Direct observation of electrons in microwave vacuum components

Apparatus which is used to directly observe electrons in microwave vacuum components was designed and implemented into a WR-284 like waveguide operated at 2.85 GHz with up to approx. 1 MW power. To generate desired electric field levels for driving secondary emission, the waveguide structure is manipulated by reducing the test section height to 6 mm from the standard WR-284 rectangular waveguide height of 34 mm. Both test and standard sections were operated in the dominant TE₁₀ mode. A 1 mm aperture was cut into the broadside wall of the waveguide section enabling a portion of electrons in the waveguide to enter a properly biased electron multiplier tube mounted atop of the test section. Waveforms are presented showing the direct measurement of electrons, providing a local detection method with nanosecond temporal resolution. Future work will incorporate the test setup for multipactor studies.

Abstract P6-09-04: Predictive factors for considering to avoid axillar lymphadenectomy in selected node positive breast cancer patients after neoadjuvant chemotherapy

Background:

To perform a systematic axillar lymphadenectomy (ALND) in clinical node positive (N+) patients after neoadjuvant chemotherapy (NACT) is currently under discussion. We aimed to study which factors are related to a pathological complete axillar response (ypN0) after NACT in order to select which patients could benefit from a sentinel lymph node biopsy without interfering with survival.

Material and methods

N+ patients who underwent ALND after NACT between June 2008 and December 2016 were retrospectively analyzed. Clinical features, molecular and histological factors, recurrence and specific mortality rates were compared between patients achieving a complete pathological axillary response vs not (ypN0 vs ypN+).

Results

345 N+ patients were reviewed. After NACT, 137 (39.6%) become ypN0[CF1] , 9 (2.6%) ypN1 mic, 113 (32.7%) ypN1, 60 (17.3%) ypN2 and 22 (6.4%) N3. Univariate analysis results regarding the predictive factors for ypN0 are detailed in [table 1]. Multivariate analyses showed molecular subtype (TN and Her2+) and clinical response as independent predictors of ypN0 [table 2]. After a mean follow-up of 58 months, overall survival was statistically superior in ypN0 vs ypN1 (p= 0.001).

Table 1.Predictive factors for ypN0 YpN0 (n = 137)YpN+ (n = 208)pAge (mean, years)58.3 ± 13.2758.59 ± 12.340.799BMI (mean)27.8±5.4927.8±5.360.973Dosis of QT (median)(%)  0.575IIA6 (31.6)13 (68.4) IIB71 (39.3)110 (60.8) IIIA28 (36.8)48 (63.2) IIIB24 (43.6)31 (56.4) IIIC7 (58.3)5 (41.7) Radiological image(%)  0.930Nodule77 (38.1)125 (61.9) Non-mass distortion10 (43.5)13 (56.5) Radiological size (median)32 (0-115)29 (0-130)0.246Suspicious a-LN by US(%)  0.486130 (30.9)37 (24.3) 25 (5.2)14 (9.2) >257 (58.8)91 (59.9) Histological subtype(%)  0.093Invasive Ductal Carcinoma133 (40.9)192 (59.1) Invasive Lobular Carcinoma2 (20)8 (80) Others2 (22.2)7 (78.8) Nottingham grade(%)  <0.001G11 (6.2)15 (93.8) G244 (28.6)110 (71.4) G386 (53.4)75 (46.6) Molecular-like subtype(%)  <0.001Luminal A-like2 (5.3)36 (94.7) Luminal B-like (Her2 -)21(18.1)95 (81.9) Luminal B-like (Her2 +)40 (63.5)23 (36.5) HER-2 enriched (non luminal)43 (74.1)15 (25.9) Triple Negative31 (44.9)38 (55.1) Vascular invasion19 (42.2)26 (57.8)0.889Clinical Response(%)  <0.001Complete61 (75.3)20 (24.7) Partial69 (31.8)148 (68.2) No response6 (20.7)23 (79.3) Progression1 (10)9 (90) Percentage are given per row.

Table 2.Multivariate analysis logistic regression of clinical predictive factors of ypN0. OR95% Confidence Intervalp valueMolecular subtype   No-luminal vs Luminal7,7483,913-15,343<0,001Clinical response   Response vs not response6,8491,834-25,5710,04OR: Odd ratio. No-luminal includes: luminal B (HER2 +), HER2 Henriched and triple negative. Luminal includes: Luminal A and Luminal B (HER2 -).

Conclusions

A remarkable percentage of N+ became ypN0 after NATC. Molecular subtype and complete clinical response were independent predictive factors of ypN0. We propose to offer the benefit of a targeted axillary procedure in those patients.

Citation Format: Fernandez-Gonzalez S, Falo Zamora C, Nuñez D, Vethencourt A, Pla MJ, Soler T, Guma A, Perez X, Gil M, Ponce J, Garcia A. Predictive factors for considering to avoid axillar lymphadenectomy in selected node positive breast cancer patients after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-04.

Abstract P2-08-58: Prognostic factors of survival in node positive breast cancer patients after neoadjuvant chemotherapy in a large series after 5y follow-up: Can response overcome the poor prognosis of nodal stage?

Background: Status of the axilla is one of the most significant prognostic factors in breast cancer (BC) patients. On the other hand, response to neoadjuvant chemotherapy (NACT) is related to survival. The aim of the present study is to analyze which prognostic factors impact most on Node positive (N+) BC patient survival after NATC. Material and methods: Retrospective analyses on a series of N+ BC patients treated with NATC based on anthracyclines and taxanes +/- trastuzumab if HER2 positive tumors, between June 2008 and December 2016. Clinical, radiological and pathological outcomes have been evaluated. Residual cancer burden (RCB) 1 and the neoadjuvant response index (INR) 2 have been recorded. Survival was calculated with Kaplan-Meier survival curve since the start of NATC to the first documented disease recurrence (DFS) or death (OS). Hazard ratios (HRs) with 95% CIs were estimated with cox proportional hazards regression analysis and subgroups were compared with a two-sided log-rank test. Results: A total of 345 N+ BC patients were included. Pathological complete response was achieved in 72 (20.8%) patients. After NACT, 137 (39.6%) become ypN0, 9 (2.6%) ypN1 mic, 113 (32.7%) ypN1, 60 (17.3%) ypN2 and 26 (7.6%) N3. Those independent predictive factor of ypN0 were molecular subtype (TN and Her2+) with OR: 7.7, p<0.001 and clinical response with OR 6.88, p: 0.04. At a mean follow-up of 58 months there have been 73 (21.1%) recurrences: 9 (2.3%) local, 45 (13%) systemic, 15 (4.3%) systemic+ local, 3 (0.9%) axilla, 1 (0.3%) supraclavicular. The estimated 5y OS was 87.8%. The univariate analysis according to DSF is detailed in Table1.

Adjusted univariate anaalysis cox regression of clinical and pathological factors of desease free survivalBMI10.989-1.010.963AGE0.9960.953-1.0420.876Dose NATC0.9940.979-1.0080.402Clinical Stage1.4021.077-1.8260.012Rx Image1.260.803-1.9940.311Rx size1.0090.995-1.0240.217Number suspicious ALN1.0950.801-1.4970.57Molecular subtype TN,HER20.8800.534-1.450.616Nottinghan grade1.0460.753-1.4530.789Histological subtype1.4651.044-2.0570.27MOlecular subtype1.1510.956-1.3850.137Vascular invasion1.6761.137-24710.009Clinical response2.3691.709-3.284<0.001Fibrosis tumor bed0.980.972-0.989<0.001Nodal fibrosis>50%1.7950.874-3.6860.111Pathological tumoral response1.6861.175-2.4180.005ypN03.561.853-6.838<0.001NRI0.330.192-0.565<0.001RCB1.2741.106-1.4680.001

In the multivariate model those parameters that were independently prognostic were clinical response HR: 5.44 (IC95% 2.275-13.042, p<0.001) and clinical stage HR: 2.364 (IC95% 1.018-5.490, p: 0.045). Conclusions: The most significant prognostic factor in our N+ series was response to NATC, followed by clinical stage. Those independently predictive factors of axillar response (ypN0) were molecular subtype (TN and Her2+) and clinical response. In conclusion, in those patients with chemo sensitive tumors, lymphadenectomy could be safely spared with a more selective axillary approach.

Citation Format: Fernandez S, Garcia A, Vethencourt A, Vazquez S, Petit A, Pla MJ, Ortega R, Pérez J, Gil M, Ponce J, Pernas S, Lopez A, Falo C. Prognostic factors of survival in node positive breast cancer patients after neoadjuvant chemotherapy in a large series after 5y follow-up: Can response overcome the poor prognosis of nodal stage? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-58.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Evaluation of large clinically atypical vulvar pigmentation with RCM: atypical melanosis or early melanoma?

BACKGROUND

Vulvar melanosis can occasionally be clinically challenging by mimicking an early melanoma.

OBJECTIVE

To report our experience of initial evaluation and follow-up in this peculiar subset of vulvar melanosis using reflectance confocal microscopy (RCM).

METHODS

We retrospectively evaluated 18 consecutive cases referred for atypical vulvar pigmentation or for which melanoma was considered and that underwent both RCM examination and histopathological assessment. In 13 cases with available dermoscopic pictures, RCM classification was compared to dermoscopic diagnosis, and in all cases, the density of melanocytes was evaluated on biopsies using MelanA immunostaining.

RESULTS

Among the 18 atypical pigmented lesions, 17 vulvar melanosis and one melanoma were histologically determined. RCM concluded a benign vulvar melanosis in 10 of 17 cases, whereas dermoscopy did so in three of 12 cases. RCM identified the only early malignant lentiginous melanoma. In several cases of vulvar melanosis, RCM could identify foci of melanocytic hyperplasia in an otherwise benign pattern.

CONCLUSIONS

In this clinically and dermoscopically challenging subset of vulvar pigmentations, RCM appears relevant for initial extensive evaluation, especially to target initial biopsy sampling, and to perform non-invasive monitoring of foci of melanocytic hyperplasia.

Determinants of primary healthcare seeking behaviours for children during the first 18 months of life in Benin

Background

Primary healthcare is a key element of management of childhood illness in Africa. The objectives were to identify primary care seeking determinants among infants and young children up to 18 mo in a birth cohort from Benin.

Methods

From 2007 to 2009 in Benin, a birth cohort was followed until the age of 18 mo in three health centres. Multilevel Poisson regression models were fitted to identify the factors related to the monthly number of consultations. Maternal and newborn characteristics and infant general health parameters were considered.

Results

A total of 566 children were followed. On average, 0.46 consultations per month per child were recorded. The number of consultations was significantly lower after the first 6 mo of life (p<0.001). A distance >1000 m was associated with fewer consultations (p=0.01). Primiparity was significantly associated with higher care seeking (relative risk 1.17 [95% CI 1.05 to 1.30], p<0.01). No child characteristics at birth were significantly associated with the number of consultations (all p>0.16).

Conclusions

Development of health structures and improvement of access remain important goals for strengthening of the primary care health system. Studying factors of care seeking behaviour, like parity, can help to identify women more prone to seek care for their child during the first year of life.

Prevention of Highly Emetogenic Chemotherapy-Induced Vomiting: A Double Blind, Randomized Crossover Study to Compare Pancopride (LAS 30451) and Pancopride plus Dexamethasone

Aims

Pancopride (PNC) is a new 5HT3 receptor antagonist which has demonstrated complete protection from nausea and vomiting in 25-73% of patients treated with highly emetogenic chemotherapy. A double-blind, randomized crossover study was carried out to assess whether the addition of dexamethasone (DXM) to PNC increases the antiemetic efficacy.

Methods

PNC (0.2 mg/kg. i.v. 30 min before chemotherapy) plus placebo (PLC) was compared with PNC (same dose and schedule) plus DXM (20 mg. i.v. immediately before PNC). In the second cycle, patients received the alternative antiemetic treatment. Eighty patients were included in the study (PNC+DXM=39, PNC+PLC=41), 29 of whom were women and 51 men. Fifty-four percent of the patients in the PNC+DXM group and 59% of those in the PNC+PLC group received chemotherapy containing cisplatin. Seventy-seven patients completed the first cycle and 70 the second.

Results

Complete protection was obtained in 19/16 patients (50/46%) with PNC+PLC and in 32/22 (82/63%) with PNC+DXM (P<0.001). Latency was significantly longer in the PNC+DXM group. The efficacy of both treatments was unaffected by the order of administration. Side effects were mild in both groups.

Conclusions

The combination of PNC+DXM is more efficacious than PNC+PLC in protection against highly emetogenic chemotherapy-induced vomiting.

Correlation of the Glomerular Filtration Rate Measured With the Use of DTPA-Tc99m in Live Kidney Donors With Equations Based on Creatinine and Cystatin C

BACKGROUND

Renal donation leads to a risk of developing chronic kidney disease, with an incidence of 0.47%. To evaluate for its presence, formulas based on serum creatinine are used, but up to 80% of these formulas underestimate the glomerular filtration rate (GFR) in donors. The aim of this work was to confirm the highest correlation of the GFR as measured with the use of DTPA-Tc99m with the GFR as estimated by means of the formula based on serum cystatin C (CKD-EPI creatinine-cystatin C) in healthy kidney donors.

METHODS

In this observational, analytic, cross-sectional study, the GFR of kidney donors was determined ≥1 year after donation by means of DTPA gammagram and estimation with the use of conventional formulations and with cystatin C.

RESULTS

Of 112 donors, 38 (34%) were included, 20 (60%) were female, with an overall average age of 40 years, 36.5 months after donation, and body mass index of 25.5 kg/m². Correlation with the GFR as measured by means of DTPA gammagram was better with the use of CKD-EPI cystatin C (0.402; P = .020) and CKD-EPI creatinine-cystatin (0.549; P < .001) than the conventional formulas. Linear correlation with serum cystatin C was 0.825 (P < .001; 95% confidence interval, -105.3 to -63.2) for the CKD-EPI cystatin C formula, 0.77 (P < .001; -89.9 to -48.1) for the CKD-EPI creatinine-cystatin formula, and 0.525 (P = .002; -91.1 to -23.2) for DTPA-Tc99m scintigraphy.

CONCLUSIONS

There is a strong correlation between estimate the GFR by equations based on cystatin C and the measurement of the GFR by DTPA-Tc99m gammagram.