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The outbreak of coronavirus disease 2019 (COVID-19) has led to significant challenges for schools and communities during the pandemic, requiring policy makers to ensure both safety and operational feasibility. In this paper, we develop mixed-integer programming models and simulation tools to redesign routes and bus schedules for operating a real university campus bus system during the COVID-19 pandemic. We propose a hub-and-spoke design and utilize real data of student activities to identify hub locations and bus stops to be used in the new routes. To reduce disease transmission via expiratory aerosol, we design new bus routes that are shorter than 15 minutes to travel and operate using at most 50% seat capacity and the same number of buses before the pandemic. We sample a variety of scenarios that cover variations of peak demand, social distancing requirements, and bus breakdowns to demonstrate the system resiliency of the new routes and schedules via simulation. The new bus routes were implemented and used during the academic year 2020–2021 to ensure social distancing and short travel time. Our approach can be generalized to redesign public transit systems with a social distancing requirement to reduce passengers’ infection risk. History: This paper was refereed. This article has been selected for inclusion in the Special Issue on Analytics Remedies to COVID-19. Funding: This work was supported by the National Science Foundation [Grant CMMI-2041745] and the University of Michigan, College of Engineering.

With development of the nanomedicine field and increasing hazards of exposure to nanobiological materials, research on the protein corona is urgently required. In particular, the understanding of the mechanism of structural changes of protein on a nanosurface should be improved. Herein, we focus on exploring the role of ligand adsorption modes (physiosorbed citrates or chemisorbed GSH) in the regulation of conformational rearrangement of three blood proteins (serum albumin, globulin, and fibrinogen) on the surface of gold nanoparticles. Through experimental measurements, protein adsorption features (thermodynamics, kinetics, adsorption orientation, and structural changes) were estimated. Molecular dynamics simulations further indicated that physiosorbed citrates could be gradually peeled off by approaching proteins and that the bare Au surface provided a stronger interface interaction than the chemisorbed GSH layer. Protein structure rearrangements were due to the reduction in protein internal energy, with an increase in H-bond formation involving a decrease in the α-helical content and an increase in the β-sheet content, to offset the high interfacial energy. Rearrangement of protein structures could occur either intramolecularly or intermolecularly. These findings enhanced our understanding of nano-protein interaction in the biological milieu and facilitate biomedical exploration of engineered nanomaterials.

Quantum control aims to manipulate quantum systems toward specific quantum states or desired operations. Designing highly accurate and effective control steps is vitally important to various quantum applications, including energy minimization and circuit compilation. In this paper we focus on discrete binary quantum control problems and apply different optimization algorithms and techniques to improve computational efficiency and solution quality. Specifically, we develop a generic model and extend it in several ways. We introduce a squared L2-penalty function to handle additional side constraints, to model requirements such as allowing at most one control to be active. We introduce a total variation (TV) regularizer to reduce the number of switches in the control. We modify the popular gradient ascent pulse engineering (GRAPE) algorithm, develop a new alternating direction method of multipliers (ADMM) algorithm to solve the continuous relaxation of the penalized model, and then apply rounding techniques to obtain binary control solutions. We propose a modified trust-region method to further improve the solutions. Our algorithms can obtain high-quality control results, as demonstrated by numerical studies on diverse quantum control examples.

A luminescent terbium metal–organic framework (Tb-MOF) was prepared using Tb3+ as metal ions and a boronic acid ligand (3,5-dicarboxybenzeneboronic acid) as linkers, which was successfully employed for the detection and scavenging of reactive oxygen species (ROS) in living cells. After the formation of the Tb-MOF, the luminescence of Tb3+ is sensitized by the organic linkers. In addition, the functionalization of boronic acid groups in the channels of MOFs also enhances the luminescence of Tb3+ ions through the antenna effect by adjusting the energy level of the ligand. In addition, the free boronic acid groups act as active sites and react with ROS due to a rapid nucleophilic addition reaction, which leads to the luminescence quenching of Tb-MOF. On the basis of these findings, the boronic acid-functionalized Tb-MOF can be used as an excellent ROS scavenger and a nanoprobe for highly selective and sensitive detection of ROS in living cells.

Pt nanoparticle (Pt NP)@UiO-66-NH2 composites were synthesized and encompassed the benefits of permanent porosity, high thermal and chemical stability of metal–organic frameworks (MOFs), together with the functional behavior of isolated Pt NPs. The PVP-stabilized Pt NPs with the average diameter of 2.48 nm were well dispersed and confined within the framework of UiO-66-NH2. Pt NPs possess highly peroxidase-like activities and make the composites oxidize 3,3′,5,5′-tetramethylbenzidine in the presence of H2O2. Moreover, the specific interaction between Hg2+ and Pt NPs leads to the effective suppression of the peroxidase-like activity of Pt NP@UiO-66-NH2, which endows excellent selectivity for Hg2+ measurement over the interfering metal ions. Based on the colorimetric sensing system, Hg2+ is linearly measured over the range from 0 to 10 nM with a detection limit of 0.35 nM. Moreover, the as-obtained Pt NP@UiO-66-NH2 nanocomposites exhibit high capacity and good selectivity for Hg2+ adsorption, which is succe...