Extreme stresses can be produced in nanoscale structures; this feature has been used to realize enhanced materials properties, such as the high mobility of silicon in modern transistors. We show how ...nanoscale stress can be used to realize exceptionally low mechanical dissipation when combined with "soft-clamping"-a form of phononic engineering. Specifically, using a nonuniform phononic crystal pattern, we colocalize the strain and flexural motion of a free-standing silicon nitride nanobeam. Ringdown measurements at room temperature reveal string-like vibrational modes with quality (
) factors as high as 800 million and
× frequency exceeding 10
hertz. These results illustrate a promising route for engineering ultracoherent nanomechanical devices.
Quantum correlations between imprecision and backaction are a hallmark of continuous linear measurements. Here, we study how measurement-based feedback can be used to improve the visibility of ...quantum correlations due to the interaction of a laser field with a nanomechanical oscillator. Backaction imparted by the meter laser, due to radiation-pressure quantum fluctuations, gives rise to correlations between its phase and amplitude quadratures. These quantum correlations are observed in the experiment both as squeezing of the meter field fluctuations below the vacuum level in a homodyne measurement and as sideband asymmetry in a heterodyne measurement, demonstrating the common origin of both phenomena. We show that quantum feedback, i.e., feedback that suppresses measurement backaction, can be used to increase the visibility of the sideband asymmetry ratio. In contrast, by operating the feedback loop in the regime of noise squashing, where the in-loop photocurrent variance is reduced below the vacuum level, the visibility of the sideband asymmetry is reduced. This is due to backaction arising from vacuum noise in the homodyne detector. These experiments demonstrate the possibility, as well as the fundamental limits, of measurement-based feedback as a tool to manipulate quantum correlations.
Histopathologic regression following neoadjuvant treatment (NT) of oesophageal cancer is a prognostic factor of survival, but the nodal status is not considered. Here, a score combining both to ...improve prediction of survival after neoadjuvant therapy is developed.
Seven hundred and fifteen patients with oesophageal squamous cell (SCC) or adenocarcinoma (AC) undergoing NT and esophagectomy were analysed. Histopathologic response was classified according to percentage of vital residual tumour cells (VRTC): complete response (CR) without VRTC, major response with <10% VRTC, minor response with >10% VRTC. Nodal stage was classified as ypN0 and ypN+. Kaplan-Meier and Cox regression were used for survival analysis.
Survival analysis identified three groups with significantly different mortality risks: (1) low-risk group for CR (ypT0N0) with 72% 5-year overall survival (5y-OS), (2) intermediate-risk group for minor/major responders and ypN0 with 59% 5y-OS, and (3) high-risk group for minor/major responders and ypN+ with 20% 5y-OS (p < 0.001). Median survival in AC and SCC cohorts were comparable (3.8 (CI 95%: 3.1, 5.3) vs. 4.6 years (CI 95%: 3.3, not reached), p = 0.3).
Histopathologic regression and nodal status should be combined for estimating AC and SCC prognosis. Poor survival in the high-risk group highlights need for adjuvant therapy.
Mechanical resonators with high quality factors are widely used in precision experiments, ranging from gravitational wave detection and force sensing to quantum optomechanics. Beams and membranes are ...well known to exhibit flexural modes with enhanced quality factors when subjected to tensile stress. The mechanism for this enhancement has been a subject of debate, but is typically attributed to elastic energy being “diluted” by a lossless potential. Here we clarify the origin of the lossless potential to be the combination of tension and geometric nonlinearity of strain. We present a general theory of dissipation dilution that is applicable to arbitrary resonator geometries and discuss why this effect is particularly strong for flexural modes of nanomechanical structures with high aspect ratios. Applying the theory to a nonuniform doubly clamped beam, we show analytically how dissipation dilution can be enhanced by modifying the beam shape to implement “soft clamping,” thin clamping, and geometric strain engineering, and derive the ultimate limit for dissipation dilution.
This study was aimed to investigate the risk factors for mortality in patients with COVID-19.
For this retrospective cohort study, we included 121 deceased and 436 discharged cases with COVID-19 in ...Babol, Northern Iran. The cases were between March 1 to April 1, 2020.
Multivariate Poisson regression analysis revealed that older age (aRR: 1.03, 95% CI: 1.01, 1.05, p < 0.001), hospital length of stay (aRR: 0.94, 95% CI: 0.90, 0.97, p = 0.003), ICU admission (aRR: 4.34, 95% CI: 2.95, 6.37, p < 0.001), cerebrovascular disease (aRR: 1.96, 95% CI: 1.20, 3.19, p = 0.007), ventilator-associated pneumonia (VAP) (aRR: 2.09, 95% CI: 1.22, 3.55, p = 0.006), septic shock (aRR: 2.98, 95% CI: 1.44, 6.19, p = 0.003), acute respiratory distress syndrome (ARDS) (aRR: 3.80, 95% CI: 2.28, 6.31, p < 0.001), acute kidney failure (AKF) (aRR: 1.45, 95% CI: 1.12, 3.76, p = 0.021), acute heart failure (AHF) (aRR: 1.63, 95% CI: 1.01, 2.62, p = 0.043) and lymphocyte count (aRR: 3.01, 95% CI: 1.99, 4.57, p < 0.001) were associated with mortality.
Findings showed that elderly with comorbidities such as cerebrovascular diseases had an increased risk of death. Some complications such as: pneumonia, septic shock, ARDS, AHF, and AKF played crucial roles as well death (Tab. 2, Ref. 25).
To identify metabolic pathways that are perturbed in pancreatic ductal adenocarcinoma (PDAC), we investigated gene-metabolite networks with integration of metabolomics and transcriptomics.
We ...conducted global metabolite profiling analysis on two independent cohorts of resected PDAC cases to identify critical metabolites alteration that may contribute to the progression of pancreatic cancer. We then searched for gene surrogates that were significantly correlated with the key metabolites, by integrating metabolite and gene expression profiles.
Fifty-five metabolites were consistently altered in tumors as compared with adjacent nontumor tissues in a test cohort (N = 33) and an independent validation cohort (N = 31). Weighted network analysis revealed a unique set of free fatty acids (FFA) that were highly coregulated and decreased in PDAC. Pathway analysis of 157 differentially expressed gene surrogates revealed a significantly altered lipid metabolism network, including key lipolytic enzymes PNLIP, CLPS, PNLIPRP1, and PNLIPRP2. Gene expressions of these lipases were significantly decreased in pancreatic tumors as compared with nontumor tissues, leading to reduced FFAs. More importantly, a lower gene expression of PNLIP in tumors was associated with poorer survival in two independent cohorts. We further showed that two saturated FFAs, palmitate and stearate, significantly induced TRAIL expression, triggered apoptosis, and inhibited proliferation in pancreatic cancer cells.
Our results suggest that impairment in a lipolytic pathway involving lipases, and a unique set of FFAs, may play an important role in the development and progression of pancreatic cancer and provide potential targets for therapeutic intervention.
Forced expression of gap junction proteins, connexins, enables gap junction-deficient cell lines to propagate intercellular calcium waves. Here, we show that ATP secretion from the poorly coupled ...cell lines, C6 glioma, HeLa, and U373 glioblastoma, is potentiated 5- to 15-fold by connexin expression. ATP release required purinergic receptor-activated intracellular Ca2+mobilization and was inhibited by Cl-channel blockers. Calcium wave propagation also was reduced by purinergic receptor antagonists and by Cl-channel blockers but insensitive to gap junction inhibitors. These observations suggest that cell-to-cell signaling associated with connexin expression results from enhanced ATP release and not, as previously believed, from an increase in intercellular coupling.
A new engineering medium, called nanofluid attracted a wide range of researches on many cooling processes in engineering applications, which are prepared by dispersing nanoparticles or nanotubes in a ...host fluid. In this paper, the stability of nanofluids is discussed as it has a major role in heat transfer enhancement for further possible applications. It also represents general stabilization methods as well as various types of instruments for stability inspection. Characterization, analytical models and measurement techniques of nanofluids after preparation by a single step or two-step method are studied.
Background
This study analyzed the long-term survival after pathological complete response (pCR) with and without nodal metastases and associated recurrence following multimodal treatment of ...esophageal cancer. The recurrence pattern after pCR is of importance for different postoperative surveillance strategies.
Methods
A cohort of 890 patients with esophageal cancer received neoadjuvant therapy followed by transthoracic esophagectomy. Only patients with pCR of the primary tumor with and without nodal metastasis were analyzed. A clinicopathological database was set up and completed with long-term follow up information on recurrent disease.
Results
The specimen of 201 patients (23%) demonstrated pCR, 84% without (ypT0N0) and 16% with residual nodal disease (ypT0N+). For ypT0N0 patients, the 5-year overall survival was significantly higher than for patients with metastatic nodes (77% vs. 24%) (
p
< 0.0001). Sixty-eight percent of patients had no evidence of tumor recurrence, whereas 32% had proven relapse. For patients with and without tumor recurrence, 5-year survival rates were 14% and 93%, respectivel
y
(
p
< 0.0001). For patients with recurrent disease, median survival time was 27 for locoregional, 44 for distant, and 24 months for combined recurrence (
p
= 0.302). In the multivariable Cox-regression analysis, node-positive disease predicted both locoregional and metastatic recurrence.
Conclusions
Pathological CR offers long-term survival in patients without nodal metastases but outcome significantly deteriorates with the presence of nodal metastases. Follow-up recommendations may therefore be adopted in patients with pCR. Furthermore, “watch-and-wait” surveillance strategies with suspected clinical complete response have to be considered with caution.
•Stability, conductivity and viscosity of low concentration titania nanofluids.•SDS as an anionic surfactant increases the stability of nano-suspension.•Three-hour ultrasonic bath processing with SDS ...gives highest stability.
Nanofluid, as a brand new cooling fluid, is a colloidal suspension which enhances the heat transfer but its stability and durability are matters of concern for the industrial applications in the future. The aim of this research is to investigate the stability of titania nano-suspensions by comparing the effect of surfactant addition and ultrasonic processing. In the present research, six different nanofluids with 0.1wt.% loading of TiO2 nanoparticles (25nm diameter) were prepared using a two-step method. Ultrasonic processing (i.e. bath and horn) were applied to help the homogeneity and Sodium Dodecyl Sulfate (SDS) as anionic surfactant was added to monitor the stability of the samples. UV–vis spectrometry, particle size distribution, zeta potential, Transmission Electron Microscopy (TEM) and sedimentation photo capturing were applied to visualize the stability and sedimentation rate of the prepared nanofluids. In addition, thermal conductivity and viscosity of these six samples were measured. The optimized nanofluid was selected in terms of better stability, thermal conductivity and viscosity. The results revealed that 3-h ultrasonic bath process with the addition of 0.1wt.% of surfactant can be the most stable suspension with the highest thermal conductivity for further applications within 1month.
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