Electronic band structures dictate the mechanical, optical and electrical properties of crystalline solids. Their experimental determination is therefore crucial for technological applications. ...Although the spectral distribution in energy bands is routinely measured by various techniques
, it is more difficult to access the topological properties of band structures such as the quantized Berry phase, γ, which is a gauge-invariant geometrical phase accumulated by the wavefunction along an adiabatic cycle
. In graphene, the quantized Berry phase γ = π accumulated by massless relativistic electrons along cyclotron orbits is evidenced by the anomalous quantum Hall effect
. It is usually thought that measuring the Berry phase requires the application of external electromagnetic fields to force the charged particles along closed trajectories
. Contradicting this belief, here we demonstrate that the Berry phase of graphene can be measured in the absence of any external magnetic field. We observe edge dislocations in oscillations of the charge density ρ (Friedel oscillations) that are formed at hydrogen atoms chemisorbed on graphene. Following Nye and Berry
in describing these topological defects as phase singularities of complex fields, we show that the number of additional wavefronts in the dislocation is a real-space measure of the Berry phase of graphene. Because the electronic dispersion relation can also be determined from Friedel oscillations
, our study establishes the charge density as a powerful observable with which to determine both the dispersion relation and topological properties of wavefunctions. This could have profound consequences for the study of the band-structure topology of relativistic and gapped phases in solids.
Raman spectroscopy and texture analysis (TPA) studies were carried out to determine the effect of adding different levels of microbial transglutaminase (MTGase) to meat systems. This addition ...produced a significant (p<0.05) increase in hardness, springiness and cohesiveness in the meat systems. Raman spectroscopy analysis revealed the occurrence of secondary structural changes in meat proteins due to MTGase. Modifications in the amide I (1650–1680cm−1) and amide III (1200–1300cm−1) regions indicated a significant (p<0.05) decrease in α-helix content, accompanied by a significant (p<0.05) increase in β-sheets and turns due to the addition of the enzyme to meat systems. Significant (p<0.05) correlations were found between these secondary structural changes in meat proteins and the textural properties (hardness, adhesiveness, springiness and cohesiveness) of meat systems.
Most risk estimations for lymph node metastasis in adenocarcinoma of the esophagus and cardia (AEC) with invasion into the muscularis mucosae (m3) or submucosa are based on surgical series. This ...study aimed to correlate the lymph node metastasis rate with m3 and submucosal infiltration depth of AEC in endoscopic resection specimens.
Patients undergoing endoscopic resection for AEC between January 2000 and March 2008 at two centers were included if the endoscopic resection specimen showed m3 or submucosal cancer. Infiltration into the muscularis mucosae was defined as m3. Submucosal invasion was classified as sm1 (≤ 500 µm) or sm2/3 (> 500 µm). Exclusion criteria were chemotherapy or radiotherapy and nonradical endoscopic resection.
82 patients included 57 with m3, 12 with sm1, and 13 with sm2/3 cancers. Of the tumors, 13 were poorly differentiated and five showed lymphovascular invasion. After initial endoscopic resection, seven patients underwent surgery and 75 endoscopic therapy. No lymph node metastases were found in 158 lymph nodes of the esophagectomy specimens and none of the endoscopically treated patients were diagnosed with lymph node metastasis during a median follow-up of 26 months (interquartile range IQR 14 - 41).
This study suggests that lymph node metastasis risk for m3 and submucosal AEC may be lower than has been assumed on the basis of surgical series, and that current guidelines are valid regarding suitability of m3 AECs for endoscopic therapy. It may also suggest that selected patients with submucosal cancers are also eligible for endoscopic management. Confirmation of these results is needed in larger series with longer follow-up.
In order to assess its usefulness for monitoring textural properties of dry fermented sausages (chorizo, salchichon, salami, fuet and mini-fuet) the determination of breaking strength (BS) was ...evaluated. Texture profile analysis (TPA) and physico-chemical measurements (pH, aw, dry matter, fat content) were also performed. The BS determined by tensile test and TPA analysis produced complementary information that allowed these meat products to be grouped according to four different textural profiles. These profiles were characterized (
p
<
0.05) by the values of BS, hardness, adhesiveness, cohesiveness and springiness. Multivariate analysis confirmed that BS and TPA parameters were correlated significantly (
p
<
0.00005). On basis of these results, TPA parameters could be used to construct regression models to predict BS and therefore, to obtain a more complete textural property description of the dry fermented sausages. The resulting regression model was BS
=
−0.777
+
0.728∗adhesiveness
−
16881∗cohesiveness
+
1884.61∗springiness
+
0.042∗hardness (
R
2
=
0.634,
p
<
0.00005).
Context.
Following a multi-year minimum of solar activity, a solar energetic particle event on 2020 Nov. 29 was observed by multiple spacecraft covering a wide range of solar longitudes including ...ACE, the Solar Terrestrial Relations Observatory-A, and the recently launched Parker Solar Probe and Solar Orbiter.
Aims.
Multi-point observations of a solar particle event, combined with remote-sensing imaging of flaring, shocks, and coronal mass ejections allows for a global picture of the event to be synthesized, and made available to the modeling community to test, constrain, and refine models of particle acceleration and transport according to such parameters as shock geometries and particle mass-to-charge ratios.
Methods.
Detailed measurements of heavy ion intensities, time dependence, fluences, and spectral slopes provided the required test data for this study.
Results.
The heavy ion abundances, timing, and spectral forms for this event fall well within the range found in prior surveys at 1 au. The spectra were well fitted by broken power law shapes; the Fe/O ratio was somewhat lower than the average of other events. In addition,
3
He/
4
He was very low, with only the upper limits established here.
•Evaluation of presence and exposure of processing contaminants to oil consumers.•Seven 3-MCPD diesters determined in one hundred EVOO and other edible oils samples.•High content of 3-MCPD diesters ...was detected in pomace and refined olive oils.•Potato chips daily intake should be limited to reduce the health risk.
During the industrial refining process of edible oils and the manufacture of oil-based foodstuff, contaminants such as 3-monochloropropanediol (3-MCPD) fatty acid diesters can be produced. One hundred samples of different edible oils and related fatty food purchased from local Spanish markets were analyzed to evaluate the occurrence of these contaminants. Data of seven 3-MCPD diesters together with corresponding total 3-MCPD equivalents are presented. The procedure is based on a modified QuEChERS protocol followed by LC-MS/MS analysis. Extra virgin olive oil (EVOO) and unrefined oils did not contain detectable levels of the target analytes. The highest levels of 3-MCPD diesters were found in palm oils, for 1,2-Dilinoleoyl-3-chloropropanediol (LILI) and 1–2-Bispalmitoyl-3-chloropropanediol (PAPA) with concentrations close to 10 mg kg−1 and in the lipid fraction of margarines (8.09, 3.77 and 3.72 mg kg−1 for LILI, PAPA and 1-Oleoyl-2-linoleoyl-3-chloropropanediol (OLLI), respectively).
•Coupling of Raman spectroscopy with OPLSR as a method for PMI estimation.•OPLS modelling of Raman spectral modifications experienced by real buried human skeletons.•Application to human skeletons ...with a PMI between 15 and 87 years buried in equal or similar conditions.
An important demand exists in the field of forensic analysis to objectively determine the post-mortem interval (PMI) when human skeletal remains are discovered. It is widely known that bones undergo different chemical and physical processes after death, mainly due to their interaction with the environment in which they are found, although it is not known exactly what these processes consist of. Multiple techniques have been used so far to follow up these and other post-mortem changes and thus establish the time elapsed since the individual’s death, but they present important drawbacks in terms of reliability and accuracy. The aim of this research was to propose an analytical methodology capable of determining the PMI by using non-destructive Raman spectroscopy measurements of human skeletal remains. The recorded Raman spectra provided valuable and potentially useful information from which a multivariate study was performed by means of orthogonal partial least squares regression (OPLSR) in order to correlate the PMI with the detected spectral modifications. A collection of 53 real human skeletal remains with known PMI (15 years ≤ PMI ≤ 87 years) was analysed and used for building and validating the OPLS model. The PMI of 10 out of 14 validation samples could be determined with an accuracy error of less than 30%, demonstrating the adequate predictive performance of the OPLS model even in spite of the large inter-individual variability it handled. This opens up the possibility of applying the OPLS model in combination with non-destructive techniques to the determination of the PMI of human skeletal remains that have been buried in conditions similar or equal to those of cemetery niches and in a geographic location with a Mediterranean climate, which is an important achievement for forensic medicine and anthropology.
Multiband mucosectomy (MBM) is a relatively new technique for endoscopic resection in Barrett's esophagus. This ligate-cut technique uses a modified variceal band ligator allowing for six consecutive ...resections without prior submucosal lifting. The aim was to evaluate the safety of MBM and its efficacy for complete endoscopic removal of delineated target areas in Barrett's esophagus.
Prospective registration of all MBM procedures in Barrett's esophagus was carried out between November 2004 and October 2009 in two hospitals. Prior to MBM, the target area was delineated with coagulation markings, followed by endoscopic resection until the delineated area was completely resected. Primary end points were acute (during procedure) plus early complications (<30 days) and the rate of complete endoscopic resection of the delineated target area.
A total of 243 MBM procedures, with 1060 resections, were performed in 170 patients. MBM was performed for focal lesions (n=113), for Barrett's esophagus removal as part of a (stepwise) radical endoscopic resection protocol (n=117), and as escape treatment after radiofrequency ablation (n=13). The only acute complication was bleeding (in 3%, endoscopically managed); no perforations occurred despite absence of submucosal lifting. Early complications consisted of delayed bleeding (in 2%, endoscopically managed) and stenosis, which occurred in 48% of patients treated in a (stepwise) radical resection protocol; patients treated for focal lesions or in escape treatment showed no stenosis. Complete endoscopic resection was achieved in 91% of the focal lesions, in 86% of cases treated under the (stepwise) radical endoscopic resection protocol, and 100% for escape treatment after radiofrequency ablation.
MBM is a safe and effective technique for the removal of delineated target areas in Barrett's esophagus.
Purpose
The optimal duration of post-radiation temozolomide in newly diagnosed glioblastoma remains unclear, with no published phase III randomised trials. Standard-of-care stipulates 6 months. ...However, in routine care, it is often extended to 12 months, despite lacking robust supporting data.
Methods
GEINO14-01 (Spain) and EX-TEM (Australia) studies enrolled glioblastoma patients without progression at the end of 6 months post-radiation temozolomide. Participants were randomised 1:1 to six additional months of temozolomide or observation. Primary endpoint was 6-month progression free survival from date of randomisation (6mPFS). Secondary endpoints included overall survival (OS) and toxicity. 204 patients were required to detect an improvement in 6mPFS from 50 to 60% (80% power). Neither study recruited sufficient patients. We performed a combined analysis of individual patient data.
Results
205 patients were recruited: 159 in GEINO14-01 (2014–2018) and 46 in EX-TEM (2019–2022). Median follow-up was 20.0 and 14.5 months. Baseline characteristics were balanced. There was no significant improvement in 6mPFS (57.2% vs 64.0%, OR0.75, p = 0.4), nor across any subgroups, including MGMT methylated; PFS (HR0.92, p = 0.59, median 7.8 vs 9.7 months); or OS (HR1.03, p = 0.87, median 20.1 vs 19.4 months). During treatment extension, 64% experienced any grade adverse event, mainly fatigue and gastrointestinal (both 54%). Only a minority required treatment changes: 4.5% dose delay, 7.5% dose reduction, 1.5% temozolomide discontinuation.
Conclusion
For glioblastoma patients, extending post-radiation temozolomide from 6 to 12 months is well tolerated but does not improve 6mPFS. We could not identify any subset that benefitted from extended treatment. Six months should remain standard-of-care.
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