To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Increasing evidence indicates that gut microbiota may influence colorectal cancer risk. Diet, particularly fibre intake, may modify gut microbiota composition, which may affect cancer risk. We investigated the relationship between dietary fibre intake and gut microbiota in adults. Using 16S rRNA gene sequencing, we assessed gut microbiota in faecal samples from 151 adults in two independent study populations: National Cancer Institute (NCI), n 75, and New York University (NYU), n 76. We calculated energy-adjusted fibre intake based on FFQ. For each study population with adjustment for age, sex, race, BMI and smoking, we evaluated the relationship between fibre intake and gut microbiota community composition and taxon abundance. Total fibre intake was significantly associated with overall microbial community composition in NYU (P=0·008) but not in NCI (P=0·81). In a meta-analysis of both study populations, higher fibre intake tended to be associated with genera of class Clostridia, including higher abundance of SMB53 (fold change (FC)=1·04, P=0·04), Lachnospira (FC=1·03, P=0·05) and Faecalibacterium (FC=1·03, P=0·06), and lower abundance of Actinomyces (FC=0·95, P=0·002), Odoribacter (FC=0·95, P=0·03) and Oscillospira (FC=0·96, P=0·06). A species-level meta-analysis showed that higher fibre intake was marginally associated with greater abundance of Faecalibacterium prausnitzii (FC=1·03, P=0·07) and lower abundance of Eubacterium dolichum (FC=0·96, P=0·04) and Bacteroides uniformis (FC=0·97, P=0·05). Thus, dietary fibre intake may impact gut microbiota composition, particularly class Clostridia, and may favour putatively beneficial bacteria such as F. prausnitzii. These findings warrant further understanding of diet–microbiota relationships for future development of colorectal cancer prevention strategies.
One common assumption in interpreting ice-core CO2 records is that diffusion in the ice does not affect the concentration profile. However, this assumption remains untested because the extremely small CO2 diffusion coefficient in ice has not been accurately determined in the laboratory. In this study we take advantage of high levels of CO2 associated with refrozen layers in an ice core from Siple Dome, Antarctica, to study CO2 diffusion rates. We use noble gases (Xe/Ar and Kr/Ar), electrical conductivity and Ca2+ ion concentrations to show that substantial CO2 diffusion may occur in ice on timescales of thousands of years. We estimate the permeation coefficient for CO2 in ice is ∼4 × 10−21 mol m−1 s−1 Pa−1 at −23°C in the top 287 m (corresponding to 2.74 kyr). Smoothing of the CO2 record by diffusion at this depth/age is one or two orders of magnitude smaller than the smoothing in the firn. However, simulations for depths of ∼930–950 m (∼60–70 kyr) indicate that smoothing of the CO2 record by diffusion in deep ice is comparable to smoothing in the firn. Other types of diffusion (e.g. via liquid in ice grain boundaries or veins) may also be important but their influence has not been quantified.
We describe a high-precision method, now in use in our laboratory, for measuring the CO2 mixing ratio of ancient air trapped in polar ice cores. Occluded air in ice samples weighing ∼8–15 g is liberated by crushing with steel pins at −35°C and trapped at −263°C in a cryogenic cold trap. CO2 in the extracted air is analyzed using gas chromatography. Replicate measurements for several samples of high-quality ice from the Siple Dome and Taylor Dome Antarctic ice cores have pooled standard deviations of <0.9 ppm. This high-precision technique is directly applicable to high-temporal-resolution studies for detection of small CO2 variations, for example CO2 variations of a few parts per million on millennial to decadal scales.
Complex oxides and semiconductors exhibit distinct yet complementary properties owing to their respective ionic and covalent natures. By electrically coupling complex oxides to traditional semiconductors within epitaxial heterostructures, enhanced or novel functionalities beyond those of the constituent materials can potentially be realized. Essential to electrically coupling complex oxides to semiconductors is control of the physical structure of the epitaxially grown oxide, as well as the electronic structure of the interface. Here we discuss how composition of the perovskite A- and B-site cations can be manipulated to control the physical and electronic structure of semiconductor—complex oxide heterostructures. Two prototypical heterostructures, Ba1−xSrxTiO3/Ge and SrZrxTi1−xO3/Ge, will be discussed. In the case of Ba1−xSrxTiO3/Ge, we discuss how strain can be engineered through A-site composition to enable the re-orientable ferroelectric polarization of the former to be coupled to carriers in the semiconductor. In the case of SrZrxTi1−xO3/Ge we discuss how B-site composition can be exploited to control the band offset at the interface. Analogous to heterojunctions between compound semiconducting materials, control of band offsets, i.e., band-gap engineering, provides a pathway to electrically couple complex oxides to semiconductors to realize a host of functionalities.
Point of care ultrasound in the emergency department (ED) is increasingly being used to diagnose time-sensitive, vision-threatening conditions. We present a case of a 64-year-old female who presented to the ED with a three-day history of worsening left eye floaters. Point of care ocular ultrasound demonstrated a posterior chamber containing many echogenic opacities of varying size without acoustic shadowing. Movement of the eye resulted in significant after-movement of these opacities, giving the classic “washing machine” appearance seen with vitreous hemorrhage (VH). Based on these ultrasound findings, the patient was diagnosed with a VH and was referred to ophthalmology. The consulting ophthalmologist ultimately diagnosed the patient with asteroid hyalosis without VH. Asteroid hyalosis is a benign condition of the vitreous resulting in calcium phosphate and lipid deposits that can mimic more serious VH on point of care ultrasound. Knowledge of this mimic is helpful for communication with specialists and for awareness of the potential for misdiagnosis with ocular ultrasound.
Introduction: Acute upper gastrointestinal bleeding is a potentially life-threatening medical emergency that frequently requires red blood cell (RBC) transfusions. However, the optimal hemoglobin thresholds for transfusion is controversial. The objective of this study was to establish the most efficacious transfusion threshold. Methods: A systematic review of the published literature was completed. MEDLINE, Health technology assessment database, Cochrane central register, Cochrane database of systematic reviews, and EMBASE were searched from inception to May 2015 using search terms including “blood transfusions”, “hemoglobin”, and “red blood cell”. Studies were included if they: reported original data, were peer-reviewed, studied adult populations, were randomized controlled clinical trials and primarily focused on clinical efficacy or effectiveness of liberal and restrictive pre-transfusion hemoglobin level thresholds. Quality was assessed using the Cochrane Risk of Bias tool. Data were extracted and meta-analysis was conducted using a random effects model to determine the risk ratio for: all-cause mortality, further bleeding and any adverse events. All steps were completed independently by two reviewers. Results: The literature search identified 4037 unique abstracts. Of these, 156 abstracts proceeded to full text review. 154 articles were excluded during full-text review resulting in 2 articles for final analysis. The total number of participants included was 701. The hemoglobin threshold to transfuse RBC varied between 70-80g/L versus 90-100g/L in restrictive and liberal policies, respectively. Both studies were at low risk of bias. Meta-analysis resulted in a pooled decreased risk of all-cause mortality (RR 0.65, 95% CI 0.44-0.96), re-bleeding (RR 0.63, 95% CI 0.46-0.85) and adverse events (RR 0.83, 95% CI 0.73-0.95) in the restrictive blood transfusion group versus the liberal blood transfusion group. Conclusion: While the evidence is limited, the risk of death is lower and there is no significant harm for a restrictive strategy. In this context, there is a decreased risk of transfusion associated adverse events among those receiving a restrictive strategy and should be considered for its impact on patient safety and health system resources.
To evaluate differences in product characteristics and user preferences of safety-engineered protection mechanisms of winged blood collection needles.
Randomized model-based simulation study.
University medical center.
A total of 33 third-year medical students.
Venipuncture was performed using winged blood collection needles with 4 different safety mechanisms: (a) Venofix Safety, (b) BD Vacutainer Push Button, (c) Safety-Multifly, and (d) Surshield Surflo. Each needle type was used in 3 consecutive tries: there was an uninstructed first handling, then instructions were given according to the operating manual; subsequently, a first trial and second trial were conducted. Study end points included successful activation, activation time, single-handed activation, correct activation, possible risk of needlestick injury, possibility of deactivation, and preferred safety mechanism.
The overall successful activation rate during the second trial was equal for all 4 devices (94%–100%). Median activation time was (a) 7 s, (b) 2 s, (c) 9 s, and (d) 7 s. Single-handed activation during the second trial was (a) 18%, (b) 82%, (c) 15%, and (d) 45%. Correct activation during the second trial was (a) 3%, (b) 64%, (c) 15%, and (d) 39%. Possible risk of needlestick injury during the second trial was highest with (d). Possibility of deactivation was (a) 0%, (b) 12%, (c) 9%, and (d) 18%. Individual preferences for each system were (a) 11, (b) 17, (c) 5, and (d) 0. The main reason for preference was the comprehensive safety mechanism.
Significant differences exist between safety mechanisms of winged blood collection needles.
Complex oxides and semiconductors exhibit distinct yet complementary properties
owing to their respective ionic and covalent natures. By electrically coupling
oxides to semiconductors within epitaxial heterostructures, enhanced or novel
functionalities beyond those of the constituent materials can potentially be
realized. Key to electrically coupling oxides to semiconductors is controlling
the physical and electronic structure of semiconductor – crystalline
oxide heterostructures. Here we discuss how composition of the oxide can be
manipulated to control physical and electronic structure in
Ba1-xSrxTiO3/ Ge and
SrZrxTi1-xO3/Ge heterostructures. In the
case of the former we discuss how strain can be engineered through composition
to enable the re-orientable ferroelectric polarization to be coupled to carriers
in the semiconductor. In the case of the latter we discuss how composition can
be exploited to control the band offset at the semiconductor - oxide interface.
The ability to control the band offset, i.e. band-gap engineering, provides a
pathway to electrically couple crystalline oxides to semiconductors to realize a
host of functionalities.
Integrating oxide heterostructures on silicon has the potential to leverage the
multifunctionalities of oxide systems into semiconductor device technology. We
present the growth and characterization of two-dimensional electron gas (2DEG)
oxide systems LaTiO3/SrTiO3 (LTO/STO) and
GdTiO3/SrTiO3 (GTO/STO) on Si(001). We show
interface-based conductivity in the oxide films and measure high electron
densities ranging from ∼9 × 1013 cm-2
interface-1 in GTO/STO/Si to ∼9 ×
1014 cm-2 interface-1 in LTO/STO/Si. We
attribute the higher measured carrier density in the LTO/STO films to a higher
concentration of interface-bound oxygen vacancies arising from a lower oxygen
partial pressure during growth. These vacancies donate conduction electrons and
result in an increased measured carrier density. The integration of such 2DEG
oxide systems with silicon provides a bridge between the diverse electronic
properties of oxide systems and the established semiconductor platform and
points toward new devices and functionalities.
Understanding the morphological structure of membranes is essential to improve performance of membrane-based applications. In this paper, macroporous membranes were investigated and two methods introduced as an alternative for characterization of stereo-structure of the membranes. We combined the use of synchrotron X-ray nanotomography and small-angle X-ray scattering to examine the internal structure of cellulose acetate membranes with studies of the capture of surface-modified gold nanoparticles within these membranes. Finally, the morphological structures of macroporous membranes were visualized and their relationships with penetration tendency of surface-modified gold nanoparticles were explained.
Trematode tyrosinases (TYRs) play a major role in the tanning process during eggshell formation. We investigated the molecular and biochemical features of Paragonimus westermani TYR (PwTYR). The PwTYR cDNA was composed of 1568-bp encompassing a 1422-bp-long open reading frame (474-amino acid polypeptide). A strong phylogenetic relationship with Platyhelminthes and Deuterostomian orthologues was evident. The recombinant PwTYR expressed in prokaryotic cells promptly oxidized diphenol substrates, with a preferential affinity toward ortho-positioned hydroxyl groups. It demonstrated fairly weak activity for monophenol compounds. Diphenol oxidase activity was augmented with an increase of pH from 5·0 to 8·0, while monophenol oxidase activity was highest at an acidic pH and gradually decreased as pH increased. Transcription profile of PwTYR was temporally upregulated along with worm development. PwTYR was specifically localized in vitellocytes and eggs. The results suggested that conversion of tyrosine to L-dihydroxyphenylalanine by PwTYR monophenol oxidase activity might be rate-limiting step during the sclerotization process of P. westermani eggs. The pH-dependent pattern of monophenol and diphenol oxidase activity further proposes that the initial hydroxylation might slowly but steadily progress in acidic secreted vesicles of vitellocytes and the second oxidation process might be rapidly accelerated by neural or weak alkaline pH environments within the ootype.
Depression is common after acute coronary syndrome (ACS) with adverse effects on prognosis. There is little evidence on whether depression treatment improves quality of life (QoL) in ACS patients. The aim of this study was to investigate the effects of co-morbid depression and its treatment on QoL in ACS.
In total, 1152 patients were recruited at baseline, 2–14 weeks after a confirmed ACS episode, and 828 were followed 1 year thereafter. Of 446 baseline participants with co-morbid depressive disorders, 300 were randomized to a 24-week double blind trial of escitalopram or placebo, while the remaining 146 received medical treatment only (MTO). QoL was measured by the World Health Organization Quality of Life –Abbreviated form (WHOQOL-BREF).
At baseline, QoL was significantly lower in patients with co-morbid depressive disorder than those without. QoL improvement was significantly greater in those receiving escitalopram than those receiving placebo over the 24-week treatment period. In the 1-year follow-up, the better outcomes associated with escitalopram remained evident against both placebo and MTO.
Depression was significantly associated with worse QoL even in patients with recently developed ACS. Depression treatment was associated with QoL improvement in ACS patients in the 24-week treatment period, the effects of which extended to 1 year.
The modified TiO2 nanoparticles were incorporated into the Bulk heterojunction system of P3HT:PCBM to improve the performance of P3HT:PCBM bulk heterojunction organic solar cells. The organically-modified TiO2 nanoparticle compounds were synthesized in aqueous media at room temperature. These TiO2 compounds in various solution concentrations were deposited on the top of the P3HT:PCBM active layer by spin coating. The performance of organic solar cells was carefully investigated in the respect of the scattering and the localized surface plasmon resonance (LSPR) that couple strongly to the incident light. In addition to the device, P3HT:PCBM solar cells with the use of the TiO2 nanoparticles, enhanced Fill Factor (FF) due mainly to improved shunt resistance (Rsh). The TiO2 plays a critical role in improving the interface between P3HT:PCBM active layer and Al electrode.
Increase of fat cells (FCs) in adipose tissue is attributed to proliferation of preadipocytes or immature adipocytes in the early stage, as well as adipogenic differentiation in the later stage of adipose development. Although both events are involved in the FC increase, they are contrary to each other, because the former requires cell cycle activity, whereas the latter requires cell cycle withdrawal. Therefore, appropriate regulation of cell cycle inhibition is critical to adipogenesis. In order to explore the important cell cycle inhibitors and study their expression in adipogenesis, we adopted a strategy combining the Gene Expression Omnibus (GEO) database available on the NCBI website and the results of quantitative real-time PCR (qPCR) data in porcine adipose tissue. Three cell cycle inhibitors – cyclin G2 (CCNG2), cyclin-dependent kinase inhibitor 2C (CDKN2C) and peripheral myelin protein (PMP22) – were selected for study because they are relatively highly expressed in adipose tissue compared with muscle, heart, lung, liver and kidney in humans and mice based on two GEO DataSets (GDS596 and GDS3142). In the latter analysis, they were found to be more highly expressed in differentiating/ed preadipocytes than in undifferentiated preadipocytes in human and mice as shown respectively by GDS2366 and GDS2743. In addition, GDS2659 also suggested increasing expression of the three cell cycle inhibitors during differentiation of 3T3-L1 cells. Further study with qPCR in Landrace pigs did not confirm the high expression of these genes in adipose tissue compared with other tissues in market-age pigs, but confirmed higher expression of these genes in FCs than in the stromal vascular fraction, as well as increasing expression of these genes during in vitro adipogenic differentiation and in vivo development of adipose tissue. Moreover, the relatively high expression of CCNG2 in adipose tissue of market-age pigs and increasing expression during development of adipose tissue was also confirmed at the protein level by western blot analysis. Based on the analysis of the GEO DataSets and results of qPCR and Western blotting we conclude that all three cell cycle inhibitors may inhibit adipocyte proliferation, but promote adipocyte differentiation and hold a differentiated state by inducing and maintaining cell cycle inhibition. Therefore, their expression in adipose tissue is positively correlated with age and mature FC number. By regulating the expression of these genes, we may be able to control FC number, and, thus, reduce excessive fat tissue in animals and humans.
Dense thin β/β’’-alumina electrolyte films of less than 50 μm thickness were fabricated using vacuum dip-coating on porous substrate tubes. The porous substrate tubes were fabricated using a slip casting method. Fine Na-β/β’’-alumina powder was obtained via traditional solid state reaction processing. It was found that vacuum dip-coating is an effective method for fabricating thin dense layers coated on the porous tube. The mechanical properties of the porous tube, with and without the dense layer, were tested using a C-ring method. The optimized sintering process was also studied.
The Ultra-Fast Flash Observatory (UFFO) is a space observatory for optical follow-ups of
gamma ray bursts (GRBs), aiming to explore the first 60 seconds of GRBs optical emission.
UFFO is utilized to catch early optical emissions from GRBs within few sec after trigger
using a Gimbal mirror which redirects the optical path rather than slewing entire
spacecraft. We have developed a 15 cm two-axis Gimbal mirror stage for the UFFO-Pathfinder
which is going to be on board the Lomonosov satellite which is to be launched in 2013. The
stage is designed for fast and accurate motion with given budgets of 3 kg of mass and 3
Watt of power. By employing stepping motors, the slewing mirror can rotate faster than 15
deg/sec so that objects in the UFFO coverage (60 deg × 60 deg) can be targeted in
~1 sec. The obtained targeting resolution is better 2 arcmin using a close-loop
control with high precision rotary encoder. In this presentation, we will discuss details
of design, manufacturing, space qualification tests, as well as performance tests.