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University of Massachusetts Amherst

2014

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Articles 1 - 30 of 159

Full-Text Articles in Life Sciences

Meeting Calendar Dec 2014

Meeting Calendar

Journal of Medicinally Active Plants

No abstract provided.


Modelling Non-Euclideanmovement And Landscape Connectivity In Highly Structured Ecological Networks, Chris Sutherland, Angela Fuller, J. Royle Dec 2014

Modelling Non-Euclideanmovement And Landscape Connectivity In Highly Structured Ecological Networks, Chris Sutherland, Angela Fuller, J. Royle

Environmental Conservation Faculty Publication Series

1. Movement is influenced by landscape structure, configuration and geometry, but measuring distance as perceived by animals poses technical and logistical challenges. Instead, movement is typically measured using Euclidean distance, irrespective of location or landscape structure, or is based on arbitrary cost surfaces. Arecently proposed extension of spatial capture-recapture (SCR)models resolves this issue using spatial encounterhistories of individuals to calculate least-cost paths (ecological distance: Ecology, 94, 2013, 287) thereby relaxingthe Euclidean assumption. We evaluate the consequences of not accounting for movement heterogeneity whenestimating abundance in highly structured landscapes, and demonstrate the value of this approach for estimatingbiologically realistic space-use ...


Physiological Models Of Geobacter Sulfurreducens And Desulfobacter Postgatei To Understand Uranium Remediation In Subsurface Systems, Roberto Orellana Nov 2014

Physiological Models Of Geobacter Sulfurreducens And Desulfobacter Postgatei To Understand Uranium Remediation In Subsurface Systems, Roberto Orellana

Doctoral Dissertations

Geobacter species are often the predominant Fe(III)-reducing microorganisms in many sedimentary environments due to their capacity for extracellular electron transfer. This exceptional physiological capability allows them to couple acetate oxidation to uranium (U(VI)) reduction, that is one of the most significant interactions between radionuclides and microorganisms that naturally takes place in uranium-contaminated environments. Although this process has been proposed as a promising strategy for the in situ bioremediation of uranium-contaminated groundwater, little is known about the molecular mechanisms involved in U(VI) reduction and the interaction between Geobacter and other microbial species.

In the first two research ...


Engineering Surface Functionality Of Nanoparticles For Biological Applications, Yi-Cheun Yeh Nov 2014

Engineering Surface Functionality Of Nanoparticles For Biological Applications, Yi-Cheun Yeh

Doctoral Dissertations

Engineering the surface functionality of nanomaterials is the key to investigate the interactions between nanomaterials and biomolecules for potent biological applications such as therapy, imaging and diagnostics. My research has been orientted to engineer both of the surface monolayers and core materials to fabricate surface-functionalized nanomaterials through the synergistic multidisciplinary approach that combine organic chemistry, materials science and biology. This thesis illustrates the design and synthesis of the surface-funcitonalized quantum dots (QDs) and gold nanoparticles (AuNPs) for the fundamental studies and practical applications. For QDs, A new class of cationic QDs with quaternary ammonium derivatives was synthesized to provide permanent ...


Elucidating Cellular Signaling Pathways That Contribute To The Immunopathogenesis Of Aplastic Anemia, Christina M. Kuksin Nov 2014

Elucidating Cellular Signaling Pathways That Contribute To The Immunopathogenesis Of Aplastic Anemia, Christina M. Kuksin

Doctoral Dissertations

Aplastic Anemia is a rare immune mediated bone marrow failure disease that is mediated by autoreactive T cells that cause destruction to the stem, progenitor, and stromal cells in the bone marrow. Because little is known about the etiology of the disease, our lab has developed a major MHC mismatch GVHD model to examine cellular pathways in autoreactive T cells that contribute to disease. We examined three pathways that are important in T cell activation and differentiation and asked if they were important in the development of Aplastic Anemia. First, we were able to show that expression of active PKCθ ...


Movements And Conservation Of The Migratory White-Eared Kob (Kobus Kob Leucotis) In South Sudan, Malik D. Marjan Mr. Nov 2014

Movements And Conservation Of The Migratory White-Eared Kob (Kobus Kob Leucotis) In South Sudan, Malik D. Marjan Mr.

Doctoral Dissertations

The annual movements of white-eared kob (Kobus kob leucotis), tiang (Damaliscus korrigum tiang), in eastern South Sudan was investigated to provided appropriate information for developing effective conservation actions for the migratory kob. Although kob is the focus of the study tiang has been included as the two migrations are ecologically linked and overlap at least in the wet season.

During the 20 years of the civil war which ravaged South Sudan, the kob and tiang populations were thought to be severely hunted for food by both the combatants and local people to the extent that their populations may have drastically ...


Guanidinium-Rich Romp Polymers Drive Phase, Charge, And Curvature-Specific Interactions With Phospholipid Membranes, Michael T W Lis Nov 2014

Guanidinium-Rich Romp Polymers Drive Phase, Charge, And Curvature-Specific Interactions With Phospholipid Membranes, Michael T W Lis

Doctoral Dissertations

Protein transduction domains (PTDs) and their and their synthetic mimics are short sequences capable of unusually high uptake in cells. Several varieties of these molecules, including the arginine-rich Tat peptide from HIV, have been extensively used as vectors for protein, DNA, and siRNA delivery into cells. Despite the wide-ranging utility of PTDs and their mimics, their uptake mechanism is still under considerable debate. How the molecules are able to cross phospholipid membranes, and what structural components are necessary for optimal activity are poorly understood. This thesis explores how PTDMs interact with phospholipid membrane phase, anionic lipid content and negative Gaussian ...


The Role Of Napping On Memory Consolidation In Preschool Children, Laura Kurdziel Nov 2014

The Role Of Napping On Memory Consolidation In Preschool Children, Laura Kurdziel

Doctoral Dissertations

Nocturnal sleep has been shown to benefit memory in adults and children. During the preschool age range (~3-5 years), the distribution of sleep across the 24-hour period changes dramatically. Children transition from biphasic sleep patterns (a nap in addition to overnight sleep) to a monophasic sleep pattern (only overnight sleep). In addition, early childhood is a time of neuronal plasticity and pronounced acquisition of new information. This dissertation sought to examine the relationship between daytime napping and memory consolidation in preschool-aged children during this transitional time. Children were taught either a declarative or an emotional task in the morning, and ...


Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya Nov 2014

Impact Of Surface Active Minor Components On Physicochemical Properties Of Association Colloids And Lipid Oxidation In Bulk Oil, Ketinun Kittipongpittaya

Doctoral Dissertations

Lipid oxidation is a great concern for food manufacturers and consumers as it negatively impacts not only food quality and nutritive values of food lipids, but also consumer health. Lipid oxidation in bulk oil is impacted by chemical factors, such as, prooxidants and antioxidants, and is also related to the existence of physical structures. Bulk oils contain a variety of surface active minor components which are able to form physical structures known as association colloids. These physical structures create oil-water interfaces which seem to be an important site where lipid oxidation occurs in bulk oil. Thus, this research focused on ...


Nanoparticle Building Blocks For Functional Structures, Youngdo Jeong Nov 2014

Nanoparticle Building Blocks For Functional Structures, Youngdo Jeong

Doctoral Dissertations

A major goal in material science is achieving a desired function using structures fabricated with designed building blocks. Advanced synthetic and self-assembly techniques allow various nanomaterials to become promising building blocks, providing the control of the interaction between building blocks. The unique properties of nanomaterials can be transferred to structured systems. Among nanomaterials, inorganic nanoparticles such as gold nanoparticles (AuNPs), magnetic particles, and quantum dots (QDs) provide useful physical properties stemming from their inorganic core, large surface areas, and oriented surface functionalities. My research has focused on fabricating functional systems using gold nanoparticles (AuNPs), manipulating the interaction between AuNPs, bio-entities ...


Aggressive Signaling In New World Warblers, David Hof Nov 2014

Aggressive Signaling In New World Warblers, David Hof

Doctoral Dissertations

In many animal species, communication can enable individuals to resolve conflict without the high potential costs involved in direct fighting. During contests, animals may exchange information about their aggressive motivational state. A central question throughout the study of animal communication research has been whether animal signals convey reliable information, and this question has been particularly relevant to communication during conflicts where the evolutionary interests of competitors directly oppose. Deceptive signaling of aggressive motivation would be highly favored by natural selection because it could allow individuals to gain access to resources they might not gain through direct combat. However, selection should ...


Factor Inhibiting Hif's (Fih) Structure Controls O2 Activation And Reactivity, John A. Hangasky Iii Nov 2014

Factor Inhibiting Hif's (Fih) Structure Controls O2 Activation And Reactivity, John A. Hangasky Iii

Doctoral Dissertations

Factor Inhibiting HIF (FIH) is a Fe(II)-αKG dependent oxygenase that acts as a cellular oxygen sensor in humans. FIH regulates the transcriptional activity of the hypoxia-inducible factor-1 (HIF-1a or HIF), a transcription factor responsible cellular O2 homeostasis. Hydroxylation of the target residue HIF-Asn803, found in the C-terminal transactivation domain (CTAD), inactivates HIF-dependent gene expression. Central to FIH’s function is the activation of O2 after CTAD binding. The mechanistic and structural features of FIH leading to tight coupling between CTAD binding and subsequent O2-activation and reactivity are key for efficient O2 sensing ...


Understanding The Transcriptional Regulation Of Secondary Cell Wall Biosynthesis In The Model Grass Brachypodium Distachyon, Pubudu Handakumbura Nov 2014

Understanding The Transcriptional Regulation Of Secondary Cell Wall Biosynthesis In The Model Grass Brachypodium Distachyon, Pubudu Handakumbura

Doctoral Dissertations

Secondary cell wall synthesis occurs in specialized cell types following completion of cell enlargement. By virtue of mechanical strength provided by a wall thickened with cellulose, hemicelluloses, and lignin, these cells can function as water-conducting vessels and provide structural support. Several transcription factor families regulate genes encoding wall synthesis enzymes. Certain NAC and MYB proteins directly bind upstream of structural genes and other transcription factors. The most detailed model of this regulatory network is established predominantly for a eudicot, Arabidopsis thaliana. In grasses, both the patterning and the composition of secondary cell walls are distinct from that of eudicots. These ...


Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo Nov 2014

Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo

Doctoral Dissertations

Assessment and management of ecosystem services demands diverse knowledge of the system components. Land use change occurring mainly through deforestation, expansion of agriculture and unregulated extraction of natural resources are the greatest challenges of the Congo basin and yet is central to supporting over 100 million people. This study undertook to implement an integrated modeling of multiscale ecosystems of central African watersheds and model the impact of anthropogenic factors on elephant population in Greater Virunga landscape. The study was conducted at varied scales, regional, landscape, and community. Regional study included watershed analysis and hydrological assessment using remotely sensed data implemented ...


The Identification And Characterization Of A Group Of Er Tpr-Containing Adapter Proteins, Johan C. Sunryd Dr. Nov 2014

The Identification And Characterization Of A Group Of Er Tpr-Containing Adapter Proteins, Johan C. Sunryd Dr.

Doctoral Dissertations

The endoplasmic reticulum (ER) is an organelle responsible for a variety of functions in all eukaryotic cells. Some of these functions are localized to specific regions in the ER, such as the ribosome-studded rough ER sheets or the ribosome-free smooth ER sheets. The smooth ER sheets have the ability to form ER tubules, which extend throughout the cell and make contact with other organelles. In order to accommodate these localized functional regions, a certain degree of heterogeneity and compartmentalization into sub-domains exists within the ER. Since the ER membrane and lumen are contiguous, the compartmentalization of the ER into sub-domain ...


Dried Whole Plant Artemisia Annua As A Novel Antimalarial Therapy, Mostafa A. Elfawal Nov 2014

Dried Whole Plant Artemisia Annua As A Novel Antimalarial Therapy, Mostafa A. Elfawal

Doctoral Dissertations

Dried Whole plant Artemisia annua as a novel antimalarial therapy

September 2014

Mostafa Ahmed Elfawal

Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST

Directed by: Professor Stephen M. Rich

Malaria is one of the worst vector-borne parasitic diseases in the developing world. The World Health Organization (WHO) estimated that 215 million cases of malaria occurred, with >655,000 deaths; half the world’s population is at risk of contracting the disease. Drugs are primary weapons for reducing malaria in human populations. Successful drugs are highly efficacious and inexpensive to manufacture synthetically. However, emergence of resistant parasites has repeatedly curtailed the lifespan of ...


Turning Up The Heat On The Little Things That Run The World: Evaluating The Impacts Of Climate Change On Ant Biodiversity In The Temperate Forest Communities Of The Northeastern United States, Israel Del Toro Nov 2014

Turning Up The Heat On The Little Things That Run The World: Evaluating The Impacts Of Climate Change On Ant Biodiversity In The Temperate Forest Communities Of The Northeastern United States, Israel Del Toro

Doctoral Dissertations

Climatic change threatens biodiversity worldwide. In the forests of the northeastern United States, climate change is expected to increase mean annual temperatures by up to 4.5˚C and change precipitation seasonality. These changes in climate are likely to have impacts on the biodiversity of the region. In order to better understand the impacts of climate change on biodiversity, I used ants, an indicator taxonomic group, to predict how ant communities and ant-mediated ecosystem processes change as the climate warms. In the first chapter of this dissertation, I review the major ecosystem processes and services mediated by ants using the ...


Characterization Of Ca2+ Influx Pathway(S) During Mouse Oocyte Maturation, Banyoon Cheon Nov 2014

Characterization Of Ca2+ Influx Pathway(S) During Mouse Oocyte Maturation, Banyoon Cheon

Doctoral Dissertations

Ca2+ signaling induced at fertilization, also known as oscillations, is essential in mammalian eggs to initiate early embryonic development. The generation of the oscillations relies on optimization of Ca2+ toolkit components during oocyte maturation. In this dissertation, we intend to deepen our understanding of how this differentiation of the Ca2+ toolkit, especially those components associated with Ca2+ influx, is achieved during maturation, and how it contributes to the filling of the ER Ca2+ store during the maturation and fertilization.

We first identified the expression and characterized the function of the components of the Store Operated ...


Influence Of Lipoteichoic Acid On Listeria Monocytogenes Biofilm Formation And Cellular Stress, Imelda T. Brooks Nov 2014

Influence Of Lipoteichoic Acid On Listeria Monocytogenes Biofilm Formation And Cellular Stress, Imelda T. Brooks

Doctoral Dissertations

Lipoteichoic acid (LTA) is an important polymer on the surface of Gram-positive organisms, including the foodborne, biofilm-forming pathogen Listeria monocytogenes, and is connected to the cell membrane through a glycolipid backbone. Previous results have shown the importance of LTA in cell viability and biofilm formation. The purpose of this research is to further investigate the influence of LTA in L. monocytogenes biofilm formation and how the bacterium responds to environmental stress caused by antimicrobial exposures, and a combination of low temperature and high osmolarity. We created in frame deletion mutants along the operon lmo-2555-lmo2554-lmo2553, which have been shown to reduce ...


Understanding Lipid Oxidation In Low-Moisture Food, Leann M. Barden Nov 2014

Understanding Lipid Oxidation In Low-Moisture Food, Leann M. Barden

Doctoral Dissertations

Low-moisture snacks account for much of the saturated fat in the diet, making them a key target for improving consumers’ health. However, it is not currently feasible to maintain the same shelf life when replacing saturated fats with unsaturated fats in these products.

The first study characterized the microstructure of a low-moisture cracker model system and determined the impact of iron, chelators, and free fatty acids (FFA) on lipid oxidation kinetics. Confocal microscopy showed that lipids form a continuous layer surrounding the small and/or minimally gelatinized starch granules. Lipid-starch, lipid-air, and starch-lipid-protein interfaces all existed. Oxidation studies showed a ...


Landscape Predictors Of Current And Future Distribution Of Mountain Gorillas (Gorilla Beringei Beringei) In Bwindi Impenetrable National Park, Uganda, Dennis Babaasa Nov 2014

Landscape Predictors Of Current And Future Distribution Of Mountain Gorillas (Gorilla Beringei Beringei) In Bwindi Impenetrable National Park, Uganda, Dennis Babaasa

Doctoral Dissertations

Context: The impacts of ecological, anthropogenic and future climate change on the distribution of wild mountain gorillas (Gorilla beringei beringei) are of ongoing concern. Knowing the factors that determine gorilla habitat suitability now and in future is essential for conservation planning. The mountain gorilla is recognized by IUCN Red Data Book as critically endangered and a great tourist attraction. However, the factors that impact on their spatial use of Bwindi are poorly understood.

Aims: I aimed at determining the major factors that determine gorilla distribution, predict the wild gorilla habitat suitability and establish the vulnerability index of the gorillas to ...


The Estradiol-Induced Transcriptome Of The Female Mouse Anteroventral Periventricular Nucleus: More Than Just A Kiss, Leah K. Aggison Nov 2014

The Estradiol-Induced Transcriptome Of The Female Mouse Anteroventral Periventricular Nucleus: More Than Just A Kiss, Leah K. Aggison

Doctoral Dissertations

Estradiol (E2) is critical in the reproductive mechanisms of mammals. In female rodents E2 acts through the neurons of the anteroventral periventricular nucleus (AVPV) to exert neuroendocrine control over ovulation, via synaptic activation of the gonadotropin releasing hormone (GnRH) neurons. The neurocircuitry of the AVPV is complex, receiving input from the suprachiasmatic nucleus and ventral premammillary nucleus and the as well as projecting to organum vasculosum of lamina terminalis and the arcuate. This suggests a broader role for the AVPV as a center of multisignal-integration in regards to ovulation. I used full genome expression microarrays to assess the ...


Susceptibility Of Escherichia Coli O157:H7, Salmonella Enterica Sp., And Listeria Monocytogenes To Antimicrobial Mixed Micelle Delivery Systems, Chanelle N. Adams Nov 2014

Susceptibility Of Escherichia Coli O157:H7, Salmonella Enterica Sp., And Listeria Monocytogenes To Antimicrobial Mixed Micelle Delivery Systems, Chanelle N. Adams

Doctoral Dissertations

Within the food industry, there is an ever increasing demand to improve the quality of food and ensure safety from pathogenic/spoilage microorganisms. Globalization of the food industry in the 1990’s, in conjunction with the worldwide shipment of food created a need for the extension of shelf-life and enhanced maintenance of food quality (12). In the United States alone, the Centers for Disease Control and Prevention report that each year, roughly 1 in 6 Americans (or 48 million people) gets sick, 128,000 are hospitalized, and 3,000 die of foodborne diseases; this correlates to approximately $77.7 billion ...


Physiology Of Cold Acclimation And Deacclimation Responses Of Cool-Season Grasses: Carbon And Hormone Metabolism, Xian Guan Nov 2014

Physiology Of Cold Acclimation And Deacclimation Responses Of Cool-Season Grasses: Carbon And Hormone Metabolism, Xian Guan

Masters Theses

Winter injury of cool-season turfgrasses in northern climates is a significant issue, leading to losses in turf cover and subsequent increased inputs for recovery. Despite the different potential causes for winter injury, the overall level of plant freezing tolerance has been shown to account for a majority of the variation in winter survival of grasses. Freezing tolerance is achieved through cold acclimation, based on a series of physiological and biochemical changes that increase cell stability at freezing temperatures. Winter injury can result from insufficient cold acclimation, or rapid cold deacclimation triggered by temperature fluctuations or freeze-thaw cycles. Previous research has ...


Attention Modulates Erp Indices Of The Precedence Effect, Benjamin H. Zobel Nov 2014

Attention Modulates Erp Indices Of The Precedence Effect, Benjamin H. Zobel

Masters Theses

When presented with two identical sounds from different locations separated by a short onset asynchrony, listeners report hearing a single source at the location of the lead sound, a phenomenon called the precedence effect (Wallach et al., 1949; Haas, 1951). When the onset asynchrony is above echo threshold, listeners report hearing the lead and lag sounds as separate sources with distinct locations. Event-related potential (ERP) studies have shown that perception of separate sound sources is accompanied by an object-related negativity (ORN) 100-250 ms after onset and a late posterior positivity (LP) 300-500 ms after onset (Sanders et al., 2008; Sanders ...


Properties Of Potential Substrates Of A Cyanobacterial Small Heat Shock Protein, Yichen Zhang Nov 2014

Properties Of Potential Substrates Of A Cyanobacterial Small Heat Shock Protein, Yichen Zhang

Masters Theses

Most proteins must fold into native three-dimensional structures to be functional. But, newly synthesized proteins are at high risk of misfolding and aggregating in the cell. Stress, disease or mutations can also cause protein aggregation. A cyanobacterial small heat shock protein, Hsp16.6, can act as a chaperone to prevent irreversible protein aggregation during heat stress. This thesis is focused on the properties of proteins that were associated with Hsp16.6 during heat stress, and which therefore may be “substrates” of Hsp16.6. Bioinformatics were used to determine if Hsp16.6 preferentially binds to proteins with certain properties, and biochemical ...


Expression And Purification Of Human Lysosomal Β-Galactosidase From Pichia Pastoris, Sarah E. Tarullo Nov 2014

Expression And Purification Of Human Lysosomal Β-Galactosidase From Pichia Pastoris, Sarah E. Tarullo

Masters Theses

Lysosomal storage diseases are genetically inherited diseases caused by the dysfunction of lysosomal enzymes. In a normal cell, lysosomal enzymes cleave specific macromolecules as they are transported to the lysosome. However, in diseased cells, these lysosomal enzymes are either absent or malfunctioning, causing macromolecular substrates to accumulate, becoming toxic to the cell. Over fifty lysosomal storage diseases have been identified, collectively occurring in one out of 7,700 live births. We investigated the lysosomal enzyme β-galactosidase (β-gal). In order to study the biochemistry and enzymology of this protein a robust expression system was needed. The GLB1 gene has been inserted ...


Age-Related Changes In Sleep-Dependent Consolidation Of Visuo-Spatial Memory, Akshata Sonni Nov 2014

Age-Related Changes In Sleep-Dependent Consolidation Of Visuo-Spatial Memory, Akshata Sonni

Masters Theses

Healthy aging is associated with a reduction in slow-wave sleep (SWS), crucial for declarative memory consolidation in young adults; consequently, previously observed benefits of sleep on declarative learning in older adults could reflect a passive role of sleep in protecting memories from waking interference, rather than an active, stabilizing effect. To dissociate the passive and active roles of sleep, a visuo-spatial task was administered; memory was probed after a 12 hr interval consisting of either daytime wake or overnight sleep and post-wake/post-sleep stability of the memories was tested following task-related interference. Ninety five older adults (mean=65.43 yrs ...


Intuitive Eating, Attitudes To Food, And Body Size: A Comparison Between Nutrition Majors And Non-Majors, Katelyn Russell Nov 2014

Intuitive Eating, Attitudes To Food, And Body Size: A Comparison Between Nutrition Majors And Non-Majors, Katelyn Russell

Masters Theses

Dietitians are expected to deliver sound and scientifically objective advice to the general public, yet their personal beliefs and behaviors could influence delivery of nutrition care. Increased understanding of the personal attitudes and behaviors of dietitians concerning eating behavior and body image could help improve dietetic practice. Traditional nutrition education emphasizes cognitive eating, i.e., monitoring energy intake and comparing macronutrient intakes to the current acceptable ranges. Intuitive eating, however, promotes the release of cognitive eating in favor of greater attention to physiologic cues, or “body wisdom”. We hypothesized that nutrition students in a traditional curriculum would report eating less ...


Volatile Profiles And Resistance To Herbivory In Eastern Hemlock, Elizabeth A. Mckenzie Nov 2014

Volatile Profiles And Resistance To Herbivory In Eastern Hemlock, Elizabeth A. Mckenzie

Masters Theses

Eastern hemlock hosts the hemlock woolly adelgid, an introduced sap-feeding insect that causes rapid deterioration of the host. Like most conifers, eastern hemlock produces a variety of constitutive and induced defenses, primarily terpenoids. To explore the relationship of terpenoid defenses with adelgid infestations, we artificially infested hemlocks at a forest site and a plantation site, and compared their terpenoid concentrations to those in control trees. Infested trees showed lower terpenoid concentrations than control trees, suggesting that eastern hemlock not only fails to induce production of terpenoids in response to adelgid infestation, but becomes less able to produce carbon-based defenses due ...