bluuebunny/crossref_metadata_2025 huggingface dataset:
Waking Up from the American Dream: On the Experience of Young Americans during the Housing Boom of the 2000s
Authors: LAEVEN LUC , POPOV ALEXANDER
Published: July 2017

We exploit regional variations in house price fluctuations in the United States during the early to mid‐2000s to study the impact of the housing boom on young Americans' choices related to home ownership, household formation, and fertility. We also introduce a novel instrument for changes in house prices based on the predetermined industrial structure of the local economy. We find that in regions that experienced large increases in house prices between 2001 and 2006, the youngest households were substantially less likely to purchase residential property, to be married, and to have a child, both in 2006 and in 2011.
A distinctive patchy osteomalacia characterises Phospho1‐deficient mice
Authors: Boyde Alan , Staines Katherine A. , Javaheri Behzad , Millan Jose Luis , Pitsillides Andrew A. , Farquharson Colin
Published: July 2017

The phosphatase PHOSPHO1 is involved in the initiation of biomineralisation. Bones in Phospho1 knockout (KO) mice show histological osteomalacia with frequent bowing of long bones and spontaneous fractures: they contain less mineral, with smaller mineral crystals. However, the consequences of Phospho1 ablation on the microscale structure of bone are not yet fully elucidated. Tibias and femurs obtained from wild‐type and Phospho1 null (KO) mice (25–32 weeks old) were embedded in PMMA, cut and polished to produce near longitudinal sections. Block surfaces were studied using 20 kV backscattered‐electron (BSE) imaging, and again after iodine staining to reveal non‐mineralised matrix and cellular components. For 3D characterisation, we used X‐ray micro‐tomography. Bones opened with carbide milling tools to expose endosteal surfaces were macerated using an alkaline bacterial pronase enzyme detergent, 5% hydrogen peroxide and 7% sodium hypochlorite solutions to produce 3D surfaces for study with 3D BSE scanning electron microscopy (SEM). Extensive regions of both compact cortical and trabecular bone matrix in Phospho1 KO mice contained no significant mineral and/or showed arrested mineralisation fronts, characterised by a failure in the fusion of the calcospherite‐like, separately mineralising, individual micro‐volumes within bone. Osteoclastic resorption of the uncalcified matrix in Phospho1 KO mice was attenuated compared with surrounding normally mineralised bone. The extent and position of this aberrant biomineralisation varied considerably between animals, contralateral limbs and anatomical sites. The most frequent manifestation lay, however, in the nearly complete failure of mineralisation in the bone surrounding the numerous transverse blood vessel canals in the cortices. In conclusion, SEM disclosed defective mineralising fronts and extensive patchy osteomalacia, which has previously not been recognised. These data further confirm the role of this phosphatase in physiological skeletal mineralisation.
Comparative cranial ontogeny of Tapirus (Mammalia: Perissodactyla: Tapiridae)
Authors: Moyano S. Rocio , Giannini Norberto P.
Published: July 2017

Skull morphology in tapirs is particularly interesting due to the presence of a proboscis with important trophic, sensory and behavioral functions. Several studies have dealt with tapir skull osteology but chiefly in a comparative framework between fossil and recent species of tapirs. Only one study examined an aspect of cranial ontogeny, development of the sagittal crest (Holbrook. J Zool Soc Lond 2002; 256; 215). Our goal is to describe in detail the morphological changes that occur during the postnatal ontogeny of the skull in two representative tapir species, Tapirus terrestris and Tapirus indicus, and to explore possible functional consequences of their developmental trajectories. We compared qualitative features of the skull on a growth series of 46 specimens of T. terrestris ordered on the basis of the sequence of eruption and tooth wear, dividing the sample into three age classes: class Y (very young juvenile), class J (from young juvenile to young adult) and class A (full and old adult). The qualitative morphological analysis consisted of describing changes in the series in each skull bone and major skull structure, including the type and degree of transformation (e.g. appearance, fusion) of cranial features (e.g. processes, foramina) and articulations (sutures, synchondroses, and synovial joints). We then measured 23 cranial variables in 46 specimens of T. terrestris that included the entire ontogenetic series from newborn to old adults. We applied statistical multivariate techniques to describe allometric growth, and compared the results with the allometric trends calculated for a sample of 25 specimens of T. indicus. Results show that the skull structure was largely conserved throughout the postnatal ontogeny in T. terrestris, so class Y was remarkably similar to class A in overall shape, with the most significant changes localized in the masticatory apparatus, specifically the maxillary tuber as a support of the large‐sized permanent postcanine dentition, and correlated changes in diastemata, mandibular body, and sagittal and nuchal crests. In the nasal region, ontogenetic remodeling affected the space for the meatal diverticulum and the surfaces for the origin of the proboscis musculature. Overall, ontogenetic trajectories exhibited more negative allometric components in T. indicus than in T. terrestris, and they shared 47.83% of allometric trends. Tapirus indicus differed most significantly from T. terrestris in the allometry of postcanine toothrows, diastemata and mandibular body. Thus, some allometric trends seem to be highly conserved among the species studied, and the changes observed showed a strong functional and likely adaptive basis in this lineage of ungulates.
Cutaneous squamous cell carcinoma of the scalp extending to the skull: A case report and review of the literature
Authors: Handler Marc Z , Goldberg David J
Published: July 2017

Squamous cell carcinoma (SCC) of the scalp has increased prevalence in older patients and often presents later in life. Mohs micrographic surgery remains the most effective treatment in most cases. Delayed presentation may result in localized bony invasion or distant metastases. We present a case of an elderly woman presenting with extension of SCC into the parietal bone of the skull.
Hypoxia: Animal experiments and clinical implications
Authors: Kawagoe Yasuyuki , Sameshima Hiroshi
Published: July 2017

The developing fetus has some unique physiological properties that differ from properties in extra‐uterine life. The fetus exists in a hypoxemic condition as a result of the presence of the placenta, which serves as a limiting interface between maternal and fetal circulation. In addition, the fetus is prone to be exposed to uterine contractions, which place it under a further hypoxic burden. Thus, the fetal response to hypoxic insults is important. There has been marked progression in the understanding of fetal physiology since the introduction of the ‘chronic preparation model’. Based upon information from animal research, we now utilize medical technologies in daily medical care, for example, fetal heart rate monitoring and high‐resolution ultrasonographic devices. In this review, we discuss the main findings in relation to fetal physiology and their clinical relevance.
Factors associated with the severity of premenstrual syndrome among Iranian college students
Authors: Farahmand Maryam , Ramezani Tehrani Fahimeh , Khalili Davood , Amin Gholamreza , Negarandeh Reza
Published: July 2017

Aim

Premenstrual syndrome (PMS) is characterized by physical, cognitive, and behavioral symptoms that occur cyclically, from several days to 2 weeks before menses, which resolve either quickly or during the early days of menstruation. The aim of this study was to determine the factors associated with the severity of PMS in Iranian college students.

Methods

The cross‐sectional study was performed among 298 college students (aged 18–35 years) with PMS, of whom, 271 college students completed the Iranian version of the Premenstrual Symptoms Screening Tool questionnaire to determine the severity of PMS. Factors associated with PMS severity were identified using linear regression analysis with a stepwise method.

Results

Factors associated with severity of PMS were age (years), family income (low vs high income), marital status (unmarried vs married), and familial history of dysmenorrhea or PMS after adjustment for dysmenorrheal severity with β (95% confidence interval) of 0.31 (0.45–0.57), 11.6 (1.2–23.54), 3.2 (0.4–5.2), and 2.22 (0.04–4.4), respectively.

Conclusion

In this study, factors associated with severity of PMS were age, marital status, family income, and familial history of PMS. We observed that some outcomes were consistent with some previously reported results, which indicates the need for further studies.
Mental Well‐Being Differences in Cohabitation and Marriage: The Role of Childhood Selection
Authors: Perelli‐Harris Brienna , Styrc Marta
Published: July 2017

Prior studies have found that marriage benefits well‐being, but cohabitation may provide similar benefits. An analysis of the British Cohort Study 1970, a prospective survey following respondents to age 42, examines whether partnerships in general, and marriage in particular, influence mental well‐being in midlife. Propensity score matching indicates whether childhood characteristics are a sufficient source of selection to eliminate differences in well‐being between those living with and without a partner and those cohabitating and married. The results indicate that matching on childhood characteristics does not eliminate advantages to living with a partner; however, matching eliminates differences between marriage and cohabitation for men and women more likely to marry. On the other hand, marriage may provide benefits to women less likely to marry unless they have shared children and are in long‐lasting partnerships. Hence, childhood selection attenuates differences between cohabitation and marriage, except for women less likely to marry.
Validation of the albumin‐bilirubin grade‐based integrated model as a predictor for sorafenib‐failed hepatocellular carcinoma
Authors: Lee Pei‐Chang , Chen Yi‐Tzen , Chao Yee , Huo Teh‐Ia , Li Chung‐Pin , Su Chien‐Wei , Lee Mei‐Hsuan , Hou Ming‐Chih , Lee Fa‐Yauh , Lin Han‐Chieh , Huang Yi‐Hsiang
Published: July 2017

Background & Aims

Sorafenib is the standard treatment for advanced hepatocellular carcinoma (HCC) but is challenging after treatment failure. Appropriate criteria for enrolling patients into second‐line trials are still limited. In this study, we aimed to establish more objective criteria based on Albumin‐Bilirubin (ALBI) grade to select patients with better post‐progression survival (PPS) for second‐line treatment.

Methods

Consecutive 404 advanced HCC patients receiving sorafenib were retrospectively enrolled. All patients were in Child‐Pugh class A and BCLC stage C with either portal vein invasion or extrahepatic metastasis at the beginning of sorafenib treatment. Radiological evaluation based on mRECIST criteria and clinical assessments with compliance were performed on schedule.

Results

During the median follow‐up period of 5.8 months, 310 patients developed progressive disease (PD) and 350 deaths occurred. The PD patients were randomized into derivation and validation cohorts by a 1:1 ratio. The independent predictors of poor PPS in derivation cohort were ALBI grade 3 at PD (hazard ratio [HR]=3.24, P = .002), new extrahepatic lesions (NEH) (HR=1.75, P = .011), and early PD within 4 months (HR=1.88, P = .037). ALBI‐PD criteria were proposed by incorporating these three risk factors. In the validation cohort, PPS could be independently predicted by presence of early PD, NEH as well as ALBI grade 3 at PD. Patients within ALBI‐PD criteria had significant longer median PPS than those beyond it even in Child‐Pugh A (9.7 vs 4.9 months, P = .005) subpopulations.

Conclusions

The ALBI‐PD criteria can differentiate PPS and stratify the patients with advanced HCC for the second‐line trials or salvage therapy.
Shock fabrics in fine‐grained micrometeorites
Authors: Suttle M. D. , Genge M. J. , Russell S. S.
Published: July 2017

The orientations of dehydration cracks and fracture networks in fine‐grained, unmelted micrometeorites were analyzed using rose diagrams and entropy calculations. As cracks exploit pre‐existing anisotropies, analysis of their orientation provides a mechanism with which to study the subtle petrofabrics preserved within fine‐grained and amorphous materials. Both uniaxial and biaxial fabrics are discovered, often with a relatively wide spread in orientations (40°–60°). Brittle deformation cataclasis and rotated olivine grains are reported from a single micrometeorite. This paper provides the first evidence for impact‐induced shock deformation in fine‐grained micrometeorites. The presence of pervasive, low‐grade shock features in CM chondrites and CM‐like dust, anomalously low‐density measurements for C‐type asteroids, and impact experiments which suggest CM chondrites are highly prone to disruption all imply that CM parent bodies are unlikely to have remained intact and instead exist as a collection of loosely aggregated rubble‐pile asteroids, composed of primitive shocked clasts.
Invasive fungal infection following chemotherapy for acute myeloid leukaemia—Experience from a developing country
Authors: Korula Anu , Abraham Aby , Abubacker Fouzia N. , Viswabandya Auro , Lakshmi Kavitha M. , Abraham O. C. , Rupali Priscilla , Varghese George M. , Michael Joy S. , Srivastava Alok , Mathews Vikram , George Biju
Published: July 2017

The incidence of invasive fungal infections (IFI) is believed to be higher in patients with acute myeloid leukaemia (AML) undergoing chemotherapy in non‐HEPA‐filtered rooms. The aim of this study is to review the incidence of IFI in a large cohort of patients with AML treated at a single centre in India. Two hundred and twenty‐two patients with AML treated with either induction chemotherapy or salvage chemotherapy between 2008 and 2013 were studied retrospectively. IFI was defined as per the revised EORTC‐MSG criteria. Data on type of chemotherapy, prophylactic strategies, engraftment (ANC>500), the presence of IFI and survival were collected. IFI was diagnosed in 86 patients (38.7%) with proven IFI in 12 (5.4%). Use of posaconazole prophylaxis (P=.001) was the only factor associated with reduced incidence of IFI. Survival in patients with proven IFI was lower than those without proven IFI, but not statistically significant (59.4% vs 78.5%; P=.139). There is a high incidence of IFI during induction chemotherapy for acute myeloid leukaemia in developing countries. Posaconazole prophylaxis was associated with a significantly lower incidence of IFI. Optimal yet cost‐effective strategies for prevention and early diagnosis of IFI are required to improve survival in patients undergoing chemotherapy for AML.
Evaluating the efficacy of pentoxifylline in the treatment of oral submucous fibrosis: A meta‐analysis
Authors: Liu J , Chen F , Wei Z , Qiu M , Li Z , Dan H , Chen Q , Jiang L
Published: July 2017

Oral submucous fibrosis (OSMF), a potentially malignant oral cavity disorder that causes speech and mastication problems, lacks an established treatment regimen; moreover, no treatment can effectively reverse the course of OSMF. A meta‐analysis was conducted to investigate the efficacy of the peripheral vasodilator, pentoxifylline, in the treatment of OSMF. We searched five different databases for studies meeting our eligibility criteria (up to June 30, 2017). Statistical analyses were performed using RevMan 5.3 software. Three randomized controlled trials (247 OSMF patients) were selected. Pentoxifylline increased the objective sign maximal mouth opening (MMO; WMD: −4.59, 95% CI: −8.65, −0.53; p < 0.05) following short‐term (under 1 month; WMD: −1.94, 95% CI: −3.12, −0.77; p < 0.05) and long‐term (over 1 month; WMD: −5.44, 95% CI: −6.81, −4.07; p < 0.05) application. Pentoxifylline improved the subjective symptom burning sensation (WMD: −0.11, 95% CI: −0.17, −0.05; p < 0.05) only following long‐term application (WMD: 0.42, 95% CI: 0.18, 0.96; p < 0.05). The efficacy on MMO and burning sensation increased with time. Although OSMF lacks definitive treatment modalities, our meta‐analysis shows that pentoxifylline effectively improves the objective signs and subjective symptoms of OSMF and its therapeutic efficacy increases with time.
Intraoperative hemodynamic factors predicting early postoperative renal function in pediatric kidney transplantation
Authors: Michelet Daphné , Brasher Christopher , Marsac Lucile , Zanoun Nabil , Assefi Mona , Elghoneimi Alaa , Dauger Stephane , Dahmani Souhayl
Published: July 2017

Background

The anesthetic management of kidney transplantation in children remains somewhat empirical. The goal of the present study was to investigate intraoperative hemodynamic factors affecting posttransplantation kidney function.

Methods

We performed a retrospective analysis of data from patients undergoing kidney transplantation in our pediatric teaching hospital from 2000 to 2014. Data collected included: donor and recipient demographic data, recipient comorbidities, fluids administered intraoperatively, and intraoperative blood pressure and central venous pressure. The main outcome of the study was the creatinine clearance at day 1 corrected to a body surface area of 1.73 m². Analysis was performed using Classification Tree Analysis with 10‐fold cross‐validation.

Results

One hundred and two patients were included. The following predictors of increased postoperative creatinine clearance at day 1 were identified: decreasing recipient weight, mean blood pressure‐to‐weight ratio 10 minutes after reperfusion, reduced cold ischemia duration, and increased intraoperative albumin infusion. Increased creatinine clearance was observed when mean blood pressure‐to‐weight ratio 10 minutes after reperfusion was ≥4.3 in patients weighing 13‐21 kg and ≥2.5 in those ≥22 kg. Overall, the model explained 64% (and at cross‐validation 60%) of creatinine clearance variability at day 1.

Conclusion

Intraoperative hemodynamics during kidney transplantation should be optimized in order to increase mean blood pressure according to values indicated by our analyses. Cold ischemia duration should be shortened as far as possible.
Position and relative size of the vertebral artery according to age: Implications for internal jugular vein access
Authors: Jung Chul‐Woo , Jalilov Gulomjon , Song In‐Kyung , Kim Eun‐Hee , Kim Hee‐Soo , Kim Jin‐Tae , Lee Ji‐Hyun
Published: July 2017

Aim

The purpose of this retrospective observational study was to investigate the anatomical characteristics of the vertebral artery in pediatric patients using computed tomography images.

Methods

We evaluated anatomical characteristics of the right and left vertebral artery at the cricoid level and at a lower level, which was mid‐level between the cricoid cartilage and the origin of vertebral artery from the subclavian artery. At each level, the cross‐sectional areas of the vertebral artery and internal jugular vein, the relative size of vertebral artery to internal jugular vein, the minimum distance between them, and the extent of overlap between them were investigated.

Results

According to the chest computed tomography images of 344 patients, the sizes of internal jugular vein and vertebral artery were found to increase with age. On the other hand, the relative size of the vertebral artery to internal jugular vein was found to increase conversely with decreasing age. The distance between the vertebral artery and internal jugular vein increased with age at both sides and levels. The vertebral artery was mostly located at the medial side of the internal jugular vein, and overlapped with the internal jugular vein in at least 54% of the patients at the cricoid level and in 74% at the lower level.

Conclusion

The theoretical risk of vertebral artery puncture is higher in younger children during internal jugular vein catheterization.
Exteroceptive stimuli override interoceptive state in reaction time control
Authors: Yang Xiao , Jennings J. Richard , Friedman Bruce H.
Published: July 2017

The processing of reaction time (RT) stimulus is modulated by its timing relative to the cardiac cycle. RT stimulus processing is also influenced by task‐irrelevant stimuli: a sensory stimulus speeds RT when it accompanies a cue to react in another sensory modality. Different theories have been proposed to explain this accessory stimulus effect (ASE). However, it is unclear whether the ASE interacts with the cardiac timing effect. In the present study, the relationship of the ASE, cardiac timing, and stimulus valence was examined. Fifty‐two subjects performed 400 trials of a simple RT task. Images of neutral and fear faces served as visual accessory stimuli; the RT stimulus was a 75 dB tone. Electrocardiography was recorded. Visual and auditory stimuli were presented at either cardiac systole or diastole. The stimulus onset asynchrony between visual and auditory stimuli was either 0 or 75 ms. Repeated measures ANOVAs showed that cardiac timing modulated RT, but only when accessory stimuli were absent. RT was shorter when the accessory stimulus preceded the imperative stimulus with respect to simultaneous presentation. The ASE was not influenced by visual stimulus valence or cardiac timing. Results indicate that the ASE overrides cardiac timing effects, suggesting a dynamic balance between exteroceptive stimuli and interoceptive states, and highlight the importance of embodied information processing.
Commentary: Are We Finally Ready to Attend to the Social Dimensions of Educational Reform?
Authors: Vodicka Devin
Published: July 2017

Related Content: Siciliano, et al. (PAR November/December 2017)
A relational study of the Black middle classes and globalised White hegemony: Identities, interactions, and ideologies in the United States, United Kingdom, and South Africa
Authors: Meghji Ali
Published: July 2017

In this paper, I explore the experiences of the Black middle classes across the United States, United Kingdom (UK), and South Africa. I argue that the similar experiences the Black middle classes face across these nations are not coincidental but represent the process of globalised White hegemony. Globalised White hegemony refers to how the middle class, transnationally, is often understood as a symbolic category informed by specific White norms, identifications, and practices. I explore globalised White hegemony through three areas of Black middle‐class experience: identity, interactions, and ideologies. Thus, I examine how across the UK, United States, and South Africa, the Black middle classes construct public identities according to White norms, encounter interactions through which their blackness negatively trumps their middle‐class status, and confront classed‐racialised ideologies, which construe the Black middle class as inauthentic. I argue in this paper that central to fleshing out the similarities in Black middle‐class experiences across the globe is engaging in relational sociology, which stresses the globalised nature of contemporary raciality.
Electrochemical disinfection of repeatedly recycled blackwater in a free‐standing, additive‐free toilet
Authors: Hawkins Brian T. , Sellgren Katelyn L. , Klem Ethan J. D. , Piascik Jeffrey R. , Stoner Brian R.
Published: July 2017

Decentralized, energy‐efficient waste water treatment technologies enabling water reuse are needed to sustainably address sanitation needs in water‐ and energy‐scarce environments. Here, we describe the effects of repeated recycling of disinfected blackwater (as flush liquid) on the energy required to achieve full disinfection with an electrochemical process in a prototype toilet system. The recycled liquid rapidly reached a steady state with total solids reliably ranging between 0.50 and 0.65% and conductivity between 20 and 23 mS/cm through many flush cycles over 15 weeks. The increase in accumulated solids was associated with increased energy demand and wide variation in the free chlorine contact time required to achieve complete disinfection. Further studies on the system at steady state revealed that running at higher voltage modestly improves energy efficiency, and established running parameters that reliably achieve disinfection at fixed run times. These results will guide prototype testing in the field.
Reuse of treated municipal wastewater in irrigation: a case study from Lebanon and Jordan
Authors: Mcheik Majida , Toufaily Joumana , Haj Hassan Bachar , Hamieh Tayssir , Abi Saab Marie Therese , Rouphael Youssef , Ferracin Enrico , da shio Berardo , Bashabshah Ibrahim , Al Hadidi Luna
Published: July 2017

In this study, we present the results of scenarios where secondary‐treated municipal wastewater was used for table grapes irrigation in the region of Ablah, Bekaa valley in Lebanon, and fodder crops irrigation (vetch and barley) in the region of Ramtha in Jordan. In Lebanon, we carried out experiments to assess the response of drip‐irrigated table grapes grown under two water quality regimes (Freshwater (FW) and treated wastewater (TW) and two water levels (100% of evapotranspiration (ETc) and 75% of ETc). While in Jordan, we carried out experiments to assess the response of drip‐irrigated fodder crops considering 4 irrigation levels (Q1: Rain fed; Q2: 80% of ETc; Q3: 100% of ETc; Q4: 120% of ETc) and three crop patterns (C1: Barley 100%; C2: Vetch 100%; C3: Mix 50% barley and 50% vetch). Based on the production and quality components, table grapes were successfully grown on plots that are supplied with TW. Fodder crops were successfully grown using TW with remarkable increase in biomass and grain yield production for the irrigated treatments.
Analysis of microbiota in rhizosphere, water and gut of grass carp (Ctenopharyngodon idella) in ponds treated with artificial floating beds
Authors: Li Jian , Hu Jun , Wu Kang , Chen Yuanyuan , Wang Li , Zhang Xuezhen
Published: July 2017

With the increasing demand for environment friendly aquaculture, artificial floating beds have been now widely applied. However, there are few data available on the effect on microbiota in ponds. This study assessed the rhizobacteria community of artificial floating beds with three different kinds of aquatic plants [water spinach (Ipomoea aquatic), water hyacinth (Eichhornia crassipes) and alligator weed (Alternanthera philoxeroides)]. We used Polymerase Chain Reaction‐Denaturing Gradient Gel Electrophoresis to assess whether artificial floating beds would result in changes in microbiota of pond water and gut of grass carp (Ctenopharyngodon idella). The results showed that there existed no significant differences in rhizobacterial composition, and artificial floating beds would not greatly affect the microbiota of pond water. The dominant microbiota in the guts of grass carp changed from Aeromonas jandaei to Paenibacillus sp. Our results indicated that artificial floating beds may serve as a candidate of modulating fish gut microbiota.
Comparative study of survival of altered and hybrid Vibrio cholerae O1 El Tor in association with Anabaena variabilis in fresh and brackish water microcosms
Authors: Akter Tanzina , Mahmud Zahid Hayat , Islam Mohammad Shafiqul , Mahmud Hafij Al , Ahmed Mir Alvee , Rahman Mohammad Hasibur , Parvez Mohammad Anowar Khasru , Islam Khairul , Clemens John David , Islam Mohammad Sirajul
Published: July 2017

The survival of altered and hybrid Vibrio cholerae O1 El Tor in association with a cyanobacterium, Anabaena variabilis in pond (fresh) and brackish water microcosms was investigated. Survival of culturable bacteria was monitored on taurocholate tellurite gelatine agar plate. Viable but nonculturable (VBNC) bacteria were examined using fluorescent antibody (FA) technique. In pond water, altered and hybrid El Tor survived with cyanobacteria 10 and 18 days respectively and in control water 6 and 12 days respectively in culturable state. In pond water VBNC state altered and hybrid El Tor were found to persist 48 and 53 days respectively but in brackish water 65 and 70 days respectively in association with cyanobacteria. Brackish water was found to be a better habitat than pond water for the survival of these strains. Hybrid El Tor survived longer inside the mucilaginous sheath of A. variabilis than altered El Tor both in pond and brackish water microcosms.
Circulating leucocytes perpetuate stroke‐induced aortic dysfunction
Authors: Asano Shinichi , O'Connell Grant C. , Lemaster Kent C. , DeVallance Evan R. , Branyan Kayla W. , Simpkins James W. , Frisbee Jefferson C. , Barr Taura L. , Chantler Paul D.
Published: July 2017

New Findings

What is the central question of this study?

Does a stroke event influence aortic endothelial function; and what is the role of peripheral circulating leucocytes in stroke on the vascular reactivity of the aorta?

What is the main finding and its importance?

In vitro co‐culture experiments demonstrated that aortic endothelium‐dependent relaxation was impaired when rat aortic rings were co‐cultured with leucocytes stimulated with serum from stroke patients. Impaired vascular reactivity was not observed in aortic rings without leucocytes stimulated with serum from stroke patients or age‐matched control patients with or without leucocytes. These data suggest that leucocyte‐dependent altered aortic endothelium‐dependent relaxation with stroke and the systemic consequences of stroke on vascular inflammation may occur in the aorta.

Post‐stroke inflammation has been linked to poor stroke outcomes. The vascular endothelium senses and responds to circulating factors, in particular inflammatory cytokines. Although stroke‐associated local cerebrovascular dysfunction is well reported, the effects of a stroke on conduit artery function are not fully understood. We tested the hypothesis that serum from stroke patients triggers leucocyte‐dependent aortic endothelial dysfunction that is associated with elevated concentrations of cytokines. Total leucocytes were isolated from healthy individuals, and the cells were incubated in serum from control subjects or stroke patients for 6 h. The quantity of cytokines in media was determined using an immunoassay. Vascular reactivity was determined by the rat aortic rings that were co‐cultured with or without leucocytes and stimulated with serum samples from control subjects or stroke patients. Endothelium‐dependent dilatation was significantly impaired in aortic rings co‐cultured with leucocytes plus serum from stroke patients (50 ± 30 versus 85 ± 13%, P < 0.05) versus serum from control subjects. In contrast, no difference was observed in aortic function stimulated with serum from control subjects or stroke patients without total leucocytes. Likewise, total leucocyte‐derived cytokine concentrations were significantly increased in a time‐dependent manner on stimulation with serum from stroke patients (P < 0.05). These observations support the concept that the increased response of leucocytes drives the development of stroke‐associated vascular endothelial dysfunction. As such, pharmacologically targeting the source of inflammatory cytokines might alleviate stroke‐associated peripheral vascular dysfunction.
Decline in cellular function of aged mouse c‐kit+ cardiac progenitor cells
Authors: Castaldi Alessandra , Dodia Ramsinh Mansinh , Orogo Amabel M. , Zambrano Cristina M. , Najor Rita H. , Gustafsson Åsa B. , Heller Brown Joan , Purcell Nicole H.
Published: July 2017

Key points

While autologous stem cell‐based therapies are currently being tested on elderly patients, there are limited data on the function of aged stem cells and in particular c‐kit+ cardiac progenitor cells (CPCs). We isolated c‐kit+ cells from young (3 months) and aged (24 months) C57BL/6 mice to compare their biological properties.

Aged CPCs have increased senescence, decreased stemness and reduced capacity to proliferate or to differentiate following dexamethasone (Dex) treatment in vitro, as evidenced by lack of cardiac lineage gene upregulation.

Aged CPCs fail to activate mitochondrial biogenesis and increase proteins involved in mitochondrial oxidative phosphorylation in response to Dex.

Aged CPCs fail to upregulate paracrine factors that are potentially important for proliferation, survival and angiogenesis in response to Dex.

The results highlight marked differences between young and aged CPCs, which may impact future design of autologous stem cell‐based therapies.

Therapeutic use of c‐kit+ cardiac progenitor cells (CPCs) is being evaluated for regenerative therapy in older patients with ischaemic heart failure. Our understanding of the biology of these CPCs has, however, largely come from studies of young cells and animal models. In the present study we examined characteristics of CPCs isolated from young (3 months) and aged (24 months) mice that could underlie the diverse outcomes reported for CPC‐based therapeutics. We observed morphological differences and altered senescence indicated by increased senescence‐associated markers β‐galactosidase and p16 mRNA in aged CPCs. The aged CPCs also proliferated more slowly than their young counterparts and expressed lower levels of the stemness marker LIN28. We subsequently treated the cells with dexamethasone (Dex), routinely used to induce commitment in CPCs, for 7 days and analysed expression of cardiac lineage marker genes. While MEF2C, GATA4, GATA6 and PECAM mRNAs were significantly upregulated in response to Dex treatment in young CPCs, their expression was not increased in aged CPCs. Interestingly, Dex treatment of aged CPCs also failed to increase mitochondrial biogenesis and expression of the mitochondrial proteins Complex III and IV, consistent with a defect in mitochondria complex assembly in the aged CPCs. Dex‐treated aged CPCs also had impaired ability to upregulate expression of paracrine factor genes and the conditioned media from these cells had reduced ability to induce angiogenesis in vitro. These findings could impact the design of future CPC‐based therapeutic approaches for the treatment of older patients suffering from cardiac injury.
Residual Stress Distribution and the Concept of Total Fatigue Stress in Laser and Mechanically Formed Commercially Pure Grade 2 Titanium Alloy Plates
Authors: Mjali Kadephi V. , Els-Botes Annelize , Mashinini Peter M.
Published: July 2017

This paper discusses the investigation of residual stresses developed as a result of mechanical and laser forming processes in commercially pure grade 2 Titanium alloy plates as well as the concept of total fatigue stress. The intention of the study was to bend the plates using the respective processes to a final radius of 120mm using both processes. The hole drilling method was used to measure residual strains in all the plates. High stress gradients were witnessed in the current research and possible cases analyzed and investigated. The effects of processing speeds and powers used also played a significant role in the residual stress distribution in all the formed plates. A change in laser power resulted in changes to residual stress distribution in the plates evaluated. This study also dwells into how the loads that are not normally incorporated in fatigue testing influence fatigue life of commercially pure grade 2 Titanium alloy plates. Also, the parent material was used to benchmark the performance of the two forming processes in terms of stresses developed. Residual stresses developed from the two forming processes and those obtained from the parent material were used. The residual stress values were then added to the mean stress and the alternating stress from the fatigue machine to develop the concept of total fatigue stress. This exercise indicated the effect of these stresses on the fatigue life of the parent material, laser and mechanically formed plate samples. A strong link between these stresses was obtained and formulae explaining the relationship formulated. A comparison between theory and practical application shown by test results is found to be satisfactory in explaining concerns that may arise. The laser forming process is more influential in the development of residual stress, compared to the mechanical forming process. With each parameter change in laser forming there is a change in residual stress arrangement. Under the influence of laser forming the stress is more tensile in nature making the laser formed plate specimens more susceptible to early fatigue failure. The laser and mechanical forming processes involve bending of the plate samples and most of these samples experienced a two-dimensional defect which is a dislocation. The dislocation is the defect responsible for the phenomenon of slip by which most metals deform plastically. Also the high temperatures experienced in laser forming were one of the major driving factors in bending.
Geometry-Driven Finite Element for Four-Dimensional Printing
Authors: Kwok Tsz-Ho
Published: July 2017

Four-dimensional (4D) printing is a new category of printing that expands the fabrication process to include time as the forth dimension, and its process planning and simulation have to take time into consideration as well. The common tool to estimating the behavior of a deformable object is the finite element method (FEM). Although FEM is powerful, there are various sources of deformation from hardware, environment, and process, just to name a few, which are too complex to model by FEM. This paper introduces Geometry-Driven Finite Element (GDFE) as a solution to this problem. Based on the study on geometry changes, the deformation principles can be drawn to predict the relationship between the 4D-printing process and the shape transformation. Similar to FEM, the design domain is subdivided into a set of GDFEs, and the principles are applied on each GDFE, which are then assembled to a larger system that describes the overall shape. The proposed method converts the complex sources of deformation to a geometric optimization problem, which is intuitive and effective. The usages and applications of the GDFE framework have also been presented in this paper, including freeform design, reserve design, and design validation.
Non-Contact Ultrasonic Abrasive Machining of Wire-Electrical Discharge Machined SUS304 Steel
Authors: Tan K. L. , Yeo S. H.
Published: July 2017

Non-contact ultrasonic abrasive machining (NUAM) is a variant of ultrasonic machining (USM). In NUAM, material is removed predominantly by cavitation erosion in abrasive slurry. Due to a significantly lower material removal rate than traditional USM, NUAM is investigated for its applicability on surface modification and finishing in this study. Experiments were conducted on SUS304 steel samples machined by wire electrical discharged machining (WEDM). Due to the thermal spark phenomenon during WEDM, a thermal recast layer, of thickness approximately 15 μm, is often left over on the specimen’s surface after the process. The undesired thermal recast layer contributes to the poor surface integrity of specimens. A NUAM system was configured using a 40 kHz ultrasonic system. Ultrasonic vibration amplitude of 70 μm at the horn tip was used to generate cavitation bubbles in the abrasive slurry. NUAM was found to be effective in removing the unstable thermal recast layers by means of cavitation erosion. As a result, the average surface roughness, Ra, of the specimens improved from approximately 2.5 μm to ∼1.7 μm after 20 minutes of processing time. Furthermore, the addition of abrasive particles was observed to aid in more efficient removal of thermal recast layers than a pure cavitation condition.
Design of Hardware TCP/IP Stack for Sensing Systems Intended for Monitoring of Mechanical Equipment
Authors: Xu Zhiqiang , Liu Quan , Li Zhengying
Published: July 2017

Fiber Bragg grating (FBG) sensors have been widely used in monitoring of the mechanic equipment. However, for measuring high-speed dynamic signal of a large mechanical equipment, the demodulation rate of the interrogator should be very high, while the number of sensors could be tens or hundreds, thus, a large amount of sensing data could be generated. Nonetheless, a network throughput of the interrogator based on the software stack is relatively low and a large amount of data cannot be transmitted simultaneously, which becomes the bottleneck of the sensing system. In order to promote the network throughput, a hardware TCP/IP stack based on the field programmable gate array (FPGA) is proposed. In contrast to the existing hardware stacks, this stack is designed with a new module structure that is divided according to functions instead of protocol types. It can realize both UDP and TCP transmissions with less logic elements than similar designs. Unlike ASIC TCP/IP stack, the entire system can be realized on a single FPGA chip and upgraded without changing of the original hardware circuit. The proposed design has two key features. Firstly, the hardware stack can be connected directly to the data acquisition logic part without software operations thus the data throughput from the signal acquisition to the network transmission can maintain a relatively high speed. Therefore, the system can demodulate data from hundreds of sensors at high speed and transmit them in real time. Secondly, the module structure is clear and independent of specific FPGA platform. Consequently, it can be transplanted or upgraded easily in order to meet different practical demands. The proposed design embodies the characteristics and advantages of the system on a programmable chip (SOPC). In order to validate the proposed design, all logic modules were simulated and the design was tested on the circuit board. Performance test results have shown that UDP and TCP throughputs of the proposed hardware stack are up to 80Mbps in the case of 100Mbps Ethernet controller chip, which is about eight times higher than throughput of software design. Finally the design was verified by monitoring of the oil pipeline platform. The obtained results have shown that proposed design can detect the vibration frequencies of the oil pipeline that are around 600Hz and it can sample 288 FBG sensors and transmit sensor data correctly. Thus the proposed design is suitable for a large sensing system intended for the dynamic monitoring of the mechanical equipment.
Ball Burnishing Under High Velocities Using a New Rolling Tool Concept
Authors: Hiegemann Lars , Tekkaya A. Erman
Published: July 2017

Ball burnishing is a process used to smooth rough surfaces. For not rotational symmetric parts, the process is typically conducted on milling machines. Since it is an incremental process, it is relatively time consuming. Therefore, a rolling tool is developed, which superposes the rotation of the milling spindle with the feed of the machine to increase the rolling velocity. In order to achieve constant rolling forces, hydrostatic ball burnishing tools are used. Within this work, the influence of this tool concept on the processing time as well as on the leveling of surface irregularities is investigated. This is achieved by a comparison with a conventional ball burnishing process. Finally, the rotating tool is used to investigate the influence of high rolling speeds on the leveling of the surface. All experiments were carried out with thermally coated specimens. A model for calculating the strain rates at the roughness peaks during ball burnishing is derived. For the experiments carried out with the rotating rolling tool, rolling velocities of 50,000 mm/min were realized. Calculations with the developed model showed that this results in local strain rates at the roughness peaks of up to 1,384 s−1. In addition, the flow stresses at the roughness peaks were calculated. Compared with quasi static experiments, the flow stress drops to less than the half under high velocities. This results in a better leveling of the surface for rolling velocities between 10,000 mm/min and 25,000 mm/min. A further rise of the rolling speed increases the flow stress again and thereby reduces the possible leveling.
Predicting Multi-Scale Dimensional Accuracy of Engine Cylinder by Honing
Authors: Zhou Zaoyang , Zhang Xueping , Yao Zhenqiang , Xi Lifeng
Published: July 2017

The deviations of cylinder bore dimensional accuracy have tremendous influence on engine performances including friction power loss, vibration, leak tightness between piston ring and cylinder wall, and abrasive resistance. Many researches were devoted to capturing cylinder dimensional accuracies by honing using analytical, experimental and simulation methods. These researches investigated the topography and roughness of the honed surface, the relationship between the process parameters and the dimensional accuracies. However, most researches focused on macro-scale dimensional accuracy and micro-scale surface texture respectively. To overcome the limitation, a multi-scale model for cylinder bore honing is proposed to predict the dimensional accuracy and surface texture of cylinder bore at macro-scale and micro-scale simultaneously. The model integrates the microscale factors of the honing stone abrasives distribution characteristics, abrasive wear process, previous cylinder surface topography, and macro-scale factors of cylinder geometry and honing head motion trajectory. A Force matching method is adopted to determine the feed depth of cylinder honing process. Thus the model can predict the roundness, cylindricity, roughness and Abbott-Firestone curve of the honed cylinder bore at multi-scale levels. Simulation results show that material removal distribution is closely related to cylinder bore initial shape deviations. The deviations with long wavelengths cannot be eliminated by the sequential honing.
Study on Oil Adsorption and Polishing Characteristics by Novel Nanofiber Pad for Ultra-Precision Abrasive Machining
Authors: Wu Wei , Ma Lei , Hirogaki Toshiki , Aoyama Eiichi , Ikegaya Morihiko , Echizenya Takatsugu , Sota Hiroyoshi
Published: July 2017

Nanofibers can be used in such fields/applications as medical care, environment protection, apparel, and agriculture. We also believe this field will continue to show fast growth in the next few years. In this paper, we focused an abrasive machining application for oil adsorbing and polishing performances that achieved polymeric nanofiber mass production by a melt blowing method. In the present report, we proposed an oil adsorption physical model and compared experiment results to develop a nanofiber polishing pad. We used this model and calculated the mass ratio of oil to abrasive grains and abrasive size in abrasive machining when the fiber mass and bulk density were constant. For realizing a free-form nano surface, such as a molding die surface, we conducted base experiments with different fiber diameters and grain sizes and compared the base polishing characteristics with commercial felt buff. The polished surface roughness of the workpiece became smaller, and the polishing processes on it were more stable with this new, low cost abrasive material on abrasive machining. We believe that the nanofiber abrasive pad can be used in abrasive machining with oil slurry as a next-generation abrasive material.