Spatial scales of COVID-19 transmission in Mexico.

During outbreaks of emerging infectious diseases, internationally connected cities often experience large and early outbreaks, while rural regions follow after some delay. This hierarchical structure of disease spread is influenced primarily by the multiscale structure of human mobility. However, during the COVID-19 epidemic, public health responses typically did not take into consideration the explicit spatial structure of human mobility when designing nonpharmaceutical interventions (NPIs).

Dynamics of cold random hyperbolic graphs with link persistence.

We consider and analyze a dynamic model of random hyperbolic graphs with link persistence. In the model, both connections and disconnections can be propagated from the current to the next snapshot with probability ω∈[0,1). Otherwise, with probability 1-ω, connections are reestablished according to the random hyperbolic graphs model.

Entropy of labeled versus unlabeled networks.

The structure of a network is an unlabeled graph, yet graphs in most models of complex networks are labeled by meaningless random integers. Is the associated labeling noise always negligible, or can it overpower the network-structural signal? To address this question, we introduce and consider the sparse unlabeled versions of popular network models and compare their entropy against the original labeled versions. We show that labeled and unlabeled Erdős-Rényi graphs are entropically equivalent, even though their degree distributions are very different.

Dynamic hidden-variable network models.

Models of complex networks often incorporate node-intrinsic properties abstracted as hidden variables. The probability of connections in the network is then a function of these variables. Real-world networks evolve over time and many exhibit dynamics of node characteristics as well as of linking structure.

Network comparison and the within-ensemble graph distance.

Quantifying the differences between networks is a challenging and ever-present problem in network science. In recent years, a multitude of diverse, solutions to this problem have been introduced. Here, we propose that simple and well-understood ensembles of random networks-such as Erdős-Rényi graphs, random geometric graphs, Watts-Strogatz graphs, the configuration model and preferential attachment networks-are natural benchmarks for network comparison methods.

Transient chaos and associated system-intrinsic switching of spacetime patterns in two synaptically coupled layers of Morris-Lecar neurons.

Spatiotemporal chaos collapses to either a rest state or a propagating pulse solution in a single layer of diffusively coupled, excitable Morris-Lecar neurons. Weak synaptic coupling of two such layers reveals system intrinsic switching of spatiotemporal activity patterns within and between the layers at irregular times. Within a layer, switching sequences include spatiotemporal chaos, erratic and regular pulse propagation, spontaneous network wide neuron activity, and rest state.

Identification of a second ATF/CREB-like element in the herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) promoter.

The herpes simplex virus type-1 (HSV-1) latency-associated transcript (LAT) promoter (LP) has been shown to function in a cell type-specific manner. We have constructed an extensive series of PCR deletion mutations of the LP from nucleotides +1 to -348 to delineate the specific sequences involved in the cell type-specific activity of the HSV-1 LP. This series of 5' LP deletion constructs has been transiently transfected into both C1300 (neuronal) and L929 (nonneuronal) cells.

Effect of gamma-interferon on the expression of major histocompatibility complex class I and II gene products in neural cells isolated from the developing human fetal peripheral nervous system.

The effect of gamma-interferon (gamma-IFN) on the expression of major histocompatibility complex (MHC) gene products was examined in the developing human fetal peripheral nervous system. RNA blot hybridization analysis of total RNA isolated from human fetal dorsal root ganglia (DRG) neural cell populations cultured in vitro for 5 days resulted in the detection of both MHC class I- and class II-specific RNAs. As determined by protein immunoblotting and fluorescence-activated flow cytometry, MHC class I and II proteins were also readily detectable in cultured human fetal DRG neural cell populations 5 days after isolation.

Analysis of major histocompatibility complex gene products in tissues isolated from the developing human nervous system.

We have examined the expression of the major histocompatibility complex (MHC) class I and II gene products in the developing human fetal peripheral nervous system. As determined by RNA blot hybridization analysis, MHC class I RNA was readily detectable in extracts prepared from dorsal root ganglia (DRG) obtained from aborted human fetal material. However, utilizing similar methodology, it was not possible to detect MHC class II RNA.

Infection of human fetal dorsal root ganglion glial cells with human immunodeficiency virus type 1 involves an entry mechanism independent of the CD4 T4A epitope.

Human immunodeficiency virus type 1 (HIV-1) has been implicated in the generation of acquired immunodeficiency syndrome-associated neurological dysfunction, and it is believed that the presence of CD4 in the nervous system may be involved in the susceptibility of selected neural cell populations to HIV-1 infection. We previously demonstrated (B. Wigdahl, R.

CD4-independent infection of human neural cells by human immunodeficiency virus type 1.

A number of studies have indicated that central nervous system-derived cells can be infected with human immunodeficiency virus type 1 (HIV-1). To determine whether CD4, the receptor for HIV-1 in lymphoid cells, was responsible for infection of neural cells, we characterized infectable human central nervous system tumor lines and primary fetal neural cells and did not detect either CD4 protein or mRNA. We then attempted to block infection with anti-CD4 antibodies known to block infection of lymphoid cells; we noted no effect on any of these cultured cells.

Cloning of a cDNA coding for P-450 LM3c from rabbit liver microsomes and regulation of its expression.

Liver cytochromes P-450 LM3c in the rabbit and P-450p in the rat are two related forms, inducible by macrolide antibiotics such as triacetyloleandomycin (TAO) and glucocorticoids such as dexamethasone. We prepared a cDNA library from TAO induced rabbit liver mRNA and characterized a cDNA (pLM3c-4.1) that hybridized to pDex 3.

Demonstration in multiple species of inducible hepatic cytochromes P-450 and their mRNAs related to the glucocorticoid-inducible cytochrome P-450 of the rat.

We have recently demonstrated that P-450p, a form of rat liver cytochrome P-450 inducible by steroids such as dexamethasone and pregnenolone-16 alpha-carbonitrile, by the macrolide antibiotic triacetyloleandomycin, and by phenobarbital, is immunochemically related to and shares 73% NH2-terminal amino acid sequence homology with rabbit cytochrome LM3c. Extending this interspecies comparison we now report that liver microsomes prepared from the rabbit, hamster, gerbil, and mouse contain inducible cytochromes P-450 that resemble P-450p in: (a) converting triacetyloleandomycin to a metabolite that forms a distinct spectral complex with cytochrome P-450 heme, (b) catalyzing the demethylation of erythromycin, and (c) reacting on immunoblots with antibodies directed against P-450p or LM3c. These three characteristics changed in parallel within treatment groups of a given species receiving different inducers of cytochrome P-450.

A 78-kilobase region of mouse chromosome 3 contains salivary and pancreatic amylase genes and a pseudogene.

Genetic studies have demonstrated that salivary and pancreatic amylase genes are closely linked in human and mouse. To analyze the arrangement of genes within the amylase cluster, a library of YBR mouse genomic DNA was cloned in the cosmid vector pJB8. Clones containing amylase genes were identified by hybridization with amylase cDNA probes.