We show the effects of simulated supersonic granular flow made up of smooth particles passing over two prototypical bodies: a wedge and a disk. We describe a way of computationally identifying shock wave locations in granular flows and tabulate the shock wave locations for flow over wedges and disks. We quantify the shock structure in terms of oblique shock angle for wedge impediments and shock standoff distance for disk impediments. We vary granular flow parameters including upstream volume fraction, average upstream velocity, granular temperature, and the collision coefficient of restitution. Both wedges and disks have been used in the aerospace community as prototypical impediments to flowing air in order to investigate the fundamentally different shock structures emanating from sharp and blunt bodies, and we present these results in order to increase the understanding of the fundamental behavior of supersonic granular flow.

Three to 5 days after a primary HSV-1 infection, macrophages infiltrate into the trigeminal ganglia (TG) and produce anti-viral cytokines to reduce viral replication. Previous research demonstrated that social disruption stress (SDR) enhances the trafficking of monocytes/macrophages from the bone marrow to the spleen and increases pro-inflammatory cytokine production in vitro and in vivo. The impact of SDR on the trafficking of these cells to loci of herpes simplex virus type 1 (HSV-1) infection and subsequent function has not been examined. The following studies were designed to determine whether SDR would enhance the innate immune response during a primary HSV-1 infection by increasing the number of macrophages in the cornea and TG, thus increasing anti-viral cytokine production and reducing viral replication. BALB/c mice were exposed to six cycles of SDR prior to ocular infection with HSV-1 McKrae virus. Flow cytometric analysis of cells from the TG revealed an increase in the percentage of CD11b+ macrophages in SDR mice compared to controls. Immune cell infiltration into the cornea, however, could not be determined due to low cell numbers. Although gene expression of IFN-β was decreased, SDR increased gene expression of IFN-α, and TNF-α, in the cornea and TG. Examination of viral proteins showed decreased expression of infected cell protein 0 (ICP0), glycoprotein B (gB), glycoprotein H (gH) and latency-associated transcript (LAT) in the TG, however, expression of ICP0 and gB were elevated in the cornea of SDR mice. These results indicate that the innate immune response to HSV-1 was altered and enhanced by the experience of repeated social defeat.

Immunological memory (MEM) development is affected by stress-induced neuroendocrine mediators. Current knowledge about how a behavioral interaction, such as social defeat, alters the development of adaptive immunity, and MEM is incomplete. In this study, the experience of social disruption stress (SDR) prior to a primary influenza viral infection enhanced the frequency and function of the T cell memory pool. Socially stressed mice had a significantly enlarged population of CD8+ T cells specific for the immunodominant NP366–74 epitope of A/PR/8/34 virus in lung and spleen tissues at 6–12 wk after primary infection (resting memory). Moreover, during resting memory, SDR-MEM mice responded with an enhanced footpad delayed-type hypersensitivity response, and more IFN-γ–producing CD4+ T cells were detected after ex vivo stimulation. When mice were rechallenged with A/PR/8/34 virus, SDR-MEM mice terminated viral gene expression significantly earlier than MEM mice and generated a greater DbNP366–74CD8+ T cell response in the lung parenchyma and airways. This enhancement was specific to the T cell response. SDR-MEM mice had significantly attenuated anti-influenza IgG titers during resting memory. Similar experiments in which mice were primed with X-31 influenza and challenged with A/PR/8/34 virus elicited similar enhancements in the splenic and lung airway DbNP366–74CD8+ T cell populations in SDR-MEM mice. This study demonstrates that the experience of repeated social defeat prior to a primary viral infection significantly enhances virus-specific memory via augmentation of memory T cell populations and suggests that social stressors should be carefully considered in the design and analysis of future studies on antiviral immunity.

Abstract Social disruption (SDR) stress increases splenic CD11b+ myeloid cells, which produce high levels of proinflammatory cytokines upon Toll-like receptor ligation and show impaired nuclear translocation of the GC receptor (GCr) after corticosterone (cort) stimulation. To uncover the mechanism of GC resistance, p38 MAPK (p38) expression and phosphorylation were investigated along with phosphorylation of the GCr. To examine the mechanism(s) of enhanced proinflammatory cytokine responses, CD11b+ splenocytes from control (HCC) and SDR mice were stimulated with lipopolysaccharide in the presence of cort. SDR and HCC CD11b+ cells show similar levels of unphosphorylated p38 protein. CD11b+ cells from SDR mice exhibited an increase in phosphorylation of p38 and of the GCr. Since phosphorylation of p38 has been linked to GCr phosphorylation in humans, it is likely that a same phenomenon occurs here, though it must be confirmed. Since, phosphorylation of the GCr reduces steroid-induced cytokine repression; this may explain the enhanced cytokine expression. These data show that phosphorylated forms of p38 and GCr play a role in GC resistance. Support: NIH grants NIMH/RO1MH046801-16 and NIDCR/T32DE014320-6

Psychological stress is associated with an increased expression of markers of peripheral inflammation, and there is a growing literature describing a link between periodontal pathogens and systemic inflammation. The hypothesis of the present work is that exposing mice to the social stressor, called social disruption (SDR), would enhance the inflammatory response to lipopolysaccharide (LPS) derived from the oral pathogen, Porphyromonas gingivalis. Mice were exposed to SDR for 2 h per day on 6 consecutive days. On the morning following the last cycle of SDR, mice were tested for anxiety-like behavior in the open field test and novel object test. The mice were sacrificed the following day and their spleens harvested. Spleen cells were stimulated with LPS derived from P. gingivalis in the absence or presence of increasing doses of corticosterone. Social disruption resulted in anxiety-like behavior, and the production of IL-1β and TNF-α was significantly higher in spleen cells from mice exposed to SDR in comparison to levels from non-stressed control mice. In addition, the viability of spleen cells from mice exposed to SDR was significantly greater than the viability of cells from non-stressed control mice, even in the presence of high doses of corticosterone. The use of cultures enriched for CD11b+ cells indicated that the stressor was affecting the activity of splenic myeloid cells. This study demonstrates that social stress enhances the inflammatory response to an oral pathogen and could provide a critical clue in the reported associations between stress, inflammation, and oral pathogens.

This paper presents observations regarding the frequency response behavior of the lumbar spine. The frequency response ratio is calculated using a model of the spine which treats the vertebrae as cubic masses and the discs as systems of springs and dampers. The frequency response of the spinal model under healthy spine conditions is cataloged. The model is varied to simulate intervertebral disc degradation, spinal fusions, and artificial disc replacements, and the frequency response for these cases are calculated and compared with the response of the healthy spine.

Exposure to psychosocial stress is a risk factor for cardiovascular disease. Given that dipeptidyl peptidase-4 (DPP4) regulates several intracellular signaling pathways associated with glucagon-like peptide-1 (GLP-1) metabolism, we investigated the role of DPP4 in stress-related vascular senescence and atherosclerosis in apolipoprotein E-deficient (ApoE−/−) mice.ApoE−/− mice fed a high-fat (HF) diet were randomly assigned to one of non-stress and immobilized stress groups for 12 weeks. Chronic stress accelerated vascular senescence and atherosclerotic plaque growth at the aortic roots. Stressed mice had increased levels of plasma DPP4 and decreased levels of plasma GLP-1 and adiponectin (APN) and adipose APN expression. Stress increased plaque macrophage infiltration, neovessel density, and elastin fragmentation, lessened the plaque collagen content, and increased the levels of toll-like receptor-2 (TLR2), TLR4, C-X-C chemokine receptor-4, cathepsins S and K, osteopontin, peroxisome proliferator-activated receptor-α, p16INK4A, p21, and gp91phox mRNAs and/or proteins. Stressed aortas had also increased matrix metalloproteinase-2 (MMP-2) and MMP-9 activities. DPP4 inhibition with anagliptin reversed stress-related atherosclerotic lesion formation, and this benefit was abrogated by APN blocking. In vitro, the GLP-1 receptor agonist exenatide stimulated APN expression in 3T3-L1 cells.These results indicate that the DPP4 inhibition-mediated benefits are likely attributable, at least in part, to attenuation of plaque inflammation, oxidative stress and proteolysis associated with GLP-1-mediated APN production in ApoE−/− mice under stress. Thus, DPP4 will be a novel therapeutic target for the treatment of stress-related cardiovascular disease.

Psychological stress has a significant impact on the anti‐viral immune response. In previous studies, social disruption stress (SDR) enhanced the adaptive response to influenza A/PR/8 infection, particularly at the level of the immunodominant DbNP366+T cell subset. This study was designed to determine the effect of SDR‐primed dendritic cells (DCs) on the development of enhanced influenza‐specific immune responses. Mice were infected with A/PR/8 24 hours after the transfer of purified DCs from the spleens of HCC or SDR mice. Mice receiving SDR‐primed DCs had significantly increased DbNP366+T cells in the lung 9 days post‐infection when compared to mice receiving HCC DCs. In addition, recipients of SDR‐primed DCs had decreased levels of M1 mRNA expression and increased levels of IFN‐γ mRNA expression in the lung 9 days post‐infection when compared to HCC DC recipients. Companion in vitro cultures showed increased IFN‐γ in the supernatants of SDR‐primed DCs co‐cultured with influenza peptide NP366–74 and CD8+T cells from influenza‐infected mice, compared to cultures containing HCC DCs. Taken together, these data indicate that SDR‐primed DCs enhance the immune response to A/PR/8 infection through the increase in DbNP366+T cell frequency and overall IFN‐γ secretion, which leads to enhanced viral clearance in the SDR‐primed DC recipient mice. Supported by NIH grants NIMH/RO1MH046801–15 and NIDCR/T32DE014320–6.

Porphyromonas gingivalis is an important pathogen in the development of periodontal disease. Our study investigated if the treatment with antimicrobial photodynamic therapy (aPDT) that employs a nontoxic dye, followed by irradiation with harmless visible light can attenuate the experimental infection of P. gingivalis in Galleria mellonella. Firstly, different concentrations of P. gingivalis ranging from 102 to 106 cells/larva were injected into the animal to obtain a lethal concentration. Next, the following groups of G. mellonella infected with P. gingivalis were evaluated: inoculation of the photosensitizer and application of laser (P + L+), inoculation of physiologic solution and application of laser (P-L+), inoculation the photosensitizer without laser (P + L-) and inoculation of physiologic solution without Laser (P-L-). The effects of aPDT on infection by P. gingivalis were evaluated by survival curve analysis and hemocytes count. A lethal concentration of 106 cells/larva was adopted for evaluating the effects of aPDT on experimental infection with P. gingivalis. We found that after 120 s of PDT application, the death of G. mellonella was significantly lower compared to the control groups (p = 0.0010). Moreover, the hemocyte density in the P+L+ group was increased by 9.6 × 106 cells/mL (2.62-fold increase) compared to the infected larvae with no treatment (L-P- group) (p = 0.0175). Finally, we verified that the aPDT led to a significant reduction of the number of P. gingivalis cells in G. mellonella hemolymph. In conclusion, PDT application was effective against P. gingivalis infection by increasing the survival of G. mellonella and was able to increase the circulating hemocytes indicating that PDT activates the G. mellonella immune system.

Murine studies have demonstrated that the experience of social defeat (social disruption stress, SDR) before a primary influenza virus challenge augmented memory CD8+T cell responses to viral re‐challenge. Patterning of immune memory is established by the immune response to a primary infection, and the present study was designed to investigate potential mechanisms for memory enhancement during a primary challenge. C57BL/6 mice underwent 2 hrs of SDR per night for 6 nights (SDR‐INF group), which entailed introducing an aggressive mouse that physically defeated all resident mice. After night 6 of SDR, mice were intranasally infected with 1 HAU of influenza A/PR/8. Clonal expansion was significantly enhanced in the SDR‐INF group (p<0.05) for the immunodominant DbNP366+T cell subset, but not the DbPA224+ subset. SDR‐INF mice terminated viral replication significantly earlier than INF mice, and expressed more IFNγ mRNA prior to and during A/PR/8 infection. This study suggests that social defeat‐induced enhancement of virus‐specific immune memory occurs at the activation/clonal expansion phase of a primary infection, and is mediated by both cellular and environmental factors.Supported by NIH grants F30DE17068‐02, RO1MH46801‐13, T32DE014320‐04.

Stress hormones significantly impact dendritic cell (DC) activation and function, typically in a suppressive fashion. However, a social stressor termed social disruption (SDR) has been shown to induce an increase in inflammatory responses and a state of glucocorticoid resistance in splenic CD11b+ monocytes. These experiments were designed to determine the effects of SDR on DC activation, Toll-like receptor-induced cytokine secretion, and glucocorticoid sensitivity. Compared to cells obtained from control animals, splenic DCs from SDR mice displayed increased levels of MHC I, CD80, and CD44, indicative of an activated phenotype. In addition, DCs from SDR mice produced comparatively higher TNF-α, IL-6, and IL-10 in response to in vitro stimulation with LPS and CpG DNA. Increased amounts of TNF-α and IL-6 were also evident in SDR DC cultures stimulated with poly(I:C). Furthermore, as shown previously in CD11b+ monocytes, the CD11c+ DCs obtained from SDR mice were glucocorticoid resistant. Taken together, the data suggest that social stress, in the absence of any immune challenge, activates DCs, increases DC cytokine secretion in response to Toll-specific stimuli and renders DCs glucocorticoid resistant.

Wound healing involves many cell types whose functions are dependent upon the coordinated production of multiple cytokines, chemokines, and growth factors. Recent data show that behavioral stress disrupts the cytokine profile and slows wound closure. For example, in mice, restraint stress (RST) suppressed IL-1β, PDGF, and MCP-1 production, and delayed healing of a 3.5 mm circular wound by more than 3 days. The RST-induced delay in healing was due, in part, to elevated glucocorticoids (GC) and could be blocked by administration of the androgen hormone, androstenediol (AED). Therefore, it was hypothesized that AED would antagonize GC-mediated regulation of cytokine gene expression at the transcriptional level, prevent RST-mediated/GC-dependent suppression of cytokine expression at the tissue level, and restore healing to that of controls. Total wound RNA was collected after injury, cDNA was synthesized, and real-time PCR was used to quantify IL-1β RNA as a measure of proinflammatory gene expression and IκBα RNA as a measure of NF-κB transcriptional activation. Compared to controls, RST delayed wound closure (P < 0.001) and decreased IL-1β(P = 0.021) and IκBα expression within 12–24 hours of wounding (P = 0.021). In contrast, treatment of RST animals with AED restored IL-1β gene expression and restored wound closure to that of controls. Additionally, AED enhanced IκBα RNA postinjury (P < 0.001) suggestive of enhanced NF-κB activation. Because of the macrophage’s ability to coordinate inflammatory responses during healing, RAW 264.7 murine macrophages were used to examine modulation of NF-κB activity in AED and GC-treated cells. The data showed that dexamethasone blocked translocation of active p65 which correlated with diminished cytokine gene expression. In contrast, AED restored cytokine gene expression and nuclear p65 levels in GC-treated cultures. In sum, these data suggest that AED antagonized GC-mediated regulation of cytokine gene expression at the transcriptional level and restored cutaneous wound healing to that of unstressed controls. Supported by MH5689, AG16321, DE14304, and DE14320

The majority of conservation efforts and public attention are focused on large, charismatic mammals and birds such as tigers, pandas and penguins, yet the bulk of animal life, whether measured by biomass, numerical abundance or numbers of species, consists of invertebrates such as insects. Arguably, these innumerable little creatures are far more important for the functioning of ecosystems than their furry or feathered brethren, but until recently we had few long-term data on their population trends. Recent studies from Germany and Puerto Rico suggest that insects may be in a state of catastrophic population collapse: the German data describe a 76% decline in biomass over 26 years, while the Puerto Rican study estimates a decline of between 75% and 98% over 35 years. Corroborative evidence, for example from butterflies in Europe and California (which both show slightly less dramatic reductions in abundance), suggest that these declines are not isolated. The causes are much debated, but almost certainly include habitat loss, chronic exposure to pesticides, and climate change. The consequences are clear; insects are integral to every terrestrial food web, being food for numerous birds, bats, reptiles, amphibians and fish, and performing vital roles such as pollination, pest control and nutrient recycling. Terrestrial and freshwater ecosystems will collapse without insects. These studies are a warning that we may have failed to appreciate the full scale and pace of environmental degradation caused by human activities in the Anthropocene.

Phagocytes of the innate immune system, such as monocytes/macrophages, represent a first line of defense against invading microorganisms. Psychological stress is often thought to suppress the functioning of these cells, in part due to the immunosuppressive activity of stress-induced glucocorticoid hormones. However, exposure to the stressor social disruption (SDR) has been shown to increase cytokine production by monocytes/macrophages and to reduce their sensitivity to corticosterone. Thus, it was hypothesized that splenic monocytes/macrophages from socially stressed mice would be primed to be more physiologically active than cells from nonstressed controls. Flow cytometry was used to demonstrate that exposure to SDR significantly increased the expression of Toll-like receptors (TLR) 2 and 4 on the surface of splenic macrophages. In a follow-up experiment, exposure to SDR also increased the ability of these macrophages to kill Escherichia coli ex vivo and in vivo. However, SDR failed to increase the bactericidal activity of splenic macrophages from C3H/HeJ mice, which lack functional TLR4. In mice with functional TLR4, the stress-induced increase in bactericidal activity was associated with a significant increase in macrophage gene expression for inducible nitric oxide synthase and subunits of the NADPH oxidase complex, which are responsible for generating reactive nitrogen and oxygen intermediates, respectively. This stress-induced increase in gene expression was not evident in the TLR4-deficient mice. These data indicate that SDR increases TLR expression, which in turn enhances the bactericidal activity of splenic macrophages, in part by increasing pathways responsible for reactive oxygen and nitrogen intermediate production.