A spintronic source of circularly polarized single photons

We present a spintronic single photon source which emits circularly polarized light, where the helicity is determined by an applied magnetic field. Photons are emitted from an InGaAs quantum dot inside an electrically operated spin light-emitting diode, which comprises the diluted magnetic semiconductor ZnMnSe. The circular polarization degree of the emitted light is high, reaching 83% at an applied magnetic field of 2T and 96% at 6 T. Autocorrelation traces recorded in pulsed operation mode prove the emitted light to be antibunched. The two circular polarization states could be used for representing quantum states |0> and |1> in quantum cryptography implementations

Eine Methodik zur präventiven CO2-Reduzierung

Welche Faktoren können Unternehmen heranziehen, um einen Standort mit niedrigen Kohlendioxidemissionen zu ermitteln? Eine Methodik für unternehmerischen Umweltschutz

Treatment options, complications and long‐term outcomes for limb fractures in pet rabbits

Background Limb fractures represent the most common orthopaedic disease in pet rabbits. However, only a few studies have evaluated therapeutic details of limb fractures. There are no data available for long‐term outcomes of limb fracture treatment. Methods The medical records of six institutions were reviewed retrospectively to identify cases of traumatic limb bone fractures in pet rabbits between 1999 and 2020. The medical records (n = 387) were analysed for details of fracture prevalence, aetiology, therapy protocols, treatment complications, outcome and long‐term effects. In addition to the retrospective data evaluation, 13 rabbits were re‐evaluated in person in recent clinical analyses, including orthopaedic examination, radiography and computed‐tomographic imaging. Details of long‐term effects of fracture treatment were requested over the telephone for a further 232 animals using a standardised questionnaire. Results Long bone fractures accounted for the majority of all fractures (296/387; 76.5%). Hindlimb fractures (301/387; 77.7%) were more common than forelimb fractures (86/387; 22.2%), and tibial fractures and combined fractures of the tibia and fibula (119/387; 30.8%) were observed most frequently. Most fracture treatments were based on osteosynthesis procedures (243/328; 74.1%). Treatment complications occurred in 130 out of 328 (39.6%) cases. A high bodyweight (p = 0.047) and an older age (p = 0.01) were found to be significant risk factors for the emergence of therapy complications. Overall, 75.4% of animals (175/232) had a satisfactory long‐term outcome. Limb posture anomalies were evaluated in 61 cases (26.3%). Limitations The multi‐centre approach led to the inclusion of various institutions, veterinarians, treatment protocols and rabbit populations that might have influenced the results. The medical records were reviewed retrospectively, so there were some data that were lacking or could not be collected in a standardised manner. Furthermore, rabbit owners' evaluation of long‐term outcomes might be prone to error, despite the use of a standardised interview questionnaire. Conclusion Limb fractures are a common orthopaedic issue in pet rabbits. The patient's bodyweight and age are significant risk factors for the emergence of complications during the fracture treatment process. Long‐term orthopaedic effects, such as abnormal limb posture and permanent lameness of the affected limb, were observed regularly

CacheWarp: Software-based Fault Injection using Selective State Reset

AMD SEV is a trusted-execution environment (TEE), providing confidentiality and integrity for virtual machines (VMs). With AMD SEV, it is possible to securely run VMs on an untrusted hypervisor. While previous attacks demonstrated architectural shortcomings of earlier SEV versions, AMD claims that SEV-SNP prevents all attacks on the integrity. In this paper, we introduce CacheWarp, a new software-based fault attack on AMD SEV-ES and SEV-SNP, exploiting the possibility to architecturally revert modified cache lines of guest VMs to their previous (stale) state. Unlike previous attacks on the integrity, CacheWarp is not mitigated on the newest SEV-SNP implementation, and it does not rely on specifics of the guest VM. CacheWarp only has to interrupt the VM at an attacker-chosen point to invalidate modified cache lines without them being written back to memory. Consequently, the VM continues with architecturally stale data. In 3 case studies, we demonstrate an attack on RSA in the Intel IPP crypto library, recovering the entire private key, logging into an OpenSSH server without authentication, and escalating privileges to root via the sudo binary. While we implement a software-based mitigation proof-of-concept, we argue that mitigations are difficult, as the root cause is in the hardware

Temperature-dependent studies of exciton binding energy and phase-transition suppression in (Cs,FA,MA)Pb(I,Br)3_{3} perovskites

Multiple-cation mixed-halide (Cs,FA,MA)Pb(I,Br)3 perovskites containing cesium, formamidinium (FA), and methylammonium (MA) possess excellent properties for a wide range of optoelectronic applications such as thin-film photovoltaics or lasers. We investigate the role of excitons and the exciton binding energy EB, relevant for the effectiveness of charge separation in solar cells, as well as the temperature-dependent bandgap energy Eg which is used as an indicator for crystal phase transitions. Generalized Elliott fits of absorption spectra offer the possibility to determine both EB and Eg. However, since excitonic effects are non-negligible even at room temperature, a careful and detailed analysis of the spectra is crucial for a correct interpretation. Therefore, an additional evaluation based on a so-called f-sum rule is applied to achieve an improved reliability of the results at higher temperatures. The obtained EB values of 20–24 meV for Cs-containing mixed perovskite compounds are below the ones of 24–32 meV and 36–41 meV for pure methylammonium lead iodide (MAPbI3) and bromide (MAPbBr3), respectively, and, thus, facilitate charge-carrier separation in photovoltaic applications. Furthermore, temperature-dependent (T = 5–300 K) studies of Eg in (Cs,FA,MA)Pb(I,Br)3 indicate a suppressed crystal phase transition by the absence of any phase-transition related signatures such as the well-known jump of about 100 meV in MAPbI3. We verify these results using temperature-dependent electroreflectance spectroscopy, which is a very reliable technique for the direct and non-destructive determination of optical resonances of the absorber layer in complete solar cells. Additionally, we confirm the suppression of the phase transition in Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3 by temperature-dependent X-ray diffraction

Clinical impact of delaying initiation of adjuvant chemotherapy in patients with early triple negative breast cancer

Purpose The optimal time to initiation of adjuvant chemotherapy (TTAC) for triple negative breast cancer (TNBC) patients is unclear. This study evaluates the association between TTAC and survival in TNBC patients. Methods We conducted a retrospective study using data from a cohort of TNBC patients diagnosed between January 1, 2010 to December 31, 2018, registered in the Tumor Centre Regensburg was conducted. Data included demographics, pathology, treatment, recurrence and survival. TTAC was defined as days from primary surgery to first dose of adjuvant chemotherapy. The Kaplan–Meier method was used to evaluate impact of TTAC on overall survival (OS) and 5-year OS. Results A total of 245 TNBC patients treated with adjuvant chemotherapy and valid TTAC data were included. Median TTAC was 29 days. The group receiving systemic therapy within 22 to 28 days after surgery had the most favorable outcome, with median OS of 10.2 years. Groups receiving systemic therapy between 29–35 days, 36–42 days, and more than 6 weeks after surgery had significantly decreased median survival, with median OS of 8.3 years, 7.8 years, and 6.9 years, respectively. Patients receiving therapy between 22–28 days had significantly better survival compared to those receiving therapy between 29–35 days (p = 0.043), and patients receiving therapy after 22–28 days also demonstrated significantly better survival compared to those receiving therapy after more than 43 days (p = 0.033). Conclusion Timing of adjuvant systemic therapy can influence OS in TNBC patients. Efforts should be made to avoid unnecessary delays in administering chemotherapy to ensure timely initiation of systemic therapy and optimize patient outcomes

Does timing of neoadjuvant chemotherapy influence the prognosis in patients with early triple negative breast cancer?

Purpose For patients with triple negative breast cancer (TNBC), the optimal time to initiate neoadjuvant chemotherapy (TTNC) is unknown. This study evaluates the association between TTNC and survival in patients with early TNBC. Methods A retrospective study using data from of a cohort of TNBC patients diagnosed between January 1, 2010 to December 31, 2018 registered in the Tumor Centre Regensburg was performed. Data included demographics, pathology, treatment, recurrence, and survival. Interval to treatment was defined as days from pathology diagnosis of TNBC to first dose of neoadjuvant chemotherapy (NACT). The Kaplan–Meier and Cox regression methods were used to evaluate the impact of TTNC on overall survival (OS) and 5 year OS. Results A total of 270 patients were included. Median follow up was 3.5 years. The 5-year OS estimates according to TTNC were 77.4%, 66.9%, 82.3%, 80.6%, 88.3%, 58.3%, 71.1% and 66.7% in patients who received NACT within 0–14, 15–21, 22–28, 29–35, 36–42, 43–49, 50–56 and > 56 days after diagnosis. Patients who received systemic therapy early had the highest estimated mean OS of 8.4 years, while patients who received systemic therapy after more than 56 days survived an estimated 3.3 years. Conclusion The optimal time interval between diagnosis and NACT remains to be determined. However, starting NACT more than 42 days after diagnosis of TNBC seems to reduce survival. Therefore, it is strongly recommended to carry out the treatment in a certified breast center with appropriate structures, in order to enable an adequate and timely care

Reconstruction of coronary arteries from X-ray angiography: A review.

Despite continuous progress in X-ray angiography systems, X-ray coronary angiography is fundamentally limited by its 2D representation of moving coronary arterial trees, which can negatively impact assessment of coronary artery disease and guidance of percutaneous coronary intervention. To provide clinicians with 3D/3D+time information of coronary arteries, methods computing reconstructions of coronary arteries from X-ray angiography are required. Because of several aspects (e.g. cardiac and respiratory motion, type of X-ray system), reconstruction from X-ray coronary angiography has led to vast amount of research and it still remains as a challenging and dynamic research area. In this paper, we review the state-of-the-art approaches on reconstruction of high-contrast coronary arteries from X-ray angiography. We mainly focus on the theoretical features in model-based (modelling) and tomographic reconstruction of coronary arteries, and discuss the evaluation strategies. We also discuss the potential role of reconstructions in clinical decision making and interventional guidance, and highlight areas for future research