bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecosystems off track: rate‐induced critical transitions in ecological models
Authors: Siteur Koen , Eppinga Maarten B. , Doelman Arjen , Siero Eric , Rietkerk Max
Published: September 2016

Theory suggests that gradual environmental change may erode the resilience of ecosystems and increase their susceptibility to critical transitions. This notion has received a lot of attention in ecology in recent decades. An important question receiving far less attention is whether ecosystems can cope with the rapid environmental changes currently imposed. The importance of this question was recently highlighted by model studies showing that elevated rates of change may trigger critical transitions, whereas slow environmental change would not. This paper aims to provide a mechanistic understanding of these rate‐induced critical transitions to facilitate identification of rate sensitive ecosystems. Analysis of rate sensitive ecological models is challenging, but we demonstrate how rate‐induced transitions in an elementary model can still be understood. Our analyses reveal that rate‐induced transitions 1) occur if the rate of environmental change is high compared to the response rate of ecosystems, 2) are driven by rates, rather than magnitudes, of change and 3) occur once a critical rate of change is exceeded. Disentangling rate‐induced transitions from classical transitions in observations would be challenging. However, common features of rate‐sensitive models suggest that ecosystems with coupled fast–slow dynamics, exhibiting repetitive catastrophic shifts or displaying periodic spatial patterns are more likely to be rate sensitive. Our findings are supported by experimental studies showing rate‐dependent outcomes. Rate sensitivity of models suggests that the common definition of ecological resilience is not suitable for a subset of real ecosystems and that formulating limits to magnitudes of change may not always safeguard against ecosystem degradation.

Synthesis

Understanding and predicting ecosystem response to environmental change is one of the key challenges in ecology. Model studies have suggested that slow, gradual environmental change beyond some critical threshold can trigger so‐called critical transitions and abrupt ecosystem degradation. An important question remains however whether ecosystems can cope with the ongoing rapid anthropogenic environmental changes to which they are currently imposed. In this study we demonstrate that in some ecological models elevated rates of change can trigger critical transitions even if slow environmental change of the same magnitude would not. Such rateinduced critical transitions in models suggest that concepts like resilience and planetary boundaries may not always be sufficient to explain and prevent ecosystem degradation.
UVR protection influences fructosamine level after sun exposure of healthy adults
Authors: Mianowska Beata , Narbutt Joanna , Young Antony Richard , Fendler Wojciech , Małachowska Beata , Młynarski Wojciech , Lesiak Aleksandra
Published: September 2016

Background

Seasonal variation in glycated hemoglobin levels has been observed, and sun exposure has been considered as one of the factors associated with this relationship. Fructosamine is a short‐time marker of blood protein glycation.

Aim

We investigated the effect of seven days of sunbathing on blood fructosamine concentration in healthy volunteers using different ultraviolet radiation (UVR) protections.

Materials and Methods

Participants were assigned to one of three groups: group A – used a UVA and UVB absorbing sunscreen (N = 15), group B – used a UVB absorbing sunscreen (N = 18), and group C – followed uncontrolled sun protection habits (N = 22).

Results

Overall, the fructosamine concentration did not change after sun exposure (baseline 248.8 μmol/l, 25–75%: 238.5 to 258.8 μmol/l vs. after 247.3 μmol/l, 25–75%: 234.9 to 261.8 μmol/l, P = 0.6637). Median change of fructosamine differed significantly between groups (A: −1.90 μmol/l, 25–75%: −17.10 to 1.80 μmol/l vs. B: −3.80 μmol/l, 25–75%: −18.50 to 2.40 μmol/l vs. C: +4.05 μmol/l, 25–75%: −3.20 to 22.0 μmol/l; one‐way ANOVAP = 0.0277). After age adjustment and combining groups A and B, the difference in change of fructosamine concentration was statistically significant between groups A + B (decrease) vs. group C (increase, P = 0.0193).

Conclusion

Appropriate sunscreen use during sunbathing resulted in decreased fructosamine concentrations, while inadequate UVR protection resulted in its increase.
Is tumour necrosis factor α the molecular basis of concomitant immunity in schistosomiasis?
Authors: Hagan Paul , Garside Paul , Kusel John R.
Published: September 2016

Prior to the development of high levels of resistance to infection with schistosomes, some mechanism appears to limit the number of productive worms in individuals, since children do not become superinfected, despite continued exposure to infection. One way in which infection levels might be limited, is through the generation of a concomitant immunity. Concomitant immunity results in the destruction of newly invading schistosomula whilst established adult worms continue to survive. Recent studies have provided evidence that TNFα enhances worm fecundity and is essential for granuloma formation. TNFα may therefore be important in worm reproduction and transmission, since the granuloma may serve to assist the passage oft he eggs out of the tissues. With the additional evidence that the cytotoxic activity of lymphokine‐activated macrophages against schistosomula may be, at least in part, due to the action of TNFα, we propose that TNFα may also be responsible for the phenomenon of concomitant immunity.
Defective mucosal immunity and normal systemic immunity of Mongolian gerbils, Meriones unguiculatus, to reinfection with Strongyloides venezuelensis
Authors: Khan A.I. , Horii Y. , Nawa Y.
Published: September 2016

The systemic and local protective activity of Mongolian gerbils was examined after re‐infection with Strongyloides venezuelensis. Mongolian gerbils were unable to expel S. venezuelensis adult worms from the intestine for over ten weeks after a primary infection. Therefore, immune animals were prepared by treating with mebendazole four weeks after a primary infection and then they were challenged by different maturation stages of the parasite; subcutaneous inoculation with the infective larvae ( L3) obtained by faecal culture, oral administration of L3 obtained from the lungs of rats three days after a primary infection, or oral implantation of adult worms obtained from the intestines of rats seven days after a primary infection. The results show that, although immune animals were highly resistant against challenge infection by subcutaneous inoculation with cultured L3, they were unable to expel orally administered lung‐recovered L3 nor orally implanted adult worms. Although potentiated mastocytosis was induced by challenge infections with lung‐recovered L3 and adult worms, all mast cells were formalin‐resistant, heparin‐containing cells and never seen in the epithelial layer. In spite of the defective protective capacity at the intestinal mucosa, circulating antibody production specific to S. venezuelensis adult as well as L3 antigen was positive. Therefore, the inability of Mongolian gerbils to expel S. venezuelensis adult worms from the intestine seems to be due to the defects of effector/regulator cells, presumably mast cells, but not due to immune unresponsiveness to parasite antigen.
A theoretical framework for immune responses and predisposition to helminth infection
Authors: Woolhouse M.E.J.
Published: September 2016

Many field studies of human helminth infections have reported a positive correlation between parasite burdens and the rate of re‐establishment of infection following chemotherapy, i.e., predisposition. Some studies have also reported the relationships between re‐establishment and exposure and immune responses. The interpretation of these data is made difficult by the complexity of the underlying immunoepidemiological processes. In this paper, simple mathematical models are used to explore expected patterns, especially in relation to host age. These patterns are determined by rates of infection, parasite life expectancy, the level of immunological responsiveness, the duration of immunological memory, and may be greatly affected by the immunogenic roles of different parasite stages. In general, acquired immunity is predicted to reduce the degree of predisposition. This reduction is age‐dependent and may generate ‘negative predisposition’ in some age classes. Age‐dependent reductions in the correlation between re‐establishment and exposure are also predicted. The correlation between re‐establishment and protective immune responses is also predicted to be age‐dependent, but may remain positive for all ages despite significant acquired immunity. The results suggest that great care is needed in the interpretation of immunoepidemiological data from treatment‐reinfection studies.
Correlations between worm burden and markers of Th1 and Th2 cell subset induction in an inbred strain of mouse infected with Trichuris muris
Authors: Else K.J. , Entwistle G.M. , Grencis R.K.
Published: September 2016

Helper T cell subset induction was examined within a single inbred strain of mouse ( B10.D2/n) where individuals varied in their ability to expel the nematode parasite Trichuris muris. In this mouse strain approximately half of infected individuals resist infection whilst half are unable to expel the parasite and harbour chronic mature adult worm infections. We here assess various T cell and serological parameters in individual B10.D2/n mice infected with T. muris in relation to the number of parasites harboured. Worm burdens showed very significant negative correlations with five different parameters indicative of the selective expansion within the host of helper T cells of the Th2 subset. Thus, in vitro IL‐5 and 1L‐9 production by restimulated mesenteric lymph node cells, totallgE levels, the early parasite‐specific IgG1 response (all P < 0·01) and intestinal eosinophilia (P < 0·05), were all significantly negatively correlated with worm burden. In addition, levels of IL‐3 were significantly greater in mice resistant to infection (P < 0·01). In contrast there was a significant positive correlation between worm burden and parasite‐specific IgG2a levels (P < 0·05), IgG2a production being under the tight control of the Th1‐specific cytokine IFN‐y and thus a reliable marker for in vivo Th1 cell activation. The data demonstrates that an individual infected with T. muris is capable of mounting either a protective Th2‐type response or an inappropriate Th1‐type response. Thus, under conditions where host genetic factors and route of antigen introduction into the host are identical, polarized helper T cell responses can arise and hence may be due to a parasite‐derived influence rather than an intrinsic difference between hosts per se.
The Human Race as Geological Agents: Communicating Climate Change Science
Authors: Knox Claire Connolly
Published: September 2016

Related Content: Balfour and Newbold (PAR November/December 2016)

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Variability of breathing during wakefulness while using CPAP predicts adherence
Authors: Fujita Yukio , Yamauchi Motoo , Uyama Hiroki , Kumamoto Makiko , Koyama Noriko , Yoshikawa Masanori , Strohl Kingman P. , Kimura Hiroshi
Published: September 2016

Background and objective

The standard therapy for obstructive sleep apnoea (OSA) is continuous positive airway pressure (CPAP) therapy. However, long‐term adherence remains at ~50% despite improvements in behavioural and educational interventions. Based on prior work, we explored whether regularity of breathing during wakefulness might be a physiologic predictor of CPAP adherence.

Methods

Of the 117 consecutive patients who were diagnosed with OSA and prescribed CPAP, 79 CPAP naïve patients were enrolled in this prospective study. During CPAP initiation, respiratory signals were collected using respiratory inductance plethysmography while wearing CPAP during wakefulness in a seated position. Breathing regularity was assessed by the coefficient of variation (CV) for breath‐by‐breath estimated tidal volume (VT
) and total duration of respiratory cycle (Ttot). In a derivation group (n = 36), we determined the cut‐off CV value which predicted poor CPAP adherence at the first month of therapy, and verified the validity of this predetermined cut‐off value in the remaining participants (validation group; n = 43).

Results

In the derivation group, the CV for estimated VT
was significantly higher in patients with poor adherence than with good adherence (median (interquartile range): 44.2 (33.4–57.4) vs 26.0 (20.4–33.2), P < 0.001). The CV cut‐off value for estimated VT
for poor CPAP adherence was 34.0, according to a receiver‐operating characteristic (ROC) curve. In the validation group, the CV value for estimated VT
>34.0 confirmed to be predicting poor CPAP adherence (sensitivity, 0.78; specificity, 0.83).

Conclusion

At the initiation of therapy, breathing regularity during wakefulness while wearing CPAP is an objective predictor of short‐term CPAP adherence.
Structural Mapping of the Bentong‐Raub Suture Zone Using PALSAR Remote Sensing Data, Peninsular Malaysia: Implications for Sediment‐hosted/Orogenic Gold Mineral Systems Exploration
Authors: Pour Amin Beiranvand , Hashim Mazlan , Makoundi Charles , Zaw Khin
Published: September 2016

The Bentong‐Raub Suture Zone (BRSZ) of Peninsular Malaysia is one of the major structural zones in Sundaland, Southeast Asia. It forms the boundary between the Gondwana‐derived Sibumasu terrane in the west and Sukhothai Arc in the east. The BRSZ is genetically related to the sediment‐hosted/orogenic gold deposits associated with the major lineaments in the Central Gold Belt of Peninsular Malaysia. In this investigation, the Phased Array type L‐band Synthetic Aperture Radar (PALSAR) satellite remote sensing data were used to map major geological structures in Peninsular Malaysia and provide detailed characterization of lineaments and curvilinear structures in the BRSZ, as well as their implication for sediment‐hosted/orogenic gold exploration in tropical environments. Major structural lineaments such as the Bentong‐Raub Suture Zone (BRSZ) and Lebir Fault Zone, ductile deformation related to crustal shortening, brittle disjunctive structures (faults and fractures) and collisional mountain range (Main Range granites) were detected and mapped at regional scale using PALSAR ScanSAR data. The major geological structure directions of the BRSZ were N–S, NNE–SSW, NE–SW and NW–SE, which derived from directional filtering analysis to PALSAR fine and polarimetric data. The pervasive array of N–S faults in the Central Gold Belt and surrounding terrain is mainly linked to the N–S trending of the Suture Zone. N–S striking lineaments are often cut by younger NE–SW and NW–SE‐trending lineaments. Gold mineralized trend lineaments are associated with the intersection of N–S, NE–SW, NNW–SSE and ESE–WNW faults and curvilinear features in shearing and alteration zones. Compressional tectonic structures such as the NW–SE trending thrust, ENE–WSW oriented faults in mylonite and phyllite, recumbent folds and asymmetric anticlines in argillite are high potential zones for gold prospecting in the Central Gold Belt. Three generations of folding events in Peninsular Malaysia have been recognized from remote sensing structural interpretation. Consequently, PALSAR satellite remote sensing data is a useful tool for mapping major geological structural features and detailed structural analysis of fault systems and deformation areas with high potential for sediment‐hosted/orogenic gold deposits and polymetallic vein‐type mineralization along margins of Precambrian blocks, especially for inaccessible regions in tropical environments.
Risk, Benefit, and Moderators of the Affect Heuristic in a Widespread Unlawful Activity: Evidence from a Survey of Unlawful File‐Sharing Behavior
Authors: Watson Steven J. , Zizzo Daniel J. , Fleming Piers
Published: September 2016

Increasing the perception of legal risk via publicized litigation and lobbying for copyright law enforcement has had limited success in reducing unlawful content sharing by the public. We consider the extent to which engaging in file sharing online is motivated by the perceived benefits of this activity as opposed to perceived legal risks. Moreover, we explore moderators of the relationship between perceived risk and perceived benefits; namely, trust in industry and legal regulators, and perceived online anonymity. We examine these questions via a large two‐part survey of consumers of music (n = 658) and eBooks (n = 737). We find that perceptions of benefit, but not of legal risk, predict stated file‐sharing behavior. An affect heuristic is employed: as perceived benefit increases, perceived risk falls. This relationship is increased under high regulator and industry trust (which actually increases perceived risk in this study) and low anonymity (which also increases perceived risk). We propose that, given the limited impact of perceived legal risk upon unlawful downloading, it would be better for the media industries to target enhancing the perceived benefit and availability of lawful alternatives.
Offshoring, Sourcing Substitution Bias, and the Measurement of Growth in U.S. Gross Domestic Product and Productivity
Authors: Reinsdorf Marshall , Yuskavage Robert
Published: September 2016

The decade before the financial crisis of 2008 was a time of large changes in sourcing patterns for manufactured goods, particularly after China's entry into the WTO in 2001. Sourcing substitution reduced the prices paid by wholesale level buyers of these goods, but these price reductions were mostly not captured in the U.S. import price indexes and the U.S. GDP deflator. To find plausible values for sourcing bias we first use data on changes in sourcing patterns over 1997–2007 to predict the effect of the reported price discount from the new emerging market suppliers. Next, we compare adjusted import price indexes for products used for household consumption with consumer price indexes. In the GDP deflator for apparel imports, sourcing bias is found to average 0.6 percent per year, and for durable goods it averages 1 percent per year. During the decade of rapidly changing sourcing patterns, a tenth of the reported speedup in multifactor productivity growth of the U.S. private business sector may have come from sourcing bias in the deflators for imports.
Models for Extremal Dependence Derived from Skew‐symmetric Families
Authors: Beranger Boris , Padoan Simone A. , Sisson Scott A.
Published: September 2016

Skew‐symmetric families of distributions such as the skew‐normal and skew‐t represent supersets of the normal and t distributions, and they exhibit richer classes of extremal behaviour. By defining a non‐stationary skew‐normal process, which allows the easy handling of positive definite, non‐stationary covariance functions, we derive a new family of max‐stable processes – the extremal skew‐t process. This process is a superset of non‐stationary processes that include the stationary extremal‐t processes. We provide the spectral representation and the resulting angular densities of the extremal skew‐t process and illustrate its practical implementation.
Patterns and predictors of severe postpartum anemia after Cesarean section
Authors: Butwick Alexander J. , Walsh Eileen M. , Kuzniewicz Michael , Li Sherian X. , Escobar Gabriel J.
Published: September 2016

BACKGROUND

Postpartum anemia is associated with maternal and perinatal morbidity. Population‐level data may inform guideline development for postpartum anemia screening. Our objectives were to evaluate the associations between potential predictors (predelivery anemia and postpartum hemorrhage [PPH]) with severe postpartum anemia after Cesarean section.

STUDY DESIGN AND METHODS

Data were collected from 70,939 hospitalizations for Cesarean section performed at Kaiser Permanente Northern California facilities between 2005 and 2013. Severe postpartum anemia was defined as a hemoglobin (Hb) level of less than 8 g/dL before hospital discharge. Using multivariable logistic regression, we assessed the associations between predelivery anemia and PPH with severe postpartum anemia. Distributions of these characteristics among women with severe postpartum anemia were evaluated.

RESULTS

The overall rate of severe postpartum anemia was 7.3% (95% confidence interval [CI], 7.1%‐7.4%). Severe postpartum anemia was strongly associated with a predelivery Hb level between 10 and 10.9 g/dL (adjusted odds ratio [aOR], 5.4; 95% CI, 4.89‐5.91), predelivery Hb level of less than 10 g/dL (aOR, 30.6; 95% CI, 27.21‐34.6), and PPH (aOR, 8.45; 95% CI, 7.8‐9.16). The proportions of women with severe postpartum anemia were highest for those experiencing PPH but no predelivery anemia (12.2%; 95% CI, 11.0%‐13.6%) and those who did not incur PPH nor predelivery anemia (10.7%; 95% CI, 9.6%‐12.0%).

CONCLUSIONS

Our findings suggest that PPH and predelivery anemia are strong independent risk factors for severe postpartum anemia. Optimization of patients' Hb before delivery may reduce the incidence of severe anemia after Cesarean section.
Can ultraviolet light C decrease the environmental burden of antimicrobial‐resistant and ‐sensitive bacteria on textiles?
Authors: Bentley Jennifer J. , Santoro Domenico , Gram Dunbar W. , Dujowich Mauricio , Marsella Rosanna
Published: September 2016

Background

The environment is important in transmission of bacteria. Textiles are difficult and time consuming to clean; ultraviolet light C (UVC) is germicidal and may be an effective disinfection method for textile surfaces.

Objective

This study evaluated the efficacy of UVC, a commercial quaternary ammonium compound antimicrobial spray (FAS) and UVC+FAS combined for reducing bacterial colonization on experimentally contaminated textiles.

Methods

Microfibre, cotton and polyester were inoculated with meticillin‐sensitive and ‐resistant Staphylococcus aureus (MSSA and MRSA), Staphylococcus pseudintermedius (MSSP and MRSP), Pseudomonas aeruginosa or Escherichia coli. ATCC® strains were used except for MRSP, for which ten canine clinical isolates were collected. Textiles were treated with three doses of UVC (13 mJ/cm2, 54 mJ/cm2 or 270 mJ/cm2), FAS or both (FAS and UVC at 270 mJ/cm2). UVC was delivered using a modified mercury‐based lamp. Bleach (8.25%) was used as a positive control. Negative controls received no treatment. Surface bacterial counts were determined 24 h post‐treatment.

Results

The lower dosages (13 mJ/cm2 and 54 mJ/cm2) of UVC had >90% colony forming unit (CFU) reduction, 270 mJ/cm2 had >99% CFU reduction and combined UVC+FAS had 100% CFU reduction against all bacterial strains on all surfaces (P < 0.05). Ten experiments showed that treatment with UVC had a greater CFU reduction when compared to FAS alone (P < 0.05). A majority of those experiments (seven of 10) involved Gram‐negative species (P. aeruginosa or E. coli).

Conclusion

UVC quickly reduced the bacterial burden on textiles to greater than 90%; UVC may be a better disinfecting agent than FAS for Gram‐negative species.
Laparoscopic Closure of the Nephrosplenic Space in Horses with Nephrosplenic Colonic Entrapment: Factors Associated with Survival and Colic Recurrence
Authors: Nelson Brad B. , Ruple‐Czerniak Audrey A. , Hendrickson Dean A. , Hackett Eileen S.
Published: September 2016

Objectives

1) To identify factors associated with short‐term survival and time to death after hospital discharge in horses with nephrosplenic entrapment (NSE). 2) To compare the frequency of recurrent colic episodes in horses with and without laparoscopic closure of the nephrosplenic space.

Study Design

Historical cohort with a nested case control.

Animals

Client‐owned horses.

Methods

Medical records of horses treated for NSE from January 1, 2002 to June 1, 2014 were reviewed. Data collected included signalment, physical examination parameters, laboratory results, diagnostic findings, and treatments. Factors associated with short‐term survival to discharge were analyzed with a multivariable logistic regression model and time to death after hospital discharge was analyzed with a Cox proportional hazards model.

Results

During the study period, 211 horses had 231 NSE events and 192/211 (91%) horses survived to discharge. A positive difference in packed cell volume (PCV at admission – PCV after treatment) was associated with reduced odds of nonsurvival with each increment (OR: 0.899, 95% CI 0.816–0.991,P=.03) while the presence of concurrent alimentary lesions (OR: 8.47, 95% CI 1.42–50.4,P=.02) were significantly associated with increased odds of nonsurvival in the short term. Of 156 horses that survived to discharge for which follow‐up was available, 152 (97%) were alive for ≥1 year. Increasing age (incremental years) at hospital admission was significantly associated with death after discharge (hazard ratio 1.078, 95% CI 1.002–1.16,P=.049). Recurrence of NSE was documented in 49/211 (23%) horses. The overall change in colic score indicated a reduction in colic in horses following laparoscopic closure of the nephrosplenic space compared with horses that did not have closure of the nephrosplenic space (P<0.001).

Conclusion

An increase in PCV from admission to after treatment and concurrent abdominal lesions were associated with increased odds of nonsurvival to discharge in horses with NSE. Horses that underwent laparoscopic closure had reduced colic episodes compared with horses without laparoscopic closure.
Assessing Risk of Falling in Older Adults—A Comparison of Three Methods
Authors: Strupeit Steve , Buss Arne , Wolf‐Ostermann Karin
Published: September 2016

Background

Various risk assessment methods have been developed to assess fall risk. Diagnostic accuracy of fall risk assessments is low and there is a scarcity of evidence regarding clinical effectiveness.

Aims

The aim of this study was to evaluate the diagnostic accuracy and clinical effectiveness of a standardized fall risk assessment relative to clinical and self‐report assessment.

Methods

A single‐site, prospective, longitudinal study was performed in a group of geriatric patients. Participants were patients being admitted to a geriatric rehabilitation hospital. The St. Thomas's risk assessment tool (STRATIFY), clinical assessment, and a self‐report assessment (fear of falling) were used to assess fall risk at two time points (at baseline and 3‐week follow‐up). The primary outcome was fall events. Contingency tables were used to calculate sensitivity, specificity, positive predictive values, and negative predictive values. Fisher's exact test was used to test the association between assessments and fall events.

Results

A total of 124 patients participated in the study. The self‐report technique demonstrated the highest sensitivity and negative predictive validity. The STRATIFY tool showed the highest specificity but the lowest sensitivity. The self‐report technique was associated with a lower number of fall events.

Discussion

Given the lack of diagnostic accuracy of all three assessment techniques and the lack of evidence regarding clinical effectiveness, the usefulness of these fall risk assessments can be challenged.

Implications for Practice

At least in settings in which fall prevention programs are a part of standard care, additional time consuming assessments may not be required.

Linking Evidence to Action

It is questionable whether time‐consuming assessments examined in this study are necessary. Further studies are needed to examine the diagnostic accuracy and clinical effectiveness of fall risk assessments.
Hepatitis E Virus Antibodies in Finnish Veterinarians
Authors: Kantala T. , Kinnunen P. M. , Oristo S. , Jokelainen P. , Vapalahti O. , Maunula L.
Published: September 2016

We investigated hepatitis E virus (HEV) infections in Finnish veterinarians engaged in different practice specialties and evaluated the effect of different background factors on HEV exposure by examining total HEV antibodies in samples collected from the participants of the 2009 National Veterinary Congress in Helsinki, Finland. Finnish veterinarians commonly have total HEV antibodies with seroprevalence of 10.2%. Of the non‐veterinarians, 5.8% were seropositive. Increasing age was associated with HEV seropositivity, and, surprisingly, the highest HEV seroprevalence (17.8%) among veterinarians was detected among small animal practitioners. Although no positive correlation between swine contacts and HEV seropositivity was found, 22.7% of veterinarians who had had needle stick by a needle that had previously been injected into a pig versus 9.0% of those who had not were seropositive, even though the finding was statistically non‐significant (P = 0.07). Our results suggest that, although contact with swine is a known risk factor for HEV infection, the sources of HEV infections are probably numerous, including travelling abroad and possibly also other reservoirs of HEV than pigs.
Denervation drives mitochondrial dysfunction in skeletal muscle of octogenarians
Authors: Spendiff Sally , Vuda Madhusudanarao , Gouspillou Gilles , Aare Sudhakar , Perez Anna , Morais José A. , Jagoe Robert T. , Filion Marie‐Eve , Glicksman Robin , Kapchinsky Sophia , MacMillan Norah J. , Pion Charlotte H. , Aubertin‐Leheudre Mylène , Hettwer Stefan , Correa José A. , Taivassalo Tanja , Hepple Russell T.
Published: September 2016

Key points

Mitochondria are frequently implicated in the ageing of skeletal muscle, although the role of denervation in modulating mitochondrial function in ageing muscle is unknown.

We show that increased sensitivity to apoptosis initiation occurs prior to evidence of persistent denervation and is thus a primary mitochondrial defect in ageing muscle worthy of therapeutic targeting.

However, at more advanced age, mitochondrial function changes are markedly impacted by persistent sporadic myofibre denervation, suggesting the mitochondrion may be a less viable therapeutic target.

Experimental denervation modulates mitochondrial function, where changes in both reactive oxygen species (ROS) and sensitivity to permeability transition are implicated in the resultant muscle atrophy. Notably, although denervation occurs sporadically in ageing muscle, its impact on ageing muscle mitochondria is unknown. Because this information has important therapeutic implications concerning targeting the mitochondrion in ageing muscle, we examined mitochondrial function in skeletal muscle from four groups of humans, comprising two active (mean ± SD age: 23.7 ± 2.7 years and 71.2 ± 4.9 years) and two inactive groups (64.8 ± 3.1 years and 82.5 ± 4.8 years), and compared this with a murine model of sporadic denervation. We tested the hypothesis that, although some alterations of mitochondrial function in aged muscle are attributable to a primary organelle defect, mitochondrial dysfunction would be impacted by persistent denervation in advanced age. Both ageing in humans and sporadic denervation in mice increased mitochondrial sensitivity to permeability transition (humans, P = 0.004; mice, P = 0.01). To determine the contribution of sporadic denervation to mitochondrial function, we pharmacologically inhibited the denervation‐induced ROS response. This reduced ROS emission by 60% (P = 0.02) in sporadically denervated mouse muscle, which is similar to that seen in humans older than 75 years (–66%, P = 0.02) but not those younger than 75 years. We conclude that an increased sensitivity to permeability transition is a primary mitochondrial defect in ageing muscle. However, at more advanced age, when muscle atrophy becomes more clinically severe, mitochondrial function changes are markedly impacted by persistent sporadic denervation, making the mitochondrion a less viable therapeutic target.
Phosphorylation regulates the sensitivity of voltage‐gated Kv7.2 channels towards phosphatidylinositol‐4,5‐bisphosphate
Authors: Salzer Isabella , Erdem Fatma Asli , Chen Wei‐Qiang , Heo Seok , Koenig Xaver , Schicker Klaus W. , Kubista Helmut , Lubec Gert , Boehm Stefan , Yang Jae‐Won
Published: September 2016

Key points

Phosphatidylinositol‐4,5‐bisphosphate (PIP2) is a key regulator of many membrane proteins, including voltage‐gated Kv7.2 channels.

In this study, we identified the residues in five phosphorylation sites and their corresponding protein kinases, the former being clustered within one of four putative PIP2‐binding domains in Kv7.2.

Dephosphorylation of these residues reduced the sensitivity of Kv7.2 channels towards PIP2.

Dephosphorylation of Kv7.2 affected channel inhibition via M1 muscarinic receptors, but not via bradykinin receptors.

Our data indicated that phosphorylation of the Kv7.2 channel was necessary to maintain its low affinity for PIP2, thereby ensuring the tight regulation of the channel via G protein‐coupled receptors.

The function of numerous ion channels is tightly controlled by G protein‐coupled receptors (GPCRs). The underlying signalling mechanisms may involve phosphorylation of channel proteins and participation of phosphatidylinositol‐4,5‐bisphosphate (PIP2). Although the roles of both mechanisms have been investigated extensively, thus far only little has been reported on their interaction in channel modulation. GPCRs govern Kv7 channels, the latter playing a major role in the regulation of neuronal excitability by determining the levels of PIP2 and through phosphorylation. Using liquid chromatography‐coupled mass spectrometry for Kv7.2 immunoprecipitates of rat brain membranes and transfected cells, we mapped a cluster of five phosphorylation sites in one of the PIP2‐binding domains. To evaluate the effect of phosphorylation on PIP2‐mediated Kv7.2 channel regulation, a quintuple alanine mutant of these serines (S427/S436/S438/S446/S455; A5 mutant) was generated to mimic the dephosphorylated state. Currents passing through these mutated channels were less sensitive towards PIP2 depletion via the voltage‐sensitive phosphatase Dr‐VSP than were wild‐type channels. In vitro phosphorylation assays with the purified C‐terminus of Kv7.2 revealed that CDK5, p38 MAPK, CaMKIIα and PKA were able to phosphorylate the five serines. Inhibition of these protein kinases reduced the sensitivity of wild‐type but not mutant Kv7.2 channels towards PIP2 depletion via Dr‐VSP. In superior cervical ganglion neurons, the protein kinase inhibitors attenuated Kv7 current regulation via M1 receptors, but left unaltered the control by B2 receptors. Our results revealed that the phosphorylation status of serines located within a putative PIP2‐binding domain determined the phospholipid sensitivity of Kv7.2 channels and supported GPCR‐mediated channel regulation.
Direct Printing of Capacitive Touch Sensors on Flexible Substrates by Additive E-Jet Printing With Silver Nanoinks
Authors: Qin Hantang , Cai Yi , Dong Jingyan , Lee Yuan-Shin
Published: September 2016

In this paper, techniques of direct printing of capacitive touch sensors on flexible substrates are presented. Capacitive touch sensors were fabricated by using electrohydrodynamic inkjet (E-jet) printing onto flexible substrates. Touch pad sensors can be achieved with optimized design of silver nanoink tracks. An analytical model was developed to predict touch pad capacitance, and experiments were conducted to study the effects of sensor design (e.g., number of electrodes, electrode length, and electrode distance) on the capacitance of printed coplanar capacitance touch sensors. Details of the fabrication techniques were developed to enable rapid prototype flexible sensors with simple structure and good sensitivity. The presented techniques can be used for the on-demand fabrication of different conductive patterns for flexible electronics with high resolution and good transparency
Loading–Unloading Cycles of Three-Dimensional-Printed Built Bimaterial Structures With Ceramic and Elastomer
Authors: Kao Yi-Tang , Zhang Ying , Wang Jyhwen , Tai Bruce L.
Published: September 2016

This paper studies the loading–unloading behaviors of a three-dimensional (3D)-printing built bimaterial structure consisting of an open-cellular plaster frame filled with silicone. The combination of the plaster (ceramic phase) and silicone (elastomer phase) is hypothesized to possess a nonlinearly elastic property and a better ductility. Four-point bending tests with programmed cycles of preceding deformations were conducted. The results show that there exists a linear–nonlinear transition when the bending deflection is around 2 mm in the first cycle bending. As the cycle proceeds, this linear–nonlinear transition is found at the maximum deflection of the previous cycle; meanwhile, the bending stiffness degrades. It is believed that the occurrence of microcracks inside the plaster frame is the mechanism behind the phenomenon. The silicone provides a strong network suppressing the abrupt crack propagation in a brittle material. The effects of the frame structure and plaster–silicone ratio were also compared. A high plaster content and large cell size tend to have a higher stiffness and obvious linear to nonlinear transition while it also has more significant stiffness degradation.
Parameter Study of Three-Dimensional Printing Graphene Oxide Based on Directional Freezing
Authors: Zhang Feng , Yang Feng , Lin Dong , Zhou Chi
Published: September 2016

Graphene is one of the most promising carbon nanomaterial due to its excellent electrical, thermal, optical, and mechanical properties. However, it is still very challenging to unlock its exotic properties and widely adopt it in real-world applications. In this paper, we introduce a new three-dimensional (3D) graphene structure printing approach with pure graphene oxide (GO) material, better interlayer bonding, and complex architecture printing capability. Various parameters related to this novel process are discussed in detail in order to improve the printability, reliability, and accuracy. We have shown that the print quality largely depends on the duty cycle of print head, applied pressure, and traveling velocity during printing. A set of printed samples are presented to demonstrate the effectiveness of the proposed technique along with the optimal parameter settings. The proposed process proves to be a promising 3D printing technique for fabricating multiscale nanomaterial structures. The theory revealed and parameters investigated herein are expected to significantly advance the knowledge and understanding of the fundamental mechanism of the proposed directional freezing-based 3D nano printing process. Furthermore, the outcome of this research has the potential to open up a new avenue for fabricating multifunctional nanomaterial objects.
Switch-Based Sliding Mode Control for Position-Based Visual Servoing of Robotic Riveting System
Authors: Zhao Yi Min , Lin Yu , Xi Fengfeng , Guo Shuai , Ouyang Puren
Published: September 2016

The robotic riveting system requires a rivet robotic positioning process for rivet-in-hole insertions, which can be divided into two stages: rivet path-following and rivet spot-positioning. For the first stage, varying parameter-linear sliding surfaces are proposed to achieve robust rivet path-following against robot errors and external disturbances of the robotic riveting system. For the second stage, a second-order sliding surface is applied to attain accurate rivet spot-positioning within a finite time required by the riveting process. In order to improve the dynamic performance of the robot riveting system, the motion of robot end-effector between the two adjacent riveting spots has been properly designed. Overall, the proposed control scheme can guarantee not only the stability of the robot control system but also the robust rivet path-following and quick rivet spot-positioning in the presence of the robot errors and external disturbances of the robotic riveting system. The simulation and experimental results demonstrate the effectiveness of the proposed control scheme.
Computational and Theoretical Analyses of the Precessing Vortex Rope in a Simplified Draft Tube of a Scaled Model of a Francis Turbine
Authors: Rajan Girish K. , Cimbala John M.
Published: September 2016

Results on flows in a draft tube of a constant-head, constant-specific speed, model Francis turbine are presented based on computational fluid dynamics (CFD) simulations and theoretical analysis. A three-dimensional, unsteady, Navier–Stokes solver with the detached-eddy simulation (DES) model and the realizable k–ϵ (RKE) model is used to analyze the vortex rope formed at different discharge coefficients. The dominant amplitude of the pressure fluctuations at a fixed point in the draft tube increases by 13 times, and the length of the rope increases by 3.4 times when the operating point of the turbine shifts from a discharge coefficient of 0.37 to 0.34. A perturbation analysis based on a steady, axisymmetric, inviscid, incompressible model for the mean flow is performed to obtain a Sturm–Liouville (SL) system, the solutions of which are oscillatory if the discharge coefficient is greater than 0.3635, and nonoscillatory otherwise.
A Computationally Efficient Implementation of Nonzero-Speed Transient Green Functions for Zero-Speed Nonlinear Seakeeping Problems
Authors: Gkikas G. D. , van Walree F.
Published: September 2016

The proposed methodology is a time-domain panel method where the transient Green functions (GFs) used for the estimation and implementation of the free-surface effects on the vessel's motions are estimated assuming constant low lateral speed, instead of the common practice zero-speed influence functions. The main difference between the proposed method and standard practice lies in the use of the proposed scheme on a typical zero-speed problem, as the solution scheme is conditioned to the mean drift velocity instead of zero-speed. Furthermore, in this way, a significant improvement in accuracy accompanied by a large reduction in computational times is also achieved. The low lateral-speed GFs are computed for a speed similar to the one that the vessel is expected to drift. Estimation of this speed can be initially based on model tests or by means of an iterative process where we start the computations with the zero-speed GFs and adjust the latter's input speed according to the calculated drift speed until convergence is obtained. As a representative case study, we apply this method for the simulation of seakeeping behavior of a cruise ship in extreme dead ship conditions. For the validation of the proposed methodology, the first- and second-order motions, i.e., heave, roll, and the drift velocity, respectively, as well as lateral accelerations of the vessel were investigated for two cases of severe beam seas further combined with a constant strong wind load. The results were compared against experimental model tests.
Continuous leaf optimization for IMRT leaf sequencing
Authors: Long Troy , Chen Mingli , Jiang Steve , Lu Weiguo
Published: September 2016

Purpose

Conventional step‐and‐shoot intensity modulated radiation therapy leaf sequencing methods, where a nonhomogeneous fluence map is converted to a set of apertures and associated intensities, assume that target fluence is stratified into a fixed number of discrete levels and/or aperture leaf positions are restricted to a discrete set of locations. These assumptions induce a deviation from the planned fluence map and/or reduce the feasible region of potential plans, respectively. A continuous leaf optimization (CLO) framework is developed as a postprocessing methodology to improve upon conventional leaf sequencing so that the resulting plan avoids these two main drawbacks.

Methods

The CLO model directly represents leaf positions and aperture intensities with continuous variables with the goal of reproducing some target fluence profile. Fluence through leaf edges is modeled using the error function, and continuous fluence is approximated using a 0.1 mm discretization across the aperture opening. Conventional leaf sequencing methods provide feasible solutions to the CLO model, and a first‐order descent algorithm is used to converge onto a locally optimal solution.

Results

As a proof‐of‐concept, the authors test this framework on 1D (single leaf pair) fluence maps. The CLO model was applied to conventional leaf sequencing and direct aperture optimization solutions. Consistent improvements to existing leaf sequencing methods were found when tested on 232 generated instances of potential target fluence. In addition to improvements in matching the target fluence, the CLO model was able to keep MUs at similar values to the initial conventional sequence.

Conclusions

The CLO model can improve upon existing leaf sequencing methods by avoiding the restrictions of fluence stratification and discretized leaf positions. This study lays the foundation for future models and solution methodologies that can incorporate continuous leaf positions explicitly into the treatment planning model.
Automatic multiorgan segmentation in CT images of the male pelvis using region‐specific hierarchical appearance cluster models
Authors: Li Dengwang , Zang Pengxiao , Chai Xiangfei , Cui Yi , Li Ruijiang , Xing Lei
Published: September 2016

Purpose

Accurate segmentation of pelvic organs in CT images is of great importance in external beam radiotherapy for prostate cancer. The aim of this studying is to develop a novel method for automatic, multiorgan segmentation of the male pelvis.

Methods

The authors’ segmentation method consists of several stages. First, a pretreatment includes parameterization, principal component analysis (PCA), and an established process of region‐specific hierarchical appearance cluster (RSHAC) model which was executed on the training dataset. After the preprocessing, online automatic segmentation of new CT images is achieved by combining the RSHAC model with the PCA‐based point distribution model. Fifty pelvic CT from eight prostate cancer patients were used as the training dataset. From another 20 prostate cancer patients, 210 CT images were used for independent validation of the segmentation method.

Results

In the training dataset, 15 PCA modes were needed to represent 95% of shape variations of pelvic organs. When tested on the validation dataset, the authors’ segmentation method had an average Dice similarity coefficient and mean absolute distance of 0.751 and 0.371 cm, 0.783 and 0.303 cm, 0.573 and 0.604 cm for prostate, bladder, and rectum, respectively. The automated segmentation process took on average 5 min on a personal computer equipped with Core 2 Duo CPU of 2.8 GHz and 8 GB RAM.

Conclusions

The authors have developed an efficient and reliable method for automatic segmentation of multiple organs in the male pelvis. This method should be useful for treatment planning and adaptive replanning for prostate cancer radiotherapy. With this method, the physicist can improve the work efficiency and stability.
Science Signaling
Podcast for 13 September 2016: DMF and the immune system
Authors: Cravatt Benjamin F. , Blewett Megan M. , Teijaro John R. , VanHook Annalisa M.
Published: September 2016

Covalent modification of a kinase by the immunosuppressive drug DMF inhibits T cell activation.
More roles for mitochondria in the immune response
Authors: Foley John F.
Published: September 2016

Macrophages remodel complexes in the electron transport chain of mitochondria to mediate appropriate immune responses to bacteria.
How bacteria induce animal metamorphosis
Authors: Mushegian Alexandra A.
Published: September 2016

Structurally complex bacterial signals and MAPK signaling in tubeworms are involved in interspecies control of metamorphosis.
Papers of note in
Science Translational Medicine
Authors: Ferrarelli Leslie K.
Published: September 2016

This week’s articles describe new treatments to overcome drug resistance in chronic myeloid leukemia and to prevent stress-induced cell death in various lysosomal storage diseases.