8 research outputs found
Encryption in the past, present, and future : an honors thesis (HONRS 499)
To ensure the confidentiality and integrity of data in storage and transit, various cryptography systems have been developed. Each of these systems has individual strengths and weaknesses. As the number of computer security threats increases, it becomes even more crucial to use methods of concealing the true meaning of data. This paper will look to strike a balance in providing details of how each of the methods works without explaining in so much detail that a casual reader will be completely lost. It is the goal of this paper to enlighten readers about the cryptography systems all around them and help them to gain a better understanding of how these systems work. The paper will then conclude with a brief discussion of what future advancements are likely to mean to current cryptography systems.Honors CollegeThesis (B.?
Galaxy mapping with the SAURON integral-field spectrograph: The star formation history of NGC 4365
We report the first wide-field mapping of the kinematics and stellar
populations in the E3 galaxy NGC 4365. The velocity maps extend previous
long-slit work. They show two independent kinematic subsystems: the central 300
x 700 pc rotates about the projected minor axis, and the main body of the
galaxy, 3 x 4 kpc, rotates almost at right angles to this. The line-strength
maps show that the metallicity of the stellar population decreases from a
central value greater than solar, to one-half solar at a radius of 2 kpc. The
decoupled core and main body of the galaxy have the same luminosity-weighted
age, of ~14 Gyr, and the same elevated magnesium-to-iron ratio. The two
kinematically distinct components have thus shared a common star formation
history. We infer that the galaxy underwent a sequence of mergers associated
with dissipative star formation that ended >12 Gyr ago. The misalignment
between the photometric and kinematic axes of the main body is unambiguous
evidence of triaxiality. The similarity of the stellar populations in the two
components suggests that the observed kinematic structure has not changed
substantially in 12 Gyr.Comment: 5 pages, accepted for publication in ApJ Letter
The SAURON project. II. Sample and early results
Early results are reported from the SAURON survey of the kinematics and
stellar populations of a representative sample of nearby E, S0 and Sa galaxies.
The survey is aimed at determining the intrinsic shape of the galaxies, their
orbital structure, the mass-to-light ratio as a function of radius, the age and
metallicity of the stellar populations, and the frequency of kinematically
decoupled cores and nuclear black holes. The construction of the representative
sample is described, and its properties are illustrated. A comparison with
long-slit spectroscopic data establishes that the SAURON measurements are
comparable to, or better than, the highest-quality determinations. Comparisons
are presented for NGC 3384 and NGC 4365 where stellar velocities and velocity
dispersions are determined to a precision of 6 km/s, and the h3 and h4
parameters of the line-of-sight velocity distribution to a precision of better
than 0.02. Extraction of accurate gas emission-line intensities, velocities and
line widths from the datacubes is illustrated for NGC 5813. Comparisons with
published line-strengths for NGC 3384 and NGC 5813 reveal uncertainties of <
0.1 A on the measurements of the Hbeta, Mgb and Fe5270 indices. Integral-field
mapping uniquely connects measurements of the kinematics and stellar
populations to the galaxy morphology. The maps presented here illustrate the
rich stellar kinematics, gaseous kinematics, and line-strength distributions of
early-type galaxies. The results include the discovery of a thin, edge-on, disk
in NGC 3623, confirm the axisymmetric shape of the central region of M32,
illustrate the LINER nucleus and surrounding counter-rotating star-forming ring
in NGC 7742, and suggest a uniform stellar population in the decoupled core
galaxy NGC 5813.Comment: 20 pages, 17 figures. To be published in MNRAS. Version with full
resolution images available at
http://www.strw.leidenuniv.nl/~dynamics/Instruments/Sauron/pub_list.htm
Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines
The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (âMISEVâ) guidelines for the field in 2014. We now update these âMISEV2014â guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two
Background
The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd.
Methods
We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background.
Results
First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001).
Conclusions
In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival
Recommended from our members
31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016): part two: National Harbor, MD, USA. 9-13 November 2016
Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines
The last decade has seen a sharp increase in the number
of scientific publications describing physiological and
pathological functions of extracellular vesicles (EVs), a
collective term covering various subtypes of cell-released,
membranous structures, called exosomes, microvesicles,
microparticles, ectosomes, oncosomes, apoptotic bodies, and many
other names. However, specific issues arise when working with
these entities, whose size and amount often make them difficult
to obtain as relatively pure preparations, and to characterize
properly. The International Society for Extracellular Vesicles
(ISEV) proposed Minimal Information for Studies of Extracellular
Vesicles ("MISEV") guidelines for the field in 2014. We now
update these "MISEV2014" guidelines based on evolution of the
collective knowledge in the last four years. An important point
to consider is that ascribing a specific function to EVs in
general, or to subtypes of EVs, requires reporting of specific
information beyond mere description of function in a crude,
potentially contaminated, and heterogeneous preparation. For
example, claims that exosomes are endowed with exquisite and
specific activities remain difficult to support experimentally,
given our still limited knowledge of their specific molecular
machineries of biogenesis and release, as compared with other
biophysically similar EVs. The MISEV2018 guidelines include
tables and outlines of suggested protocols and steps to follow
to document specific EV-associated functional activities.
Finally, a checklist is provided with summaries of key points