34 research outputs found

    Utilizing simulation and optimization techniques to evaluate different CAR T cell therapy manufacturing paradigms

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    In an effort to understand major cost drivers and assess processing risk, Juno Therapeutics has developed a plant simulation of its global manufacturing network. With this simulation, Juno can assess the impact various control levers and sources of variability will have on key performance metrics. Juno has the ability to modify various aspects of its manufacturing operations, such as process design, staffing totals, shift schedules, facility configuration, and activity prioritization. Various sources of variability, such as time of patient specific raw material arrival at the plant, treatment rescheduling, and unit operation duration, will need to be mitigated in order to ensure robust manufacturing. In turn, with a representative simulation in place, optimization techniques can be leveraged in an effort to maximize the number of treated patients and revenue, while minimizing cost of goods and product cycle time. This work helps inform feasibility of future manufacturing paradigms and process design. An overview of Juno’s simulation and optimization methodology is presented here. Evaluations and trade-offs of point-of-care vs. centralized manufacturing and workstation vs. flexible facility configurations are presented

    Long Tandem Arrays of Cassandra Retroelements and Their Role in Genome Dynamics in Plants

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    Retrotransposable elements are widely distributed and diverse in eukaryotes. Their copy number increases through reverse-transcription-mediated propagation, while they can be lost through recombinational processes, generating genomic rearrangements. We previously identified extensive structurally uniform retrotransposon groups in which no member contains the gag, pol, or env internal domains. Because of the lack of protein-coding capacity, these groups are non-autonomous in replication, even if transcriptionally active. The Cassandra element belongs to the non-autonomous group called terminal-repeat retrotransposons in miniature (TRIM). It carries 5S RNA sequences with conserved RNA polymerase (pol) III promoters and terminators in its long terminal repeats (LTRs). Here, we identified multiple extended tandem arrays of Cassandra retrotransposons within different plant species, including ferns. At least 12 copies of repeated LTRs (as the tandem unit) and internal domain (as a spacer), giving a pattern that resembles the cellular 5S rRNA genes, were identified. A cytogenetic analysis revealed the specific chromosomal pattern of the Cassandra retrotransposon with prominent clustering at and around 5S rDNA loci. The secondary structure of the Cassandra retroelement RNA is predicted to form super-loops, in which the two LTRs are complementary to each other and can initiate local recombination, leading to the tandem arrays of Cassandra elements. The array structures are conserved for Cassandra retroelements of different species. We speculate that recombination events similar to those of 5S rRNA genes may explain the wide variation in Cassandra copy number. Likewise, the organization of 5S rRNA gene sequences is very variable in flowering plants; part of what is taken for 5S gene copy variation may be variation in Cassandra number. The role of the Cassandra 5S sequences remains to be established

    Diversity of long terminal repeat retrotransposon genome distribution in natural populations of the wild diploid wheat Aegilops speltoides

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    Background: The environment can have a decisive influence on the structure of the genome, changing it in a certain direction. Therefore, the genomic distribution of environmentally sensitive transposable elements may vary measurably across a species area. In the present research, we aimed to detect and evaluate the level of LTR retrotransposon intraspecific variability in Aegilops speltoides (2n=2x=14), a wild cross-pollinated relative of cultivated wheat. Results: The inter-retrotransposon amplified polymorphism (IRAP) protocol was applied to detect and evaluate the level of LTR retrotransposon intraspecific variability in Ae. speltoides and closely related species of sect. Sitopsis. IRAP analysis revealed significant diversity in TE distribution. Various genotypes from the same population significantly differ with respect to the patterns of the four explored LTR retrotransposons (WIS2, Wilma, Daniela, and Fatima). This diversity points to a constant ongoing process of LTR retrotransposon fraction restructuring in populations of Ae. speltoides throughout the species’ range and within single populations in time. Maximum changes were recorded in genotypes from small stressed populations. Principal component analysis showed that the dynamics of the Fatima element in populations of Ae. speltoides significantly differ from those of WIS2, Wilma, and Daniela. In terms of relationships between Sitopsis species, IRAP analysis of WIS2, Wilma, and Daniela elements revealed a grouping similar to groupings determined by other methods, with Ae. sharonensis and Ae. longissima forming a separate unit, Ae. speltoides appearing as a dispersed group, and Ae. bicornis being in an intermediate position. Conclusions: IRAP display data revealed dynamic changes in LTR retrotransposon fractions in the genome of Ae. speltoides. The process is permanent and population-specific, ultimately leading to the separation of small stressed populations from the main bunch.Peer reviewe

    Repetitive DNA in the Architecture, Repatterning, and Diversification of the Genome of Aegilops speltoides Tausch (Poaceae, Triticeae)

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    The genome’s adaptability to environmental changes, especially during rapid climatic fluctuations, underlies the existence and evolution of species. In the wild, genetic and epigenetic genomic changes are accompanied by significant alterations in the complex nuclear repetitive DNA fraction. Current intraspecific polymorphism of repetitive DNA is closely related to ongoing chromosomal rearrangements, which typically result from erroneous DNA repair and recombination. In this study, we addressed tandem repeat patterns and interaction/reshuffling both in pollen mother cell (PMC) development and somatogenesis in the wild diploid cereal Aegilops speltoides, with a focus on genome repatterning and stabilization. Individual contrasting genotypes were investigated using the fluorescent in situ hybridization (FISH) approach by applying correlative fluorescence and electron microscopy. Species-specific Spelt1 and tribe-specific Spelt52 tandem repeats were used as the markers for monitoring somatic and meiotic chromosomal interactions and dynamics in somatic interphase nuclei. We found that, the number of tandem repeat clusters in nuclei is usually lower than the number on chromosomes due to the associations of clusters of the same type in common blocks. In addition, tightly associated Spelt1–Spelt52 clusters were revealed in different genotypes. The frequencies of nonhomologous/ectopic associations between tandem repeat clusters were revealed in a genotype-/population-specific manner. An increase in the number of tandem repeat clusters in the genome causes an increase in the frequencies of their associations. The distal/terminal regions of homologous chromosomes are separated in nuclear space, and nonhomologous chromosomes are often involved in somatic recombination as seen by frequently formed interchromosomal chromatin bridges. In both microgametogenesis and somatogenesis, inter- and intrachromosomal associations are likely to lead to DNA breaks during chromosome disjunction in the anaphase stage. Uncondensed/improperly packed DNA fibers, mainly in heterochromatic regions, were revealed in both the meiotic and somatic prophases that might be a result of broken associations. Altogether, the data obtained showed that intraorganismal dynamics of repetitive DNA under the conditions of natural out-crossing and artificial intraspecific hybridization mirrors the structural plasticity of the Ae. speltoides genome, which is interlinked with genetic diversity through the species distribution area in contrasting ecogeographical environments in and around the Fertile Crescent

    Transposable elements in a marginal plant population : temporal fluctuations provide new insights into genome evolution of wild diploid wheat

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    Background How new forms arise in nature has engaged evolutionary biologists since Darwin's seminal treatise on the origin of species. Transposable elements (TEs) may be among the most important internal sources for intraspecific variability. Thus, we aimed to explore the temporal dynamics of several TEs in individual genotypes from a small, marginal population of Aegilops speltoides. A diploid cross-pollinated grass species, it is a wild relative of the various wheat species known for their large genome sizes contributed by an extraordinary number of TEs, particularly long terminal repeat (LTR) retrotransposons. The population is characterized by high heteromorphy and possesses a wide spectrum of chromosomal abnormalities including supernumerary chromosomes, heterozygosity for translocations, and variability in the chromosomal position or number of 45S and 5S ribosomal DNA (rDNA) sites. We propose that variability on the morphological and chromosomal levels may be linked to variability at the molecular level and particularly in TE proliferation. Results Significant temporal fluctuation in the copy number of TEs was detected when processes that take place in small, marginal populations were simulated. It is known that under critical external conditions, outcrossing plants very often transit to self-pollination. Thus, three morphologically different genotypes with chromosomal aberrations were taken from a wild population of Ae. speltoides, and the dynamics of the TE complex traced through three rounds of selfing. It was discovered that: (i) various families of TEs vary tremendously in copy number between individuals from the same population and the selfed progenies; (ii) the fluctuations in copy number are TE-family specific; (iii) there is a great difference in TE copy number expansion or contraction between gametophytes and sporophytes; and (iv) a small percentage of TEs that increase in copy number can actually insert at novel locations and could serve as a bona fide mutagen. Conclusions We hypothesize that TE dynamics could promote or intensify morphological and karyotypical changes, some of which may be potentially important for the process of microevolution, and allow species with plastic genomes to survive as new forms or even species in times of rapid climatic change.Peer reviewe

    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    Former Soviet Union countries and European Union : overcoming the energy efficiency gap

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    This paper evaluates convergence of energy intensity for the former USSR countries during 1995-2010. We divide these countries into three clubs and show convergence in income and in energy intensity for each club. We also demonstrate that rate of convergence is higher in countries with a low level of development

    Transposable Elements in the Organization and Diversification of the Genome of Aegilops speltoides Tausch (Poaceae, Triticeae)

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    Repetitive DNA—specifically, transposable elements (TEs)—is a prevailing genomic fraction in cereals that underlies extensive genome reshuffling and intraspecific diversification in the wild. Although large amounts of data have been accumulated, the effect of TEs on the genome architecture and functioning is not fully understood. Here, plant genome organization was addressed by means of cloning and sequencing TE fragments of different types, which compose the largest portion of the Aegilops speltoides genome. Individual genotypes were analyzed cytogenetically using the cloned TE fragments as the DNA probes for fluorescence in situ hybridization (FISH). The obtained TE sequences of the Ty1-copia, Ty3-gypsy, LINE, and CACTA superfamilies showed the relatedness of the Ae. speltoides genome to the Triticeae tribe and similarities to evolutionarily distant species. A significant number of clones consisted of intercalated fragments of TEs of various types, in which Fatima (Ty3-gypsy) sequences predominated. At the chromosomal level, different TE clones demonstrated sequence-specific patterning, emphasizing the effect of the TE fraction on the Ae. speltoides genome architecture and intraspecific diversification. Altogether, the obtained data highlight the current species-specific organization and patterning of the mobile element fraction and point to ancient evolutionary events in the genome of Ae. speltoides

    Two large-scale network design problems

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    Two Large-Scale Network Design Problems In this work we consider two large-scale network design problems arising in network routing and provisioning. The first problem combines long-term business and de-sign decisions on large-scale telecommunication networks. The problem integrates different elements of network business planning such as capacity expansion, routing and protection and equipment maintenance as well as a complicated pricing model; which altogether make the optimization particularly hard. We propose a scalable optimization algorithm that exploits the structure of the model and produces a fast, high-quality solution. In the second part of this work we consider the maximum concurrent flow problem and analyze one of the first special-purpose approaches, proposed in 1971 by Fratta, Gerla and Kleinrock, and show that it yields a full

    Asymptotic Analysis of the Flow Deviation Method for the Maximum Concurrent Flow Problem

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    We analyze the asymptotic behavior of the Flow Deviation Method, rst presented in 1971 by Fratta, Gerla and Kleinrock, and show that when applied to packing linear programs such as the maximum concurrent ow problem, it yields a fully polynomial-time approximation scheme.
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