Packing a flexible fiber into a cavity.

The insertion of an elastic rod or fiber into a confining cavity is studied. Such an insertion is a feature of a variety of problems, including packing and unpacking of DNA in viral capsids and the insertion of catheters during surgery. We consider a simplified geometry in which the container is a smooth (frictionless) circular cylinder of radius a. The fiber is pushed through a hole in the curved surface of the cylinder and is then assumed to stay in a cross-sectional plane perpendicular to the cylinder axis. A solution is found for the fiber shape in which most of the fiber lies against the curved interior surface of the cylinder, apart from the final end section of the fiber, of length 2.0888a, which crosses the interior of the cylinder before ending at the opposite side, which it meets at an angle 1.15 rad to the normal. The force required to push the fiber into the cylinder is EI/2a^{2}, where E is the fiber's Young's modulus and I its cross-sectional moment of inertia. The shape of the final end section of the fiber is confirmed by experiment.

Source attributed case-control study of campylobacteriosis in New Zealand.

BACKGROUND: Following an initial reduction in human campylobacteriosis in New Zealand after the implementation of poultry food chain-focused interventions during 2006-2008, further decline has been relatively small. We report a year-long study of notified campylobacteriosis cases, incorporating a case control study combined with a source attribution study. The purpose was to generate up-to-date evidence on the relative contributions of different sources of campylobacteriosis in New Zealand. METHODS: The study approach included: • A case-control study of notified cases (aged six months or more) sampled in a major urban centre (Auckland, every second case) and a mixed urban/rural area (Manawatu/Whanganui, every case), between 12 March 2018 and 11 March 2019. • Source attribution of human campylobacteriosis cases sampled from these two regions over the study period by modelling of multilocus sequence typing data of Campylobacter jejuni and C. coli isolates from faecal samples of notified human cases and relevant sources (poultry, cattle, sheep). RESULTS: Most cases (84%) were infected with strains attributed to a poultry source, while 14% were attributed to a cattle source. Approximately 90% of urban campylobacteriosis cases were attributed to poultry sources, compared to almost 75% of rural cases. Poultry consumption per se was not identified as a significant risk factor. However specific risk factors related to poultry meat preparation and consumption did result in statistically significantly elevated odds ratios. CONCLUSIONS: The overall findings combining source attribution and analysis of specific risk factors indicate that poultry meat remains a dominant pathway for exposure and infection.

Cases of Eastern equine encephalitis in humans associated with Aedes canadensis, Coquillettidia perturbans and Culiseta melanura mosquitoes with the virus in New York State from 1971 to 2012 by analysis of aggregated published data.

From 1971 to 2012, in New York State, years with human Eastern equine encephalitis (EEE) were more strongly associated with the presence of Aedes canadensis, Coquillettidia perturbans and Culiseta melanura mosquitoes infected with the EEE virus (Fisher's exact test, one-sided P = 0.005, 0.03, 0.03) than with Culiseta morsitans, Aedes vexans, Culex pipiens-restuans, Anopheles quadrimaculatus or Anopheles punctipennis (P = 0.05, 0.40, 0.33, 1.00, 1.00). The estimated relative risk of a case in a year in which the virus was detected vs. not detected was 14.67 for Ae. canadensis, 6.38 for Cq. perturbans and 5.50 for Cs. morsitans. In all 5 years with a case, Cs. melanura with the virus was detected. In no year was there a case in the absence of Cs. melanura with the virus. There were 18 years with no case in the presence of Cs. melanura with the virus. Such observations may identify the time of increased risk, and when the methods may be used to prevent or reduce exposure to vector mosquito species in this geographic region.

Incarcerated aboriginal women's experiences of accessing healthcare and the limitations of the 'equal treatment' principle.

BACKGROUND: Colonization continues in Australia, sustained through institutional and systemic racism. Targeted discrimination and intergenerational trauma have undermined the health and wellbeing of Australia's Aboriginal and Torres Strait Islander population, leading to significantly poorer health status, social impoverishment and inequity resulting in the over-representation of Aboriginal people in Australian prisons. Despite adoption of the 'equal treatment' principle, on entering prison in Australia entitlements to the national universal healthcare system are revoked and Aboriginal people lose access to health services modelled on Aboriginal concepts of culturally safe healthcare available in the community. Incarcerated Aboriginal women experience poorer health outcomes than incarcerated non-Indigenous women and Aboriginal men, yet little is known about their experiences of accessing healthcare. We report the findings of the largest qualitative study with incarcerated Aboriginal women in New South Wales (NSW) Australia in over 15 years. METHODS: We employed a decolonizing research methodology, 'community collaborative participatory action research', involving consultation with Aboriginal communities prior to the study and establishment of a Project Advisory Group (PAG) of community expert Aboriginal women to guide the project. Forty-three semi-structured interviews were conducted in 2013 with Aboriginal women in urban and regional prisons in NSW. We applied a grounded theory approach for the data analysis with guidance from the PAG. RESULTS: Whilst Aboriginal women reported positive and negative experiences of prison healthcare, the custodial system created numerous barriers to accessing healthcare. Aboriginal women experienced institutional racism and discrimination in the form of not being listened to, stereotyping, and inequitable healthcare compared with non-Indigenous women in prison and the community. CONCLUSIONS: 'Equal treatment' is an inappropriate strategy for providing equitable healthcare, which is required because incarcerated Aboriginal women experience significantly poorer health. Taking a decolonizing approach, we unpack and demonstrate the systems level changes needed to make health and justice agencies culturally relevant and safe. This requires further acknowledgment of the oppressive transgenerational effects of ongoing colonial policy, a true embracing of diversity of worldviews, and critically the integration of Aboriginal concepts of health at all organizational levels to uphold Aboriginal women's rights to culturally safe healthcare in prison and the community.

Effect of Nonzero Solid Permittivity on the Electrical Repulsion between Charged Surfaces.

The electrical repulsion between two charged solid surfaces separated by an electrolyte is studied as a function of the permittivity ϵs of the solid in the limit in which potentials are small, and the gap between the plane solid surfaces is small compared to the Debye length κ-1 within the electrolyte. The solid surfaces are uniformly charged in a central region |x|< L outside which they are uncharged. When ϵs = 0, ions from the charge cloud between the charged surfaces spill out into regions of length O(κ-1) beyond x = ± L, thereby reducing the pressure between the surfaces from that predicted by Derjaguin-Landau-Verwey-Overbeek theory for infinite, uniformly charged surfaces. When ϵs>0, ions spill out over much larger O(L) regions, thereby reducing still further both the electrical potential between the solid surfaces and the repulsive force between them. However, this reduction becomes smaller as κL becomes large.

Development and validation of a hemangiosarcoma likelihood prediction model in dogs presenting with spontaneous hemoabdomen: The HeLP score.

OBJECTIVE: To calculate a risk prediction model for hemangiosarcoma (HSA) diagnosis in dogs presenting with nontraumatic hemoabdomen. DESIGN: Retrospective multicenter observational cohort study enrolling dogs presented 2003-2016. SETTING: Five academic veterinary medical centers. ANIMALS: A total of 406 dogs with nontraumatic hemoabdomen as the presenting complaint that underwent surgical exploration or necropsy and received a histological diagnosis. Overall, 219 dogs from 3 centers provided the data for model construction, and 187 dogs from 2 centers provided the population for external validation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The risk score was modeled on 4 predictors: bodyweight (P = 0.01), total plasma protein (P < 0.01), platelet count (P < 0.01), and thoracic radiograph findings (P = 0.02). The incidence of HSA diagnosis was 36%, 76%, and 96% in the low risk (≤40), medium risk (41-55), and high risk (>55) score groups, respectively. The risk score AUROC was 0.85 (95% CI 0.79-0.90) on the construction population, and 0.77 (95% CI 0.70-0.84) on the validation population. CONCLUSIONS: The risk of HSA diagnosis in dogs presenting with nontraumatic hemoabdomen could be predicted using a simple risk score, which could aid in identification and treatment of dogs at lower risk for this diagnosis.

Osteoarthritis year in review 2018: biology.

This Year in Review highlights a selection of articles published between the 2017 and 2018 Osteoarthritis Research Society International (OARSI) World Congress meetings within the field of osteoarthritis biology, presented at OARSI 2018. Selected articles were obtained from a PubMed search covering cartilage, subchondral bone, inflammation, ageing, pain and animal models. Studies focused on biomechanics, biomarkers, genetics and epigenetics, imaging and clinical studies were excluded due to their coverage in other articles within the OARSI Year in Review series. Significant themes including the role of progenitor cells in cartilage homeostasis and repair, novel signalling mechanisms controlling chondrocyte phenotypic stability and the influence of disrupted or senescent chondrocytes were identified and are discussed in this review. Overarching conclusions derived from these study areas indicate that promising avenues of intervention are on the horizon, however further understanding is required in order to target therapeutic treatments to suitable patient subgroups and disease stages.

T1-Enhanced MRI-visible nanoclusters for imaging-guided drug delivery.

Iron oxide nanoparticles with extremely low dimensions have recently been explored as positive (T1) contrast agent for magnetic resonance imaging (MRI). However, their small sizes lead to fast renal clearance and limit their use in elongated in vivo tracking or therapy monitoring. In this paper, we present a state of art approach to forming nanoclusters by crosslinking ultrasmall iron oxide nanoparticles with bovine serum albumin. This novel design not only maintains the T1 performance of the ultrasmall nanoparticles, but also significantly increases their blood circulation times from 15 minutes to over two hours. Our breast tumor model study also exhibited enhanced contrast at tumor sites for more than 24 hours. The ability of maintaining the T1 performance of the ultrasmall nanoparticles is significant, because previous studies have shown complete T1 loss or signal decrease upon polymer encapsulation. This design also shows great potential in encapsulating model drug molecules, which will greatly benefit the field of imaging-guided drug delivery.

Comparison of immunomagnetic separation beads for detection of six non-O157 Shiga toxin-producing Escherichia coli serogroups in different matrices.

Immunomagnetic separation used with culture based methods has been a useful technique in the detection of pathogens. However, previous studies have not answered many of the necessary questions for real world applications. The objective of this study was to assess the efficacy of different immunomagnetic separation (IMS) bead types in recovery of the correct serogroup from a mixture of big six non-O157 Shiga toxin-producing Escherichia coli strains. To determine the impact of different matrices on recovery, samples of sterile phosphate buffered saline (PBS), sterile and non-sterile cattle faeces, ground beef and lettuce were inoculated with 10 CFU per ml mixture of isolates representing the six serogroups. After a 6 h incubation at 37°C, samples were mixed with IMS beads from three different commercial sources and plated on eosin methylene blue agar (EMB). Three suspect E. coli colonies were selected from each EMB plate and multiplex polymerase chain reaction was used to determine the serogroup. The rate of correct identification varied with the serogroup, IMS bead manufacturer and matrix. Overall, recovery of the correct serogroup became less likely with increase in matrix complexity, with enrichments containing lettuce having the greatest number of bead types with significantly lower likelihood of correct recovery compared to recovery in PBS. SIGNIFICANCE AND IMPACT OF THE STUDY: The need to accurately and efficiently detect Shiga toxin-producing Escherichia coli (STEC) O26, O45, O103, O111, O121 and O145, which have caused outbreaks on numerous occasions, is a major public health and food safety concern in the United States. Detecting these STEC serogroups can be challenging because methods to detect non-O157 serogroups have not been refined as compared to those for O157. Immunomagnetic separation (IMS) has the potential to isolate STEC from a mixture in complex matrices. Our results highlight the need for optimization of IMS-based detection of STEC to effectively recover the targeted serogroup from a variety of sample matrices.

Red blood cell aggregate flux in a bifurcating microchannel.

Red blood cell aggregation plays a key role in microcirculatory flows, however, little is known about the transport characteristics of red blood cell aggregates in branching geometries. This work reports on the fluxes of red blood cell aggregates of various sizes in a T-shaped microchannel, aiming to clarify the effects of different flow conditions in the outlet branches of the channel. Image analysis techniques, were utilised, and moderately aggregating human red blood cell suspensions were tested in symmetric (∼50-50%) and asymmetric flow splits through the two outlet (daughter) branches. The results revealed that the flux decreases with aggregate size in the inlet (parent) and daughter branches, mainly due to the fact that the number of larger structures is significantly smaller than that of smaller structures. However, when the flux in the daughter branches is examined relative to the aggregate size flux in the parent branch an increase with aggregate size is observed for a range of asymmetric flow splits. This increase is attributed to size distribution and local concentration changes in the daughter branches. The results show that the flow of larger aggregates is not suppressed downstream of a bifurcation, and that blood flow is maintained, for physiological levels of red blood cell aggregation.

Low-temperature Raman spectra of the 2-(α-methylbenzylamino)-5-nitropyridine crystal.

The polar organic 2-(α-methylbenzylamino)-5-nitropyridine crystal (MBANP) has been studied by Raman spectroscopy at low temperatures (from 300 to 10K). The effect of temperature change on the vibrational spectrum is discussed with the aid of DFT calculations. The behavior of the Raman spectra indicates that MBANP molecules present a different conformation at low temperatures associated with the rotation of the phenyl and pyridine rings. Temperature-dependent X-ray measurements and differential scanning calorimetry (DSC) analysis were utilized as complementary techniques to investigate the structural stability of MBANP crystal.

Genetic and environmental factors influence Listeria monocytogenes nisin resistance.

AIMS: Listeria monocytogenes nisin resistance increases when first exposed to NaCl and other stresses, such as low pH. In addition to environmental stressors, specific genomic elements can confer nisin resistance, such as the stress survival islet (SSI-1). As SSI-1 is variably present among L. monocytogenes strains, we wanted to determine if SSI-1 was associated with salt-induced nisin resistance. METHODS AND RESULTS: The presence of SSI-1 was determined using PCR for 48 strains of L. monocytogenes. When combined with multilocus sequence typing data, we found that the distribution of SSI-1 is clonal, where strains from clonal complexes (CC) 2, 6 and 11 do not have SSI-1, while strains from CCs 3, 5, 7 and 9 contain SSI-1. The impact of SSI-1 on salt-induced nisin resistance was dependent on CC. The average log decrease after 24 h of exposure to nisin at 7°C under salt-inducing conditions was 2·6 ± 1·1 for CC 9 strains and 2·3 ± 0·7 for CC 11 strains, which had significantly lower survival compared to the other CCs, such as 1·3 ± 0·3 for CC 6. Deletion of SSI-1 from a CC 7 strain demonstrated the role SSI-1 plays in salt-induced nisin resistance, as the deletion mutant had lower resistance compared to the parent strain. CONCLUSIONS: These data suggest that inducible nisin resistance in L. monocytogenes can be influenced by environmental conditions as well as the genetic composition of the strain, which should be considered when selecting control measures for ready-to-eat foods. SIGNIFICANCE AND IMPACT OF THE STUDY: The foodborne pathogen L. monocytogenes can grow in suboptimal conditions, including low temperature and high osmolarity, which makes it a safety concern for ready-to-eat foods. When using antimicrobial peptide inhibitors such as nisin, it is important to understand how food components can impact antimicrobial resistance across the genetic diversity of L. monocytogenes.

Partitioning of red blood cell aggregates in bifurcating microscale flows.

Microvascular flows are often considered to be free of red blood cell aggregates, however, recent studies have demonstrated that aggregates are present throughout the microvasculature, affecting cell distribution and blood perfusion. This work reports on the spatial distribution of red blood cell aggregates in a T-shaped bifurcation on the scale of a large microvessel. Non-aggregating and aggregating human red blood cell suspensions were studied for a range of flow splits in the daughter branches of the bifurcation. Aggregate sizes were determined using image processing. The mean aggregate size was marginally increased in the daughter branches for a range of flow rates, mainly due to the lower shear conditions and the close cell and aggregate proximity therein. A counterintuitive decrease in the mean aggregate size was apparent in the lower flow rate branches. This was attributed to the existence of regions depleted by aggregates of certain sizes in the parent branch, and to the change in the exact flow split location in the T-junction with flow ratio. The findings of the present investigation may have significant implications for microvascular flows and may help explain why the effects of physiological RBC aggregation are not deleterious in terms of in vivo vascular resistance.

Prospective Evaluation of Intra-Articular Dextrose Prolotherapy for Treatment of Osteoarthritis in Dogs.

The objective of this study was to evaluate intra-articular dextrose prolotherapy for osteoarthritis of the elbow or stifle in dogs in a randomized, double-blind, placebo-controlled, prospective pilot study. Seventeen dogs were evaluated with 10 meeting inclusion criteria for this study. Evaluations included orthopedic exam, visual lameness scoring, Canine Brief Pain Inventory (CBPI), goniometry, kinetic gait analysis, and radiography. Initial lameness score, age, body weight, duration of lameness, and CBPI scores did not differ between groups. Change in CBPI pain severity score in the prolotherapy group from wk 6-12 was significantly less improved than in the placebo group, with no other significant differences in pain severity or pain interference scores between groups. Range of motion and radiographic scores did not differ between groups at any time. Mean kinetic forces improved in prolotherapy dogs but were not significantly different between treatment groups at any time. Although easily performed and well-tolerated, there were no statistically significant benefits of dextrose prolotherapy for treatment of osteoarthritis of the elbow and stifle in dogs. Post hoc power analysis of these sample means and standard deviations found that 29-106 animals per group would be necessary to demonstrate significant differences in kinetic forces, providing useful guidance for future studies.

Shape-dependent cellular behaviors and relaxivity of iron oxide-based T1 MRI contrast agents.

Recent research efforts about iron oxide nanoparticles has focused on the development of iron oxide-based T1 contrast agents for magnetic resonance imaging (MRI), such as ultrasmall iron oxide nanospheres (USNPs <4 nm) and ultrathin nanowires (NW, diameter <4 nm). In this paper, we report the cellular uptake behaviors of these two types of ultrasmall scale nanostructures on HepG2 cells. Both these two nanostructures were functionalized with tannic acid and their physical and chemical properties were carefully analyzed before cellular tests. Both USNPs and NWs exhibited strong paramagnetic signals, a property suitable for T1 MRI contrast agents. The distinct shapes also caused much difference in their cellular uptake behaviors. Specifically, the uptake of USNPs was five times higher than that of NWs after 72 hours incubation. The shape-dependent cellular uptake can potentially lead to different blood circulation times, and subsequently different applications of these two types of ultrasmall nanostructures.

Occurrence and Clinicopathologic Features of Splenic Neoplasia Based on Body Weight: 325 Dogs (2003-2013).

Medical records of 396 dogs undergoing splenectomy for treatment of a splenic mass or nodular disease were reviewed retrospectively. Overall distribution of histopathologic diagnosis and clinicopathologic features were evaluated for 325 dogs that met inclusion criteria. Dogs were dichotomized into two groups based on weight, with the statistically derived cutoff identified as 27.8 kg. Malignancy was diagnosed in 58% of dogs, with no difference between small (55%) and large (61%) dogs (P = .291). Overall, 32% of splenic masses were hemangiosarcoma (HSA), which comprised 25 and 39% of all masses in small and large dogs, respectively. The diagnosis of HSA, non-HSA malignancy, or benign splenic disease was significantly different between the groups (P = .019). Of malignant diagnoses, HSA comprised 46 and 65% of small and large dog splenic neoplasms, respectively (P = .009). In both groups, dogs with HSA were significantly more likely to have preoperative anemia, hemoabdomen, thrombocytopenia, and a blood transfusion, as compared to dogs with non-HSA malignancy or benign lesions. Overall, dogs had similar odds of having a malignant splenic lesion regardless of weight, but dogs ≤27.8 kg were significantly less likely to be diagnosed with HSA.

An assessment of the doses received by members of the public in Japan following the nuclear accident at Fukushima Daiichi nuclear power plant.

The earthquake and tsunami on 11 March 2011, centred off the east coast of Japan, caused considerable destruction and substantial loss of life along large swathes of the Japanese coastline. The tsunami damaged the Fukushima Daiichi nuclear power plant (NPP), resulting in prolonged releases of radioactive material into the environment. This paper assesses the doses received by members of the public in Japan. The assessment is based on an estimated source term and atmospheric dispersion modelling rather than monitoring data. It is evident from this assessment that across the majority of Japan the estimates of dose are very low, for example they are estimated to be less than the annual average dose from natural background radiation in Japan. Even in the regions local to Fukushima Daiichi NPP (and not affected by any form of evacuation) the maximum lifetime effective dose is estimated to be well below the cumulative natural background dose over the same period. The impact of the urgent countermeasures on the estimates of dose was considered. And the relative contribution to dose from the range of exposure pathways and radionuclides were evaluated. Analysis of estimated doses focused on the geographic irregularity and the impact of the meteorological conditions. For example the dose to an infant's thyroid received over the first year was estimated to be greater in Hirono than in the non-evacuated region of Naraha, despite Hirono being further from the release location. A number of factors were identified and thought to contribute towards this outcome, including the local wind pattern which resulted in the recirculation of part of the release. The non-uniform nature of dose estimates strengthens the case for evaluations based on dispersion modelling.

Chronic splenic torsion in two dogs.

A 5 yr old spayed female poodle (case 1) was presented with a 4 mo history of lethargy, inappetence, and nonregenerative anemia. A 5 yr old castrated male French bulldog (case 2) was presented with a 2 wk history of mild abdominal pain, dyschezia, and intermittent anorexia. Both dogs were diagnosed with chronic splenic torsion based on changes in splenic position, echogenicity, and/or echotexture identified on B-mode abdominal ultrasonography, as well as either decreased or absent splenic blood flow on color-flow Doppler ultrasonography. Both dogs underwent splenectomy and had full resolution of clinical signs. Presentation of chronic splenic torsion is variable, and clinical signs can be nonspecific. Abdominal ultrasound with Doppler evaluation is an important diagnostic step that can lead to appropriate surgical intervention and good long-term prognosis.

Moderate drop in water table increases peatland vulnerability to post-fire regime shift.

Northern and tropical peatlands represent a globally significant carbon reserve accumulated over thousands of years of waterlogged conditions. It is unclear whether moderate drying predicted for northern peatlands will stimulate burning and carbon losses as has occurred in their smaller tropical counterparts where the carbon legacy has been destabilized due to severe drainage and deep peat fires. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland subjected to decadal drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition previously observed within only severely disturbed tropical peatlands. The combined impact of moderate drainage followed by wildfire converted the low productivity, moss-dominated peatland to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy of stored peat carbon.

Electrically generated eddies at an eightfold stagnation point within a nanopore.

Electrically generated flows around a thin dielectric plate pierced by a cylindrical hole are computed numerically. The geometry represents that of a single nanopore in a membrane. When the membrane is uncharged, flow is due solely to induced charge electroosmosis, and eddies are generated by the high fields at the corners of the nanopore. These eddies meet at stagnation points. If the geometry is chosen correctly, the stagnation points merge to form a single stagnation point at which four streamlines cross at a point and eight eddies meet.