die than patients with negative culture (15.2 % vs 4.4 %, P<0.01). Among S. aureus isolates, 11/20 (55%) were methicillin-resistant (MRSA) and ST30 : USA1100 was dominant sequence type (88.9%). Antimicrobial-susceptibility was well preserved in S. enterica Typhi. Among hospitalized patients with clinically suspected community-acquired bacterial bloodstream infection in Metro Manila, the Philippines, 5.9% had a blood culture confirmed infection of whom 15.6% died. S. aureus, including a significant number of MRSA (USA1100 clones), S. enterica Typhi, E.coli and Neisseria meningitidis were frequently identified pathogens
Gate-Voltage-Controlled Threading DNA into Transistor Nanopores
We present a simple method for DNA
translocation driven by applying
AC voltages, such as square and sawtooth waves, on an embedded thin
film as a gate electrode inside of a dielectric nanopore, without
applying a conventional bias voltage externally across the pore membrane.
Square waveforms on a gate can drive a single DNA molecule into a
nanopore, which often returns from the pore, causing an oscillation
across the membrane. An optimized sawtooth-like negative voltage pulse
on the gate can thread a fraction of a DNA molecule into a pore after
a single pulse. This trapped DNA molecule continues to finish its
translocation slowly through the pore. The DNA’s slow speed
was comparable to previous findings of the escaping DNA speed from
a nanopore estimated by the Smoluchowski equation with excluded-volume
interactions of a long-chain molecule and electrophoresis by extremely
low electric fields. This simple scheme, controlling DNA molecules
only by gate potential modulation at a nanopore, will provide an additional
method to thread, translocate, or oscillate a single biomolecule at
a gated nanopore
Interconnected pores on the walls of a polymeric honeycomb monolith structure created by the unidirectional freezing of a binary polymer solution
Interconnected submicron pores were created on the walls of a honeycomb monolith structure by the unidirectional freezing of a binary polymer solution. Agglomerated globules of polyethylene glycol (PEG) in a binary solution of polystyrene (PS) and PEG in 1, 4-dioxane solvent were frozen unidirectionally in a liquid nitrogen bath. Removing the frozen solvent and the agglomerated globules of PEG by freeze-drying and leaching, respectively, enabled us to create interconnected pores in the PS walls. The combination of PS and PEG was effective in creating interconnected pores in the walls because PS and PEG are poorly soluble in one another. The higher freezing rate and lower PEG weight fraction of the binary solution effectively reduced the pore size in the microtube walls