315 research outputs found
Defense-through-Deception Network Security Model: Securing University Campus Network from DOS/DDOS Attack
Denial of Service (DOS) and (DDOS) Distributed Denial of Service attacks have become a major security threat to university campus network security since most of the students and teachers prepare online services such as enrolment, grading system, library etc. Therefore, the issue of network security has become a priority to university campus network management. Using online services in university network can be easily compromised. However, traditional security mechanisms approach such as Defense-In-Depth (DID) Model is outdated in today’s complex network and DID Model has been used as a primary cybersecurity defense model in the university campus network today. However, university administration should realize that Defense-In-Depth (DID) are playing an increasingly limited role in DOS/DDoS protection and this paper brings this fact to light. This paper presents that the Defense-In-Depth (DID) is not capable of defending complex and volatile DOS/DDOS attacks effectively. The test results were presented in this study in order to support our claim. The researchers established a Defense-In-Depth (DID) Network model at the Central Luzon State University and penetrated the Network System using DOS/DDOS attack to simulate the real network scenario. This paper also presents the new approach Defense-through-Deception network security model that improves the traditional passive protection by applying deception techniques to them that give insights into the limitations posed by the Defense-In-Depth (DID) Model. Furthermore, this model is designed to prevent an attacker who has already entered the network from doing damage
Zig-Zag magnetic order and potential Kitaev interactions in the spin-1 honeycomb lattice KNiAsO
Despite the exciting implications of the Kitaev spin-Hamiltonian, finding and
confirming the quantum spin liquid state has proven incredibly difficult.
Recently the applicability of the model has been expanded through the
development of a microscopic description of a spin-1 Kitaev interaction. Here
we explore a candidate spin-1 honeycomb system, KNiAsO , which meets many
of the proposed criteria to generate such an interaction. Bulk measurements
reveal an antiferromagnetic transition at 19 K which is generally robust
to applied magnetic fields. Neutron diffraction measurements show magnetic
order with a ordering vector which results in
the well-known ``zig-zag" magnetic structure thought to be adjacent to the
spin-liquid ground state. Field dependent diffraction shows that while the
structure is robust, the field can tune the direction of the ordered moment.
Inelastic neutron scattering experiments show a well defined gapped spin-wave
spectrum with no evidence of the continuum expected for fractionalized
excitations. Modeling of the spin waves shows that the extended Kitaev
spin-Hamiltonians is generally necessary to model the spectra and reproduce the
observed magnetic order. First principles calculations suggest that the
substitution of Pd on the Ni sublattice may strengthen the Kitaev interactions
while simultaneously weakening the exchange interactions thus pushing
KNiAsO closer to the spin-liquid ground state.Comment: 13 pages, 7 figure
Microscopic mechanisms of spin-dependent electric polarization in 3d oxides
We present a short critical overview of different microscopic models for
nonrelativistic and relativistic magnetoelectric coupling including the
so-called "spin current scenario", ab-initio calculations, and several recent
microscopic approaches to a spin-dependent electric polarization in 3d oxides.Comment: 8 pages, 3 figure
Spin-orbit coupling controlled ground states in the double perovskite iridates A2BIrO6 (A = Ba, Sr; B = Lu, Sc)
Iridates with the 5 electronic configuration have attracted recent
interest due to reports of magnetically-ordered ground states despite
longstanding expectations that their strong spin-orbit coupling would generate
a electronic ground state for each Ir ion. The major focus of
prior research has been on the double perovskite iridates BaYIrO and
SrYIrO, where the nature of the ground states (i.e. ordered vs
non-magnetic) is still controversial. Here we present neutron powder
diffraction, high energy resolution fluorescence detected x-ray absorption
spectroscopy (HERFD-XAS), resonant inelastic x-ray scattering (RIXS), magnetic
susceptibility, and muon spin relaxation data on the related double perovskite
iridates BaLuIrO, SrLuIrO, BaScIrO, and SrScIrO
that enable us to gain a general understanding of the electronic and magnetic
properties for this family of materials. Our HERFD-XAS and RIXS measurements
establish electronic ground states for the Ir ions in all cases,
with similar values for Hund's coupling and the spin-orbit coupling
constant . Our bulk susceptibility and muon spin relaxation
data find no evidence for long-range magnetic order or spin freezing, but they
do reveal weak magnetic signals that are consistent with extrinsic local
moments. Our results indicate that the large is the key
driving force behind the electronic and magnetic ground states realized in the
5 double perovskite iridates, which agrees well with conventional wisdom.Comment: 13 pages, 7 figures, accepted for publication by PR
Fully human anti-CD39 antibody potently inhibits ATPase activity in cancer cells via uncompetitive allosteric mechanism
The extracellular ATP/adenosine axis in the tumor microenvironment (TME) has emerged as an important immune-regulatory pathway. Nucleoside triphosphate diphosphohydrolase-1 (NTPDase1), otherwise known as CD39, is highly expressed in the TME, both on infiltrating immune cells and tumor cells across a broad set of cancer indications. CD39 processes pro-inflammatory extracellular ATP to ADP and AMP, which is then processed by Ecto-5MODIFIER LETTER PRIME-nucleotidase/CD73 to immunosuppressive adenosine. Directly inhibiting the enzymatic function of CD39 via an antibody has the potential to unleash an immune-mediated anti-tumor response via two mechanisms: 1) increasing the availability of immunostimulatory extracellular ATP released by damaged and/or dying cells, and 2) reducing the generation and accumulation of suppressive adenosine within the TME. Tizona Therapeutics has engineered a novel first-in-class fully human anti-CD39 antibody, TTX-030, that directly inhibits CD39 ATPase enzymatic function with sub-nanomolar potency. Further characterization of the mechanism of inhibition by TTX-030 using CD39(+) human melanoma cell line SK-MEL-28 revealed an uncompetitive allosteric mechanism (alpha < 1). The uncompetitive mechanism of action enables TTX-030 to inhibit CD39 at the elevated ATP concentrations reported in the TME. Maximal inhibition of cellular CD39 ATPase velocity was 85%, which compares favorably to results reported for antibody inhibitors to other enzyme targets. The allosteric mechanism of TTX-030 was confirmed via mapping the epitope to a region of CD39 distant from its active site, which suggests possible models for how potent inhibition is achieved. In summary, TTX-030 is a potent allosteric inhibitor of CD39 ATPase activity that is currently being evaluated in clinical trials for cancer therapy
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