University of Massachusetts Amherst
  • Amherst Center, MA, United States
Recent publications
Experiments were performed to explore the impact of sulfur nanoparticles (SNPs) on growth, Cu accumulation, and physiological and biochemical responses of oilseed rape (Brassica napus L.) inoculated with 5 mg/L Cu-amended MS medium supplemented with or without 300 mg/L SNPs exposure. Cu exerted severe phytotoxicity and inhibited plant growth. SNPs application enhanced the shoot height, root length, and dry weight of shoot and root by 34.6%, 282%, 41.7% and 37.1%, respectively, over Cu treatment alone, while the shoot and root Cu contents and Cu-induced lipid perodixation as the malondialdehyde (MDA) levels in shoots and roots were decreased by 37.6%, 35%, 28.4% and 26.8%. Further, the increases in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST) enzyme activities caused by Cu stress were mitigated in shoots (10.9–37.1%) and roots (14.6–35.3%) with SNPs addition. SNPs also positively counteracted the negative effects on shoot K, Ca, P, Mg, Mn, Zn and Fe contents and root K, Ca, Mg and Mn contents from Cu exposure alone, and significantly promoted the nutrients accumulation in plant. Additionally, in comparison with common bulk sulfur particles (BSPs) and sulfate, SNPs showed more positive effects on promoting growth in shoots (6.7% and 19.5%) and roots (10.9% and 15.1%), as well as lowering the shoot Cu content (40.1% and 43.3%) under Cu stress. Thus, SNPs application has potential to be a green and sustainable technology for increasing plant productivity and reducing accumulation of toxic metals in heavy metal polluted soils.
Mass spectrometry (MS) has become an indispensable tool in structural characterization and quality control of monoclonal antibodies (mAbs). Intact-mass analysis is a particularly attractive option that provides a powerful and cost-effective means to not only confirm the structural integrity of the protein, but also probe its interactions with therapeutic targets. To a certain extent, this success can be attributed to relatively modest glycosylation levels exhibited by IgG molecules, which limits their structural heterogeneity and enables straightforward mass measurements at the intact molecule level. The recent surge of interest in expanding the repertoire of mAbs to include other classes of immunoglobulins places a premium on efforts to adapt the IgG-tailored experimental strategies to other classes of antibodies, but their dramatically higher levels of glycosylation may create insurmountable obstacles. The monoclonal murine IgE antibody explored in this work provides a challenging model system, as its glycosylation level exceeds that of conventional IgG mAbs by a factor of nine. The commercial sample, which included various IgE fragments, yields a poorly resolved ionic signal in intact-mass measurements, from which little useful information can be extracted. However, coupling MS measurements with the limited charge reduction of select polycationic species in the gas phase gives rise to well-defined charge ladders, from which both ionic masses and charges can be readily determined. The measurements reveal significant variation of the extent of glycosylation within intact IgE molecules, as well as the presence of low-molecular weight impurities in the commercial IgE sample. Furthermore, incubation of the monoclonal IgE with its antigen (ovalbumin) gives rise to the formation of complexes with varying stoichiometries, which can also be uniquely identified using a combination of native MS, limited charge reduction in the gas phase and data fitting procedures. This work demonstrates that following appropriate modifications, intact-mass analysis measurements can be successfully applied to mAbs beyond the IgG isotype, providing a wealth of information not only on the mass distribution of the intact IgE molecules, but also their large-scale conformational integrity, the integrity of their covalent structure, and their interactions with antigens.
Conventional vision-based systems, such as cameras, have demonstrated their enormous versatility in sensing human activities and developing interactive environments. However, these systems have long been criticized for incurring privacy, power, and latency issues due to their underlying structure of pixel-wise analog signal acquisition, computation, and communication. In this research, we overcome these limitations by introducing in-sensor analog computation through the distribution of interconnected photodetectors in space, having a weighted responsivity, to create what we call a computational photodetector. Computational photodetectors can be used to extract mid-level vision features as a single continuous analog signal measured via a two-pin connection. We develop computational photodetectors using thin and flexible low-noise organic photodiode arrays coupled with a self-powered wireless system to demonstrate a set of designs that capture position, orientation, direction, speed, and identification information, in a range of applications from explicit interactions on everyday surfaces to implicit activity detection.
The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
The ATLAS experiment at the Large Hadron Collider has a broad physics programme ranging from precision measurements to direct searches for new particles and new interactions, requiring ever larger and ever more accurate datasets of simulated Monte Carlo events. Detector simulation with Geant4 is accurate but requires significant CPU resources. Over the past decade, ATLAS has developed and utilized tools that replace the most CPU-intensive component of the simulation—the calorimeter shower simulation—with faster simulation methods. Here, AtlFast3, the next generation of high-accuracy fast simulation in ATLAS, is introduced. AtlFast3 combines parameterized approaches with machine-learning techniques and is deployed to meet current and future computing challenges, and simulation needs of the ATLAS experiment. With highly accurate performance and significantly improved modelling of substructure within jets, AtlFast3 can simulate large numbers of events for a wide range of physics processes.
The beneficial effect of crop residue amendment on soil organic carbon (SOC) stock and stability depends on the functional response of soil microbial communities. Here we synchronized microbial metagenomic analysis, nuclear magnetic resonance and plant- ¹⁵ N labeling technologies to gain understanding of how microbial metabolic processes affect SOC accumulation in responses to differences in N supply from residues. Residue amendment brought increases in the assemblage of genes involved in C-degradation profiles from labile to recalcitrant C compounds as well as N mineralization. The N mineralization genes were correlated with the C and N accumulation in the particulate and mineral-associated C pools, and plant-derived aliphatic forms of SOC. Thus, the combined C and N metabolic potential of the microbial community transforms residue into persistent organic compounds, thereby increasing C and N sequestration in stable SOC pools. This study emphasizes potential microbially mediated mechanisms by which residue N affects C sequestration in soils.
We develop a protocol for entanglement generation in the quantum internet that allows a repeater node to use n -qubit Greenberger-Horne-Zeilinger (GHZ) projective measurements that can fuse n successfully entangled links , i.e., two-qubit entangled Bell pairs shared across n network edges, incident at that node. Implementing n -fusion, for n ≥ 3, is in principle not much harder than 2-fusions (Bell-basis measurements) in solid-state qubit memories. If we allow even 3-fusions at the nodes, we find—by developing a connection to a modified version of the site-bond percolation problem—that despite lossy (hence probabilistic) link-level entanglement generation, and probabilistic success of the fusion measurements at nodes, one can generate entanglement between end parties Alice and Bob at a rate that stays constant as the distance between them increases. We prove that this powerful network property is not possible to attain with any quantum networking protocol built with Bell measurements and multiplexing alone. We also design a two-party quantum key distribution protocol that converts the entangled states shared between two nodes into a shared secret, at a key generation rate that is independent of the distance between the two parties.
The tourism industry is extremely important to the world economy; yet, the industry falls short when it comes to economic, social, and environmental issues. Blockchain as an information technology can be utilized to help solve these issues and establish sustainable tourism globally. However, the challenges to blockchain adoption in the tourism industry have not yet been examined systematically. The goal of this study, therefore, is three-fold: we first identify the challenges to blockchain using literature review and expert opinions. Then, we examine them using the proposed rough Interpretive Structural Modeling - Cross-Impact Matrix Multiplication based on expert judgments. Finally, we link these challenges to diffusion of innovation theory. The results suggest that “lack of technical maturity” and “lack of interoperability” are the most important challenges of blockchain in the tourism industry. The findings of the study support macro- and micro-level decision-making in tourism industry's prospective applications of blockchain.
Glioblastoma is an aggressive brain cancer characterized by diffuse infiltration. Infiltrated glioma cells persist in the brain post-resection where they interact with glial cells and experience interstitial fluid flow. We use patient-derived glioma stem cells and human glial cells (i.e., astrocytes and microglia) to create a four-component 3D model of this environment informed by resected patient tumors. We examine metrics for invasion, proliferation, and putative stemness in the context of glial cells, fluid forces, and chemotherapies. While the responses are heterogeneous across seven patient-derived lines, interstitial flow significantly increases glioma cell proliferation and stemness while glial cells affect invasion and stemness, potentially related to CCL2 expression and differential activation. In a screen of six drugs, we find in vitro expression of putative stemness marker CD71, but not viability at drug IC 50 , to predict murine xenograft survival. We posit this patient-informed, infiltrative tumor model as a novel advance toward precision medicine in glioblastoma treatment.
This work presents a new class of micromachined electrostatic actuators capable of producing output force and displacement unprecedented for MEMS electrostatic actuators. The actuators feature submicron high aspect ratio transduction gaps lined up in two-dimensional arrays. Such an arrangement of microscale actuator cells allows the addition of force and displacements of a large number of cells (up to 7600 in one demonstrated array), leading to displacements ranging in the hundreds of microns and several gram forces of axial force. For 50 µm thick actuators with horizontal dimensions in the 1–4 millimeter range, an out-of-plane displacement of up to 678 µm at 46 V, a bending moment of up to 2.0 µNm, i.e., 0.08 N (~8 gram-force) of axial force over a 50 µm by 2 mm cross-sectional area of the actuator (800 kPa of electrostatically generated stress), and an energy density (mechanical work output per stroke per volume) up to 1.42 mJ/cm ³ was demonstrated for the actuators.
Introduction Elevated shock index pediatric age-adjusted (SIPA) has been shown to be associated with the need for both blood transfusion and intervention in pediatric patients with blunt liver and spleen injuries (BLSI). SIPA has traditionally been used as a binary value, which can be classified as elevated or normal, and this study aimed to assess if discreet values above SIPA cutoffs are associated with an increased probability of blood transfusion and failure of nonoperative management (NOM) in bluntly injured children. Materials and methods Children aged 1-18 y with any BLSI admitted to a Level-1 pediatric trauma center between 2009 and 2020 were analyzed. Blood transfusion was defined as any transfusion within 24 h of arrival, and failure of NOM was defined as any abdominal operation or angioembolization procedure for hemorrhage control. The probabilities of receiving a blood transfusion or failure of NOM were calculated at different increments of 0.1. Results There were 493 patients included in the analysis. The odds of requiring blood transfusion increased by 1.67 (95% CI 1.49, 1.90) for each 0.1 unit increase of SIPA (P < 0.001). A similar trend was seen initially for the probability of failure of nonoperative management, but beyond a threshold, increasing values were not associated with failure of NOM. On subanalysis excluding patients with a head injury, increased 0.1 increments were associated with increased odds for both interventions. Conclusions Discreet values above age-related SIPA cutoffs are correlated with higher probabilities of blood transfusion in pediatric patients with BLSI and failure of NOM in those without head injury. The use of discreet values may provide clinicians with more granular information about which patients require increased resources upon presentation.
Studies of word class processing have found verb retrieval impairments in individuals with primary progressive aphasia (Bak et al., 2001; Cappa et al., 1998; Cotelli et al., 2006; Hillis, Heidler-Gary, et al., 2006; Hillis, Oh, & Ken, 2004; Marcotte et al., 2014; Rhee, Antiquena, & Grossman, 2001; Silveri & Ciccarelli, 2007; Thompson, Lukic, et al., 2012) associated primarily with the agrammatic variant. However, fewer studies have focused on verb comprehension, with inconsistent results. Because verbs are critical to both production and comprehension of clauses and sentences, we investigated verb processing across domains in agrammatic, logopenic, and semantic PPA and a group of age-matched healthy controls. Participants completed a confrontation naming task for verb production and an eye-tracking word-picture matching task for online verb comprehension. All PPA groups showed impaired verb production and comprehension relative to healthy controls. Most notably, the PPA-S group performed more poorly than the other two PPA variants in both domains. Overall, the results indicate that semantic deficits in the PPA-S extend beyond object knowledge to verbs as well, adding to our knowledge concerning the nature of the language deficits in the three variants of primary progressive aphasia.
Microplastics (MPs) are recognized as vectors for the transport of organic contaminants in aquatic environments in addition to their own adverse effects on aquatic organisms. Per- and polyfluoroalkyl substances (PFASs) are widely present in aquatic environments due to their widespread applications, and thus coexist with MPs. Therefore, we focus on the interaction of MPs and PFASs and related combined toxicity in aquatic environments in this work. The adsorption of PFASs on MPs is critically reviewed, and new mechanisms such as halogen bonding, π-π interaction, cation-π interactions, and micelle formation are proposed. Moreover, the effect of MPs on the transport and transformation of PFASs in aquatic environments is discussed. Based on four typical aquatic organisms (shellfish, Daphnia, algae, and fish), the toxicity of MPs and/or PFASs at the organismal or molecular levels is also evaluated and summarized. Finally, challenges and research perspectives are proposed, and the roles of the shapes and aging process of MPs on PFAS biogeochemical processes and toxicity, especially on PFAS substitutes, are recommended for further investigation. This review provides a better understanding of the interactions and toxic effects of coexisting MPs and PFASs in aquatic environments.
Cancer drug response is heavily influenced by the extracellular matrix (ECM) environment. Despite a clear appreciation that the ECM influences cancer drug response and progression, a unified view of how, where, and when environment-mediated drug resistance contributes to cancer progression has not coalesced. Here, we survey some specific ways in which the ECM contributes to cancer resistance with a focus on how materials development can coincide with systems biology approaches to better understand and perturb this contribution. We argue that part of the reason that environment-mediated resistance remains a perplexing problem is our lack of a wholistic view of the entire range of environments and their impacts on cell behavior. We cover a series of recent experimental and computational tools that will aid exploration of ECM reactions space, and how they might be synergistically integrated.
The purpose of this study was to investigate the cognitive impacts of tablet use on young children’s inhibitory control and error monitoring. A total of 70 children (35 boys) aged 3.5 to 5 years completed an age-appropriate go/no-go task and were then randomly assigned to a technology group or a comparison group. In the technology group, children completed a cooking task on a tablet for 15 min. In the comparison group, children completed a similarly structured cooking task with toys for the same length of time. Children then completed the go/no-go task again. Compared with children in the comparison group, children in the technology group demonstrated poorer inhibitory control as evidenced by lower accuracy on no-go trials after the cooking task. However, both groups displayed post-error reaction time slowing. Collectively, these results suggest that brief tablet use can impose selective impairment on young children’s cognitive abilities for a short period of time following use.
Neolamarckia cadamba (Roxb.) Bosser (Rubiaceae) is a fast-growing and economically important tree in Asia, which has a wide range of biological and pharmacological activities. Using the UPLC-MS fingerprints of the barks of N. cadamba that sampled from 12 different provenance (10 trees per provenance) in a provenance trail, the difference in the components of these samples was visualized. Analyzing the spectrum data and the cytotoxic activity, the relationships of chemical composition and in vitro anti-tumor activity had been established. It was noted that 3α-dihydrocadambine (3a-Dhc), one of the characteristic components in N. cadamba, could bind to the active pocket of P-glycoprotein (P-gp), and then inhibit its efflux activity, leading to reverse the adriamycin (ADR) resistance in MCF7/ADR cells with no toxicity. Taken together, our data pointed out that N. cadamba in different families had high but different contents of cadambine alkaloids, and the UPLC-MS fingerprint could be a powerful tool for guiding the variety breeding, and Sample 12, the provenance from Mengla County, may be a valued source for the best prospect of anti-tumor application. More importantly, 3a-Dhc could be a potential lead for developing a P-gp inhibitor with high potency and low toxicity.
Urine contains high concentrations of nitrogen and phosphorus, which can be utilized as fertilizer in sustainable agriculture, forestry, and landscaping. Before urine application, the nitrogen can be stabilized with calcium hydroxide (lime), which raises the pH and inhibits urea hydrolysis. However, the impact of lime-treated urine on plants and soils remains unclear. Here, lime-treated urine diluted 1:10 with water was applied to soils with sunflowers (Helianthus annuus L.), and growth and soil bacterial diversity was examined at 2 months. We show that lime-treated urine significantly increased sunflower growth up to 85 %, plant biomass up to 151 %, leaf area up to 137 %, and the number of leaves per plant by 2.5 compared to untreated plants. No major differences in bacterial Shannon or Simpson diversity indices were detected between treatment groups, though small shifts in phyla composition were observed, depending on treatment and plant presence. This work demonstrates that recycled urine can effectively be used for the fertilization of non-food crops and landscaping plants.
In type A we find equivalences of geometries arising in three settings: Nakajima's (“framed”) quiver varieties, conjugacy classes of matrices and loop Grassmannians. These are all given by explicit formulas. In particular, we embedd the framed quiver varieties into Beilinson-Drinfeld Grassmannians. This provides a compactification of Nakajima varieties and a decomposition of affine Grassmannians into Nakajima varieties. As an application we provide a geometric version of symmetric and skew (GL(m),GL(n)) dualities.
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10,214 members
Krishna C. Poudel
  • Department of Health Promotion and Policy
Om Parkash Dhankher
  • Stockbridge School of Agriculture
Edward Rietman
  • School of Computer Science
Susanne Moser
  • Department of Landscape Architecture and Regional Planning
Mario Parente
  • Department of Electrical and Computer Engineering
362 Whitmore Administration Building, 01003-9313, Amherst Center, MA, United States
Head of institution
Kumble R. Subbaswamy