First Measurement of the Nuclear-Recoil Ionization Yield in Silicon at 100 eV

We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a monoenergetic beam scatter off of the silicon nuclei at angles corresponding to energy depositions from 4 keV down to 100 eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100 eV. These results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.

Abstract P5-02-09: Quantitative analysis of fiber-level collagen features in H&E whole-slide images predicts neoadjuvant therapy response in patients with HER2+ breast cancer

Background: Neoadjuvant treatment (NAT) combining chemotherapy and HER2-targeted agents is frequently administered to HER2-positive (HER2+) breast cancer (BC) patients, with some experiencing a pathological complete response (pCR) and others having residual disease measured by the residual cancer burden (RCB) score. Here, we use a physics-guided machine learning (ML)-based approach to extract fiber-level collagen features from hematoxylin and eosin (H&E)-stained whole slide images (WSIs) and identify collagen-related associations with treatment response in HER2+ patients receiving NAT.

Methods: Clinical data and specimens from stage II-III HER2+ BC patients enrolled on the De-escalation to Adjuvant Antibodies Post-pCR to Neoadjuvant THP (DAPHNe; NCT03716180) clinical trial and treated with neoadjuvant paclitaxel/trastuzumab/pertuzumab were analyzed. An ML-based model trained to identify regions of BC tissue as invasive carcinoma, ductal carcinoma in situ (DCIS), diffuse inflammatory infiltrate, stroma, necrosis, or normal tissue was deployed on WSIs of H&E-stained diagnostic core needle biopsies (N=89) to generate tissue overlays. Additional tissue areas were computed from the tissue model predictions using heatmap transformation, including tumor nests (continuous regions predicted as invasive cancer epithelium or DCIS), tumor nest borders (stromal region boundaries 10 μm from tumor nests), and bulk tumor borders (stromal region boundaries 300 μm from aggregated tumor nests). A separate ML-based model trained to identify fiber-level collagen features in WSIs of H&E-stained specimens was also deployed to generate collagen overlays. A fiber feature extraction pipeline was utilized to characterize properties of all identified collagen fibers in the WSI (on the order of hundreds of thousands per slide), including length, width, tortuosity, and angle. These fiber features were then assessed based on their position within the tumor (e.g. relative to the tumor nest border). Combinatorial features (e.g. angle of fibers with respect to tumor boundary) were then explored univariately for associations (N=609) with treatment response. Patients with pCR (RCB=0; N=53) were considered responders, while all other cases (RCBI-III; N=36) were designated non-responders. Due to the small size of the cohort analyzed here, raw p-values are reported.

Results: Using estrogen receptor status as a clinical covariate, a logistic regression-based univariate analysis of 609 collagen-associated features revealed six features to strongly associate with pCR (p< 0.05, AUC≥0.75; Table 1). Notable feature themes were identified: 1) fiber tortuosity in tumor nest borders and tumor borders, 2) angle of fibers in tumor border with respect to tumor boundary, and 3) distribution patterns of fiber width in tumor nest borders. The presence of fibers perpendicular to tumor boundary tangents was negatively associated with pCR, as was higher fiber tortuosity and thickness in tumor nest borders.

Conclusions: Improved prediction of response to NAT in patients with BC is needed to determine appropriate treatment strategies for each patient. Here, using ML-based models to identify tissue features and collagen fibers, we identify collagen-associated features, measured directly from WSIs of H&E-stained diagnostic BC biopsies, that negatively correlate with pCR. Additional development of this strategy, including the addition of cell identification models and known clinical information, is underway to further refine this novel predictive model.

Development of machine learning–powered models for prostate cancer HRD prediction

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Background: In prostate cancer, homologous recombination deficiency (HRD) is associated with poor prognosis, and sensitivity to DNA damaging agents and DNA damage repair (DDR) inhibitors. As new classes of DDR inhibitors become available, identifying patients with HRD will be critical for treatment selection. Here, we present machine learning (ML)-based models trained to predict HRD status directly from hematoxylin and eosin (H&E) whole slide images (WSI). Methods: ML models were trained to predict and segment cells and tissue regions within the tumor microenvironment (TME) using annotated (N=91,021 annotations) WSI of H&E-stained resections from the cancer genome atlas prostate adenocarcinoma (TCGA PRAD) dataset (N=401) and needle core biopsies from a proprietary dataset (N=1,000). Quantified Human Interpretable Features (HIFs) that describe the TME composition were extracted. Three models were trained to predict HRD status using 373 WSI with known HRD score (TCGA PRAD; train N=259, validation N=76, and test N=38). Two models used input from the TME model: An HIF multivariate logistic regression model, and a graph neural network (GNN) where predictions are based on the complex spatial relationships within the TME. An end-to-end (E2E) multiple instance learning model predicted directly from the WSI. Two cutoffs for HRD were defined using Gaussian Mixture Models, resulting in 99 WSI (train N=72, validation N=18, and test N=9) positive for the Genomic Instability (>16 events) cutoff, and 58 WSI (train N=44, validation N=10, test N=4) positive for the Genomic Instability (>22 events) cutoff. An independent validation set of 45 biopsies and 16 resections from a biobank of metastatic castration resistant prostate cancer with HRD status determined by whole-exome sequencing was compared to ML model H&E-based HRD prediction. Results: In the TCGA test set of resection samples, all three models moderately or strongly predicted HRD status, with the HIF model showing the best performance (AUROC 0.87, sensitivity 0.88, specificity 0.62). The same HIF model performed equally well (AUROC 0.85, Sensitivity 0.93, specificity 0.67) in the resection samples from the independent validation set. However, the model performance went down (AUROC 0.69, sensitivity 0.91, specificity: 0.3) when both resection and needle biopsy samples were included, highlighting the importance of a representative training set to achieve robust performance in a real world setting. Further model training and validation with a more diverse dataset is required to accurately assess the performance of the model on needle biopsies. Conclusions: ML models trained on resection prostate cancer samples performed well in predicting HRD status when applied to the same sample type, demonstrating the potential of ML models to predict genomic biomarkers status in surgical specimens for treatment decision.

Constraints on Lightly Ionizing Particles from CDMSlite

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e/(3×10^{5}), as well as the strongest limits for charge ≤e/160, with a minimum vertical intensity of 1.36×10^{-7}  cm^{-2} s^{-1} sr^{-1} at charge e/160. These results apply over a wide range of LIP masses (5  MeV/c^{2} to 100  TeV/c^{2}) and cover a wide range of βγ values (0.1-10^{6}), thus excluding nonrelativistic LIPs with βγ as small as 0.1 for the first time.

Light Dark Matter Search with a High-Resolution Athermal Phonon Detector Operated above Ground

We present limits on spin-independent dark matter-nucleon interactions using a 10.6 g Si athermal phonon detector with a baseline energy resolution of σ_{E}=3.86±0.04(stat)_{-0.00}^{+0.19}(syst)  eV. This exclusion analysis sets the most stringent dark matter-nucleon scattering cross-section limits achieved by a cryogenic detector for dark matter particle masses from 93 to 140  MeV/c^{2}, with a raw exposure of 9.9 g d acquired at an above-ground facility. This work illustrates the scientific potential of detectors with athermal phonon sensors with eV-scale energy resolution for future dark matter searches.

Understanding young peoples' and family members' views of treatment for first episode psychosis in a randomised controlled trial (MAPS)

BACKGROUND

There is limited evidence to inform treatment decision-making in adolescents experiencing first episode psychosis (FEP). In the MAPS trial (Managing Adolescent first Episode Psychosis: a feasibility Study), adolescents with FEP received either antipsychotic medication (AP), psychological intervention (PI), or both. We investigated treatment views of young people and family members across each treatment arm of MAPS.

METHODS

Thirteen adolescents participating in MAPS and eighteen family members attended in-depth audio-recorded interviews to discuss trial treatments. Interviews were analysed using inductive Thematic Analysis, identifying salient themes across these accounts.

FINDINGS

Family members in particular reported an urgent need for treatment regardless of type. Both AP and PI were broadly viewed as acceptable treatment approaches, but for differing reasons which participants weighed against a range of concerns. AP were often seen to reduce symptoms of psychosis, though participants expressed concerns about side effects. PI were viewed as interactive treatment approaches that helped improve understanding of psychosis and enhanced coping, although some found PI emotionally and cognitively challenging. Combining treatments was seen to maximise benefits, with a perceived interaction whereby AP facilitated engagement with PI.

INTERPRETATION

Acceptability of and engagement with treatments for FEP may differ between individual young people and their family/carers. In order to be able to offer fully informed choices, and determine an optimum treatment approach for young people with FEP, definitive trial evidence should be established to determine wanted and unwanted treatment impacts.

FUNDING

NIHR HTA programme (project number 15/31/04).

Erratum: First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector [Phys. Rev. Lett. 121, 051301 (2018)]

This corrects the article DOI: 10.1103/PhysRevLett.121.051301.

First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector

We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 g CDMS high-voltage device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1  MeV/c^{2}. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 g d). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.

Results from the Super Cryogenic Dark Matter Search Experiment at Soudan

We report the result of a blinded search for weakly interacting massive particles (WIMPs) using the majority of the SuperCDMS Soudan data set. With an exposure of 1690 kg d, a single candidate event is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4×10^{-44} (1.0×10^{-44})  cm^{2} at 46  GeV/c^{2}. These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12  GeV/c^{2}.

New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment

The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5  GeV/c^{2}.

First direct limits on lightly ionizing particles with electric charge less than e/6

While the standard model of particle physics does not include free particles with fractional charge, experimental searches have not ruled out their existence. We report results from the Cryogenic Dark Matter Search (CDMS II) experiment that give the first direct-detection limits for cosmogenically produced relativistic particles with electric charge lower than e/6. A search for tracks in the six stacked detectors of each of two of the CDMS II towers finds no candidates, thereby excluding new parameter space for particles with electric charges between e/6 and e/200.

Hexagonal magnetite nanoprisms: preparation, characterization and cellular uptake

Nearly perfect hexagonal Fe₃O₄ nanoplatelet structures, with edge length of 45 ± 5 nm and thickness of 5 to 6 nm were synthesized from iron(iii) acetylacetonate using the dual ligand system oleic and stearic acid.

Search for low-mass weakly interacting massive particles with SuperCDMS

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30  GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42)  cm(2) at 8  GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6  GeV/c(2).

Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170  eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6  GeV/c2.

Silicon detector dark matter results from the final exposure of CDMS II

We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41(-0.08)(+0.20)(stat)(-0.24)(+0.28)(syst). Other known backgrounds from neutrons and 206Pb are limited to <0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7-100 keV for a WIMP of mass 10  GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6  GeV/c2 and WIMP-nucleon cross section of 1.9×10(-41)  cm2.

Results from a low-energy analysis of the CDMS II germanium data

We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10  GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9  GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.

Search for axions with the CDMS experiment

We report on the first axion search results from the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. An energy threshold of 2 keV for electron-recoil events allows a search for possible solar axion conversion into photons or local galactic axion conversion into electrons in the germanium crystal detectors. The solar axion search sets an upper limit on the Primakov coupling g(agammagamma) of 2.4x10(-9) GeV-1 at the 95% confidence level for an axion mass less than 0.1 keV/c2. This limit benefits from the first precise measurement of the absolute crystal plane orientations in this type of experiment. The galactic axion search analysis sets a world-leading experimental upper limit on the axioelectric coupling g(aee) of 1.4x10(-12) at the 90% confidence level for an axion mass of 2.5 keV/c2.

Search for weakly interacting massive particles with the first five-tower data from the cryogenic dark matter search at the soudan underground laboratory

We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October 2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10;{-44} cm;{2} (4.6x10;{-44} cm;{2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c;{2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c;{2}, and significantly restricts the parameter space for some favored supersymmetric models.

Limits on spin-independent interactions of weakly interacting massive particles with nucleons from the two-tower run of the cryogenic dark matter search

We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 (12) kg d for the Ge (Si) targets after cuts, averaged over recoil energies 10-100 keV for a weakly interacting massive particle (WIMP) mass of 60 GeV/c2. A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1.6 x 10(-43) cm2 from Ge and 3 x 10(-42) cm2 from Si, for a WIMP mass of 60 GeV/c2. The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results and constrains predictions of supersymmetric models.

Response of serum macrophage migration inhibitory factor levels to stimulation or suppression of the hypothalamo-pituitary-adrenal axis in normal subjects and patients with Cushing's disease

Macrophage migration inhibitory factor (MIF) is a proinflammatory pituitary and immune cell cytokine and a critical mediator of septic shock. It has been reported that MIF is secreted in parallel with ACTH from the pituitary in response to stress or inflammatory stimuli. MIF release from immune cells is also induced rather than inhibited by glucocorticoids. It has therefore been suggested that MIF may be a novel counterregulatory hormone of glucocorticoid action that acts both as a paracrine and endocrine modulator of host responses. We have measured circulating MIF levels, using a human MIF ELISA, in normal subjects and patients under numerous pathophysiological conditions. Serum MIF was measured in normal subjects who underwent stimulation of the hypothalamo-pituitary-adrenal axis with an insulin tolerance test (n = 8), a CRH-stimulation test (n = 5), a short synacthen test (n = 5), and following a low-dose dexamethasone suppression test (n = 6). We also sampled from a peripheral vein and both inferior petrosal sinuses before and after CRH stimulation in four patients with a histologically proven diagnosis of Cushing's disease. Immunostaining of the pituitary tumors for MIF was also performed. In normal subjects serum MIF levels did not rise in parallel with cortisol during the insulin tolerance or CRH test or after administration of synthetic ACTH. In all subjects cortisol levels became undetectable after the low-dose dexamethasone suppression test, and no consistent change was observed in serum MIF levels during the test. In patients with Cushing's disease, there was no basal central-to-peripheral gradient in MIF, and no consistent changes occurred in serum MIF levels in either the left or right inferior petrosal sinus after CRH stimulation; however, immunostaining of the surgically removed pituitary tumors from the same patients showed strong staining for both ACTH and MIF. These results show that in humans acute modulation of the hypothalamo-pituitary-adrenal axis does not significantly alter circulating MIF levels. In addition, ACTH-secreting pituitary tumors that express MIF do not release MIF either spontaneously or in response to CRH stimulation, and there is no gradient for MIF in the venous drainage of the pituitary. Our study suggests that the pituitary gland is not the major contributor to circulating MIF; an autocrine or paracrine role for pituitary-derived MIF is more likely.

Residency training in dental public health: assessment of status, needs, and issues

The opportunities for public health training have declined over the years while the need for public health skills is likely to increase. This paper reports the results of a project, sponsored by the Health Resources and Services Administration, which answers the question of "how best to invest in the dental public health education system so as to fulfill the profession's responsibilities to protect and improve the oral health of individuals and society." An information base on dental public health education, practice, and specialization was developed from an extensive review of the literature and a survey of dentists concerning employment and practice requirements for public health dentists. An advisory group considered this information, met to discuss the issues involved in dental public health training, and provided advice to the project staff. Based on the information gathered as part of the project, recommendations were made to: (1) develop a grant program to support advanced education in dental public health; (2) increase the competencies of dentists who are working in public health positions and not eligible for board certification via off-site residencies; (3) develop model programs in areas of great need, such as general public health, management, policy, prevention, environmental health and research, that in conjunction with a basic public health core, could satisfy the eligibility requirements of the American Board of Dental Public Health; (4) develop student loan forgiveness programs for dentists and dental hygienists working in public health; and (5) develop additional credential recognition programs for dental public health workers.

Further characterization of the tracheal receptor for Pseudomonas aeruginosa

The purpose of this study was to obtain more information on the nature of the macromolecule to which Pseudomonas aeruginosa adheres. Acid-injured tracheal epithelium was treated with trypsin or lipase to determine whether the receptor molecule was a protein or a lipid. Lipase treatment significantly reduced adherence to these cells, whereas trypsin had no effect. Since the receptor appeared to be a lipid containing sialic acid, gangliosides were used to test whether they would inhibit adherence. Crude ganglioside preparations inhibited adherence in a dose-dependent manner when added to the bacteria before exposure to tracheal cells. Lastly, fibronectin, which presumably binds to gangliosides, significantly reduced the adherence of these organisms. According to these findings Pseudomonas aeruginosa appears to adhere to a sialic acid-containing glycolipid on cell surfaces, probably a ganglioside.

Role of pili in the adherence of Pseudomonas aeruginosa to injured tracheal epithelium

Pili have been demonstrated to be the adhesins of nonmucoid Pseudomonas aeruginosa for buccal cells. In this study, we examined their role in the adherence of both mucoid and nonmucoid strains to injured tracheal cells. Pili incubated with tracheal cells inhibited the adherence of a nonmucoid strain in a dose-dependent manner. Both homologous and heterologous pili inhibited this nonmucoid strain. Antibody against pili from the nonmucoid strain inhibited adherence of the homologous but not a heterologous strain. Pili failed to inhibit two mucoid strains, but inhibited nonmucoid variants derived from mucoid strains. These studies suggest that pili mediate the adherence of nonmucoid strains to injured tracheal cells but that they are not the final mediators of adherence of mucoid strains. It is also inferred that there are differences in the receptor for mucoid and nonmucoid strains.

Evidence for mucins and sialic acid as receptors for Pseudomonas aeruginosa in the lower respiratory tract

The nature of the receptors for mucoid and nonmucoid Pseudomonas aeruginosa was investigated by using adherence to injured tracheal epithelium as a model. Bovine submaxillary mucin and crude rat tracheal mucin inhibited the adherence of both types of P. aeruginosa. Among the sugars present in these mucins only N-aceylneuraminic acid inhibited adherence. Inhibition of adherence probably involved the binding of N-acetylneuraminic acid to the bacterial cells and not to the tracheal cells. The mucoid strain appeared to be much more sensitive to inhibition by N-acetylneuraminic acid. Periodate oxidation and cholera filtrate also reduced the adherence of both strains, but Clostridium perfringens neuraminidase treatment did not alter adherence. A nonmucoid isogenic mutant of an unstable mucoid strain was also inhibited by N-acetylneuraminic acid. These data suggest that the receptor for P. aeruginosa is a sialic acid moiety on cell surfaces or in mucins.

Adherence of mucoid and nonmucoid Pseudomonas aeruginosa to acid-injured tracheal epithelium

A model of the adherence of Pseudomonas aeruginosa to injured lower respiratory tract cells is described. Mouse tracheas were injured by exposure to 0.1 N HCl for 15 min, cut into pieces of 2 to 4 rings, and placed in petri dishes for adherence studies. Adherence was quantitated by direct count of the number of bacteria attached to a fixed surface area as viewed by scanning electron microscopy. Optimal conditions for study were 1 h of incubation with an inoculum of 10(7) to 10(8) CFU/ml. Both mucoid and nonmucoid P. aeruginosa adhered to the injured cells in this system, and no major differences in adherence between these strains was apparent. Adherence to injured tracheal cells was a phenomenon limited to P. aeruginosa and did not occur with Escherichia coli and Klebsiella pneumoniae. Besides adherence to injured cells, this model allowed the demonstration of adherence of mucoid P. aeruginosa and K. pneumoniae to mucin strands of uninjured control tracheas. This model is an alternative to the buccal cell model and has the advantage of allowing the study of the adherence of both mucoid and nonmucoid strains of P. aeruginosa.