bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical warning signs of life-threatening hematochezia in neurosurgical patients with long-term bed rest
Authors: Jung Ji-Ho , Cho Yong-Hwan , Park Man-Seok , Joo Sung-Pil
Published: September 2020

Rationale:

Patients with long term bed rest in intensive care unit after neurosurgery could experience splanchnic hypoperfusion. These patients have several other medical conditions that exacerbate splanchnic hypoperfusion during treatment and the splanchnic hypoperfusion could result in “stress-induced intestinal necrosis”, which could cause massive hematochezia. We report here the experience of life-threatening hematochezia in 3 patients who underwent brain surgery in our institution.

Patients concerns:

One female patient (72-year-old) and 2 male patients (58- and 35-year-old) were admitted to our institution because of traumatic intracerebral hemorrhage, subarachnoid hemorrhage due to a ruptured anterior communicating artery, and subarachnoid hemorrhage with unknown cause respectively. All patients underwent emergency brain surgery for diagnosis and treatment. After surgery, they all experienced long-term bed rest in intensive care unit. Hematochezia occurred on postoperative day 15, 17, and 49, respectively.

Diagnoses:

All of the patients were assessed by abdomen/pelvis computed tomography and underwent a colonoscopy.

Interventions:

The female patient underwent embolization through pelvic arteriography and epinephrine injection through colonoscopy, but a total colectomy and ileostomy was performed due to refractory hematochezia. 58-year-old male patient had a laparoscopic ileostomy for the bowel rest. The other patient underwent nil per os and conservative treatment for 2 weeks.

Outcomes:

The female patient was discharged without further treatment plan, 58-year-old male patient survived after laparoscopic ileostomy, while the other patient survived after 2 weeks of nil per os.

Lesson:

Abdominal symptoms, such as hematochezia, should be actively managed in neurosurgical patients who are undergoing long-term bed rest in an intensive care unit under physiologically stressful medical conditions.
Sarcomatoid hepatocellular carcinoma mimicking hepatic abscess
Authors: Yang Zheng , Lv Kun , Zhao Yanan , Pan Minqiang , Zhang Chao , Wei Shumei
Published: September 2020

Rationale:

Primary sarcomatoid hepatocellular carcinoma (SHC) is a rare subtype of morphologic hepatocellular carcinoma reported on less than 1% of surgical pathology specimens. Herein, we report a rare case of SHC. The case in question was initially misdiagnosed as a liver abscess due to the clinical and radiological similarity between these 2 pathologies. Ultrasound(US)- and contrast-enhanced ultrasound (CEUS)- guided biopsies are helpful in making an accurate diagnosis under the appropriate biopsy area and angle of puncture.

Patient concerns:

A 56-year old male presented to our hospital with a 2-month history of dull, upper abdominal pain without radiation.

Diagnoses:

Upon initial investigation with computed tomography, a cystic mass was found in the hepatic V segment and an infectious etiology was presumed. Further diagnostic examination with CEUS and magnetic resonance imaging suggested a hepatic abscess. However, a diagnosis of atypical intrahepatic cholangiocarcinoma was not excluded. The patient received the standard antibiotic treatment without alleviation of his symptoms. Through 3 diagnostic US-and CEUS-guided biopsies over a 3-month period, the pathological diagnosis of SHC was finally confirmed.

Interventions:

The patient was diagnosed by 3 diagnostic US-and CEUS-guided biopsies, the pathological diagnosis of SHC was finally confirmed.

Outcomes:

Due to the delay in diagnosis, the patient was not a candidate for surgical resection, and showed dissemination of the lesion to the portal vein. Therefore, treatment with chemotherapy was initiated. After 4 courses of this regimen, tumor progression was found on enhanced magnetic resonance imaging. Therefore, the patient received immunotherapy and targeted therapy with limited response. The patient passed away 3 months later due to tumor progression.

Lessons:

A hepatic abscess should be considered as a malignant lesion when clinical symptoms do not resolve upon standard treatment. US- and CEUS- guided biopsies are helpful in making an accurate diagnosis under the appropriate biopsy area and angle of puncture.
A Blueprint for Streamlining Patient Pathways Using a Hybrid Lean Management Approach
Authors: Rizan Chantelle , Low Rob , Harden Saskia , Groves Nick , Flaherty Breda , Welland Trevor , Das Prodip , Bhutta Mahmood F.
Published: September 2020

Background:

Streamlining patient pathways within health care systems is a complex and challenging process. While frontline clinicians often have an abundance of ideas, these rarely translate into real-world change due to nonadoption or early abandonment.

Objectives:

The aim of this article is to provide frontline clinicians with a blueprint for developing a business case for a streamlined pathway while guiding the practical implementation of this blueprint.

Methods:

The key steps outlined in streamlining a patient pathway are as follows: step 1—identify problems with the patient pathway; step 2—identify the potential to streamline; step 3—forecast the benefits of the streamlined pathway; step 4—gain approvals; step 5—plan the practicalities; step 6—implement and monitor the streamlined pathway; and step 7—monitor the streamlined pathway. Within these steps, Lean management techniques are introduced (including value stream mapping, Pareto charts, Ishikawa diagrams, demand and capacity calculations, role lane mapping) and strengthened by other methods (retrospective audit, systematic review, patient questionnaires, and cost analysis).

Results:

This roadmap is contextualized using a case study, demonstrating how streamlining pathways can result in statistically significant reductions in referral to treatment time, the number of steps in the pathway, lead time (pathway duration), and handoff (transfer of patients between health care professionals). This can be achieved while increasing patient contact time, improving patient satisfaction, and reducing costs.

Conclusion:

This blueprint demonstrates a comprehensive method for streamlining patient pathways, using Lean management techniques complemented by additional methods. This approach was developed by frontline clinicians and can be replicated by others, translating quality improvement ideas into sustainable change in practice. It enables the design of streamlined pathways that confer significant benefits to patients, health care service providers, and the health economy.
Constructing Causal Networks Through Regressions: A Tutorial
Authors: Alemi Farrokh
Published: September 2020

Background:

Significant progress has been made in the practice of conducting causal analysis using network models. Despite this progress, there is limited evidence that hospital risk managers are using these analytical models.

Objective:

This article introduces the causal network, its related concepts, and methods of analysis. The article demonstrates how hospital risk managers can use existing regression software to construct a causal network and identify root causes of an adverse event.

Methods:

Causal networks depict cause and effect in a set of variables. In this context, causes are strong correlations that meet 3 additional criteria: (1) causes occur prior to effects, (2) there is an articulated mechanism for how causes lead to effects, and (3) the association between cause and effect is not spurious, meaning the association persists even after other variables are statistically controlled for (a method of analysis called counterfactual). A causal network can be constructed through repeated use of least absolute shrinkage and selection operator (LASSO) regression. In the proposed regressions, the response variable is any variable in the data. The independent variables are variables that occur prior to the response variable. By design, the statistically significant coefficients in the time-constrained LASSO regressions identify “direct” causes of the response variables. When direct causes of all variables are identified, then the entire network model, including root causes, has been specified. In the final step, the parameters of the network model (ie, strength of causal associations) are estimated by fitting the network structure to the available data. We demonstrate these concepts through fitting a network model to simulated data for causes of excessive boarding in emergency departments.

Results:

The network (involving 12 causes, over 4 periods, and 1 sentinel event) was accurately recovered from the simulated case reports. The recovered network did not differ from the original network used to simulate the data in any of the 156 possible links. The recovered network allowed the identification of root and direct causes. It showed that hospital occupancy rate, and not emergency department efficiency, was root cause of excessive emergency department boarding.

Discussion:

Causal networks can provide insights into root, and direct, causes of an adverse event. These models provide empirical tests of causes of adverse events. We encourage the use of these methods by hospital risk managers.
Isolation of the human-associated bla
CTX-M-15-harbouring Klebsiella pneumoniae ST307 from a tortoise in the UK
Authors: Foster Geoffrey , AbuOun Manal , Pizzi Romain , Tennant Bryn , McCall Margaret , Anjum Muna F.
Published: September 2020

The ST307 multidrug-resistant CTX-M-15-producing

Klebsiella pneumoniae

is an emerging pathogen, which has become disseminated worldwide in humans but is rarely reported from other reservoirs. We report the first isolation of

K. pneumoniae

from an animal in Europe and also from a reptile, a captive tortoise, whose death it probably caused. Detection of this clone from an animal adds to evidence of niche expansion in non-human environments, where it may amplify, recycle and become of greater public health concern.
Physicochemical properties of domestic rice variety according to
pregelatinization
Authors: Jung Hee Nam
Published: September 2020

This study compared the physicochemical properties of domestic rice variety
(‘Haiami’, ‘Hopyeng’, and ‘Hyunpum’)
after pregelatinization. The proximate composition, color value, WAI, WSI,
particle analysis, X-ray diffraction, swelling power, solubility, and amylogram
pasting properties were analyzed. The results showed that pregelatinized rice
flours had lower crude ash, crude fat and crude protein contents, as compared to
raw rice flours. The L values decreased and the b value increased after
pregelatinization in all varieties. The WAI increased, whereas the WSI
decreased, with the highest value being observed for ‘Haiami’. The
particle size increased, and the dispersion decreased after pregelatinization,
resulting in more uniform particles. The changes in the X-ray diffraction
patterns indicated the transformation of the crystal structure into an amorphous
phase due to pregelatinization. As the temperature increased, the swelling power
remained largely unchanged and the solubility increased, with the highest value
being observed for ‘Haiami’. The initial pasting temperature, peak
viscosity, cold viscosity, breakdown and setback decreased, and the peak
viscosity and cold viscosity were highest for ‘Hopyeng’.
Therefore, the obtained results suggest that pregelatinized rice flours with
high water absorption, solubility and low viscosity variations with temperature
will be effective in improving the texture of processed rice products and in
retarding retrogradation.
Identification of the MMP-1 regulation mechanism of benzopyrene,
polycyclic aromatic hydrocarbons in foods
Authors: Han Chang Hee , Kang Nam Joo
Published: September 2020

Benzo[a]pyrene-7,8-diol-9,10-epoxide (B[a]PDE) has been reported to cause various
pathological lesions in humans via activation of the aryl hydrocarbon receptor
(AhR) pathway. However, the molecular mechanism by which B[a]PDE regulates
signaling pathways during skin aging remains unclear. The present study
investigated the effects of B[a]PDE on the expression of matrix
metalloproteinase-1 (MMP-1), which is a major enzyme responsible for collagen
damage, and its regulation of skin aging-related signaling pathways in HaCaT
human keratinocyte cells. MMP-1 expression was increased by B[a]PDE treatment,
and mitogen-activated protein kinase (MAPK) inhibitors suppressed
B[a]PDE-induced MMP-1 expression. Furthermore, a-naphthoflavone (a-NF, AhR
antagonist), PP2 (c-Src inhibitor), and gefitinib (EGFR inhibitor) attenuated
the B[a]PDE-induced phosphorylation of and p38 and their upstream kinases such
as c-Raf, MEK, and MKK3/6. These results suggest that AhR, c-Src, and epidermal
growth factor receptor (EGFR) activations are necessary for B[a]PDE-induced
MMP-1 upregulation by modulation of MAPK pathway activation. B[a]PDE also
stimulates the phosphorylation of ERK via c-Src-dependent EGFR transactivation.
These results demonstrate a novel mechanism by which B[a]PDE induces MMP-1
expression through the activation of AhR, c-Src, and EGFR in non-genetic
pathways. Thus, it is indicated that the molecular mechanisms of MMP-1
expression by B[a]PDE-activated AhR play an important role in promoting skin
aging.
3D-Printing and upper-limb prosthetic sockets; promises and pitfalls
Authors: Olsen Jennifer , Day Sarah , Dupan Sigrid , Nazarpour Kianoush , Dyson Matthew
Published: September 2020

Modernising the way upper-limb prosthetic sockets are made has seen limited progress. The casting techniques that are employed in clinics today resemble those developed over 50 years ago and there is still a heavy reliance on manual labour. Modern manufacturing methods such as 3D scanning and printing are often presented as ready-to-use solutions for producing low-cost functional devices, with public perceptions being largely shaped by the superficial media representation and advertising. The promise is that modern socket manufacturing methods can improve patient satisfaction, decrease manufacturing times and reduce the workload in the clinic. However, the perception in the clinical community is that total conversion to digital methods in a clinical environment is not straightforward. Anecdotally, there is currently a disconnect between those developing technology to produce prosthetic devices and the actual needs of clinicians and people with limb difference. In this paper, we demonstrate strengths and drawbacks of a fully digitised, low-cost trans-radial diagnostic socket making process, informed by clinical expertise. We present volunteer feedback on the digitally created sockets and provide expert commentary on the use of digital tools in upper-limb socket manufacturing. We show that it is possible to utilise 3D scanning and printing, but only if the process is informed by expert knowledge. We bring examples to demonstrate how and why the process may go wrong. Finally, we provide discussion on why progress in modernising the manufacturing of upper-limb sockets has been slow yet it is still too early to rule out digital methods.
Type I interferon potentiates metabolic dysfunction, inflammation, and accelerated aging in mtDNA mutator mice
Authors: Lei Yuanjiu , Martinez Camila Guerra , Torres-Odio Sylvia , Bell Samantha L. , Birdwell Christine E. , Bryant Joshua D. , Tong Carl W. , Watson Robert O. , West Laura Ciaccia , West A. Phillip
Published: September 2020

Mitochondrial dysfunction is a key driver of inflammatory responses in human disease. However, it remains unclear whether alterations in mitochondria-innate immune crosstalk contribute to the pathobiology of mitochondrial disorders and aging. Using the polymerase gamma (POLG) mutator model of mitochondrial DNA (mtDNA) instability, we report that aberrant activation of the type I interferon (IFN-I) innate immune axis potentiates immunometabolic dysfunction, reduces healthspan, and accelerates aging in mutator mice. Mechanistically, elevated IFN-I signaling suppresses activation of nuclear factor erythroid 2-related factor 2 (Nrf2), which increases oxidative stress, enhances pro-inflammatory cytokine responses, and accelerates metabolic dysfunction. Ablation of IFN-I signaling attenuates hyper-inflammatory phenotypes by restoring Nrf2 activity and reducing aerobic glycolysis, which combine to lessen cardiovascular and myeloid dysfunction in aged mutator mice. These findings further advance our knowledge of how mitochondrial dysfunction shapes innate immune responses and provide a framework for understanding mitochondria-driven immunopathology in POLG-related diseases and aging.
Breast tumors escape endocrine therapy by ER-independent mechanisms triggered by the coordinated activities of HER2/HER3 and deacetylated FOXA1
Authors: Gilfillan Siv , Wang Shixiong , Katika Madhumohan R. , Norum Jens Henrik , Bergholtz Helga , Fiorito Elisa , Nordhagen Siri , Sharma Yogita , Singh Sachin , Somisety Venkata S. , Fosdahl Anne-Marthe , Nord Silje , Engebraaten Olav , Lingjaerde Ole Christian , Børresen-Dale Anne-Lise , Sahlberg Kristine Kleivi , Sørlie Therese , Bellet Meritxell , Lopez-Aviles Sandra , Hurtado Antoni
Published: September 2020

Hormone-resistance in ER positive breast cancer is associated with high HER2 activity. Yet, the interplay between HER2 and FOXA1 in hormone resistant tumors is not elucidated. Now, we demonstrate that hormone resistant tumors have increased HER2 expression and that FOXA1 mediates the signals of HER2/3 in an Estrogen Receptor independent manner. Ourin vitroandin vivoexperiments reveal that HER2/HER3 triggers FOXA1 binding at chromatin regions of ER-regulated genes associated with poor prognosis, facilitating their expression and leading to ER-independent growth. Furthermore, our study supports that FOXA1 acetylated by the acetyltransferase EP300 is retained at ER chromatin regions, which enables ER function. By contrast, HER2/3 activation hinders FOXA1 acetylation and facilitates FOXA1 binding at non-ER interacting regions enriched towards poor prognosis genes. Moreover, FOXA1 deacetylation confers insensitivity to anti-ER drugs inhibitory effect in ER positive cells. These results elucidate how post-translational modifications of FOXA1 control transcription independently of ER in hormone-resistant tumors with enhanced HER2/3 signaling.
Ex vivo Demonstration of Functional Deficiencies in Popliteal Lymphatic Vessels from TNF-Tg Mice with Inflammatory Arthritis
Authors: Scallan Joshua P. , Bouta Echoe M. , Rahimi Homaira , Kenney H. Mark , Ritchlin Christopher T. , Davis Michael J. , Schwarz Edward M.
Published: September 2020

Background

Rheumatoid arthritis (RA) is a progressive immune-mediated inflammatory disease characterized by intermittent episodes of pain and inflammation in affected joints, or flares. Recent studies demonstrated lymphangiogenesis and expansion of draining lymph nodes during chronic inflammatory arthritis, and lymphatic dysfunction associated with collapse of draining lymph nodes in RA patients and TNF-transgenic (TNF-Tg) mice experiencing arthritic flare. As the intrinsic differences between lymphatic vessels afferent to healthy, expanding, and collapsed draining lymph nodes are unknown, we characterized the ex vivo behavior of popliteal lymphatic vessels (PLVs) from WT and TNF-Tg mice. We also interrogated the mechanisms of lymphatic dysfunction through inhibition of nitric oxide synthase (NOS).

Methods

Popliteal lymph nodes (PLNs) in TNF-Tg mice were phenotyped as Expanding or Collapsed by in vivo ultrasound and age-matched to WT littermate controls. The PLVs were harvested and cannulated for ex vivo functional analysis over a relatively wide range of hydrostatic pressures (0.5 to 10 cmH2O) to quantify the end diastolic diameter (EDD), tone, amplitude (AMP), ejection fraction (EF), contraction frequency (FREQ) and fractional pump flow (FPF) with or without NOS inhibitors Data was analyzed using repeated measures two-way ANOVA with Bonferroni’spost hoctest.

Results

Real time videos of the cannulated PLVs demonstrated the predicted phenotypes of robust versus weak contractions of the WT versus TNF-Tg PLV, respectively. Quantitative analyses confirmed that TNF-Tg PLVs had significantly decreased AMP, EF and FPF versus WT (p<0.05). EF and FPF were recovered by NOS inhibition, while the reduction in AMP was NOS independent. No differences in EDD, tone, or FREQ were observed between WT and TNF-Tg PLVs, nor between Expanding versus Collapsed PLVs.

Conclusion

These findings support the concept that chronic inflammatory arthritis leads to NOS dependent and independent draining lymphatic vessel dysfunction that exacerbates disease, and may trigger arthritic flare due to decreased egress of inflammatory cells and soluble factors from affected joints.
Isolation of SAR11 marine bacteria from cryopreserved seawater
Authors: Monaghan Elizabeth A. , Freel Kelle C. , Rappé Michael S.
Published: September 2020

In this study, we sought a means to increase current culture collections of SAR11 marine bacteria by testing the use of seawater cryopreserved with glycerol as an inoculum. In July 2017, raw seawater was collected outside of Kāne‘ohe Bay, Hawai‘i, in the tropical Pacific Ocean. A portion of this sample was diluted in seawater-based growth medium to create 576 × 2 mL dilution cultures containing 5 cells each and incubated for a high-throughput cultivation experiment, while another portion was cryopreserved in 10% glycerol. After ten months, a cryopreserved aliquot of seawater was thawed, diluted in seawater-based growth medium, and distributed to create a second high-throughput cultivation experiment of 480 × 2 mL dilution cultures containing 5 cells each and 94 cultures containing 105 cells each. The raw seawater cultivation experiment resulted in the successful isolation of 54 monocultures and 29 mixed-cultures, while cryopreserved seawater resulted in 59 monocultures and 29 mixed cultures. Combined, the cultures included 51 SAR11 isolates spanning 11 unique 16S rRNA gene amplicon sequence variants (ASVs) from raw seawater inoculum and 74 SAR11 isolates spanning 13 unique ASVs from cryopreserved seawater. A vast majority (115 of 125) of SAR11 isolates from the two HTC experiments were members of SAR11 subclade Ia, though isolates of subclades IIIa and Va were also recovered from cryopreserved seawater and subclade Ib was recovered from both. The four most abundant SAR11 subclade Ia ASVs found in the initial seawater sample used to create both culture experiments were isolated by both approaches.

Importance

High-throughput dilution culture has proved to be a successful approach to bring some difficult-to-isolate planktonic microorganisms into culture, including the highly abundant SAR11 lineage of marine bacteria. While the long-term preservation of bacterial isolates by freezing in the presence of cryoprotectants such as glycerol has been shown to be an effective method of storing viable cells over long time periods (i.e. years), to our knowledge it had not previously been tested for its efficacy in preserving raw seawater for later use as inoculum for high-throughput cultivation experiments. We found that SAR11 and other abundant marine bacteria could be isolated from seawater that was previously cryopreserved for nearly 10 months, at a rate of culturability similar to that of the same seawater used fresh, immediately after collection. Our findings expand the potential of high-throughput cultivation experiments to include opportunities where immediate isolation experiments are impractical, allow for targeted isolation experiments from specific samples based on analyses such as microbial community structure, and enable cultivation experiments across a wide range of other conditions that would benefit from having source inoculum available over extended periods of time.
An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations
Authors: de Moraes Marcos H. , Hsu FoSheng , Huang Dean , Bosch Dustin E. , Zeng Jun , Radey Matthew C. , Simon Noah , Ledvina Hannah E. , Frick Jacob P. , Wiggins Paul A. , Peterson S. Brook , Mougous Joseph D.
Published: September 2020

When bacterial cells come in contact, antagonism mediated by the delivery of toxins frequently ensues. The potential for such encounters to have long-term beneficial consequences in recipient cells has not been investigated. Here we examined the effects of intoxication by DddA, a cytosine deaminase delivered via the type VI secretion system (T6SS) ofBurkholderia cenocepacia. Despite its killing potential, we observed that several bacterial species resist DddA and instead accumulate mutations installed by the toxin, indicating that even in the absence of killing, interbacterial toxins can have profound consequences on target populations. Investigation of additional toxins from the deaminase superfamily revealed that mutagenic activity is a common feature of these proteins, including a representative we show targets single-stranded DNA and displays a markedly divergent structure. Our findings suggest that a surprising consequence of antagonistic interactions between bacteria could be the promotion of adaptation via the action of directly mutagenic toxins.
Transcriptome profiling of a multiuse model speciesLymnaea stagnalis(Gastropoda) for ecoimmunological research
Authors: Seppälä Otto , Walser Jean-Claude , Cereghetti Teo , Seppälä Katri , Salo Tiina , Adema Coen M.
Published: September 2020

Host immune function can contribute to numerous ecological/evolutionary processes. Ecoimmunological studies, however, typically use one/few phenotypic immune assays and thus do not consider the complexity of the immune system. Therefore, “omics” resources that allow quantifying immune activity across multiple pathways are needed for ecoimmunological models. We applied short-read based RNAseq (Illumina NextSeq 500, PE-81) to characterise transcriptome profiles of a multipurpose model speciesLymnaea stagnalis(Gastropoda). We used a genetically diverse snail stock and exposed individuals to immune elicitors (injury, bacterial/trematode pathogens) and changes in environmental conditions that can alter immune activity (temperature, food availability). Immune defence factors identified in thede novoassembly indicated uniform aspects of molluscan immunity: pathogen-recognition receptors (PRR) and lectins activate Toll-like receptor (TLR) pathway and cytokines that regulate cellular and humoral defences. However, also apparent differences to other taxa were detected (i.e., modest numbers of antimicrobial peptides and fibrinogen related proteins). Identified factors also indicate that several of them might contribute to the phenotypic immune assays used on this species. Experimental treatments revealed factors from non-self recognition (lectins) and signalling (TLR pathway, cytokines) to effectors [e.g., antibacterial proteins, phenoloxidase (PO) enzymes] whose gene expression depended on immune activations and environmental conditions, as well as components of snail physiology/metabolism that may drive these effects. Interestingly, gene expression of many factors (e.g., PRR, lectins, cytokines, PO enzymes, antibacterial proteins) showed high among-individual variation. Such factors are important to include in ecoimmunological research because they may explain among-individual differences in parasite resistance and fitness in natural populations.
CD8 coreceptor-mediated focusing can reorder the agonist hierarchy of peptide ligands recognized via the T cell receptor
Authors: Clement Mathew , Knezevic Lea , Dockree Tamsin , McLaren James E. , Ladell Kristin , Miners Kelly L. , Llewellyn-Lacey Sian , Francis Ore , Sewell Andrew K. , Bridgeman John S. , Price David A. , van den Berg Hugo A. , Wooldridge Linda
Published: September 2020

CD8+T cells are inherently cross-reactive and recognize numerous peptide antigens in the context of a given major histocompatibility complex class I (MHCI) molecule via the clonotypically expressed T cell receptor (TCR). The lineally expressed coreceptor CD8 interacts coordinately with MHCI at a distinct and largely invariant site to slow the TCR/peptide-MHCI (pMHCI) dissociation rate and enhance antigen sensitivity. However, this biological effect is not necessarily uniform, and theoretical models suggest that antigen sensitivity can be modulated in a differential manner by CD8. We used an intrinsically controlled system to determine how the relationship between the TCR/pMHCI interaction and the pMHCI/CD8 interaction affects the functional sensitivity of antigen recognition. Our data show that modulation of the pMHCI/CD8 interaction can reorder the agonist hierarchy of peptide ligands across a spectrum of affinities for the TCR.

SIGNIFICANCE

Sufficient immune coverage of the peptide universe within a finite host requires highly degenerate T cell receptors (TCRs). However, this inherent need for antigen cross-recognition is associated with a high risk of autoimmunity, which can only be mitigated by a process of adaptable specificity. We describe a mechanism that resolves this conundrum by allowing individual clonotypes to focus on specific peptide ligands without alterations to the structure of the TCR.
Supply chain management 4.0: a literature review and research framework
Authors: Zekhnini Kamar , Cherrafi Anass , Bouhaddou Imane , Benghabrit Youssef , Garza-Reyes Jose Arturo
Published: September 2020

Purpose

This article presents a review of the existing state-of-the-art literature concerning Supply Chain Management 4.0 (SCM 4.0) and identifies and evaluates the relationship between digital technologies and Supply Chain Management.

Design/methodology/approach

A literature review of state-of-the-art publications in the subject field and a bibliometric analysis were conducted.

Findings

The paper identifies the impact of novel technologies on the different supply chain processes. Furthermore, the paper develops a roadmap framework for future research and practice.

Practical implications

The proposed work is useful for both academics and practitioners as it outlines the pillar components for every supply chain transformation. It also proposes a range of research questions that can be used as a base to guide the future research direction of the field.

Originality/value

This paper presents a novel and original literature review-based study on SCM4.0 as no comprehensive review is available where bibliometric analysis, motivations, barriers and technologies' impact on different SC processes have been considered.
Analysis of tooth stiffness of nutation face gear
Authors: Wang Guangxin , Zhu Lili , Wang Peng
Published: September 2020

Purpose

The purpose of this paper is to obtain the single-tooth stiffness, single-tooth time-varying meshing stiffness and comprehensive meshing stiffness of the internal and external face gears and to analyze the influence of the modulus, pressure angle and tooth width of each face gear on the single-tooth stiffness of the gear in nutation face gear transmission.

Design/methodology/approach

From the point of view of material mechanics, the gear teeth of nutation face gear are simplified as spacial variable cross-section beams. The shear deformation of gear teeth, the bending deformation of tooth root and the additional elastic deformation caused by the base deformation are gotten by simplified trapezoidal section method, thus the stiffness of nutation face gear teeth can be obtained. The comparison with finite element method results verifies the rationality of simplified trapezoidal section method for calculating the tooth stiffness of nutation face gear.

Findings

The variation of stiffness of internal and external face gears along the meshing line and tooth height in nutation face gear transmission is studied, and the variation laws of single tooth stiffness, single-tooth-pair mesh stiffness and single tooth time-varying meshing stiffness of nutation face gear teeth are obtained.

Originality/value

Nutation face gear transmission is a new type of transmission. The stiffness of face gear teeth is analyzed, and the variation rules of single tooth stiffness, single-tooth-pair mesh stiffness and single tooth time-varying meshing stiffness of nutation face gear teeth are obtained, which not only enriches the research of nutation face gear transmission but also has important guiding significance for the application of nutation face gear in engineering practice.
Local community involvement in Malaysian early childhood care and education centers
Authors: Rahmatullah Bahbibi , Md Yassin Sopia , Omar Jamilah
Published: September 2020

Purpose

The paper aims to explore the role and the involvement of local community within the context of Malaysian early childhood centers (nursery and kindergarten).

Design/methodology/approach

The research used a mixed method with a questionnaire survey in the first phase and qualitative interviews in the second phase. Quantitative data were obtained from a survey completed by 3,519 staffs from nursery and kindergarten all over Malaysia. Qualitative data were collected from individual and focus group semistructured interviews conducted with 140 participants of the Malaysian public and private internal and external stakeholders ranging from the relevant personnel of the early childhood care and education (ECCE) centers (administrators, teachers and practitioners), academic experts, regulatory agencies and parents.

Findings

Survey results indicate that the parents and community involvement with ECCE centers from the perspective of the management and practitioners is in the medium category. A total of three overarching themes were identified from the interviews, namely expertise collaboration, resource sharing and operation monitoring. There exists diversity in terms of community engagement and cooperation with ECCE centers.

Practical implications

The findings are expected to provide valuable guidelines to ECCE centers' management and leadership in the aspect of community involvement where it could help to enhance their efforts of providing quality learning experiences for young children attending their centers.

Originality/value

This study is part of a larger longitudinal and mixed methods project examining the quality practices in setting the standards in the Malaysian National Quality ECCE framework. These findings contribute to the understanding of community involvement with ECCE centers in the Malaysian context.
Price Limits, the VaR calculation, and a Monte Carlo Simulation
Authors: Yoo Jin
Published: September 2020

This paper raises an issue of calculating a value at risk (VaR) of a stock price in the presence of daily price limits, suggests an appropriate methodology for it, and discusses its practical implications. One finding is that the VaR with price limits is never bigger than without. It turns out that the discrepancy between the two VaRs increases as the confidence level rises, the holding period lengthens, the volatility goes up, or the price limits get tighter.
Information Content of Implied Forward Exchange Rates
Authors: Kim Seong Hun , Cha Dong Se
Published: September 2020

This paper analyzes the information content of the forward exchange rates implied by the interest rate parity, using the Korea and U.S. interest rates and Won/dollar exchange rates observed during the period of March 1991 to December 2002. First, we test the cointegration between implied forward exchange rates and future spot exchange rates to examine their longrun relationship, and find the existence of cointegration. Next, we examine the international Fisher effect and estimate an error correction model for their shortrun relationship. Our analysis supports the international Fisher effect for longer maturities. Our result also supports the error correction model that states that the future spot exchange rates will be adjusted reflecting the information contained in the past-period implied forward rates which is not fully reflected to current spot rates. Finally, we also find that the term structure of implied forward exchange rates is associated with the changes in future spot rates for longer maturities. Based on our findings, we conclude that the longrun relationship exists between the implied forward exchange rates and future spot exchange rates, and the shortrun deviation from the relationship tend to disappear as they return to the longrun relationship in the course of time.
A Study on Information Spillover Effects from NASDAQ 100 to KOSDAQ 50 Index Futures Markets
Authors: Mun Gyu Hyeon , Hong Jeong Hyo
Published: September 2020

This paper studies the information spillover effects over price and volatility across countries by using open-to-close (daytime) returns and close-to-open (overnight) returns of NASDAQ 100 and KOSDAQ 50 index futures data from January 1, 2001 to December 31, 2001. Based on the time-varying AR(1)-GARCH (1,1)-M models, we document that statistically significant conditional mean and volatility spillover effects from the daytime returns of NASDAQ 100 index futures to both overnight returns and daytime returns of KOSDAQ 50 index futures were observed. We also find that there were information spillover effects from overnight returns of NASDAQ 100 index futures to daytime returns of KOSDAQ 50 index futures returns because investors in Korean stock markets can get information on U.S. stock market movement on real time basis due to the ECN transaction with its trading hour overlapped. Finally, we find that the daytime returns of KOSDAQ 50 index futures significantly influence the overnight and daytime returns of the NASDAQ 100 index futures.
Intraday Price Change and Trading Volume in the KTB Futures and Futures Option Markets
Authors: Go Bong Chan , Kim Jin U
Published: September 2020

This study examines the impacts of the KTB futures options, newly introduced at the Korea Futures Exchange (KOFEX) on May, 2002, on the intraday volatility and liquidity of the KTB futures markets for the period from January 17, 2002, to August 30, 2002. The results show that the volatility of the KTB futures appears to have increased since the inception of the KTB futures options. However, the increase in volatility largely disappears after controlling for the effects of volume, time-to-maturity, day-of-the-week, and bid-ask bounce. There is some mixed evidence regarding the impact on the liquidity of the KTB futures markets, in the sense that the trading volume has increased significantly whereas the bid-ask spreads have widened too. The KTB futures price changes are more likely to lead the price changes of the KTB futures options by about 15 minutes, which is probably due to the infrequent trading problem on the part of the KTB futures options. Finally, though infrequently traded, the put-futures parity condition is rarely violated, and thus is difficult to be exploited for arbitrage transactions, indicating that the two markets are closely linked each other.
Intraday Volatility and Volatility spill-over Effects in KTB and Won/Dollar Futures Markets
Authors: Yun Chang Hyeon , Jo Tae Geun , Han Sang Il
Published: September 2020

We analyze the dynamic behavior of the volatility of KTB futures price through GARCH models. In conducting this analysis we use two type data. Using dailly data we analyze the return and volatility spill-over effect between KTB spot and futures. Through 15-minute and 5-minute data we analyze return and volatility spill-over effect between KTB futures and won/dollar futures. We find that ARCH and GARCH effect exists in the volatility of KTB futures, but leverage effect does not exist in this data. Volatility spill-over effect was found only in 15-minute data. Lead and lag effect was found in 15-minute data of dollar and KTB futures where dollar return leads KTB futures and KTB volatility leads dollar volatility. In the daily data we found that KTB futures return lead KTB spot return while mutual spill-over existed between spot and futures in volatility data. Since conditional heteroscedasticity exists in KTB futures we need to consider the these effects in building up systems for arbitrage, valuation and risk management.
Transformational leadership, career adaptability, job embeddedness and perceived career success: a serial mediation model
Authors: Al-Ghazali Basheer M.
Published: September 2020

Purpose

Based on career construction theory and job embeddedness theory, the aim of the present study is to give insights into the interplay between transformational leadership and perceived career success by examining the indirect effects through serial mediation of career adaptability and job embeddedness, respectively.

Design/methodology/approach

A quantitative approach was used for this study. Data were gathered from 469 nurses working in government hospitals in Saudi Arabia. Hypotheses were tested using structural equation modeling.

Findings

The results show that transformational leaders enhance perceived career success. Moreover, the relationship between transformational leadership and perceived career success is serially mediated by career adaptability and job embeddedness.

Originality/value

The role of leadership in promoting employee's perceived career success has been seldom studied in the literature. This is the first study of its kind to examine the effect of transformational leadership on nurses' perceived career success along with the mediating roles of career adaptability and job embeddedness.
Vitamin C, phenolic compounds and antioxidant activity of Brazilian baby foods
Authors: Sousa Tainara Leal de , Silva Jessyca Pinheiro da , Lodete Ariadne Ribeiro , Lima Daniele Silva , Mesquita Abner Alves , Almeida Adrielle Borges de , Placido Geovana Rocha , Egea Mariana Buranelo
Published: September 2020

Purpose

This study aims to analyze the levels of vitamin C, phenolic compounds and antioxidants in baby food. Providing nutritious food to the infants is essential for their growth and development. Baby foods are foods prepared from any suitable nutritive material and intended for feeding children after six months of age. The search for foods that meet the nutritional needs of children and that also promote aspects of health has increased on the part of parents.

Design/methodology/approach

A total of 17 different types of baby foods (2 brands) were purchased and the vitamin C content, total phenolic compounds (TPC) and antioxidant activity were determined. The authors also assessed the adequacy of labeling in accordance with regulatory parameters. Data was submitted to analysis of variance, and the means were compared by the Tukey test at 5% probability. Principal component analysis was performed to evaluate the results (phenolic compounds, vitamin C and antioxidant activity) from the multidimensional point of view.

Findings

In general, the labeling of baby foods proved to be within the legislation, but with confusing information for the consumer. BF7-AAPO (apple pulp and juice, papaya and orange juice), BF-BAO (banana, apple juice and oatmeal) and BF-AA (apple pulp and juice) showed the highest vitamin C content (20–28 mg/100 g;p< 0.001). BF-A (apple), BF-B (banana) and BF-AA showed the highest TPC (7–8.2 mg/100 g;p< 0.001). BF-CP (cassava-parsley), BF-PCBCP (potato, carrot, beef and cassava-parsley) and BF-PCBB (potato, carrot, beef and broccoli) showed the highest antioxidant activity (44–48%;p< 0.001). High value of TPC was related to high value of antioxidant activity in baby foods. In conclusion, vitamin C content in the baby foods was different from those reported on the labels and there was a direct relationship between the content of TPC and the antioxidant capability.

Originality/value

The objective of this work was to evaluate bioactive compounds and antioxidant activity in baby foods. So far, few papers have reported on the subject as the authors seek to know about essential nutrients. However, this knowledge is important because these compounds can decrease and/or prevent inflammatory processes in the body.
Effect of post-heat treatment cooling on microstructure and mechanical properties of selective laser melting manufactured austenitic 316L stainless steel
Authors: Waqar Saad , Liu Jiangwei , Sun Qidong , Guo Kai , Sun Jie
Published: September 2020

Purpose

This paper aims to investigate the influence of different post-annealing cooling conditions, i.e. furnace cooling (heat treatment (HT) 1 – slow cooling) and air cooling (HT 2 – fast cooling), on the microstructure and mechanical properties of selective laser melting (SLM) built austenitic 316L stainless steel (SS).

Design/methodology/approach

Three sets of 316L SS samples were fabricated using a machine standard scanning strategy. Each set consists of three tensile samples and a cubic sample for microstructural investigations. Two sets were subsequently subjected to annealing HT with different cooling conditions, i.e. HT 1 and HT 2, whereas one set was used in the as-built (AB) condition. The standard metallographic techniques of X-ray diffraction, scanning electron microscopy and electron back-scattered diffraction were used to investigate the microstructural variations induced by different cooling conditions. The resultant changes in mechanical properties were also investigated.

Findings

The phase change of SLM fabricated 316L was observed to be independent of the investigated cooling conditions and all samples consist of austenite phase only. Both HT 1 and HT 2 lead to dissolved characteristic melt pools of SLM. Noticeable increase in grain size of HT 1 and HT 2 samples was also observed. Compared with AB samples, the grain size of HT 1 and HT 2 was increased by 12.5% and 50%, respectively. A decreased hardness and strength, along with an increased ductility was also observed for HT 2 samples compared with HT 1 and AB samples.

Originality/value

From previous studies, it has been noticed that most investigations on HT of SLM fabricated 316L were mainly focused on the HT temperature or holding time. However, the post-HT cooling rate is also an equally important factor in deciding the microstructure and mechanical properties of heat-treated components. Therefore, this paper investigates the influence of different post-annealing cooling conditions on microstructure and mechanical properties of SLM fabricated 316L components. This study provides a foundation for considering the post-HT cooling rate as an influential parameter that controls the properties of heat-treated SLM components.
Conventional and underwater friction stir welded AA2024-T351 aluminium alloy – a comparative analysis
Authors: Balaji Swathi , B. Sujay Aadithya , K. Balachandar
Published: September 2020

Purpose

Friction stir welding (FSW) and underwater friction stir welding (UWFSW) of aluminium alloy 2024-T351 was carried out, with a chosen set of parameters, namely, rotational speed of 450 rpm, 560 rpm and 710 rpm, welding speed of 25 mm/min, 40 mm/min and 63 mm/min and tool tilt angle of 0º, 1° and 2º. This study aims to understand the correlation between temperatures and weld parameters, finite element simulation was carried out using Abaqus®.

Design/methodology/approach

Comparative analysis of the mechanical properties of the samples welded with FSW and UWFSW was carried out and correlated with that of the microstructures. Microhardness survey was also conducted across the weldments to support the findings.

Findings

Samples welded with higher rotational speed and low traverse speed favoured good quality, defect-free welds with enhanced material flow. Underwater welded samples resulted in improved mechanical properties than that of the samples welded with conventional FSW. Higher cooling rates resulted in finer grains in all UWFSW samples than that of conventional FSW samples, which, in turn, also reflected in the microhardness survey done across the weldments. Among the chosen window of the parameter, samples welded with 710 rpm, 25 mm/min and 2° had shown improvement in mechanical properties.

Research limitations/implications

This work was carried out in a milling machine, which limits the rotational speed which could be used. Optimistically, this limitation also paves way for using the commonly available milling to be used for FSW.

Originality/value

This original research study shall open opportunities to enable FSW and UWFSW to be done on similar/dissimilar joints of varying composition. Additionally, this research study throws enough light on the age – hardenable aluminium alloy being welded in a commonly available milling machine.