Measuring higher-order modes in a low-loss, hollow-core, photonic-bandgap fiber

We perform detailed measurements of the higher-order-mode content of a low-loss, hollow-core, photonic-bandgap fiber. Mode content is characterized using Spatially and Spectrally resolved (S2) imaging, revealing a variety of phenomena. Discrete mode scattering to core-guided modes are measured at small relative group-delays. At large group delays a continuum of surface modes and core-guided modes can be observed. The LP11 mode is observed to split into four different group delays with different orientations, with the relative orientations preserved as the mode propagates through the fiber. Cutback measurements allow for quantification of the loss of different individual modes. The behavior of the modes in the low loss region of the fiber is compared to that in a high loss region of the fiber. Finally, a new measurement technique is introduced, the sliding-window Fourier transform of high-resolution transmission spectra of hollow-core fibers, which displays the dependence of HOM content on both wavelength and group delay. This measurement is used to illustrate the HOM content as function of coil diameter.

Tai chi diminishes oxidative stress in Mexican older adults

OBJECTIVE

To determine the effect of Tai Chi on oxidative stress in a population of elderly Mexican subjects.

DESIGN

It was carried out a quasi-experimental study with a sample of 55 healthy subjects randomly divided into two age-matched groups: (i) a control group with 23 subjects and (ii) an experimental group with 32 subjects. The experimental group received daily training in Tai Chi for 50 min.

MEASUREMENTS

It was measured before and after 6-month of exercise period: thiobarbituric acid reactive substances (TBARS), total antioxidant status (TAS), superoxide dismutase (SOD), and glutathione peroxidase (GPx).

RESULTS

It was found that the experimental group exhibited a statistically significant decrease in glucose levels, total cholesterol, low-density lipoprotein cholesterol (LDLC), and systolic blood pressure, as well as an increase in SOD and GPx activity and TAS compared with the control group (p < 0.05).

CONCLUSIONS

Our findings suggest that the daily practice of Tai Chi is useful for reducing OxS in healthy older adults.

Anti-vector immunity following vaccination with Venezuelan equine encephalitis replicon filovirus vaccine (113.1)

The Venezuelan equine encephalitis replicon (VRP) is the lead candidate for development as the DoD filovirus vaccine platform. One concern regarding this vaccine candidate focuses on the need to vaccinate individuals that have been pre-exposed to the VRP through previous vaccinations. To address this concern, cohorts of nonhuman primates (NHPs) were vaccinated with VRP expressing alphavirus proteins and VRP expressing Ebola virus Zaire (EBOV) glycoprotein either concurrently or sequentially. These NHPs were challenged with either 1000pfu of EBOV or 10^8 pfu of Venezuelan equine encephalitis virus (VEEV). Animals that were vaccinated with both vaccinations independent of sequence or co-administration were protected from each challenge. This data indicates that anti-vector immunity is not a concern with the VRP vaccine candidate as the product transitions into phase 1 clinical trials.

The indication of tracheotomy conditions the predictors of time to decannulation in critical patients

OBJECTIVE

Variables predicting optimal timing for tracheostomy decannulation remain unknown. We aimed to determine whether classifying patients into two groups according to their indications for tracheostomy could identify variables associated with time to decannulation.

DESIGN

A prospective, observational cohort study was carried out.

LOCATION

Two medical-surgical ICUs.

PATIENTS

We included all patients tracheostomized during ICU stay, excluding patients with do-not-resuscitate orders, tracheostomies for long-term airway control, neuromuscular disease, or neurological damage. Patients were classified into two groups: patients tracheostomized due to prolonged weaning and/or prolonged mechanical ventilation (Group 1), and patients tracheostomized due to low level of consciousness or inability to manage secretions (Group 2).

INTERVENTIONS

Patients were weaned and decannulated according to established protocols.

MAIN VARIABLES

We recorded the following variables: time to tracheostomy, forced vital capacity, peak flow, suctioning requirements, Glasgow Coma Score (GCS), characteristics of respiratory secretions, and swallowing function. Statistical analyses included Cox-proportional multivariate analysis with time to decannulation as the dependent variable.

RESULTS

A total of 227 patients were tracheostomized in the ICUs; of these, 151 were finally included in the study. In the multivariate analysis, time to decannulation in Group 1 was associated with the male gender (HR 1.74 (1.04-2.89), p= 0.03), age>60 years (HR 0.58 (0.36-0.91), p= 0.02), high suctioning frequency (HR 0.81 (0.67-0.97), p= 0.02), low forced vital capacity (HR 0.48 (0.28-0.82), p<0.01), and low peak flow (HR 0.25 (0.14-0.46), p<0.01). In Group 2 time to decannulation was associated to GCS >13 (HR 2.73 (1.51-4.91), p<0.01), high suctioning frequency (HR 0.7 (0.54-0.91), p<0.01), and inadequate swallowing (HR 1.97 (1.11-3.52), p=0.02).

CONCLUSION

Variables associated with longer time to decannulation in ICU-tracheostomized patients differ with the indications for tracheostomy.

Retrospective analysis of pathologic response in colorectal cancer liver-only metastases following treatment with bevacizumab

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Background: Recent reports have shown that pathological response predicts for better outcome (overall survival) following preoperative chemotherapy and surgical resection of colorectal cancer (CRC) liver-only metastases. The aim of this retrospective analysis was to evaluate the effect of adding bevacizumab to standard chemotherapy on pathological response in patients with CRC liver only metastases.

Methods: Patients with stage IV CRC with liver metastases who received neoadjuvant chemotherapy (oxaliplatin-or irinotecan-based) at two Spanish centres were analysed retrospectively. Pathological response was evaluated as follows: complete pathological response (cPR), PR1 (25% of residual tumour), PR2 (25–50% of residual tumour), PR3 (>50% of residual tumour). cPR or PR1 was considered to be a good response, and PR2 or PR3 a poor response.

Results: A total of 81 patients were evaluated. Of these, 43 received chemotherapy alone and 38 received chemotherapy plus bevacizumab. Baseline characteristics were as follows: median age 61.0 years (range 43.0–80.0 years); male/female (67%/33%); tumour location – colon (69%) / rectum (31%); hepatic metastases – synchronous (74%) / metachronous (26%); In terms of pathological response, 58% of patients receiving bevacizumab had a good response (cPR + PR1) compared with 28% of those receiving chemotherapy alone. At the end of the analysis, 68% of patients were still alive.

Conclusions: Adding bevacizumab to oxaliplatin-based chemotherapy in the neoadjuvant setting improves the pathological response of liver metastases in patients with stage IV CRC. These findings indicate that pathological response might be a good indicator of outcome for patients receiving bevacizumab in the neoadjuvant setting.

Changes of the nucleolus architecture in absence of the nuclear factor CTCF

CTCF is a multifunctional nuclear factor involved in many cellular processes like gene regulation, chromatin insulation and genomic organization. Recently, CTCF has been shown to be involved in the transcriptional regulation of ribosomal genes and nucleolar organization in Drosophila cells and different murine cell types, including embryonic stem cells. Moreover, it has been suggested that CTCF could be associated to the nucleolus of human erythroleukemic K562 cells. In the present work, we took advantage of efficient small hairpin RNA interference against human CTCF to analyze nucleolar organization in HeLa cells. We have found that key components of the nucleolar architecture are altered. As a consequence of such alterations, an upregulation of ribosomal gene transcription was observed. We propose that CTCF contributes to the structural organization of the nucleolus and, through epigenetic mechanisms, to the regulation of the ribosomal gene expression.

Association of CAPN1 316, CAPN1 4751 and TG5 markers with bovine meat quality traits in Mexico

We examined allele and genotype frequencies for the molecular markers CAPN1 316, CAPN1 4751 and TG5, and determined whether they are associated with beef quality traits in Mexican cattle. One hundred and twenty-four longissimus dorsi muscle samples were collected from cattle from north, central and southern Mexico. CAPN1 316 and CAPN1 4751 frequencies were determined using the allelic discrimination assay and the TG5 marker was typed by PCR-RFLP. Meat quality traits included intramuscular fat content (IMF) and tenderness determined by Warner-Bratzler shear force (WBSF) at 24 h postmortem. The association test was made using a mixed model, including genotypes, genetic group, and sampling location as fixed effects. Least squares means and significant interactions were compared using least significant differences based on the mixed procedure. CAPN1 316 CC was found at a low frequency (0.03) and has been reported as a favorable genotype associated with tenderness meat. Genotype frequencies for CAPN1 4751 were similar in favorable (CC) and unfavorable (TT) genotypes (0.26 and 0.28, respectively). The TG5 CC genotype had a frequency of 0.73, while the TT genotype frequency was 0.01. The means for WBSF and IMF were 4.08 ± 1.35 kg and 5.23 ± 2.14%, respectively. Sampling site and the CAPN1 316 genotypes significantly affected WBSF (P < 0.05). Samples collected from Hermosillo, Sonora, had the lowest WBSF (P < 0.05), while those collected in Veracruz were toughest (WBSF = 5.267 kg). The effect of GG and TG5 genotypes on IMF was significant (P < 0.05). CAPN1 316 and TG5 markers were found to be significantly associated with beef quality traits and thus will be useful for Mexican beef characterization.

Noninvasive ventilation reduces intubation in chest trauma-related hypoxemia: a randomized clinical trial

BACKGROUND

Guidelines for noninvasive mechanical ventilation (NIMV) recommend continuous positive airway pressure in patients with thoracic trauma who remain hypoxic despite regional anesthesia. This recommendation is rated only by level C evidence because randomized controlled trials in this specific population are lacking. Our aim was to determine whether NIMV reduces intubation in severe trauma-related hypoxemia.

METHODS

This was a single-center randomized clinical trial in a nine-bed ICU of a level I trauma hospital. Inclusion criteria were patients with Pao(2)/Fio(2)<200 for >8 h while receiving oxygen by high-flow mask within the first 48 h after thoracic trauma. Patients were randomized to remain on high-flow oxygen mask or to receive NIMV. The interface was selected based on the associated injuries. Thoracic anesthesia was universally supplied unless contraindicated. The primary end point was intubation; secondary end points included length of hospital stay and survival. Statistical analysis was based on multivariate analysis.

RESULTS

After 25 patients were enrolled in each group, the trial was prematurely stopped for efficacy because the intubation rate was much higher in controls than in NIMV patients (10 [40%] vs 3 [12%], P = .02). Multivariate analysis adjusted for age, gender, chronic heart failure, and Acute Physiology and Chronic Health Evaluation II at admission revealed NIMV as the only variable independently related to intubation (odds ratio, 0.12; 95% CI, 0.02-0.61; P = .01). Length of hospital stay was shorter in NIMV patients (14 vs 21 days P = .001), but no differences were observed in survival or other secondary end points.

CONCLUSION

NIMV reduced intubation compared with oxygen therapy in severe thoracic trauma-related hypoxemia.

Malnutrition alters the rates of apoptosis in splenocytes and thymocyte subpopulations of rats

Malnutrition continues to be a major public health problem throughout the developing world. Nutritional deficiencies may be the most common cause of secondary immunodeficiency states in humans. It has been suggested that nutritional imbalances can induce apoptosis in a variety of cell types. The purpose of this study was to examine the effect of severe malnutrition on cell subsets and the frequency of spontaneous and/or dexamethasone-induced cell death in vivo in the thymus and spleen from severely malnourished, lactating rats. Apoptosis frequency was estimated by flow cytometry using annexin-V and terminal transferase-mediated dUTP nick-end labelling assay assays. The results obtained in the present study indicate that malnutrition is associated with a significant increase of spontaneously apoptotic cells in the thymus (9.8-fold) and spleen (2.4-fold). Increase in apoptosis was associated largely with CD4(+)CD8(+) double-positive thymocytes. Unexpectedly, similar frequencies of spontaneous apoptosis of these cells were found in both well-nourished and malnourished rats. In contrast, consistent increases in the apoptosis of CD4(-)CD8(-) double-negative thymocytes were observed in malnourished rats. In addition, single-positive CD8(+) and single-positive CD4(+) thymocytes had higher frequencies of apoptosis in malnourished rats. The frequency of total dexamethasone-induced apoptosis was found to be similar in both groups of animals. Nevertheless, in malnourished dexamethasone-treated animals, the percentage of apoptotic double-negative thymocytes was significantly higher than in well-nourished animals, while the rate of apoptosis was lower among double-positive cells. In general, the thymus appears more sensitive to the effects of malnutrition and dexamethasone than the spleen. Furthermore, double-negative thymocytes appear to be the most affected.