Representations of Group Actions and their Applications in Cryptography

Cryptographic group actions provide a flexible framework that allows the instantiation of several primitives, ranging from key exchange protocols to PRFs and digital signatures. The security of such constructions is based on the intractability of some computational problems. For example, given the group action $(G,X,\star)$, the weak unpredictability assumption (Alamati et al., Asiacrypt 2020) requires that, given random $x_i$\u27s in $X$, no probabilistic polynomial-time algorithm can compute, on input $\{(x_i,g\star x_i)\}_{i=1,\dots,Q}$, the group element $g$. In this work, we study such assumptions, aided by the definition of group action representations and a new metric, the linear dimension, that estimates the linearity of a group action, or in other words, how much it is far from being linear. We show that under some hypotheses on the group action representation, and if the linear dimension is polynomial in the security parameter, then the weak unpredictability and other related assumptions cannot hold. This technique is applied to some actions from cryptography, like the ones arising from the equivalence of linear codes; as a result, we obtain the impossibility of using such actions for the instantiation of certain primitives. As an additional result, some bounds on the linear dimension are given for classical groups, such as $\mathcal{S}_n$, $\mathrm{GL}(\mathbb{F}^n)$ and the cyclic group $\mathbb{Z}_n$ acting on itself

Execution Time of Optimal Controls in Hard Real Time, a Minimal Execution Time Solution for Nonlinear SDRE

Many engineering fields, such as automotive, aerospace, and the emerging challenges towards industry 4.0, have to deal with Real-Time (RT) or Hard Real Time (HRT) systems, where temporal constraints must be fulfilled, to avoid critical behaviours or unacceptable system failures. For this reason, estimation of code's Worst-Case Execution Time (WCET) has received lots attention because in RT systems a fundamental requirement is to guarantee at least a temporal upper bound of the code execution for avoiding any drawbacks. However, until now there is no approved method to compute extremely tight WCET. Nowadays, indeed, HRT requirements are solved via hardware, using multi-cores embedded boards that allow the computation of the deterministic Execution Time (ET). The availability of these embedded architectures has encouraged the designers to look towards more computationally demanding optimal control techniques for RT scenarios, and to compare and analyze performances also evaluating a tight WCET. However, this area still lacks deep investigations. This paper has the intent of analysing results regarding the choice between three of the most established optimal controls (LQR, MPC, SDRE), providing the first link between WCET analysis and control algorithms performances. Moreover, this work shows how it is also possible to obtain a minimal ET solution for the nonlinear SDRE controller. The results might be useful for future implementations and for coping with Industry 4.0 emerging challenges. Furthermore, this approach can be useful in control system engineering field, especially in the design stage for RT or HRT systems, where temporal bounds have to be fulfilled jointly with all the other application's specifications

Cystic echinococcosis in cattle dairy farms: spatial distribution and epidemiological dynamics

A study monitoring cystic echinococcosis (CE) in adult dairy cattle from intensive livestock farms located in the municipality of Arborea (Sardinia, Italy) was carried out between 2012 and 2015. A retrospective study of veterinary reporting forms of post-mortem inspections in 10 different Italian slaughterhouses was also performed. In addition, data on viability and molecular characterisation of hydatid cysts removed from parasitised organs in cattle was carried out. A geographical information system (GIS) with data layers of the study area and the geo-referenced points of 160 cattle farms was constructed. CE was found in 21.9% (35/160) of the surveyed farms. The retrospective study revealed that 0.05% (13/23,656) of adult slaughtered animals (over one year of age) from Arborea had tested positive to CE. The results stratified per year showed the following CE prevalences: 0.09% (5/5673) in 2012; 0.02% (1/5682) in 2013; 0.08% (5/6261) in 2014; and 0.03% (2/6040) in 2015 (χ2 with 3 degrees of freedom=3.81; P=0.282). The E. granulosus sensu stricto (formerly called G1 or sheep strain) was detected in all cysts subjected to molecular analysis. The GIS analysis showed that CE is fairly resilient in the Arborea territory where most of cattle farms are located, while a small cluster of cases was found located in the southeastern part of Arborea, close to districts where sheep farms are situated. The present survey reports the presence of CE in Sardinian dairy cattle intensive farms and suggests that the parasitic pressure of CE in the island continues to be very strong

Removal of Koos IV acoustic neuroma and auditory brainstem implant in NF2 patient

The authors present the case of removal of a Koos grade IV right acoustic neuroma in a neurofibromatosis type 2 (NF2) patient, already operated on for left cerebellopontine angle meningioma at 7 years of age and a left acoustic neuroma at 16 years of age. A transpetrosal approach allowed cochlear sensor implantation to detect residual hearing. An enlarged retrosigmoid approach then allowed subtotal microsurgical removal of the lesion; consequently, the authors illustrate the technical nuances of an auditory brainstem implant (ABI). One month after surgery, the ABI was successfully switched on, giving back hearing perception to the patient. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID218

Cancer-associated CD43 glycoforms as target of immunotherapy

CD43 is a sialoglycosylated membrane protein that is involved in cell proliferation and differentiation. CD43 glycoforms that are recognized by the UN1 monoclonal antibody (mAb) were expressed in lymphoblastoid T-cell lines and solid tumors, such as breast, colon, gastric, and squamous cell lung carcinomas, while unexpressed in the normal counterparts. The cancer association of UN1/CD43 epitope suggested the possibility to use the UN1 mAb for tumor diagnosis and therapy. In this study, we show that the UN1 mAb was endowed with antitumor activity in vivo because its passive transfer inhibited the growth of UN1-positive HPB-ALL lymphoblastoid T cells in mice. Furthermore, we demonstrate that tumor inhibition was due to UN1 mAb-dependent natural killer-mediated cytotoxicity. By screening a phage-displayed random peptide library, we identified the phagotope 2/165 as a mimotope of the UN1 antigen, as it harbored a peptide sequence that was specifically recognized by the UN1 mAb and inhibited the binding of the UN1 mAb to UN1-positive tumor cells. On the basis of sequence homology with the extracellular region of CD43 (amino acids 64 to 83), the 2/165 peptide sequence was likely mimicking the protein core of the UN1/CD43 epitope. When used as vaccine in mice, the 2/165 phagotope raised antibodies against the UN1/CD43 antigen, indicating that the 2/165 phagotope mimicked the UN1 antigen structure, and could represent a novel immunogen for cancer immunotherapy. These findings support the feasibility of using monoclonal antibodies to identify cancer-associated mimotopes for immunotherapy

COX-2 expression positively correlates with PD-L1 expression in human melanoma cells.

Abstract BACKGROUND: The resistance to PD-1/PD-L1 inhibitors for the treatment of melanoma have prompted investigators to implement novel clinical trials which combine immunotherapy with different treatment modalities. Moreover is also important to investigate the mechanisms which regulate the dynamic expression of PD-L1 on tumor cells and PD-1 on T cells in order to identify predictive biomarkers of response. COX-2 is currently investigated as a major player of tumor progression in several type of malignancies including melanoma. In the present study we investigated the potential relationship between COX-2 and PD-L1 expression in melanoma. METHODS: Tumor samples obtained from primary melanoma lesions and not matched lymph node metastases were analyzed for both PD-L1 and COX-2 expression by IHC analysis. Status of BRAF and NRAS mutations was analyzed by sequencing and PCR. Co-localization of PD-L1 and COX-2 expression was analyzed by double fluorescence staining. Lastly the BRAFV600E A375 and NRASQ61R SK-MEL-2 melanoma cell lines were used to evaluate the effect of COX-2 inhibition by celecoxib on expression of PD-L1 in vitro. RESULTS: BRAFV600E/V600K and NRASQ61R/Q61L were detected in 57.8 and 8.9% of the metastatic lesions, and in 65.9 and 6.8% of the primary tumors, respectively. PD-L1 and COX-2 expression were heterogeneously expressed in both primary melanoma lesions and not matched lymph node metastases. A significantly lower number of PD-L1 negative lesions was found in primary tumors as compared to not matched metastatic lesions (P = 0.002). COX-2 expression significantly correlated with PD-L1 expression in both primary (P = 0.001) and not matched metastatic (P = 0.048) lesions. Furthermore, in melanoma tumors, cancer cells expressing a higher levels of COX-2 also co-expressed a higher level of PD-L1. Lastly, inhibition of COX-2 activity by celecoxib down-regulated the expression of PD-L1 in both BRAFV600E A375 and NRASQ61R SK-MEL-2 melanoma cell lines. CONCLUSIONS: COX-2 expression correlates with and modulates PD-L1 expression in melanoma cells. These findings have clinical relevance since they provide a rationale to implement novel clinical trials to test COX-2 inhibition as a potential treatment to prevent melanoma progression and immune evasion as well as to enhance the anti-tumor activity of PD-1/PD-L1 based immunotherapy for the treatment of melanoma patients with or without BRAF/NRAS mutations

Measuring social response to different journalistic techniques on Facebook

Recent studies have shown that online users tend to select information that adheres to their system of beliefs, ignore information that does not, and join groups that share a common narrative. This information environment can elicit tribalism instead of informed debate, especially when issues are controversial. Algorithmic solutions, fact-checking initiatives, and many other approaches have shown limitations in dealing with this phenomenon, and heated debate and polarization still play a pivotal role in online social dynamics (e.g. traditional vs. anti-establishment polarization). To understand the effect of different communication strategies able to smooth polarization, in this paper, together with Corriere della Sera, a major Italian news outlet, we measure the social response of users to different types of news framing. We analyse users’ reactions to 113 ad-hoc articles published on the newspaper’s Facebook page and the corresponding news articles on the topic of migration, published from March to December 2018. We examine different journalistic techniques and content types by analyzing their impact on user comments in terms of toxicity, criticism of the newspaper, and stance concerning migration. We find that visual pieces and factual news reports elicit the highest level of trust in the media source, while opinion pieces and editorials are more likely to be criticized. We also notice that data-driven pieces elicit an extremely low level of trust in the news source. Furthermore, coherently with the echo chambers behaviour, we find social conformity strongly affecting the commenting behaviour of users on Facebook

Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice

Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4(+) and CD8(+) T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation

A rare cause of recurrent syncope: chemodectoma of left carotid

Syncope is a frequent cause of access to emergency departments. Recurrent syncope may be associated with a transient lock of consciousness. When neurological or cardiological common causes of syncope are excluded, rare causes of syncope, such as solid carotid tumors, should be considered. In this study, we report a rare case of left carotid chemodectoma in a patient with frequent access to the emergency room for syncope in which a thorough differential diagnosis has been performed

Decipher non-canonical SPAST splicing mutations with the help of functional assays in patients affected by spastic paraplegia 4 (SPG4)

Flowchart showing the molecular approach used to decipher the non-canonical splicing mutations