We have solved the long-standing problem of the mechanism of terahertz (THz) generation by a two-color filament in air and found that both neutrals and plasma contribute to the radiation. We reveal ...that the contribution from neutrals by four-wave mixing is much weaker and higher in frequency than the distinctive plasma lower-frequency contribution. The former is in the forward direction while the latter is in a cone and reveals an abrupt down-shift to the plasma frequency. Ring-shaped spatial distributions of the THz radiation are shown to be of universal nature and they occur in both collimated and focusing propagation geometries. Experimental measurements of the frequency-angular spectrum generated by 130-fs laser pulses agree with numerical simulations based on a unidirectional pulse propagation model.
Current staging methods for pancreatic cancer (PC) are inadequate, and biomarkers to aid clinical decision making are lacking. Despite the availability of the serum marker carbohydrate antigen 19.9 ...(CA19.9) for over two decades, its precise role in the management of PC is yet to be defined, and as a consequence, it is not widely used.
We assessed the relationship between perioperative serum CA19.9 levels, survival and adjuvant chemotherapeutic responsiveness in a cohort of 260 patients who underwent operative resection for PC.
By specifically assessing the subgroup of patients with detectable CA19.9, we identified potential utility at key clinical decision points. Low postoperative CA19.9 at 3 months (median survival 25.6 vs 14.8 months, P = 0.0052) and before adjuvant chemotherapy were independent prognostic factors. Patients with postoperative CA 19.9 levels >90 U/ml did not benefit from adjuvant chemotherapy (P = 0.7194) compared with those with a CA19.9 of ≤90 U/ml (median 26.0 vs 16.7 months, P = 0.0108). Normalization of CA19.9 within 6 months of resection was also an independent favorable prognostic factor (median 29.9 vs 14.8 months, P = 0.0004) and normal perioperative CA19.9 levels identified a good prognostic group, which was associated with a 5-year survival of 42%.
Perioperative serum CA19.9 measurements are informative in patients with detectable CA19.9 (defined by serum levels of >5 U/ml) and have potential clinical utility in predicting outcome and response to adjuvant chemotherapy. Future clinical trials should prioritize incorporation of CA19.9 measurement at key decision points to prospectively validate these findings and facilitate implementation.
Introduction: While several studies have found a link between impaired cognition and social isolation, few have examined the relationship between cognition and loneliness. Loneliness has been thought ...to increase the risk of development of Alzheimer's dementia.
Aim: The aims of this study were to explore the relationship between loneliness and cognition and to determine whether specific cognitive domains are associated with loneliness.
Design: Cross-sectional community-based study.
Participants: This study included 466 community-dwelling subjects with mean age 75.45 (SD 6.06) years, of which 208(44%) were males.
Results: Loneliness was significantly associated with impaired global cognition independent of social networks and depression. The domains of psychomotor processing speed and delayed visual memory were specifically associated with self-reported loneliness.
Conclusion: This cross-sectional study demonstrated an association between loneliness and specific aspects of cognition independent of depression, social networks and other demographics. The mechanism for this association is unclear and warrants further investigation.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
•LEND/LRO instrument neutron counting data sets have been analyzed to create high resolution maps of epithermal neutron flux at polar regions of the Moon.•The conversion from epithermal neutron flux ...to the H/H2O abundances is presented based on the simple subsurface models.•The polar lunar maps (poleward 70S/70N) of homogeneous hydrogen distribution are derived and discussed.
We present a method of conversion of the lunar neutron counting rate measured by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) instrument collimated neutron detectors, to water equivalent hydrogen (WEH) in the top ∼1m layer of lunar regolith. Polar maps of the Moon's inferred hydrogen abundance are presented and discussed.
Adjuvant chemotherapy improves survival for patients with resected pancreatic cancer. Elderly patients are under-represented in Phase III clinical trials, and as a consequence the efficacy of ...adjuvant therapy in older patients with pancreatic cancer is not clear. We aimed to assess the use and efficacy of adjuvant chemotherapy in older patients with pancreatic cancer.
We assessed a community cohort of 439 patients with a diagnosis of pancreatic ductal adenocarcinoma who underwent operative resection in centres associated with the Australian Pancreatic Cancer Genome Initiative.
The median age of the cohort was 67 years. Overall only 47% of all patients received adjuvant therapy. Patients who received adjuvant chemotherapy were predominantly younger, had later stage disease, more lymph node involvement and more evidence of perineural invasion than the group that did not receive adjuvant treatment. Overall, adjuvant chemotherapy was associated with prolonged survival (median 22.1 vs 15.8 months; P<0.0001). Older patients (aged ≥70) were less likely to receive adjuvant chemotherapy (51.5% vs 29.8%; P<0.0001). Older patients had a particularly poor outcome when adjuvant therapy was not delivered (median survival=13.1 months; HR 1.89, 95% CI: 1.27-2.78, P=0.002).
Patients aged ≥70 are less likely to receive adjuvant therapy although it is associated with improved outcome. Increased use of adjuvant therapy in older individuals is encouraged as they constitute a large proportion of patients with pancreatic cancer.
A technique is presented to create uninterrupted long ultraviolet filaments in air using appropriately structured transmission mesh. The mesh with different cell sizes was inserted into 10-cm ...parallel beam of 0.2-J, 248-nm, and 870-fs pulse propagating along ~100-m corridor. Transverse positions of multiple filaments formed by the optimum size cells were reproducible within at least 15 m along the propagation path. 3D+time simulations confirmed uninterrupted plasma channels with fixed positions in the transverse space similar to the experiment. Unoptimized cell size resulted in filaments shifting towards the cell center and destruction of uninterrupted filaments.
This study aimed to characterize antimicrobial resistance and virulence genes in multi-drug resistant enterotoxigenic
Escherichia coli (ETEC) isolates (
n
=
117) collected from porcine post-weaning ...diarrhoea cases in Australia (1999–2005). Isolates were serotyped, antibiogram-phenotyped for 12 antimicrobial agents and genotyped by PCR for 30 plasmid-mediated antimicrobial resistance genes (ARGs), 22 intestinal and 38 extraintestinal
E. coli virulence genes (VGs). Nine serogroups were identified, the most prevalent being O149 (46.2%), O141 (11.2%) and Ont (31.6%). None of the isolates showed resistance to ceftiofur or enrofloxacin and 9.4% were resistant to florfenicol. No corresponding extended-spectrum/AmpC β-lactamase, fluoroquinolone or
floR ARGs were detected. An antimicrobial resistance index (ARI) was calculated from the combined data with a weighting for each antimicrobial agent dependent upon its significance to human health. Serogroup O141 isolates had a significantly higher ARI due to an elevated prevalence of aminoglycoside ARGs and possession of more virulence genes (VGs), including ExPEC or EHEC adhesins (
bmaE,
sfa/focDE,
fimH,
ihA) in toxin-producing strains that lacked the normally associated F4 and F18 fimbriae. Few associations between ARGs and VGs were apparent, apart from
tetC,
sfa/focDE and
ompT which, for a sub-set of O141 isolates, suggest possible plasmid acquisition from ExPEC. The multi-drug resistant ETEC ARG/VG profiles indicate a high probability of considerable strain and plasmid diversity, reflecting various selection pressures at the individual farm level rather than emergence and lateral spread of MDR resistant/virulent clones.
Atomic and Electronic Structures of a-SiN x :H Gritsenko, V A; Kruchinin, V N; Prosvirin, I P ...
Journal of experimental and theoretical physics,
11/2019, Letnik:
129, Številka:
5
Journal Article
Recenzirano
The atomic structure and the electronic spectrum of a-SiNx:H films, which are grown by plasmachemical deposition with varied ammonia and monosilane flow rates, are studied. As a result of varied flow ...rates, stoichiometric parameter x is changed over wide limits, from 0.73 to 1.33. The films are analyzed by structural and optical techniques to determine stoichiometric parameter x and its influence on the valence band top and the band gap in the density of states. The experimental and calculated electronic structure parameters of a-SiNx are compared, and good agreement between them is achieved over wide film composition (parameter x) limits. The experimental data obtained can be used to simulate the electron transport characteristics in nonstoichiometric silicon nitride films, which is important for creating memristors based on them.
Raman spectra of films of nearly stoichiometric amorphous silicon nitride (a-Si
3
N
4
) reveal a contribution due to local oscillations of silicon–silicon (Si–Si) bonds. This observation directly ...confirms that the almost stoichiometric a-Si
3
N
4
contains Si–Si bonds, which, according to theoretical predictions, act as electron and hole traps that are responsible for the memory effect in Si
3
N
4
.
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