bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Natural Deep Eutectic Solvent Formulated to Stabilize β-Lactam Antibiotics
Authors: Olivares Belén , Martínez Fabián , Rivas Lina , Calderón Cristian , M. Munita José , R. Campodonico Paola 
Published: October 2018

Abstractβ-lactam antibiotics, such as penicillin share a very unstable chemical structure. In water-based solutions, such as those used for clinical applications, the β-lactam ring is readily opened due to a nucleophilic or electrophilic attack, leading to the loss of antimicrobial activity. Since the achievement and maintenance of optimum therapeutic levels of β-lactam antibiotics is critical for the resolution of many infectious clinical situations, and to avoid antibiotic resistance generation, the design of new non-aqueous dosage forms is urgent. Recently, natural deep eutectic solvents (NADES) have emerged as alternative non-toxic and non-aqueous solvents for different biomedical applications. In this work, we formulated and characterized a NADES composed by betaine and urea (BU). Using this solvent, we evaluated the stability of clavulanic acid (CLV) and imipenem (IMP) and characterized their antimicrobial activities calculating the minimal inhibitory concentration. Characterization of BU solvent by infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR) indicated that the obtained solvent has a microstructure mainly based on hydrogen bonding interactions and water addition strongly affects its dynamic. The stability of β-lactam antibiotic IMP and CLV using this solvent was increased by 7 fold and 2.5 fold respectively compared to water when analysed seven days after being dissolved. Microbiological assays showed that antibacterial activity at day seven was significantly decreased for both CLV and IMP when dissolved in water, while no change in their antibacterial properties was observed when antibiotics were dissolved in BU. The increased stability of IMP and CLV in BU may be related to the inert behaviour of the solvent and the higher dynamic restriction that helps antibiotics to maintain a more stable conformation. These data suggest the potential use of BU as a solvent to prevent degradation of β-lactam antibiotics.
Marine Carbonates in the Mantle Source of Oceanic Basalts: Pb Isotopic Constraints
Authors: Castillo P. R. , MacIsaac C. , Perry S. , Veizer J. 
Published: October 2018

AbstractFor almost fifty years, geochemists have been interpreting the clues from Pb isotopic ratios concerning mantle composition and evolution separately. The Pb isotopes of ocean island basalts (OIB) indicate that their mantle source is heterogeneous, most likely due to the presence of end-components derived from recycled crust and sediment. Some OIB have unusually high 206Pb/204Pb coming from one of the end-components with a long time-integrated high 238U/204Pb or μ (HIMU). Most OIB and many mid-ocean ridge basalts (MORB) also have high 206Pb/204Pb, indicating a HIMU-like source. Moreover, measured 232Th/238U (κ) for most MORB are lower than those deduced from their 208Pb/204Pb and 206Pb/204Pb. Such high μ and low κ features of oceanic basalts are inconsistent with the known geochemical behavior of U, Pb and Th and temporal evolution of the mantle; these have been respectively termed the 1st and 2nd Pb paradox. Here we show that subducted marine carbonates can be a source for HIMU and a solution to the Pb paradoxes. The results are consistent with the predictions of the marine carbonate recycling hypothesis that posits the Pb isotopes of oceanic basalts indicate a common origin and/or magma generation process.
Predicting El Niño Beyond 1-year Lead: Effect of the Western Hemisphere Warm Pool
Authors: Park Jae-Heung , Kug Jong-Seong , Li Tim , Behera Swadhin K. 
Published: October 2018

AbstractDue to the profound impact of El Niño-Southern Oscillation (ENSO) on global climate and weather, extensive research has been devoted to its prediction. However, prediction accuracy based on observation is still insufficient and largely limited to less than one year of lead time. In this study, we demonstrate the possibility that anomalous sea surface temperature (SST) warming (cooling) in the Western Hemisphere Warm Pool (WHWP, a.k.a. Atlantic Warm Pool) near the Intra-Americas Sea (IAS), which is the second largest warm pool on the planet, contributes to the initiation of La Niña (El Niño) with a 17-month lag time. SST anomalies in WHWP in late boreal summer contribute significantly to the emergence of the Pacific meridional mode (PMM) via interaction between the ocean and atmosphere over the subtropical North Pacific during the subsequent winter and spring. Near-equatorial surface wind anomalies associated with the PMM can further trigger ENSO through the dynamics of the equatorial oceanic waves. Thus, this observational analysis presents a clear step-by-step explanation about the influence of WHWP on ENSO development with a 17-month lead time.
Solution processes for ultrabroadband and omnidirectional graded-index glass lenses with near-zero reflectivity in high concentration photovoltaics
Authors: He Junwen , Yao Yuan , Lee Kyu-Tae , Hong Nina , Fisher Brent , Bahabry Rabab R. , Lee Jung Woo , Kim Jeonghyun , Han Seungyong , Kalidindi Sanjay V. , Kim Jae-Hwan , Kim Sung Bong , Choi Jaewon , Jang Hongwoo , Namkoong Myeong , Burroughs Scott , Hussain Muhammad , Nuzzo Ralph G. , Rogers John A. 
Published: October 2018

AbstractConcentrator photovoltaic (CPV) systems, where incident direct solar radiation is tightly concentrated onto high-efficiency multi-junction solar cells by geometric optical elements, exhibit the highest efficiencies in converting the sun’s energy into electric power. Their energy conversion efficiencies are greatly limited, however, due to Fresnel reflection losses occurring at three air/optics interfaces in the most sophisticated dual-stage CPV platforms. This paper describes a facile one-step wet-etching process to create a nanoporous surface with a graded-index profile on both flat and curved glasses, with capabilities of achieving ~99% average transmission efficiency in a wide wavelength range from 380 nm to 1.3 µm and for a wide range of incident angles up to ±40° regardless of the polarization state of incident sunlight. The simplicity of the etching process remarkably increases their versatility in various optical elements that require unconventional form factors such as Fresnel lenses and microlens arrays, and/or demanding curvatures along with much reduced dimensions such as ball lenses. Etched glass surfaces on two-stage optical concentrating systems yield enhancements in total optical transmission efficiencies by 13.8% and in the photocurrent by 14.3%, as experimentally determined by measurements on microscale triple-junction solar cells. The presented strategy can be widely adapted in a variety of applications such as image sensors, display systems, and other optoelectronic devices.
TIP55, a splice isoform of the KAT5 acetyltransferase, is essential for developmental gene regulation and organogenesis
Authors: Acharya Diwash , Nera Bernadette , Milstone Zachary J. , Bourke Lauren , Yoon Yeonsoo , Rivera-Pérez Jaime A. , Trivedi Chinmay M. , Fazzio Thomas G. 
Published: October 2018

AbstractRegulation of chromatin structure is critical for cell type-specific gene expression. Many chromatin regulatory complexes exist in several different forms, due to alternative splicing and differential incorporation of accessory subunits. However, in vivo studies often utilize mutations that eliminate multiple forms of complexes, preventing assessment of the specific roles of each. Here we examined the developmental roles of the TIP55 isoform of the KAT5 histone acetyltransferase. In contrast to the pre-implantation lethal phenotype of mice lacking all four Kat5 transcripts, mice specifically deficient for Tip55 die around embryonic day 11.5 (E11.5). Prior to developmental arrest, defects in heart and neural tube were evident in Tip55 mutant embryos. Specification of cardiac and neural cell fates appeared normal in Tip55 mutants. However, cell division and survival were impaired in heart and neural tube, respectively, revealing a role for TIP55 in cellular proliferation. Consistent with these findings, transcriptome profiling revealed perturbations in genes that function in multiple cell types and developmental pathways. These findings show that Tip55 is dispensable for the pre- and early post-implantation roles of Kat5, but is essential during organogenesis. Our results raise the possibility that isoform-specific functions of other chromatin regulatory proteins may play important roles in development.
Visualising peripheral arterioles and venules through high-resolution and large-area photoacoustic imaging
Authors: Matsumoto Yoshiaki , Asao Yasufumi , Sekiguchi Hiroyuki , Yoshikawa Aya , Ishii Tomoko , Nagae Ken-ichi , Kobayashi Shuichi , Tsuge Itaru , Saito Susumu , Takada Masahiro , Ishida Yoshihiro , Kataoka Masako , Sakurai Takaki , Yagi Takayuki , Kabashima Kenji , Suzuki Shigehiko , Togashi Kaori , Shiina Tsuyoshi , Toi Masakazu 
Published: October 2018

AbstractPhotoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging. A PAI system comprising a hemispherical detector array (HDA) has been reported previously as a method providing high morphological reproducibility. However, further improvements in diagnostic capability will require improving the image quality of PAI and fusing functional and morphological imaging. Our newly developed PAI system prototype not only enhances the PA image resolution but also acquires ultrasonic (US) B-mode images at continuous positions in the same coordinate axes. In addition, the pulse-to-pulse alternating laser irradiation shortens the measurement time difference between two wavelengths. We scanned extremities and breasts in an imaging region 140 mm in diameter and obtained 3D-PA images of fine blood vessels, including arterioles and venules. We could estimate whether a vessel was an artery or a vein by using the S-factor obtained from the PA images at two wavelengths, which corresponds approximately to the haemoglobin oxygen saturation. Furthermore, we observed tumour-related blood vessels around breast tumours with unprecedented resolution. In the future, clinical studies with our new PAI system will help to elucidate various mechanisms of vascular-associated diseases and events.
Chromosome replication as a measure of bacterial growth rate during Escherichia coli infection in the mouse peritonitis model
Authors: Haugan Maria Schei , Charbon Godefroid , Frimodt-Møller Niels , Løbner-Olesen Anders 
Published: October 2018

AbstractThe efficacy of most antibiotics is dependent on active bacterial growth, yet little is known about the growth dynamics during infection. Therefore, means to measure in-host bacterial growth rate is of importance. Here, we use chromosome replication as readout for in situ bacterial growth rate during infection; obtained from a single biological specimen. We have applied two independent methods: quantitative PCR (qPCR) and fluorescence microscopy, to quantify the level of chromosome replication present during Escherichia coli propagation in the mouse peritonitis model. We find that the methods complement each other and allow for quantification of growth rate, both on a population average and on a single-cell level. We demonstrate the presence of heterogeneous growth rates within bacterial populations propagating during infection. Also, no growth cessation was observed during the apparent stationary phase in vivo, and, by comparison of growth dynamics at different anatomical sites, we demonstrate that E. coli is unlikely to grow independently intravascularly. These findings provide novel insight into bacterial growth during host infection, and underscore the importance of pinpointing the primary site of infection in septicaemia of unknown origin and ensuring antibiotic availability at this site.
Portable low-cost instrumentation for monitoring Rayleigh scattering from chemical sensors based on metallic nanoparticles
Authors: Vasquez Glibver , Hernández Yulán , Coello Yves 
Published: October 2018

AbstractUsing a Hg(II) sensor based on the aggregation of gold nanoparticles as a model system, we evaluated the performance of two portable low-cost devices that monitor the wavelength-ratiometric resonance Rayleigh scattering signal of the chemical sensor upon white-LED illumination. The first device uses two optical filter-photodiode combinations to detect scattered light while the second employs a novel ultra-compact (grating-free) spectral sensor. Results show that the response of the Hg(II) sensor monitored with these devices is comparable to that measured using a high-end benchtop scanning spectrofluorometer. The great potential of this new LED-spectral sensor was demonstrated with the quantification of Hg(II) in tap and spring water. Due to the promising results obtained, many reported chemical sensors based on Rayleigh scattering from metallic nanoparticles could take advantage of this compact portable instrumentation for cost-effective field-deployable applications.
Increased levels of circulating MMP3 correlate with severe rejection in face transplantation
Authors: Kollar Branislav , Shubin Andrey , Borges Thiago J. , Tasigiorgos Sotirios , Win Thet Su , Lian Christine G. , Dillon Simon T. , Gu Xuesong , Wyrobnik Iris , Murphy George F. , Pomahac Bohdan , Libermann Towia A. , Riella Leonardo V. 
Published: October 2018

AbstractFace transplantation is a viable treatment option for carefully selected patients with devastating injuries to the face. However, acute rejection episodes occur in more than 80% of recipients in the first postoperative year. Unfortunately, neither a correlation between histological grades of rejection and anti-rejection treatment nor systemic surrogate markers of rejection in face transplantation are established in clinical routine. Therefore, we utilized next generation aptamer-based SOMAscan proteomics platform for non-invasive rejection biomarker discovery. Longitudinal serum samples from face transplant recipients with long-term follow-up were included in this study. From the 1,310 proteins analyzed by SOMAscan, a 5-protein signature (MMP3, ACY1, IL1R2, SERPINA4, CPB2) was able to discriminate severe rejection from both no-rejection and nonsevere rejection samples. Technical validation on ELISA platform showed high correlation with the SOMAscan data for the MMP3 protein (rs = 0.99). Additionally, MMP3 levels were significantly increased during severe rejection as compared to no-rejection (p = 0.0009) and nonsevere rejection (p = 0.0173) episodes. Pathway analyses revealed significant activation of the metallopeptidase activity during severe face transplant rejection. This pilot study demonstrates the feasibility of SOMAscan to identify non-invasive candidate biomarkers of rejection in face transplantation. Further validation in a larger independent patient cohort is needed.
Tuneable poration: host defense peptides as sequence probes for antimicrobial mechanisms
Authors: Pfeil Marc-Philipp , Pyne Alice L. B. , Losasso Valeria , Ravi Jascindra , Lamarre Baptiste , Faruqui Nilofar , Alkassem Hasan , Hammond Katharine , Judge Peter J. , Winn Martyn , Martyna Glenn J. , Crain Jason , Watts Anthony , Hoogenboom Bart W. , Ryadnov Maxim G. 
Published: October 2018

AbstractThe spread of antimicrobial resistance stimulates discovery strategies that place emphasis on mechanisms circumventing the drawbacks of traditional antibiotics and on agents that hit multiple targets. Host defense peptides (HDPs) are promising candidates in this regard. Here we demonstrate that a given HDP sequence intrinsically encodes for tuneable mechanisms of membrane disruption. Using an archetypal HDP (cecropin B) we show that subtle structural alterations convert antimicrobial mechanisms from native carpet-like scenarios to poration and non-porating membrane exfoliation. Such distinct mechanisms, studied using low- and high-resolution spectroscopy, nanoscale imaging and molecular dynamics simulations, all maintain strong antimicrobial effects, albeit with diminished activity against pathogens resistant to HDPs. The strategy offers an effective search paradigm for the sequence probing of discrete antimicrobial mechanisms within a single HDP.
Preparation of NiAl2O4-Based Flexible Substrates for Metamaterials with Negative Dielectric Properties
Authors: Rahman Md Atiqur , Ahamed Eistiak , Faruque Mohammad Rashed Iqbal , Islam Mohammad Tariqul 
Published: October 2018

AbstractVarious techniques are commonly used to produce nano-crystalline NiAl2O4materials; however, their practical applications in the microwave region remain very limited. In this work, flexible substrates for metamaterials containing two different concentrations of NiAl2O4(labelled Ni36and Ni42) have been synthesised using a sol-gel method. The formation of spinel structures in the synthesised materials is confirmed, and their crystalline sizes are determined using scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray techniques. The dielectric properties, conductivities, loss tangents, and other parameters of the NiAl2O4-based substrates are analysed to evaluate their applicability as dielectric materials for the microwave frequency range. The obtained results show that the fabricated Ni36and Ni42nickel aluminates possess dielectric constants of 4.94 and 4.97 and loss tangents of 0.01 and 0.007, respectively; in addition, they exhibit high flexibility and light weight, which make them suitable for applications as metamaterial substrates. The synthesised structures are also validated experimentally using a commercially available electromagnetic simulator; as a result, double negative behaviour of the flexible metamaterials has been observed. Furthermore, it is found that the prepared NiAl2O4substrates can be used in the S-, C-, and X-bands of the microwave frequency region.
Dielectric Response of Quantum Critical Ferroelectric as a Function of Pressure
Authors: Coak M. J. , Haines C. R. S. , Liu C. , Jarvis D. M. , Littlewood P. B. , Saxena S. S. 
Published: October 2018

AbstractIn this work we report for the first time measurements of the dielectric loss of single-crystal SrTiO3 under the application of hydrostatic pressure up to 20 kbar and temperatures down to 200 mK which allow us to comment on the evolution of new fundamental material properties and their relationship with the recently discovered quantum critical phenomena in this material. The well known 18 K peak or shoulder was no longer observed after pressure was applied, even after subsequently removing it, suggesting it is associated with the twin walls formed at the 110 K cubic-tetragonal transition. The family of familiar peaks were all seen to increase in temperature linearly with pressure and the height of the 9.4 K peak was drastically suppressed by even the smallest pressures. This peak is discussed in the context of a postulated ferroelectric quantum critical point in SrTiO3 and the behaviour of its size linked to the position of this point on the recently established phase diagram.
The Exceptional Strong Face-centered Cubic Phase and Semi-coherent Phase Boundary in a Eutectic Dual-phase High Entropy Alloy AlCoCrFeNi
Authors: Wang Qiannan , Lu Yiping , Yu Qian , Zhang Ze 
Published: October 2018

AbstractSecond phase strengthening has been applied to high entropy alloys (HEAs) for optimizing mechanical properties. In this study, by conducting mechanical testing of a eutectic dual-phase AlCoCrFeNi HEA with homogenous distribution of body-centered cubic (BCC) and face-centered cubic (FCC) lamellar phases inside a transmission electron microscope, we found that although BCC was truly the hard phase, decreasing the proportion of BCC phase in fact increased the strength due to the existence of chemically disordered semi-coherent phase boundaries, which acted as potent impediments to dislocation motion resulting in dense dislocation storage in FCC phases. Moreover, the difficulty in dislocation glide caused massive cross-slip, and the interaction between primary slip arrays and cross-slip systems during deformation increased the rate of dislocation accumulation by forming dislocation substructures, thus making the FCC phases exceptionally strong. Our findings not only revealed the underlying strengthening mechanism of eutectic dual-phase AlCoCrFeNi HEAs, but also shed light on new ways in further optimizing the mechanical properties of HEAs.
Cortical visual processing evokes short-latency reward-predicting cue responses in primate midbrain dopamine neurons
Authors: Takakuwa Norihiro , Redgrave Peter , Isa Tadashi 
Published: October 2018

AbstractAfter classical conditioning dopamine (DA) neurons exhibit short latency responses to reward-predicting visual cues. At least two possible projections could induce such DA responses; the cortical and subcortical visual pathways. Our recent study has shown that after a lesion of the striate cortex (V1), the superior colliculus (SC), a critical node of the subcortical visual pathway, can mediate short latency cue responses in the DA neurons of macaque monkeys. An obvious question then is does the cortical pathway have a similar capacity? Using the monkeys with a unilateral V1 lesion that took part in the preceding study, we recorded DA activity while they were performing the same classical conditioning task. However, in this study conditioned visual stimuli were presented to the intact visual field, and the effects of ipsilateral SC inactivation were examined. We found that after the SC was inactivated by injections of muscimol both conditioned behavioral responding and reward-predicting, short latency (~100 ms) cue-elicited DA neuronal responses were unaffected These results indicate that the intact cortical visual pathway can also mediate short latency cue elicited responses in DA neurons in the absence of a normally functioning subcortical visual system.
Tender leaf and fully-expanded leaf exhibited distinct cuticle structure and wax lipid composition in Camellia sinensis cv Fuyun 6
Authors: Zhu Xiaofang , Zhang Yi , Du Zhenghua , Chen Xiaobing , Zhou Xin , Kong Xiangrui , Sun Weijiang , Chen Zijian , Chen Changsong , Chen Mingjie 
Published: October 2018

AbstractThe goal of the present study was to compare the structural and compositional differences of cuticle between tender leaf and fully-expanded leaf in Camellia sinensis, and provide metabolic base for the further characterization of wax biosynthesis in this economically important crop species. The tender second leaf and the fully-expanded fifth leaf from new twig were demonstrated to represent two different developmental stages, their cuticle thickness were measured by transmission electron microscopy. The thickness of the adaxial cuticle on the second and fifth leaf was 1.15 µm and 2.48 µm, respectively; the thickness of the abaxial cuticle on the second and fifth leaf was 0.47 µm and 1.05 µm, respectively. The thickness of the epicuticular wax layer from different leaf position or different sides of same leaf were similar. However, the intracuticular wax layer of the fifth leaf was much thicker than that of the second leaf. Total wax lipids were isolated from the second leaf and the fifth leaf, respectively. Gas chromatography-mass spectrometry analysis identified 51 wax constituents belonging to 13 chemical classes, including esters, glycols, terpenoids, fatty acids and their derivatives. Wax coverage on the second and fifth leaf was 4.76 µg/cm2 and 15.38 µg/cm2, respectively. Primary alcohols dominated in the tender second leaf. However, triterpenoids were the major components from the fully-expanded fifth leaf. The predominant carbon chains varied depending on chemical class. These data showed that the wax profiles of Camellia sinensis leaves are development stage dependent, suggesting distinct developmental dependent metabolic pathways and regulatory mechanisms.