bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Adaptive Evolution and Coevolution of rbcL Gene in the Genus Galdieria (Rhodophyta)
Authors: Han Yuxin , Liu Xudong , Nan Fangru , Feng Jia , Lv Junping , Liu Qi , Xie Shulian
Published: December 2020

To research the adaptive evolution and coevolution of the rbcL gene in the genus Galdieria, 36 sequences were selected. The bioinformatics of proteins encoded by rbcL genes of Galdieria were analyzed, and phylogenetic trees were constructed by the maximum‐likelihood method. Then, adaptive evolution and coevolution were analyzed. The phylogenetic tree showed that the inner groups were clustered into four branches, in which the sequences of Galdieria maxima were divided into two small branches, and the posterior probability of each branch is above 94.9%. Eleven reliable positive selection sites were detected in the branched‐site model, indicating that the rbcL protein‐coding gene of Galdieria underwent adaptive evolution to adapt to extreme environments. Site 269 F is located in the loop 6 domain, while sites 272 D and 273 W are located in the 6‐helix structure. Many coevolution pairs were detected, which were closely related to the hydrophobic and molecular weight correlation values of amino acids. The results are helpful to research the evolution process of freshwater red algae, to explore the changes of its essential genes and protein functions to adapt to different environmental pressures, and to understand the close relationship between amino acids in proteins and the molecular mechanism of evolution.
Adherence to nutritional interventions in head and neck cancer patients: a systematic scoping review of the literature
Authors: de Oliveira Faria S. , Alvim Moravia R. , Howell D. , Eluf Neto J.
Published: December 2020

Background

Dietary counselling provided by a dietitian, with or without oral nutritional supplements, can impact on nutritional and clinical outcomes in head and neck cancer (HNC) patients undergoing radiotherapy. However, little is known about the role of adherence to oral nutritional interventions in this population. This review aimed to map the literature for evidence of adherence to oral nutritional interventions in HNC patients undergoing radiotherapy and to identify gaps in knowledge in this field.

Methods

A scoping review methodology was used to identify studies, extract data, and collate and summarise results. We searched Medline, Embase, Cochrane Central and CINAHL, from the earliest available time up to 8 January 2020.

Results

In total, 2315 unique articles were identified, 163 studies were assessed in full and niner were included in the scoping review. The use of different measures to assess adherence and variability in the timing of the assessments was noted across studies. Despite identifying studies that have measured adherence to oral nutritional interventions, very few studies monitored its influence on clinical and nutritional outcomes in HNC patients or reported factors related to adherence.

Conclusions

A robust evidence base is lacking for adherence to oral nutritional intervention in HNC patients. Overall, further studies evaluating the impact of oral nutritional interventions in HNC patients undergoing radiotherapy should measure adherence to the intervention. Early recognition of non‐adherence and the contributing factors could ensure intensification of nutritional support and better health outcomes.
Id(entifying) the inhibitor of DNA binding 3 in the brain of Nothobranchius furzeri upon aging
Authors: Leggieri Adele , Palladino Antonio , Attanasio Chiara , Avallone Luigi , de Girolamo Paolo , D’Angelo Livia , Lucini Carla
Published: December 2020

Inhibitors of DNA (Id) are key transcription factors (TFs) regulating neurogenic processes. They belong to the helix‐loop‐helix (HLH) TF family and are dominant negative regulators of basic HLH proteins (bHLHs). Specifically, they inhibit cell differentiation and enhance cell proliferation and motility. The Id family includes four members, Id1, Id2, Id3, and Id4, which have been identified in nearly all vertebrates. The transcript catalog of the African turquoise killifish, Nothobranchius furzeri, contains all four TFs and has evolved showing positive selection for Id3. N. furzeri, a teleost, is the short‐lived vertebrate and is gaining increasing scientific interest as a new model organism in aging research. It is characterized by embryonic diapause, explosive sexual maturation, and rapid aging. In this study, we investigated both the expression and the role of Id3 in the brain of this model organism. Interestingly, Id3 was upregulated age‐dependently along with a distribution pattern resembling that of other vertebrates. Additionally, the gene has undergone positive selection during evolution and shows a high degree of conservation relative to that of other vertebrates. These features make N. furzeri a valid tool for aging studies and a potential model in translational research.
Clinicopathological analysis and survival outcomes of primary salivary gland tumors in pediatric patients: A systematic review
Authors: Louredo Brendo Vinícius Rodrigues , Santos‐Silva Alan Roger , Vargas Pablo Agustin , Ajudarte Lopes Márcio , Martins Manoela Domingues , Guerra Eliete Neves da Silva , Prado Ribeiro Ana Carolina , Brandão Thaís Bianca , de Mendonça Regina Maria Holanda , Kowalski Luiz Paulo , Speight Paul M. , Khurram Syed Ali , Pérez‐de‐Oliveira Maria Eduarda
Published: December 2020

Background

Salivary gland tumors are a diverse group of uncommon neoplasms that are rare in pediatric patients. The aim of this study was to evaluate the clinicopathological profile and survival outcomes of pediatric patients affected by salivary gland tumors.

Materials and methods

An extensive search was carried out using the MEDLINE/PubMed, EMBASE, Scopus databases, and grey literature. The risk of bias was available in all papers included.

Results

A total of 2,830 articles were initially retrieved with 54 remaining for data extraction, resulting in 2,937 cases. This comprised forty‐five case series’ and nine cohort studies. These tumors were slightly more prevalent in females (57.4%). The patients' age ranged from 0.3 to 19 years old, with a mean age of 13.3 years. Parotid was the most affected site (81.9%), and 99.2% of cases clinically exhibited a swelling. Presence of pain/tenderness was reported in 13.5% of the cases, with an average duration of 12.6 months for the appearance of symptoms. Most of the reported cases were malignant tumors (75.4%), with mucoepidermoid carcinoma the most common tumor of all tumors (44.8%), followed by pleomorphic adenoma (24.1%). Surgery alone was the leading treatment choice in 74.9% cases, and the 5‐year overall survival rate of patients was 93.1%. Patients with symptoms (P = .001), local recurrence (P < .001), metastasis (P < .001), and those not undergoing surgery or surgery combined with radiotherapy (P < .001) showed lower survival rates.

Conclusion

The pediatric patients present a high frequency of malignant salivary neoplasms and a high overall survival rate.
Effects of combined use of recombinant human fibroblast growth factor‐2 and β‐tricalcium phosphate on ridge preservation in dehiscence bone defects after tooth extraction: A split‐mouth study in dogs
Authors: Fukuba Shunsuke , Akizuki Tatsuya , Matsuura Takanori , Okada Munehiro , Nohara Kohei , Hoshi Shu , Shujaa Addin Ammar , Iwata Takanori , Izumi Yuichi
Published: December 2020

Background and Objective

Following tooth extraction, bone resorption is especially severe in cases complicated with buccal dehiscence bone defects. To minimize this, various bone graft materials have been used for alveolar ridge preservation. This study aimed to evaluate additional effects of the concomitant use of recombinant human fibroblast growth factor‐2 (rhFGF‐2) with β‐tricalcium phosphate (β‐TCP) on ridge preservation in a dehiscence defect model after tooth extraction in dogs.

Materials and Methods

The maxillary first premolars of six beagle dogs were extracted and dehiscence defects of 4 × 4 × 5 mm (mesio‐distal width × bucco‐palatal width × depth) were created. Bilateral defects were filled with β‐TCP combined with 0.3% (w/v) rhFGF‐2 (test sites) or the scaffold alone (control sites). Twelve weeks post‐surgery, histologic and histometric evaluations were performed.

Results

Morphological measurements using micro‐computed tomography revealed a significantly greater bone volume at the test sites (48.9 ± 9.06 mm3) than at the control sites (38.8 ± 7.24 mm3). Horizontal widths of the alveolar ridge at the coronal and middle position at the test sites (2.18 ± 0.71 mm, 2.93 ± 0.53 mm) were significantly greater than those at the control sites (1.47 ± 0.41 mm, 2.36 ± 0.45 mm, respectively). Regarding the histological parameters, the occupation rate of mineralized bone in the original defects was slightly higher at the test sites (44.07 ± 10.19%) than that at the control site (41.15 ± 6.56%).

Conclusions

These results indicate that the adjunct use of rhFGF‐2 with β‐TCP is effective for alveolar ridge preservation in fresh extraction sockets with dehiscence defects.
Asymptotic theory for QMLE for the real‐time GARCH(1,1) model
Authors: Smetanina Ekaterina , Biao Wu Wei
Published: December 2020

We investigate the asymptotic properties of the Gaussian quasi‐maximum‐likelihood estimator (QMLE) for the Real‐time GARCH(1,1) model of Smetanina (2017, Journal of Financial Econometrics, 15(4), 561–601). The developed theory relies on the functional dependence measure and recently developed theory for derivative processes in Dahlhaus etal. (2019, Bernoulli, 25(2), 1013–1044). We prove stationarity and ergodicity of the underlying processes and consistency for the QMLE estimator under mild conditions. Furthermore, under normality of the error term, we also establish asymptotic normality for QMLE, which then becomes MLE, at the usual rate. Finally, in our simulations we show that consistency and asymptotic normality holds for typical sample sizes.
Elaboration of novel and comprehensive protocols toward determination of textural properties and other sensorial attributes of canning peach fruit
Authors: Christofi Marina , Mourtzinos Ioannis , Lazaridou Athina , Drogoudi Pavlina , Tsitlakidou Petroula , Biliaderis Costas G. , Manganaris George A.
Published: December 2020

Peach (Prunus persica) products are destined for fresh consumption or are being consumed after processing in various forms. Despite its huge economic importance, no standardized protocols to define sensorial attributes and mechanical properties of canned peaches exist. Thus, the aim of the current study was dual and included the setting up of a list of sensorial descriptors and the elaboration of a toolkit to evaluate the textural properties of canned peaches using large deformation mechanical testing. A standardized vocabulary (“consensus language”) was initially developed toward the determination and quantification of 15 sensorial attributes through a descriptive quantitative analysis (QDA) approach. Textural properties were additionally evaluated with a TA‐XT Plus texture analyzer by applying three discrete large deformation tests [(a) puncture test with a flat cylindrical probe; (b) texture profile analysis (TPA) with a flat compression plunger; and (c) Kramer shear test (KST) cell with a bladed fixture]; that is, a total of nine textural properties, namely, “puncture firmness” (individual halves), “Kramer” hardness (applied in a complex mixture of peach slices), “TPA” hardness (central section of halves), fracturability, consistency, cohesiveness, springiness, chewiness, and total hardness were assessed. We hereby present novel protocols that encompass the comprehensive determination of sensorial and textural properties. The established protocols, providing complementary information, are readily applicable to the canning industry in setting up qualitative tests to determine product shelf life as well as to assist on going breeding programs for the evaluation of new candidate clingstone cultivars destined for canning purposes.
Developing a digital toolkit to enhance the communication of health claims: The Health Claims Unpacked project
Authors: Lockyer S. , Ryder C. , Jaworska S. , Benelam B. , Jones R.
Published: December 2020

Consumer understanding and acceptance of health claims are influenced by a variety of factors including personal knowledge and familiarity with the information, characteristics of the product (such as the ingredients) and the way the claim is presented (e.g. wording and visual aids such as symbols). The official wording of authorised EU health claims is set by the European Commission (EC), though there is some flexibility, in that food companies can change the wording to aid consumer understanding of the claim as long as the original meaning is retained and the modified version does not mislead. An EIT Food‐funded project with the consumer‐facing title Health Claims Unpacked, consists of an international consortium aiming to develop a digital toolkit to investigate consumers’ responses to health claims and aid their understanding thereof. Developed firstly in English (and now also in other EU languages such as German, French and Polish), the toolkit is informed by research in linguistics, design, nutrition science, technology and behavioural economics as well as focus groups with consumers and interviews with the food industry. The format of the toolkit is an interactive web app comprising activities which are used to gather data regarding consumers’ responses to different kinds of linguistic, semiotic (signs and symbols) and marketing cues related to health claims and how these cues impact their understanding of the relationship between nutrients/food components and health, trust in the message and willingness to pay for products. The data will be used to provide information on the preferences of different demographic groups on the wording of health claims and to provide recommendations for stakeholders aiming to enhance the communication of health claims on food and drink labels.
Diagnostic yield of adding solid food swallows during high‐resolution manometry in esophageal motility disorders
Authors: Araujo Isis K. , Roman Sabine , Napoléon Marie , Mion François
Published: December 2020

Background

High‐resolution manometry (HRM) is a key method to evaluate esophageal motility disorders. Current evaluation is usually performed with single water swallows (SWS) that may not challenge esophageal function or reproduce symptoms. Solid food swallows (SFS) could increase the diagnostic yield for clinically relevant disorders.

Methods

Patients with dysphagia referred for esophageal HRM during a 2‐year period in a single center were reviewed retrospectively and included if SFS was performed during HRM. Chicago classification v3.0 was used to define esophageal motility disorders.

Key Results

One hundred and four patients with dysphagia were included (59% women, mean age 57 years). Ineffective esophageal motility was the most frequent motility disorder. Compared to SWS, the diagnosis changed after SFS in 33 patients (31.7%) including a change from normal or minor diagnosis toward major motility disorders in 14 (13.4%). Fifteen subjects (14.4%) shifted from a minor disorder on SWS to normal after SFS. SFS changed the diagnosis in 53.8% of patients with previous surgery versus 29.5% of those without (p = 0.023). Pressurization during rapid drink challenge was more frequent when SFS changed the diagnosis to major motility disorders (69.2% vs. 37.3%, p = 0.033). Twenty‐nine percent of patients reported symptoms during SFS, mostly those with diagnostic change to major disorders after SFS (71.4% of patients with changes to major disorders vs. 22.2% of patients without, p < 0.0001).

Conclusion & Inferences

Solid food swallows is a simple way to improve the diagnostic yield of HRM in patients with dysphagia and should be added to manometry protocol in daily clinical practice.
Species‐specific effects of biocrust‐forming lichens on soil properties under simulated climate change are driven by functional traits
Authors: Concostrina‐Zubiri Laura , Valencia Enrique , Ochoa Victoria , Gozalo Beatriz , Mendoza Betty J. , Maestre Fernando T.
Published: December 2020

Biocrusts are key drivers of ecosystem functioning in drylands, yet our understanding of how climate change will affect the chemistry of biocrust‐forming species and their impacts on carbon (C) and nitrogen (N) cycling is still very limited.

Using a manipulative experiment conducted with common biocrust‐forming lichens with distinct morphology and chemistry (Buellia zoharyi, Diploschistes diacapsis, Psora decipiens and Squamarina lentigera), we evaluated changes in lichen total and isotopic C and N and several soil C and N variables after 50 months of simulated warming and rainfall reduction.

Climate change treatments reduced δ13C and the C : N ratio in B. zoharyi, and increased δ15N in S. lentigera. Lichens had species‐specific effects on soil dissolved organic N (DON), , β‐glucosidase and acid phosphatase activity regardless of climate change treatments, while these treatments changed how lichens affected several soil properties regardless of biocrust species. Changes in thallus δ13C, N and C : N drove species‐specific effects on dissolved organic nitrogen (DON), , β‐glucosidase and acid phosphatase activity.

Our findings indicate that warmer and drier conditions will alter the chemistry of biocrust‐forming lichens, affecting soil nutrient cycling, and emphasize their key role as modulators of climate change impacts in dryland soils.
The identification of critical time windows of postnatal root elongation in response to Wnt/β‐catenin signaling
Authors: Wang Jun , Jiang Yong , Xie Xudong , Zhang Shiwen , Xu Chunmei , Zhou Yinghong , Feng Jian Q.
Published: December 2020

Objectives

In this study, we attempted to define the precise window of time for molar root elongation using a gain‐of‐function mutation of β‐catenin model.

Materials and Methods

Both the control and constitutively activated β‐catenin (CA‐β‐cat) mice received a one‐time tamoxifen administration (for activation of β‐catenin at newborn, postnatal day 3, or 5, or 7, or 9) and were harvested at the same stage of P21. Multiple approaches were used to define the window of time of postnatal tooth root formation.

Results

In the early activation groups (tamoxifen induction at newborn, or P3 or P5), there was a lack of molar root elongation in the CA‐β‐cat mice. When induced at P7, the root length was slightly reduced at P21. However, the root length was essentially the same as that in the control when β‐cat activated at P9. This study indicates that root elongation occurs in a narrow time of window, which is highly sensitive to a change of β‐catenin levels. Molecular studies showed a drastic decrease in the levels of nuclear factor I‐C (NFIC) and osterix (OSX), plus sharp reductions of odontoblast differentiation markers, including Nestin, dentin sialoprotein (DSP), and dentin matrix protein 1 (DMP1) at both mRNA and protein levels.

Conclusions

Murine molar root elongation is precisely regulated by the Wnt/β‐catenin signaling within a narrow window of time (newborn to day 5).
No impact of mineralocorticoid receptor antagonists on long‐term recurrences of ventricular tachyarrhythmias
Authors: Schupp Tobias , Akin Ibrahim , Reiser Linda , Bollow Armin , Taton Gabriel , Borggrefe Martin , Reichelt Thomas , Ellguth Dominik , Engelke Niko , Barre Max , Müller Julian , Weidner Kathrin , Kim Seung‐hyun , Akin Muharrem , Große Meininghaus Dirk , Behnes Michael
Published: December 2020

Objective

The study sought to assess the prognostic impact of treatment with mineralocorticoid receptor antagonists (MRA) on recurrences of ventricular tachyarrhythmias in implantable cardioverter‐defibrillator (ICD) recipients with systolic heart failure (HF).

Background

Data regarding the outcome of patients with ventricular tachyarrhythmias treated with MRA is limited.

Methods

A large retrospective registry was used including consecutive ICD recipients with systolic HF (i.e., left ventricular ejection fraction < 45%) and index episodes of ventricular tachyarrhythmias from 2002 to 2016. Patients treated with MRA were compared to patients without (non‐MRA). Kaplan–Meier and multivariable Cox regression analyses were applied for the evaluation of the primary endpoint defined as first recurrence of ventricular tachyarrhythmias at five years. Secondary endpoints were appropriate ICD therapies, first cardiac rehospitalization, and all‐cause mortality.

Results

366 ICD recipients with systolic HF were included, 20% treated with MRA (spironolactone: 65%; eplerenone: 35%) and 80% without. At five years, treatment with MRA was not associated with the primary endpoint of first recurrence of ventricular tachyarrhythmias [47% vs. 48%, log‐rank p = 0.732; hazard ratio (HR) = 1.067; 95% confidence interval (CI) 0.736–1.546; p = 0.732]. Accordingly, risk of first appropriate ICD therapies, first cardiac rehospitalization, and all‐cause mortality were not affected by the presence of MRA therapy. Finally, patients with spironolactone and eplerenone had comparable risk of first recurrences of ventricular tachyarrhythmias (50% vs. 45%; p = 0.255; HR = 2.263; 95% CI 0.495–10.341; p = 0.292).

Conclusion

Treatment with MRA was not associated with recurrences of ventricular tachyarrhythmias and ICD therapies at five years.
A novel NAC family transcription factor SPR suppresses seed storage protein synthesis in wheat
Authors: Shen Lisha , Luo Guangbin , Song Yanhong , Xu Junyang , Ji JingJing , Zhang Chi , Gregová Edita , Yang Wenlong , Li Xin , Sun Jiazhu , Zhan Kehui , Cui Dangqun , Liu Dongcheng , Zhang Aimin
Published: December 2020

The synthesis of seed storage protein (SSP) is mainly regulated at the transcriptional level. However, few transcriptional regulators of SSP synthesis have been characterized in common wheat (Triticum aestivum) owing to the complex genome. As the A genome donor of common wheat, Triticum urartu could be an elite model in wheat research considering its simple genome. Here, a novel NAC family transcription factor TuSPR from T. urartu was found preferentially expressed in developing endosperm during grain‐filling stages. In common wheat transgenically overexpressing TuSPR, the content of total SSPs was reduced by c. 15.97% attributed to the transcription declines of SSP genes. Both in vitro and in vivo assays showed that TuSPR bound to the cis‐element 5′‐CANNTG‐3′ distributed in SSP gene promoters and suppressed the transcription. The homolog in common wheat TaSPR shared a conserved function with TuSPR on SSP synthesis suppression. The knock‐down of TaSPR in common wheat resulted in 7.07%–20.34% increases in the total SSPs. Both TuSPR and TaSPR could be superior targets in genetic engineering to manipulate SSP content in wheat, and this work undoubtedly expands our knowledge of SSP gene regulation.
Malignant hyperthermia during pediatric kidney transplantation—A medical and ethical quandary
Authors: Srinivasan Sangeeth P. , Eldo Nidhin , Nair Suresh G.
Published: December 2020

Malignant hyperthermia (MH) is a rare life‐threatening anesthetic complication with high mortality rates. MH during adult kidney transplant has been reported previously. However, the occurrence of MH after multiple previous uneventful anesthetic exposures in a pediatric kidney transplant recipient is rare. To our knowledge, this is the first reported case of MH in a child undergoing a live donor kidney transplant. The approaches for addressing perioperative challenges and ethical dilemmas to ensure successful outcomes are described. The recipient, a 5‐year‐old male child, weighing 20 kg, with a history of multiple previous uneventful anesthetic exposures, underwent live donor kidney transplant for end‐stage renal disease (ESRD). Post‐reperfusion he developed fulminant MH with rapidly progressing hyperthermia, hypercarbia, tachycardia, and muscle rigidity, which in addition to complicating the medical management raised several ethical issues as well. MH was successfully managed with dantrolene and other supportive measures. Judicious use of inotropes and fluids helped maintain stable hemodynamics and graft perfusion. Management of MH is complicated in a pediatric patient with ESRD undergoing live donor kidney transplant. Preference for non‐depolarizing muscle relaxants instead of succinylcholine during endotracheal intubation can result in delayed onset of clinical manifestations. However, the metabolic complications may be more severe due to preexisting electrolyte and acid‐base disturbances. Maintaining optimal graft perfusion while simultaneously combating MH can be very challenging in a child. Since the allograft is a precious commodity, critical decisions regarding the harvesting of the donor kidney need to be well thought out. Early diagnosis and prompt treatment with dantrolene are critical to preserving graft function and the recipient's life.
Thalidomide as treatment of crohn‐like disease occurred after allogeneic hematopoietic stem cell transplantation in a pediatric patient
Authors: Giardino Stefano , Bava Cecilia , Arrigo Serena , Pierri Filomena , Gandullia Paolo , Coccia Cristina , Faraci Maura
Published: December 2020

Background

Autoimmune diseases may occur after allogeneic hematopoietic stem cell transplantation (allo‐HSCT) and inflammatory bowel disease (IBD or Crohn disease) is rarely described. We describe a child who developed CD after allo‐HSCT, successfully treated with thalidomide.

Case report

A child affected by mucopolysaccharidosis type I received two allogeneic HSCTs for rejection after the first one. After cutaneous and intestinal chronic GvHD and 6 months after HSCT, the patients developed a trilinear autoimmune cytopenia successfully treated with rituximab and sirolimus. Due to persisting intestinal symptoms, colonoscopies were performed and histological findings demonstrated a picture of CD. Based on this observation and according to the recommendations for the treatment of CD, thalidomide was started. A complete stable clinical response was obtained 8 weeks after start of thalidomide. Colonoscopy performed 4.8 years later demonstrated a complete endoscopic and histological remission of CD.

Discussion

In this case, the diagnosis of CD after HSCT was based on histological findings. Indeed, repeated colonscopies were necessary for diagnosis, since both clinical and endoscopic features are often common to chronic GvHD and CD. Thalidomide was started at the dose of 1.7 mg/Kg/day, and it was well tolerated. Mild peripheral neurotoxicity occurred 5 years later but disappeared completely with the dose reduction. Currently, the patient is in complete remission from CD, despite the discontinuation of all the immunosuppressive therapies.

Conclusions

Thalidomide could represent a therapeutic option to treat CD as autoimmune disease after allogeneic HSCT.
Adventitious root formation in crops—Potato as an example
Authors: Joshi Mukul , Ginzberg Idit
Published: December 2020

The root system of potato is made up of adventitious roots (AR) that form at the base of a sprout once it emerges from the mother tuber. By definition, AR originate from dormant preformed meristems, or from cells neighboring vascular tissues in stems or leaves. This may occur as part of the developmental program of the plant (e.g., potato), or when replacing the embryonic primary roots in response to stress conditions, such as flooding, nutrient deprivation, or wounding. AR formation is studied mainly in cereals and model plants, and less is known about its developmental program in root and tuber crops. In this review, we summarize the recent data on AR development in potato and relate this knowledge to what is known from model plants. For example, AR formation following stem cutting in potato follows a pattern of initiation, expression, and emergence phases that are known for other plants and involves auxin, the master regulator of AR induction and development. Molecular regulation of AR formation and the effect of environmental stresses are discussed. Understanding the origin and nature of AR systems in important crops will contribute to increased production and improve global food security.
Disaster Recovery Communication in the Digital Era: Social Media and the 2016 Southern Louisiana Flood
Authors: Yeo Jungwon , Knox Claire Connolly , Hu Qian
Published: December 2020

This study explores disaster recovery communication in the digital era. In particular, this study analyzes Twitter communication data corresponding to the 2016 Southern Louisiana flood recovery process and examines patterns and characteristics of long‐term recovery communication. Based on network and sentiment analyses of the longitudinal Twitter data, the study identifies the dynamic changes in participants’ numbers, dominant voices, and sentiments in social media communication during the long‐term recovery process. From the additional content analysis of relevant news articles, in‐depth contextual information is provided to support and supplement the findings. Findings show the weaning communication volume during the recovery phase, lacking local voices over the long‐term recovery communication process, and prolonging negative sentiments over the recovery period. Based on the findings, the authors provide implications highlighting the need for investing in long‐term recovery communication, better utilizing information from social media, and supporting local voices during disaster recovery.
High-Rate and Long-Life Cycle of Nano-LiMn2O4 Under High Cut-Off Potential
Authors: Radzi Z. I. , Vengadaesvaran B. , Rahim N. A. , Pandey A. K. , Arifin K. H. , Kufian M. Z. , Zakuan N. S. , Abidin Z. H. Z. , Ramesh S.
Published: December 2020

Nano-LiMn2O4 was successfully synthesized by a low-temperature hydrothermal route with the absence of post-calcination treatment. Employing ethanol as an organic reagent triggers the formation of nanostructured particles approximately 30.39 nm in diameter, associated with 0.007 lattice strain. The pure phase of nano-LiMn2O4/Li displays outstanding electrochemical performances. Under 4.6 V versus Li+/Li cut-off potential, 74.3% of capacity is reserved when C-rate is increased by 50 times, while excellent capacity restoration of 96.9% after cycled again at 1 C. After 331 cycles, a capacity retention of 84.3% is harvested by nano-LiMn2O4/Li, implying the absence of phase transformations in spinel structures under such abuse conditions. This remarkable structural stability can be attributed to the small lattice strain, associated with high Li+ diffusion coefficient, which is estimated to be 10−9.76 cm2 s−1 by the EIS technique. Additionally, Li+ extraction is more favorable when nano-LiMn2O4/Li is charged up to 4.6 V versus Li+/Li, interpreted by the polarization resistance (Rp) of the cell.
Combination of Silica Gel and Surfactin Promoting Methane Hydrate Formation
Authors: Arora Amit , Cameotra Swaranjit Singh , Balomajumder Chandrajit , Kumar Rajnish , Singh Anil Kumar , Kumar Pushpendra , Laik Sukumar
Published: December 2020

Recently, gas hydrates based technologies have been exploited for few novel applications such as storage and transpiration of natural gas, gas mixtures separation, CO2 capture, and seawater desalination. Most of these applications are currently facing a challenge of low rate of gas hydrate formation. Chemical additives like surfactants can play a role of a good kinetic promoter for gas hydrate formation. The present study reports the application of biosurfactant for enhancing gas hydrate formation. Biosurfactant was produced by Bacillus subtilis strain A21. These types of microbes show their presence in the real gas hydrate sites also. The surfactin was characterized using many sophisticated techniques, conforming the formation of surfactin. It was used in the presence of fixed bed media of silica gel, and it was observed that surfactin in the presence of silica gel increased the consumption of moles of methane as well as reduced the induction time also as well as the conversion was also increased up to 27.9% for 390 min for 1000 ppm surfactin hence indicating it to be a clean and novel promoter of methane hydrate formation in combination with silica gel which can replace its synthetic counterparts which have environmental concerns.
Influence of Deposition and Fouling on Wall Temperature Distribution in Convective Path
Authors: Li Deli , Wang Enlu , Mao Jinda , Wu Wei , Wang Yiyang
Published: December 2020

To develop a method of controlling the deposit tube surface temperature, the rules of deposition and fouling on the fireside, and the influence factors of the surface distribution were determined through experiments and theoretical calculations. The surface temperature distribution of a clean tube was compared with that of a deposit tube. Through theoretical calculations, the influence factors of the deposit tube surface temperature were evaluated. Based on the investigation, surface temperature control technology applicable to a super- heater was proposed and the feasibility of this heater was determined. A bimodal distribution was obtained when the temperature distribution of the deposit tube was plotted as a function of the angle, whereas a unimodal distribution was obtained for the clean tube. The results revealed that the heat exchange tube surface temperature is most effectively controlled by controlling the flue gas temperature. Prior to the development of higher performance materials (compared with conventional materials), surface temperature control technology can be used to ensure that the super-heater surface temperature lies below the allowable temperature of existing super-heater materials.
Performance Analysis of Heat Sinks Designed for Additive Manufacturing
Authors: White Andrew Scott , Saltzman David , Lynch Stephen
Published: December 2020

Significant levels of heat are generated in contemporary electronics, and next generation devices will continue to demand higher power despite decreasing size; therefore, highly effective cooling schemes are needed. Simultaneously, advances in metal additive manufacturing have enabled production of complex heat transfer devices previously impossible to traditionally manufacture. This paper introduces three novel prototypes, originally designed for a prior ASME Student Heat Sink Design Competition sponsored by the K-16 (Heat Transfer in Electronic Devices) technical committee, to demonstrate the abilities of selective laser melting processes in the fabrication of A357 aluminum, EOS aluminum, and copper heat sinks. The performance of each of these prototypes has been determined experimentally, and the effects of specific material and design choices are analyzed. Comparisons of experimental results show that the copper and EOS aluminum prototypes performed better than the A357 aluminum due to increased thermal conductivity; however, the gains in thermal performance from EOS aluminum to copper were much lower despite the large difference in thermal conductivity.
Characterization and Prevention of Metal Overflow in Ultra-Thin Au-Sn Eutectic Chip Bonding for Packaging and Integration of Extreme Heat Flux Micro-Coolers
Authors: Hazra Sougata , Singh Yashvi , Asheghi Mehdi , Goodson Kenneth
Published: December 2020

In this study, a detailed characterization of Au-Sn eutectic ultra-thin metal stack (∼ 1 μm) bonding has been performed between Pyrex and silicon substrates using a commercial flip-chip bonder. A thorough recipe characterization and development was performed on three different bond sizes of 9, 49 and 100 mm2 by varying bonding temperature between 320 and 380°C with pressure ranging between 2 to 10 MPa. Results indicate that better bond quality was observed at higher temperatures but was relatively unaffected by the bond pressure magnitude. It was also found that flatness of contact is one of the most important parameters that determine the bond uniformity and thus the quality, which is especially important for ultra-thin metal bonding. In addition, this study puts special emphasis on observing the bond uniformity and metal overflow through the transparent Pyrex top substrate. The mean overflow width increased with increasing temperature, reaching as high as 300 μm at 380°C, but was not significantly affected by the bond pressure applied. Simultaneously, the ultra-thin bond layer made it possible for us to observe several different types of microstructures forming within the bond zone, which provided crucial information about sample cool down rate, grain size and intermetallic composition in the eutectic alloy. For a specific case, Kirkendall voids were observed under the optical microscope at the interface between Pyrex and bonded metal because of dissimilar rates of migration of Au and Sn during the eutectic reaction. We believe that this is the first successful observation of voids in bond alloy using non-destructive optical imaging techniques. Following successful characterization of metal reflow from the bond site, a simple method to control this overflow has been demonstrated by precisely controlled misalignment of the two complementary chips. This fundamental study on eutectic bonding aims to further the understanding of eutectic bonding process as well as facilitate development of effective ultra-thin layer, high strength bonding recipes between chips for versatile applications in the electronic packaging industry.
Ultra-Compact Micro-Scale Heat Exchanger for Advanced Thermal Management in Datacenters
Authors: Amalfi Raffaele L. , Salamon Todd , Cataldo Filippo , Marcinichen Jackson B. , Thome John R.
Published: December 2020

The present study is focused on the experimental characterization of two-phase heat transfer performance and pressure drops within an ultra-compact heat exchanger (UCHE) suitable for electronics cooling applications. In this specific work, the UCHE prototype is anticipated to be a critical component for realizing a new passive two-phase cooling technology for high-power server racks, as it is more compact and lighter weight than conventional heat exchangers. This technology makes use of a novel combination of thermosyphon loops, at the server-level and rack-level, to passively cool an entire rack. In the proposed two-phase cooling technology, a smaller form factor UCHE is used to transfer heat from the server-level thermosyphon cooling loop to the rack-level thermosyphon cooling loop, while a larger form factor UCHE is used to reject the total heat from the server rack into the facility-level cooling loop. The UCHE is composed of a double-side-copper finned plate enclosed in a stainless steel enclosure. The geometry of the fins and channels on both sides are optimized to enhance the heat transfer performance and flow stability, while minimizing the pressure drops. These features make the UCHE the ideal component for thermosyphon cooling systems, where low pressure drops are required to achieve high passive flow circulation rates and thus achieve high critical heat flux values. The UCHE’s thermal-hydraulic performance is first evaluated in a pump-driven system at the Laboratory of Heat and Mass Transfer (LTCM-EPFL), where experiments include many configurations and operating conditions. Then, the UCHE is installed and tested as the condenser of a thermosyphon loop that rejects heat to a pumped refrigerant system at Nokia Bell Labs, in which both sides operate with refrigerants in phase change (condensation-to-boiling). Experimental results demonstrate high thermal performance with a maximum heat dissipation density of 5455 (kW/m3/K), which is significantly larger than conventional air-cooled heat exchangers and liquid-cooled small pressing depth brazed plate heat exchangers. Finally, a thermal performance analysis is presented that provides guidelines in terms of heat density dissipations at the server- and rack-level when using passive two-phase cooling.
Validation and Parametric Investigations Using a Lumped Thermal Parameter Model of an Internal Permanent Magnet Motor
Authors: Sequeira Sebastien , Bennion Kevin , Cousineau J. Emily , Narumanchi Sreekant , Moreno Gilbert , Kumar Satish , Joshi Yogendra
Published: December 2020

One of the key challenges for the electric vehicle industry is to develop high-power-density electric motors. Achieving higher power density requires efficient heat removal from inside the motor. In order to improve thermal management, a multi-physics modeling framework that is able to accurately predict the behavior of the motor, while being computationally efficient, is essential. This paper first presents a detailed validation of a Lumped Parameter Thermal Network (LPTN) model of an Internal Permanent Magnet (IPM) synchronous motor within the commercially available Motor-CAD® modeling environment. The IPM motor’s stator is studied at steady state, and winding losses are generated by a constant DC current. The validation is based on temperature comparison with experimental data and with more detailed Finite Element Analysis (FEA). All critical input parameters of the LPTN are considered in detail for each layer of the stator, especially the contact resistances between the impregnation, liner, laminations and housing. Finally, a sensitivity analysis for each of the critical input parameters is provided. A maximum difference of 4% — for the highest temperature in the slot windings and the end windings — was found between the LPTN and the experimental data. Comparing the results from the LPTN and the FEA model, the maximum difference was 2% for the highest temperature in the slot windings and end windings. As for the LTPN sensitivity analysis, the thermal parameter with the highest sensitivity was found to be the liner-to-lamination contact resistance. The latter is often ignored in the literature, whereas its impact on temperature rise was found to be more significant than any other contact resistance within the stator.
Partitioned Heat Sinks for Improved Natural Convection
Authors: Salamon Todd , Kempers Roger , Lynch Brian , Terrell Kevin , Simon Elina
Published: December 2020

The main drivers contributing to the continued growth of network traffic include video, mobile broadband and machine-to-machine communication (Internet of Things, cloud computing, etc.). Two primary technologies that next-generation (5G) networks are using to increase capacity to meet these future demands are massive MIMO (Multi-Input Multi-Output) antenna arrays and new frequency spectrum. The massive MIMO antenna arrays have significant thermal challenges due to the presence of large arrays of active antenna elements coupled with a reliance on natural convection cooling using vertical plate-finned heat sinks. The geometry of vertical plate-finned heat sinks can be optimized (for example, by choosing the fin pitch and thickness that minimize the thermal resistance of the heat sink to ambient air) and enhanced (for example, by embedding heat pipes within the base to improve heat spreading) to improve convective heat transfer. However, heat transfer performance often suffers as the sensible heat rise of the air flowing through the heat sink can be significant, particularly near the top of the heat sink; this issue can be especially problematic for the relatively large or high-aspect-ratio heat sinks associated with massive MIMO arrays. In this study a vertical plate-finned natural convection heat sink was modified by partitioning the heat sink along its length into distinct sections, where each partitioned section ejects heated air and entrains cooler air. This approach increases overall heat sink effectiveness as the net sensible heat rise of the air in any partitioned section is less than that observed in the unpartitioned heat sink. Experiments were performed using a standard heat sink and equivalent heat sinks partitioned into two and three sections for the cases of ducted and un-ducted natural convection with a uniform heat load applied to the rear of the heat sink. Numerical models were developed which compare well to the experimental results and observed trends. The numerical models also provide additional insight regarding the airflow and thermal performance of the partitioned heat sinks. The combined experimental and numerical results show that for relatively tall natural convection cooled heat sinks, the partitioning approach significantly improves convective heat transfer and overall heat sink effectiveness.
A Porous Medium Approach for Single-Phase Flow and Heat Transfer Modeling in Manifold Microchannel Heat Exchangers
Authors: Battaglia Fabio , Mandel Raphael , Shooshtari Amir , Ohadi Michael M.
Published: December 2020

Manifold Microchannels have been proven to enhance thermal management in different fields, such as electronic cooling, dry cooling, and high temperature heat exchangers. Manifold-microchannels use a system of manifolds to divide a microgrooved surface into a system of manifolds, thereby reducing pressure drop and increasing heat transfer by utilizing the developing flow regime. Because of this, design of a manifold-microchannel heat exchanger requires the design of the manifold and microchannel. In some situations, a sequential design approach, where one first designs the microchannel and then the manifold — is sufficient to meet the requirements of the problem statements. The more demanding requirements of contemporary applications require manifold microchannel design to evolve and become more complex. In particular, reducing the volume and pitch of the manifold has become necessary. Reducing the volume of the manifold results in a higher flow maldistribution, and the ability to predict how maldistribution affects heat transfer rate is critical. Similarly, reducing the pitch of the manifold increases the effect of axial conduction in the solid, and understanding the effect on heat transfer is important. To those ends, this work shows a porous medium approach for single-phase flow in manifold microchannel, which allows to predict pressure drop, maldistribution, axial conduction, and heat transfer rate with a much smaller computational demand when compared to a full 3D simulation, while guaranteeing very similar results.
Design and Fabrication of Graded Copper Inverse Opals (g-CIOs) for Capillary-Fed Boiling in High Heat Flux Cooling Applications
Authors: Wu Qianying , Zhang Chi , Asheghi Mehdi , Goodson Kenneth
Published: December 2020

Capillary-fed boiling in microporous copper inverse opals (CIOs) is capable of removing an excess of 1 kW/cm2 at 10–15 °C superheat over small wicking distances ∼ 200 μm. In order to remove heat from large area chips (> 1 cm2), longer capillary wicking distance is desired to reduce the manufacturing complexity of the 3D manifold for liquid delivery and vapor extraction. In this study, we propose graded copper inverse opals (g-CIOs) where smaller pores at the bottom provide high capillary pressure for liquid delivery, while larger pores at the top reduce viscous pressure drop for vapor extraction. This nonhomogeneous wicking material decouples the permeability and capillary pressure in the vertical and lateral directions, resulting in greater CHFs and capillary wicking distances. In this study, we demonstrate the feasibility of fabricating g-CIOs material with up to three different pore diameters (2 μm, 5 μm, and 10 μm) using a multi-step template sintering and copper electrodeposition process. We then leverage and expand upon a well-calibrated experimental model for the prediction of CHF in monoporous CIOs to map the performance metrics for g-CIOs. The model combines a hydraulic resistance network with Darcy’s law and accounts for the nonhomogeneous permeabilities in lateral and vertical directions. Using this model, we study the impact of total wick thickness and graded pore-size combinations on the critical heat fluxes and wicking distances. Our modeling results conclude that a two-layer g-CIOs can potentially reach ∼70% enhancement in the critical heat flux or ∼30% enhancement in the wicking length compared to monoporous CIOs of the same thickness. Our fabrication capability and preliminary modeling results offer the opportunity to design boiling tests with optimized g-CIOs and exploring the potential of dissipating high heat flux for large area cooling applications.