Concurrent Geometric Multicasting

We present MCFR, a multicasting concurrent face routing algorithm that uses geometric routing to deliver a message from source to multiple targets. We describe the algorithm's operation, prove it correct, estimate its performance bounds and evaluate its performance using simulation. Our estimate shows that MCFR is the first geometric multicast routing algorithm whose message delivery latency is independent of network size and only proportional to the distance between the source and the targets. Our simulation indicates that MCFR has significantly better reliability than existing algorithms

Intelligent Reflecting Surface Enabled Sensing: Cram\'er-Rao Bound Optimization

This paper investigates intelligent reflecting surface (IRS) enabled non-line-of-sight (NLoS) wireless sensing, in which an IRS is dedicatedly deployed to assist an access point (AP) to sense a target at its NLoS region. It is assumed that the AP is equipped with multiple antennas and the IRS is equipped with a uniform linear array. We consider two types of target models, namely the point and extended targets, for which the AP aims to estimate the target's direction-of-arrival (DoA) and the target response matrix with respect to the IRS, respectively, based on the echo signals from the AP-IRS-target-IRS-AP link. Under this setup, we jointly design the transmit beamforming at the AP and the reflective beamforming at the IRS to minimize the Cram\'er-Rao bound (CRB) on the estimation error. Towards this end, we first obtain the CRB expressions for the two target models in closed form. It is shown that in the point target case, the CRB for estimating the DoA depends on both the transmit and reflective beamformers; while in the extended target case, the CRB for estimating the target response matrix only depends on the transmit beamformers. Next, for the point target case, we optimize the joint beamforming design to minimize the CRB, via alternating optimization, semi-definite relaxation, and successive convex approximation. For the extended target case, we obtain the optimal transmit beamforming solution to minimize the CRB in closed form. Finally, numerical results show that for both cases, the proposed designs based on CRB minimization achieve improved sensing performance in terms of mean squared error, as compared to other traditional schemes.Comment: 14 pages, 7 figures. arXiv admin note: substantial text overlap with arXiv:2204.1107

Review of dimensioning and tolerancing: representation and processing

The paper surveys the current state of knowledge of techniques for representing, manipulating and analysing dimensioning and tolerancing data in computer-aided design and manufacturing. The use of solid models and variational geometry, and its implications for the successful integration of CAD and CAM, are discussed. The topics explored so far can be grouped into four categories: (a) the representation of dimensioning and tolerancing (D & T), (b) the synthesis and analysis of D & T, (c) tolerance control, and (d) the implications of D & T in CAM. The paper describes in detail the recent work in each group, and concludes with speculation on a general framework for future research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29159/1/0000204.pd

Guest Editorial Special Issue on Integrated Sensing and Communication-Part I

Driving a gradual integration of the physical and digital worlds is perceived to become a reality in the 6G era, from vehicles to drones, from surveillance facilities in cities to agricultural tools in the countryside. Jointly motivated by recent advances in communication and signal processing, radio sensing functionality can be integrated into a 6G radio access network (RAN) in a low-cost and fast manner. That is, future networks have the ability to “see” the physical world through imaging and measuring the surrounding environment, which enables advanced location-aware services, ranging from the physical to application layers. In essence, a radio emission could simultaneously convey communication data from the transmitter to the receiver and deliver environmental information from the scattered echoes. Therefore, sensing and communication (S&C) functionalities are possible to be co-designed to utilize resources efficiently and to assist each other for mutual benefits. This type of research is typically referred to as integrated sensing and communication (ISAC)

Vitamin C Prevents Hypogonadal Bone Loss

Epidemiologic studies correlate low vitamin C intake with bone loss. The genetic deletion of enzymes involved in de novo vitamin C synthesis in mice, likewise, causes severe osteoporosis. However, very few studies have evaluated a protective role of this dietary supplement on the skeleton. Here, we show that the ingestion of vitamin C prevents the low-turnover bone loss following ovariectomy in mice. We show that this prevention in areal bone mineral density and micro-CT parameters results from the stimulation of bone formation, demonstrable in vivo by histomorphometry, bone marker measurements, and quantitative PCR. Notably, the reductions in the bone formation rate, plasma osteocalcin levels, and ex vivo osteoblast gene expression 8 weeks post-ovariectomy are all returned to levels of sham-operated controls. The study establishes vitamin C as a skeletal anabolic agent. © 2012 Zhu et al

Probabilistic Constellation Shaping for OFDM-Based ISAC Signaling

Integrated Sensing and Communications (ISAC) has garnered significant attention as a promising technology for the upcoming sixth-generation wireless communication systems (6G). In pursuit of this goal, a common strategy is that a unified waveform, such as Orthogonal Frequency Division Multiplexing (OFDM), should serve dual-functional roles by enabling simultaneous sensing and communications (S&C) operations. However, the sensing performance of an OFDM communication signal is substantially affected by the randomness of the data symbols mapped from bit streams. Therefore, achieving a balance between preserving communication capability (i.e., the randomness) while improving sensing performance remains a challenging task. To cope with this issue, in this paper we analyze the ambiguity function of the OFDM communication signal modulated by random data. Subsequently, a probabilistic constellation shaping (PCS) method is proposed to devise the probability distributions of constellation points, which is able to strike a scalable S&C tradeoff of the random transmitted signal. Finally, the superiority of the proposed PCS method over conventional uniformly distributed constellations is validated through numerical simulations

Activation and Monitoring of mtDNA Damage in Cancer Cells via the "proton-Triggered" Decomposition of an Ultrathin Nanosheet

Mitochondrial DNA (mtDNA) damage is a very important molecular event, which has significant effects on living organisms. Therefore, a particularly important challenge for biomaterials research is to develop functionalized nanoparticles that can activate and monitor mtDNA damage and instigate cancer cell apoptosis, and as such eliminate the negative effects on living organisms. Toward that goal, with this research, we have developed a hydroxyapatite ultrathin nanosheet (HAP-PDCns) - a high Ca2+ content biomaterial. HAP-PDCns undergoes proton-triggered decomposition after entering cancer cells via clathrin-mediated endocytosis, and then, it selectively concentrates in the charged mitochondrial membrane. This kind of proton-triggered decomposition phenomenon facilitates mtDNA damage by causing instantaneous local calcium overload in the mitochondria of cancer cells, and inhibits tumor growth. Importantly, at the same time, a real-time green-red-green fluorescence change occurs that correlates with the degree of mtDNA deterioration because of the changes in the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps during this process. Significantly, the decomposition and the fluorescence changes cannot be triggered in normal cells. Thus, HAP-PDCns can selectively induce apoptosis and the death of a cancer cell by facilitating mtDNA damage, but does not affect normal cells. In addition, HAP-PDCns can simultaneously monitor the degree of mtDNA damage. We anticipate that this design strategy can be generalized to develop other functionalized biomaterials that can be used to instigate the positive effects of mtDNA damage on living organisms while eliminating any negative effects. </p

Investigating the Direct Meltwater Effect in Terrestrial Oxygenâ Isotope Paleoclimate Records Using an Isotopeâ Enabled Earth System Model

Variations in terrestrial oxygenâ isotope reconstructions from ice cores and speleothems have been primarily attributed to climatic changes of surface air temperature, precipitation amount, or atmospheric circulation. Here we demonstrate with the fully coupled isotopeâ enabled Community Earth System Model an additional process contributing to the oxygenâ isotope variations during glacial meltwater events. This process, termed â the direct meltwater effect,â involves propagating large amounts of isotopically depleted meltwater throughout the hydrological cycle and is independent of climatic changes. We find that the direct meltwater effect can make up 15â 35% of the δ18O signals in precipitation over Greenland and eastern Brazil for large freshwater forcings (0.25â 0.50 sverdrup (106 m3/s)). Model simulations further demonstrate that the direct meltwater effect increases with the magnitude and duration of the freshwater forcing and is sensitive to both the location and shape of the meltwater. These new modeling results have important implications for past climate interpretations of δ18O.Key PointsA portion of the δ18O signal in landâ based paleoclimate proxies can be attributed to the direct meltwater effect instead of climatic changesThe direct meltwater effect can make up 15â 35% of the δ18O signals in precipitation in Greenland and eastern Brazil for large meltwater eventsThe direct meltwater effect increases with the magnitude and duration of the freshwater forcing and is sensitive to location and shape dependentPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141374/1/grl56782_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141374/2/grl56782-sup-0001-Supporting_Information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141374/3/grl56782.pd

A Dinucleotide Deletion in CD24 Confers Protection against Autoimmune Diseases

It is generally believed that susceptibility to both organ-specific and systemic autoimmune diseases is under polygenic control. Although multiple genes have been implicated in each type of autoimmune disease, few are known to have a significant impact on both. Here, we investigated the significance of polymorphisms in the human gene CD24 and the susceptibility to multiple sclerosis (MS) and systemic lupus erythematosus (SLE). We used cases/control studies to determine the association between CD24 polymorphism and the risk of MS and SLE. In addition, we also considered transmission disequilibrium tests using family data from two cohorts consisting of a total of 150 pedigrees of MS families and 187 pedigrees of SLE families. Our analyses revealed that a dinucleotide deletion at position 1527∼1528 (P1527(del)) from the CD24 mRNA translation start site is associated with a significantly reduced risk (odds ratio = 0.54 with 95% confidence interval = 0.34–0.82) and delayed progression (p = 0.0188) of MS. Among the SLE cohort, we found a similar reduction of risk with the same polymorphism (odds ratio = 0.38, confidence interval = 0.22–0.62). More importantly, using 150 pedigrees of MS families from two independent cohorts and the TRANSMIT software, we found that the P1527(del) allele was preferentially transmitted to unaffected individuals (p = 0.002). Likewise, an analysis of 187 SLE families revealed the dinucleotide-deleted allele was preferentially transmitted to unaffected individuals (p = 0.002). The mRNA levels for the dinucleotide-deletion allele were 2.5-fold less than that of the wild-type allele. The dinucleotide deletion significantly reduced the stability of CD24 mRNA. Our results demonstrate that a destabilizing dinucleotide deletion in the 3′ UTR of CD24 mRNA conveys significant protection against both MS and SLE