Cooling beyond the boundary value in supercritical fluids under vibration

Supercritical fluids when subjected to simultaneous quench and vibration have been known to cause various intriguing flow phenomena and instabilities depending on the relative direction of temperature gradient and vibration. Here we describe a surprising and interesting phenomenon wherein temperature in the fluid falls below the imposed boundary value when the walls are quenched and the direction of vibration is normal to the temperature gradient. We define these regions in the fluid as sink zones, because they act like sink for heat within the fluid domain. The formation of these zones is first explained using a one-dimensional (1D) analysis with acceleration in constant direction. Subsequently, the effect of various boundary conditions and the relative direction of the temperature gradient to acceleration are analyzed, highlighting the necessary conditions for the formation of sink zones. It is found that the effect of high compressibility and the action of self-weight (due to high acceleration) causes the temperature to change in the bulk besides the usual action of piston effect. This subsequently affects the overall temperature profile thereby leading to the formation of sink zones. Though the examined 1D cases differ from the current two-dimensional (2D) cases, owing to the direction of acceleration being normal as compared to parallel in case of former, the explanations pertaining to 1D cases are judiciously utilized to elucidate the formation of sink zones in 2D supercritical fluids subjected to thermal quench and vibrational acceleration. The appearance of sink zones is found to be dependent on several factors such as proximity to the critical point and acceleration. A surface three-dimensional plot illustrating the effect of these parameters on onset time of sink zones is presented to further substantiate these arguments.

Nuclear Dependence of the Transverse-Single-Spin Asymmetry for Forward Neutron Production in Polarized p+A Collisions at sqrt[s_{NN}]=200 GeV

During 2015, the Relativistic Heavy Ion Collider (RHIC) provided collisions of transversely polarized protons with Au and Al nuclei for the first time, enabling the exploration of transverse-single-spin asymmetries with heavy nuclei. Large single-spin asymmetries in very forward neutron production have been previously observed in transversely polarized p+p collisions at RHIC, and the existing theoretical framework that was successful in describing the single-spin asymmetry in p+p collisions predicts only a moderate atomic-mass-number (A) dependence. In contrast, the asymmetries observed at RHIC in p+A collisions showed a surprisingly strong A dependence in inclusive forward neutron production. The observed asymmetry in p+Al collisions is much smaller, while the asymmetry in p+Au collisions is a factor of 3 larger in absolute value and of opposite sign. The interplay of different neutron production mechanisms is discussed as a possible explanation of the observed A dependence.

Correlation of a new index reflecting the fluctuation of parasympathetic tone and fetal acidosis in an experimental study in a sheep model

The autonomic nervous system plays a leading role in the control of fetal homeostasis. Fetal heart rate variability (HRV) analysis is a reflection of its activity. We developed a new index (the Fetal Stress Index, FSI) reflecting parasympathetic tone. The objective of this study was to evaluate this index as a predictor of fetal acid-base status. This was an experimental study on chronically instrumented fetal lambs (n = 11, surgery at 128 +/- 2 days gestational age, term = 145 days). The model was based on 75% occlusion of the umbilical cord for a maximum of 120 minutes or until an arterial pH ≤ 7.20 was reached. Hemodynamic, gasometric and FSI parameters were recorded throughout the experimentation. We studied the FSI during the 10 minutes prior to pH samplings and compared values for pH>7.20 and pH≤ 7.20. In order to analyze the FSI evolution during the 10 minutes periods, we analyzed the minimum, maximum and mean values of the FSI (respectively FSImin, FSImax and FSImean) over the periods. 11 experimentations were performed. During occlusion, the heart rate dropped with an increase in blood pressure (respectively 160(155-182) vs 106(101-120) bpm and 42(41-45) vs 58(55-62) mmHg after occlusion). The FSImin was 38.6 (35.2-43.3) in the group pH>7.20 and was higher in the group pH less than 7.20 (46.5 (43.3-52.0), p = 0.012). The correlation of FSImin was significant for arterial pH (coefficient of -0.671; p = 0.004) and for base excess (coefficient of -0.632; p = 0.009). The correlations were not significant for the other parameters. In conclusion, our new index seems well correlated with the fetal acid-base status. Other studies must be carried out in a situation close to the physiology of labor by sequential occlusion of the cord.

A study of changes in the oral fungal flora of patients on radiotherapy for head and neck malignancies and their correlation with funguria and fungemia

BACKGROUND

Patients of head and neck malignancies often develop oral mucositis and invite various pathogens to colonize over it.

OBJECTIVES

The objective of this study is to identify the fungi isolated from patients undergoing radiotherapy (RT) for head and neck cancer, to determine the antifungal susceptibility of these isolates and to determine the time and week of fungal colonization.

PATIENTS AND METHODS

Three specimens (throat, urine, and blood) were collected from each of the head and neck cancer patients, who were advised RT. These specimens, which were collected before the start of RT, during RT (2nd and 6th week), and post-RT (8th week) were inoculated into fungal culture media. Candida species were identified by standard methods and antifungal susceptibility of the candidal isolates was done.

RESULTS

Candida infection was found in 24/42 patients (57.14%) out of which Candida albicans was isolated in 14.28%, Candida tropicalis (28.57%) and Candida parapsilosis (14.28%). Maximum isolation of yeast was in the 6th week of RT. Fungemia was found in 3/42 patients. All the yeast isolates were sensitive to fluconazole except two.

CONCLUSION

Prophylactic antifungal therapy in patients undergoing RT for head and neck malignancy is particularly important to prevent intraoral colonization and infection by Candida. Screening of such patients on RT for fungal infections can prevent fatal mold infections.

Temporal variability in aerosol characteristics and its radiative properties over Patiala, northwestern part of India: Impact of agricultural biomass burning emissions

A comprehensive measurements of aerosol optical depth (AOD), particulate matter (PM) and black carbon (BC) mass concentrations have been carried out over Patiala, a semi-urban site in northwest India during October 2008 to September 2010. The measured aerosol data was incorporated in an aerosol optical model to estimate various aerosol optical parameters, which were subsequently used for radiative forcing estimation. The measured AOD at 500 nm (AOD₅₀₀) shows a significant seasonal variability, with maximum value of 0.81 during post-monsoon (PoM) and minimum of 0.56 during winter season. The Ångström exponent (α) has higher values (i.e. more fine-mode fraction) during the PoM/winter periods, and lower (i.e. more coarse-mode fraction) during pre-monsoon (PrM). In contrast, turbidity coefficient (β) exhibits an opposite trend to α during the study period. BC mass concentration varies from 2.8 to 13.9 μg m^-3 (mean: 6.5 ± 3.2 μg m^-3) during the entire study period, with higher concentrations during PoM/winter and lower during PrM/monsoon seasons. The average single scattering albedo (SSA at 500 nm) values are 0.70, 0.72, 0.82 and 0.75 during PoM, winter, PrM and monsoon seasons, respectively. However, inter-seasonal and inter-annual variability in measured aerosol parameters are statistically insignificant at Patiala. These results suggest strong changes in emission sources, aerosol composition, meteorological parameters as well as transport of aerosols over the station. Higher values of AOD, α and BC, along with lower SSA during PoM season are attributed to agriculture biomass burning emissions over and around the station. The estimated aerosol radiative forcing within the atmosphere is positive (i.e. warming) during all the seasons with higher values (∼60 Wm^-2) during PoM-08/PoM-09 and lower (∼40 Wm^-2) during winter-09/PrM-10. The present study highlights the role of BC aerosols from agricultural biomass burning emissions during post-monsoon season for atmospheric warming at Patiala.

Degradation of euptox A by tannase-producing rumen bacteria from migratory goats

AIMS

The gut microbiota capable of degrading plant biomass and antinutritional phytometabolites are of immense importance. This study reports isolation and characterization of tannase-producing rumen bacteria that could also degrade euptox A (9-oxo-10,11-dehydroageraphorone) present in Eupatorium adenophorum (Spreng).

METHODS AND RESULTS

Migratory Gaddi goats were selected as source of inoculums for isolating rumen bacteria with ability to produce tannase which catalyses degradation of hydrolysable tannins (HTs). Three rumen bacterial isolates producing tannase were studied, and identified as Klebsiella variicola strain PLP G-17 LC, K. variicola strain PLP S-18 and Klebsiella pneumoniae strain PLP G-17 SC. The isolates exhibited optimal tannase activity at 40°C, and pH 6·0. The bacteria could also degrade euptox A, a potent hepatotoxin in E. adenophorum Spreng, a widely distributed noxious weed.

CONCLUSIONS

The rumen bacteria could degrade antinutritional HTs and euptox A. Culture-independent metagenomic interventions are envisioned to completely decipher the rumen microbial ecology and exploit its genetic and metabolic potential.

SIGNIFICANCE AND IMPACT OF THE STUDY

The bacteria producing tannase which catalyses degradation of HTs, and concurrently degrading euptox A, may have potential as microbial feed additives to increase utilization of plant biomass containing antinutritional phytometabolites.

Controlling a possible outbreak of Candida auris infection: lessons learnt from multiple interventions

BACKGROUND

Multidrug-resistant Candida auris infection has been reported from five continents in recent years. The prevalence of C. auris invasive infection has been estimated at 5.3% for intensive-care-acquired candidaemia in India. The transmission of the organism between the patients and from environment to patients is rapid.

AIM

To understand the intra-hospital dynamics of C. auris transmission and to determine the possible interventions to prevent its spread.

METHODS

Surveillance of intensive care units was carried out to assess patient colonization, environmental contamination and hand carriage of the yeast among healthcare workers. Interventions including chlorhexidine washing of patients and decontamination of environmental surfaces with stabilized hydrogen peroxide disinfectant (Ecoshield) were undertaken. We further evaluated the effectiveness of frequently used disinfectants in the hospital against C. auris on various inanimate surfaces, and its persistence on hospital fabrics.

FINDINGS

Three cases of C. auris bloodstream infection were detected over a period of three months. Many patients admitted at the same time, in the same area, were colonized by C. auris. Surveillance detected C. auris contamination of environmental surfaces and hands of healthcare workers. Interventions such as chlorhexidine washing and appropriate use of disinfectants could eradicate C. auris from patients and hospital environment.

CONCLUSION

The frequently used disinfectants in our hospital and current hand hygiene practices were efficient against C. auris if proper contact time and procedures were followed. Evaluation of possible persistence of C. auris on dry fabrics showed that they can persist for up to seven days.

Anaesthesia practices for endovascular therapy of acute ischaemic stroke: a Nordic survey

BACKGROUND

The optimal method of anaesthesia for endovascular therapy (EVT) in acute ischaemic stroke (AIS) has not been identified. Nordic departments of anaesthesiology may handle EVT cases for AIS differently. The aim of this survey was to describe the current practice patterns of Nordic anaesthesia departments in anaesthetic management of EVT in AIS.

METHODS

A survey consisting of 13 questions was sent to one qualified individual at all Nordic departments of anaesthesiology who manage anaesthesia for EVT interventions. The individual completed the questionnaire on behalf of their department.

RESULTS

Response rate was 100%. The majority of departments (84%) managed all EVT cases at their respective centres. Most departments have institutional guidelines on anaesthetic management (84%) including blood pressure management (63%) and were able to provide a 24-h immediate response to an EVT request (63%). Conscious sedation was favoured by 68% of the departments using a variety of sedation protocols. Propofol and remifentanil was preferred for GA (58%). Emergent conversion to GA due to uncontrolled patient movements or loss of airway was experienced by 82% and 35% of the departments, respectively. Majority of the departments (89%) responded that non-specialist anaesthetists occasionally handle EVT cases.

CONCLUSIONS

This survey indicates that the majority of Nordic anaesthesia departments who manage anaesthesia for EVT are able to provide immediate 24-h response to an EVT request. Most of these departments have institutional guidelines for EVT anaesthesia and haemodynamic management. Conscious sedation appears to be the preferred method of anaesthetic care.

Safety and tolerability of subcutaneous treprostinil in newborns with congenital diaphragmatic hernia and life-threatening pulmonary hypertension

BACKGROUND

Prolonged pulmonary hypertension (PH) is highly predictive for pulmonary morbidity and death in infants with congenital diaphragmatic hernia (CDH).

OBJECTIVES

To report the effects and tolerability of subcutaneous treprostinil in newborns with severe CDH and late life-threatening PH.

METHODS

We recorded clinical and echocardiography data before and after starting subcutaneous treprostinil, on patients with severe CDH and late PH, refractory to inhaled nitric oxide and oral sildenafil.

RESULTS

14 patients were treated with treprostinil (gestational age: 39.1±2.0weeks; birth weight: 3200±600g). Prior to treatment, the pre- and post-ductal SpO2 difference (Δ SpO2) was 14±10%. Treprostinil was initiated at a median age of 12days [5-157]. After starting treprostinil, ΔSpO2 decreased to 3% at day 7 (p<0.05), and the mean blood flow velocities in the right pulmonary arteries increased by 110% (p<0.05). 2 of the 14 patients died. At the age of follow up (12months to 3years), the 12 surviving infants were all weaned from respiratory support and discharged home.

CONCLUSION

The subcutaneous treprostinil improves pulmonary hemodynamics and outcomes in infants with CDH and life-threatening PH. We suggest that the treatment should be considered in infants with severe CDH and late PH.

TYPE OF STUDY

Case series with no comparison group.

LEVEL OF EVIDENCE

Level IV.

Major postoperative complications after pancreatic resection for P-NETS are not associated to earlier recurrence

BACKGROUND

The oncological impact of surgical complications has been studied in visceral and pancreatic cancer.

AIM

To investigate the impact of complications on tumour recurrence after resections for pancreatic neuroendocrine tumours.

METHODS

We have retrospectively analysed 105 consecutive resections performed at the Royal Free London Hospital from 1998 to 2014, and studied the long-term outcome of nil-minor (<3) versus major (≥3) Clavien-Dindo complications (CD) on disease-free (DFS) and overall survival (OS).

RESULTS

The series accounted for 41 (39%) pancreaticoduodenectomies, two (1.9%) central, 48 (45.7%) distal pancreatectomies, eight (7.6%) enucleations, four (3.8%) total pancreatectomies. Sixteen (15.2%) were extended to adjacent organs, 13 (12.3%) to minor liver resections. Postoperative complications presented in 43 (40.1%) patients; CD grade 1 or 2 in 23 (21.9%), grades ≥3 in 20 (19%). Among 25 (23.8%) pancreatic fistulas, 14 (13.3%) were grades B or C. Thirty-four (32.4%) patients developed exocrine, and 31 (29.5%) endocrine insufficiency. Seven patients died during a median 27 (0-175) months follow up. Thirty-day mortality was 0.9%. OS was 94.1% at 5 years. Thirty tumours recurred within 11.7 (0.8-141.5) months. DFS was 44% at 5 years. At univariate analysis, high-grade complications were not associated with shorter DFS (p = 0.744). At multivariate analysis, no parameter was independent predictor for DFS or OS. The comparison of nil-minor versus major complications showed no DFS difference (p = 0.253).

CONCLUSION

From our series, major complications after P-NETs resection are not associated to different disease recurrence; hence do not require different follow up or adjuvant regimens.

A new analysis of heart rate variability in the assessment of fetal parasympathetic activity: An experimental study in a fetal sheep model

Analysis of heart rate variability (HRV) is a recognized tool in the assessment of autonomic nervous system (ANS) activity. Indeed, both time and spectral analysis techniques enable us to obtain indexes that are related to the way the ANS regulates the heart rate. However, these techniques are limited in terms of the lack of thresholds of the numerical indexes, which is primarily due to high inter-subject variability. We proposed a new fetal HRV analysis method related to the parasympathetic activity of the ANS. The aim of this study was to evaluate the performance of our method compared to commonly used HRV analysis, with regard to i) the ability to detect changes in ANS activity and ii) inter-subject variability. This study was performed in seven sheep fetuses. In order to evaluate the sensitivity and specificity of our index in evaluating parasympathetic activity, we directly administered 2.5 mg intravenous atropine, to inhibit parasympathetic tone, and 5 mg propranolol to block sympathetic activity. Our index, as well as time analysis (root mean square of the successive differences; RMSSD) and spectral analysis (high frequency (HF) and low frequency (LF) spectral components obtained via fast Fourier transform), were measured before and after injection. Inter-subject variability was estimated by the coefficient of variance (%CV). In order to evaluate the ability of HRV parameters to detect fetal parasympathetic decrease, we also estimated the effect size for each HRV parameter before and after injections. As expected, our index, the HF spectral component, and the RMSSD were reduced after the atropine injection. Moreover, our index presented a higher effect size. The %CV was far lower for our index than for RMSSD, HF, and LF. Although LF decreased after propranolol administration, fetal stress index, RMSSD, and HF were not significantly different, confirming the fact that those indexes are specific to the parasympathetic nervous system. In conclusion, our method appeared to be effective in detecting parasympathetic inhibition. Moreover, inter-subject variability was much lower, and effect size higher, with our method compared to other HRV analysis methods.

An outbreak of Shiga toxin-producing Escherichia coli O121 infections associated with flour-Canada, 2016-2017†

As of May 23, 2017, 29 cases of a new Escherichia coli O121 infection have been identified in six provinces (Alberta, British Columbia, Newfoundland and Labrador, Ontario, Quebec and Saskatchewan) linked with the consumption of uncooked flour. One additional case was identified in a U.S. resident who traveled to Canada during the exposure period. Patients' ages ranged from 2-79 years (median = 23.5 years) and 50% were female. Eight patients were hospitalized, and one developed hemolytic uremic syndrome. Because of the recent emergence of E. coli outbreaks linked to flour, public health professionals should consider flour as a possible source in E. coli outbreaks and communicate the risk associated with flour and raw batter/dough exposure in public health messaging.

Activation of tumor suppressor LKB1 by honokiol abrogates cancer stem-like phenotype in breast cancer via inhibition of oncogenic Stat3

Tumor suppressor and upstream master kinase Liver kinase B1 (LKB1) plays a significant role in suppressing cancer growth and metastatic progression. We show that low-LKB1 expression significantly correlates with poor survival outcome in breast cancer. In line with this observation, loss-of-LKB1 rendered breast cancer cells highly migratory and invasive, attaining cancer stem cell-like phenotype. Accordingly, LKB1-null breast cancer cells exhibited an increased ability to form mammospheres and elevated expression of pluripotency-factors (Oct4, Nanog and Sox2), properties also observed in spontaneous tumors in Lkb1^-/- mice. Conversely, LKB1-overexpression in LKB1-null cells abrogated invasion, migration and mammosphere-formation. Honokiol (HNK), a bioactive molecule from Magnolia grandiflora increased LKB1 expression, inhibited individual cell-motility and abrogated the stem-like phenotype of breast cancer cells by reducing the formation of mammosphere, expression of pluripotency-factors and aldehyde dehydrogenase activity. LKB1, and its substrate, AMP-dependent protein kinase (AMPK) are important for HNK-mediated inhibition of pluripotency factors since LKB1-silencing and AMPK-inhibition abrogated, while LKB1-overexpression and AMPK-activation potentiated HNK's effects. Mechanistic studies showed that HNK inhibited Stat3-phosphorylation/activation in an LKB1-dependent manner, preventing its recruitment to canonical binding-sites in the promoters of Nanog, Oct4 and Sox2. Thus, inhibition of the coactivation-function of Stat3 resulted in suppression of expression of pluripotency factors. Further, we showed that HNK inhibited breast tumorigenesis in mice in an LKB1-dependent manner. Molecular analyses of HNK-treated xenografts corroborated our in vitro mechanistic findings. Collectively, these results present the first in vitro and in vivo evidence to support crosstalk between LKB1, Stat3 and pluripotency factors in breast cancer and effective anticancer modulation of this axis with HNK treatment.