Glass-Like Phonon Dynamics and Thermal Transport in a GeTe Nano-Composite at Low Temperature

In this work, the experimental evidence of glass-like phonon dynamics and thermal conductivity in a nanocomposite made of GeTe and amorphous carbon is reported, which is of interest for microelectronics, and specifically phase change memories. It is shown that, the total thermal conductivity is reduced by a factor of three at room temperature with respect to pure GeTe, due to the reduction of both electronic and phononic contributions. This latter, similarly to glasses, is small and weakly increasing with temperature between 100 and 300 K, indicating a mostly diffusive thermal transport and reaching a value of 0.86(7) Wm-1K-1 at room temperature. A thorough investigation of the nanocomposite's phonon dynamics reveals the appearance of an excess intensity in the low energy vibrational density of states, reminiscent of the Boson peak in glasses. These features can be understood in terms of an enhanced phonon scattering at the interfaces, due to the presence of elastic heterogeneities, at wavelengths in the 2-20 nm range. The findings confirm recent simulation results on crystalline/amorphous nanocomposites and open new perspectives in phonon and thermal engineering through the direct manipulation of elastic heterogeneities.

Therapeutically targeting type I interferon directly to XCR1+ dendritic cells reveals the role of cDC1s in anti-drug antibodies

Conventional type 1 dendritic cells (cDC1s) are superior in antigen cross-presentation and priming CD8+ T cell anti-tumor immunity and thus, are a target of high interest for cancer immunotherapy. Type I interferon (IFN) is a potent inducer of antigen cross-presentation, but, unfortunately, shows only modest results in the clinic given the short half-life and high toxicity of current type I IFN therapies, which limit IFN exposure in the tumor. CD8+ T cell immunity is dependent on IFN signaling in cDC1s and preclinical studies suggest targeting IFN directly to cDC1s may be sufficient to drive anti-tumor immunity. Here, we engineered an anti-XCR1 antibody (Ab) and IFN mutein (IFNmut) fusion protein (XCR1Ab-IFNmut) to determine whether systemic delivery could drive selective and sustained type I IFN signaling in cDC1s leading to anti-tumor activity and, in parallel, reduced systemic toxicity. We found that the XCR1Ab-IFNmut fusion specifically enhanced cDC1 activation in the tumor and spleen compared to an untargeted control IFN. However, multiple treatments with the XCR1Ab-IFNmut fusion resulted in robust anti-drug antibodies (ADA) and loss of drug exposure. Using other cDC1-targeting Ab-IFNmut fusions, we found that localizing IFN directly to cDC1s activates their ability to promote ADA responses, regardless of the cDC1 targeting antigen. The development of ADA remains a major hurdle in immunotherapy drug development and the cellular and molecular mechanisms governing the development of ADA responses in humans is not well understood. Our results reveal a role of cDC1s in ADA generation and highlight the potential ADA challenges with targeting immunostimulatory agents to this cellular compartment.

Commensal bacteria and fungi differentially regulate tumor responses to radiation therapy

Studies suggest that the efficacy of cancer chemotherapy and immunotherapy is influenced by intestinal bacteria. However, the influence of the microbiome on radiation therapy is not as well understood, and the microbiome comprises more than bacteria. Here, we find that intestinal fungi regulate antitumor immune responses following radiation in mouse models of breast cancer and melanoma and that fungi and bacteria have opposite influences on these responses. Antibiotic-mediated depletion or gnotobiotic exclusion of fungi enhances responsiveness to radiation, whereas antibiotic-mediated depletion of bacteria reduces responsiveness and is associated with overgrowth of commensal fungi. Further, elevated intratumoral expression of Dectin-1, a primary innate sensor of fungi, is negatively associated with survival in patients with breast cancer and is required for the effects of commensal fungi in mouse models of radiation therapy.

A phase 1 study of veliparib, a PARP-1/2 inhibitor, with gemcitabine and radiotherapy in locally advanced pancreatic cancer

Background

Locally advanced pancreatic cancer (LAPC) has a dismal prognosis with current treatment modalities and one-third of patients die from local progression of disease. Preclinical studies with orthotopic PC demonstrated dramatic synergy between radiotherapy (RT) and the poly(ADP-ribose) polymerase-1/2 inhibitor (PARPi), veliparib. We conducted a phase I trial of gemcitabine, radiotherapy and dose-escalated veliparib in LAPC.

Methods

This was a single institution investigator-initiated open-label, single-arm phase 1 clinical trial (NCT01908478). Weekly gemcitabine with daily IMRT and veliparib dose escalated using a Bayesian adaptive design were administered in treatment naïve LA or borderline resectable PC. The primary end point was identification of the MTD. Secondary endpoints included efficacy, characterization of PAR levels using ELISA, DDR alterations with targeted next generation sequencing and transcriptome analysis, tumor mutation burden (TMB) and microsatellite instability (MSI) status.

Findings

Thirty patients were enrolled. The MTD of veliparib was 40 mg BID with gemcitabine 400 mg/m² and RT (36 Gy/15 fractions). Sixteen DLTs were identified in 12 patients. Grade ≥ 3 adverse events included lymphopenia (96%) and anemia (36%). Median OS for all patients was 15 months. Median OS for DDR pathway gene altered and intact cases was 19 months (95% CI: 6.2–27.2) and 14 months (95% CI: 10.0–21.8), respectively. There were no significant associations between levels of PAR, TMB, or MSI with outcomes. The DDR transcripts PARP3 and RBX1 significantly correlated with OS.

Interpretation

This is the first report of a PARPi-chemoradiotherapy combination in PC. The regimen was safe, tolerable at the RP2D, and clinically active as an upfront treatment strategy in patients biologically unselected by upfront chemotherapy. Expression of the DDR transcripts, PARP3 and RBX1, were associated with OS suggesting validation in a follow up phase 2 study.

Fund

Phase One Foundation; National Institutes of Health [1R01CA188480-01A1, P01 CA098912]. Veliparib was provided by Abbvie.

Combined chemoradiotherapy and PARP inhibition in pancreatic cancer to induce a synchronous inflammatory cytokine response

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Background: Outcomes remain poor for patients with locally advanced pancreas cancer despite advances in combined modality therapy. Radiation and chemotherapy remain the mainstay of treatment for unresectable locally advanced pancreas cancer, and the addition of various agents is currently being assessed in clinical trials. There is increasing evidence that local inflammation and host immune response play a role in anti-tumor activity. We aimed to assess the impact of combined chemoradiotherapy and PARP inhibition on inflammatory cytokine production in pancreas cancer patients. Methods: A clinical trial of concurrent use of a PARP inhibitor with chemoradiation was performed on a cohort of 34 patients. Serum samples were collected at baseline and weekly during intensity modulated radiotherapy treatment. Concentrations of various inflammatory cytokines were measured in picograms per milliliter using a chemiluminescent assay. Comparisons between average percentage change from baseline to peak change of serum cytokine concentration across all patients was performed using a paired T test. Results: Multiple inflammatory cytokines experienced a statistically significant increase after patient treatment. Peak serum increase occurred within 3-5 weeks after treatment initiation for the majority of cytokines tested. The most significantly increased pro-angiogenic cytokines included placental growth factor (p = 2.21x10-6) and vascular endothelial growth factor (p = 1.19x10-4), which peaked at weeks 4 and 5, respectively. Multiple members of the interleukin family also increased significantly. Both IL-7 (p = 1.89x10-4) and IL-17a (p = 7.26x10-4) peaked at weeks 4. IL-5 (p = 8.84x10-5) and IL-15 (p = 1.26x10-15) peaked at weeks 3 and 4, respectively. Conclusions: Patients receiving combined PARP inhibitor and chemoradiation experience a stereotyped increase in inflammatory cytokine signaling that peaks at approximately 1 month after initiation of treatment. Changes in serum inflammatory cytokines may serve as biomarkers of response to treatment and could underpin future combined treatment modalities including immunomodulating agents.

InGaAs quantum dots grown by molecular beam epitaxy for light emission on Si substrates

The aim of this study is to achieve homogeneous, high density and dislocation free InGaAs quantum dots grown by molecular beam epitaxy for light emission on silicon substrates. This work is part of a project which aims at overcoming the severe limitation suffered by silicon regarding its optoelectronic applications, especially efficient light emission device. For this study, one of the key points is to overcome the expected type II InGaAs/Si interface by inserting the InGaAs quantum dots inside a thin silicon quantum well in SiO2 fabricated on a SOI substrate. Confinement effects of the Si/SiO2 quantum well are expected to heighten the indirect silicon bandgap and then give rise to a type I interface with the InGaAs quantum dots. Band structure and optical properties are modeled within the tight binding approximation: direct energy bandgap is demonstrated in SiO2/Si/InAs/Si/SiO2 heterostructures for very thin Si layers and absorption coefficient is calculated. Thinned SOI substrates are successfully prepared using successive etching process resulting in a 2 nm-thick Si layer on top of silica. Another key point to get light emission from InGaAs quantum dots is to avoid any dislocations or defects in the quantum dots. We investigate the quantum dot size distribution, density and structural quality at different V/III beam equivalent pressure ratios, different growth temperatures and as a function of the amount of deposited material. This study was performed for InGaAs quantum dots grown on Si(001) substrates. The capping of InGaAs quantum dots by a silicon epilayer is performed in order to get efficient photoluminescence emission from quantum dots. Scanning transmission electronic microscopy images are used to study the structural quality of the quantum dots. Dislocation free In50Ga50As QDs are successfully obtained on a (001) silicon substrate. The analysis of QDs capped with silicon by Rutherford Backscattering Spectrometry in a channeling geometry is also presented.

National anti-tuberculosis drug resistance survey, 2002, in Myanmar

SETTING

Thirty townships of Myanmar.

OBJECTIVES

To determine the proportions of drug-resistant tuberculosis (TB) in new and previously treated pulmonary tuberculosis (PTB) cases in Myanmar.

DESIGN

A cross-sectional study. Drug susceptibility was tested by the proportion method at the National Tuberculosis Reference Laboratory, Yangon.

RESULTS

Of 874 TB patients included from 30 sites, 849 isolates obtained from individual patients (733 from new cases and 116 from previously treated cases) were tested for susceptibility to four primary anti-tuberculosis drugs. Of 733 isolates tested from new TB patients, 10% were resistant to any one of the anti-tuberculosis drugs, 6.5% to isoniazid (INH), 4.6% to rifampicin (RMP) and 4.0% were multidrug-resistant (MDR). Of the 116 previously treated patients, 30.2% were resistant to any one of the drugs, 26.7% to INH, 15.5% to RMP and 15.5% were MDR. Previous anti-tuberculosis treatment of more than 1 month was strongly associated with the development of MDR-TB (adjusted OR 4.8, 95% CI 2.5-9.1).

CONCLUSION

The first national drug resistance survey in Myanmar revealed 4% and 15.5% MDR-TB among new and retreatment cases, respectively. Previous antituberculosis treatment was an important risk factor for MDR-TB. Continuous monitoring of drug resistance trends is needed

Private GPs contribute to TB control in Myanmar: evaluation of a PPM initiative in Mandalay Division

SETTING

Mandalay Division, Myanmar.

AIM

To assess the effect of an initiative to involve private general practitioners (GPs) in the National Tuberculosis Programme (NTP) and to identify lessons learnt for public-private mix scale-up.

METHODS

Source of referral/diagnosis and place of treatment were included in the routine recording and reporting systems to enable disaggregated analysis of the contribution of GPs to case notification and treatment outcomes. Case notification trends were compared between the intervention and control areas over a 4-year period.

RESULTS

Private GPs contributed 44% of new smear-positive cases registered during the study period (July 2002-December 2004). The notification of new sputum smear-positive TB in the study area increased by 85% between the year prior to the GP involvement and 2 years after (from 46 to 85/100,000). Case notification increased by 57% in the control townships and by 42% in all of Mandalay Division. The treatment success rate for new smear-positive cases treated by GPs was 90%.

CONCLUSIONS

The involvement of private GPs substantially increased TB case notification, while a high treatment success rate was maintained. Success factors include a well-developed local medical association branch, strong managerial support, training and supervision by the public sector and provision of drugs and consumables free of charge by the NTP.