bluuebunny/crossref_metadata_2025 huggingface dataset:
Rac‐1 and Raf‐1 kinases, components of distinct signaling pathways, activate myotonic dystrophy protein kinase
Authors: Shimizu Miho , Wang Wenfu , Walch E.Timothy , Dunne Patrick W. , Epstein Henry F.
Published: July 2002

Myotonic dystrophy protein kinase (DMPK) is a serine–threonine protein kinase encoded by the myotonic dystrophy (DM) locus on human chromosome 19q13.3. It is a close relative of other kinases that interact with members of the Rho family of small GTPases. We show here that the actin cytoskeleton‐linked GTPase Rac‐1 binds to DMPK, and coexpression of Rac‐1 and DMPK activates its transphosphorylation activity in a GTP‐sensitive manner. DMPK can also bind Raf‐1 kinase, the Ras‐activated molecule of the MAP kinase pathway. Purified Raf‐1 kinase phosphorylates and activates DMPK. The interaction of DMPK with these distinct signals suggests that it may play a role as a nexus for cross‐talk between their respective pathways and may partially explain the remarkable pleiotropy of DM.
The mitogenic signaling pathway for fibroblast growth factor‐2 involves the tyrosine phosphorylation of cyclin D2 in MCF‐7 human breast cancer cells
Authors: Vercoutter-Edouart Anne-Sophie , Lemoine Jérôme , Smart Chanel E. , Nurcombe Victor , Boilly Bénoni , Peyrat Jean-Philippe , Hondermarck Hubert
Published: July 2002

Fibroblast growth factor‐2 (FGF‐2) is mitogenic for the human breast cancer cell line MCF‐7; here we investigate some of the signaling pathways subserving this activity. FGF‐2 stimulation of MCF‐7 cells resulted in a global increase of intracellular tyrosine phosphorylation of proteins, particularly FGF receptor substrate‐2, the protooncogene product Src and the mitogen‐activated protein kinase (MAP kinase) cascade. A major increase in the tyrosine phosphorylation of a 30‐kDa protein species was also found. This protein was identified as cyclin D2 by mass spectrometry after trypsin digestion. Immunoprecipitation of cyclin D2 and immunoblotting with anti‐phosphotyrosine antibodies confirmed that the tyrosine phosphorylation of cyclin D2 was indeed induced by FGF‐2 stimulation. In addition, pharmacological inhibition of Src (with herbimycin A and PP2), and of the MAP kinase cascade (with PD98059), confirmed that Src activity is required for the FGF‐2‐induced phosphorylation of cyclin D2 whereas MAP kinase activity is not. Thus, tyrosine phosphorylation of cyclin D2 may be a key regulatory target for FGF‐2 signaling.
Intermolecular interactions between the SH3 domain and the proline‐rich TH region of Bruton's tyrosine kinase
Authors: Hansson Henrik , Okoh Michael P , Smith C.I.Edvard , Vihinen Mauno , Härd Torleif
Published: July 2002

The SH3 domain of Bruton's tyrosine kinase (Btk) is preceded by the Tec homology (TH) region containing proline‐rich sequences. We have studied a protein fragment containing both the Btk SH3 domain and the proline‐rich sequences of the TH region (PRR‐SH3). Intermolecular NMR cross‐relaxation measurements, gel permeation chromatography profiles, titrations with proline‐rich peptides, and 15N NMR relaxation measurements are all consistent with a monomer–dimer equilibrium with a dissociation constant on the order of 60 μM. The intermolecular interactions do, at least in part, involve proline‐rich sequences in the TH region. This behavior of Btk PRR‐SH3 may have implications for the functional action of Btk.
Overexpression of a nuclear protein tyrosine phosphatase increases cell proliferation
Authors: Radha Vegesna , Nambirajan Sundaram , Swarup Ghanshyam
Published: July 2002

PTP‐S2 is a widely expressed nuclear protein tyrosine phosphatase which shows increased expression upon mitogenic stimulation of a variety of cells. In order to elucidate the role of this enzyme in cell division, stable clones of HeLa cells expressing rat PTP‐S2 were isolated and their growth properties analysed. Overexpressed PTP‐S2 was located in the cell nucleus and there was no significant change in the total tyrosine phosphatase activity of PTP‐S2 overexpressing cells. PTP‐S2 overexpressing clones, D3 and B5, showed increased rate of cell division and lower serum requirement as compared with control cells. D3 and B5 cells formed larger colonies in soft agar, were not contact inhibited upon confluency, grew in multilayers, and showed altered morphology. These results are consistent with the suggestion that PTP‐S2 may be a positive regulator of cell proliferation.
Changes in the periplasmic linker and in the expression level affect the activity of ToxR and λ‐ToxR fusion proteins in Escherichia coli
Authors: Jappelli Roberto , Brenner Sydney
Published: July 2002

In order to assess the potentiality of Vibrio cholerae ToxR protein and of bacteriophage λ repressor as indicators of the dimerization of periplasmic proteins in Escherichia coli, we have constructed a series of plasmids encoding transmembrane fusion proteins. The amino‐terminal part, containing the DNA binding domain of either ToxR or λ repressor, is located in the cytoplasm and acts as reporter for dimerization. As models of periplasmic proteins we have used alkaline phosphatase (a dimer) and β‐lactamase (a monomer). Both the expression level and the distance between the transmembrane segment and the periplasmic protein substantially affect the activity of the reporter domains.
NMR analyses of the interactions of human annexin I with ATP, Ca2+, and Mg2+
Authors: Han Hee-Yong , Lee Yeon-Hee , Oh Jee-Young , Na Doe-Sun , Lee Bong-Jin
Published: July 2002

Human annexin I is a member of the annexin family of calcium‐dependent phospholipid binding proteins. The structure of an N‐terminally truncated human annexin I (Δ‐annexin I) and its interactions with Ca2+, Mg2+, and ATP were studied at the atomic level using nuclear magnetic resonance (NMR) spectroscopy. Since Δ‐annexin I is a large protein, with a molecular weight of 35 kDa, a site‐specific (carbonyl‐13C, amide‐15N) labeling technique was used to determine the interaction sites of Δ‐annexin I with Ca2+, Mg2+, and ATP. The13C NMR study focused on the carbonyl carbon resonances of the histidine residues of Δ‐annexin I. We found that ATP binds to Δ‐annexin I, and that the ATP binding site is located in the 1‐domain of annexin I. We also found that histidine‐52 is involved in that site, and that the binding ratio of ATP to Δ‐annexin I is 1:1.
Effect of squalene synthase gene disruption on synthesis of polyprenols in Saccharomyces cerevisiae
Authors: Grabowska Dorota , Karst Francis , Szkopińska Anna
Published: July 2002

Biosynthesis of polyprenols was investigated in a wild‐type strain of Saccharomyces cerevisiae and a squalene synthase deficient strain auxotrophic for ergosterol. The quantitative data showed that disruption of squalene synthase gene caused a 6‐fold increase in the synthesis of polyprenols in vitro in comparison with the wild‐type strain. Microsomal preparation from the deleted strain only slightly reacted to the additional exogenous FPP, while that from the wild‐type strain presented a 4‐fold increase of polyprenol synthesis. Restoration of ergosterol synthesis, by introducing ERG9 functional allele into the deleted strain resulted in a significant lowering of polyprenol synthesis, indicating the immediate shift of the common substrate (FPP) to the sterol pathway. The role of squalene synthase in the regulation of polyprenol synthesis and ‘flow diversion hypothesis’ is discussed.
A PCR‐based method for uniform 13C/15N labeling of long DNA oligomers
Authors: Chen Xian , Santhana Mariappan S.V. , Kelley John J. , Bushweller John H. , Bradbury E.Morton , Gupta Goutam
Published: July 2002

A polymerase chain reaction (PCR)‐based method is described for uniform 13C/15N labeling of DNA duplexes. In this method, multiple copies of a blunt‐ended duplex are cloned into a plasmid with each copy containing the sequence of interest and the restriction HincII sequences at the 5′ and 3′ ends. PCR with uniformly 13C/15N‐labeled dNTP precursors results in a labeled DNA duplex containing multiple copies of the sequence of interest. Use of bi‐directional primers, instead of self‐priming [Louis et al. (1998) J. Biol. Chem. 273, 2374–2378], produces a DNA fragment of unique length. Twenty‐four cycles of PCR of this purified product followed by restriction and purification gives (with 30% yield) the uniformly 13C/15N‐labeled duplex sequence for multi‐nuclear magnetic resonance spectroscopy.
A Cys‐less variant of the bacterial ATP binding cassette protein MalK is functional in maltose transport and regulation
Authors: Hunke Sabine , Schneider Erwin
Published: July 2002

The cysteine residues of the ABC protein MalK from Salmonella typhimurium maltose transport system (C40, C350, C360) were consecutively replaced by serines. Cys‐less MalK was fully functional in maltose transport in vivo. Moreover, the activity of MalK as a repressor of other maltose‐regulated genes was also retained. The absence of cysteine residues in the purified protein was verified by its failure to react with fluorescein‐5‐maleimide. In contrast to purified wild‐type MalK, the ATPase activity of the C40S variant was insensitive to inhibition by N‐ethylmaleimide.
Molecular organization of cholesterol in polyunsaturated phospholipid membranes: a solid state 2H NMR investigation
Authors: Brzustowicz Michael R. , Stillwell William , Wassall Stephen R.
Published: July 2002

We compared the molecular organization of equimolar [3α‐2H1]cholesterol in 18:0‐18:1PC (1‐stearoyl‐2‐oleoylphosphatidylcholine), 18:0‐22:6PC (1‐stearoyl‐2‐docosahexaenoylphosphatidylcholine), 18:0‐20:4PC (1‐stearoyl‐2‐arachidonylphosphatidylcholine) and 20:4‐20:4PC (1,2‐diarachidonylphosphatidylcholine) bilayers by solid state 2H NMR. Essentially identical quadrupolar splittings (Δνr=45±1 kHz) corresponding to the same molecular orientation characterized by tilt angle α0=16±1° were measured in 18:0‐18:1PC, 18:0‐22:6PC and 18:0‐20:4PC. A profound difference in molecular interaction with dipolyunsaturated 20:4‐20:4PC, in contrast, is indicated for the sterol. Specifically, the tilt angle α0=22±1° (derived from Δνr=37±1 kHz) is greater and its membrane intercalation is only 15 mol%.
DNA conformational dynamics in the presence of catanionic mixtures
Authors: Mel'nikov Sergey M. , Dias Rita , Mel'nikova Yuliya S. , Marques Eduardo F. , Miguel Maria G. , Lindman Björn
Published: July 2002

DNA conformational behavior in the presence of non‐stoichiometric mixtures of two oppositely charged surfactants, cetyltrimethylammonium bromide and sodium octyl sulfate, was directly visualized in an aqueous solution with the use of a fluorescence microscopy technique. It was found that in the presence of cationic‐rich catanionic mixtures, DNA molecules exhibit a conformational transition from elongated coil to compact globule states. Moreover, if the catanionic mixtures form positively charged vesicles, DNA is adsorbed onto the surface of the vesicles in a collapsed globular form. When anionic‐rich catanionic mixtures are present in the solution, no change in the DNA conformational behavior was detected. Cryogenic transmission electron microscopy, as well as measurements of translational diffusion coefficients of individual DNA chains, supported our optical microscopy observations.
Interaction between the −170 CRE and the −150 CCAAT box is necessary for efficient activation of the fibronectin gene promoter by cAMP and ATF‐2
Authors: Pesce C.Gustavo , Nogués Guadalupe , Alonso Claudio R. , Baralle Francisco E. , Kornblihtt Alberto R.
Published: July 2002

The fibronectin promoter contains an ATF/cyclic AMP (cAMP) response element (CRE) site two helical turns upstream of a CCAAT site with which it interacts. We investigated the effects of mutating these −170 CRE and −150 CCAAT elements on the promoter activity regulated by three different modulators previously known to act through CRE: ATF‐2, cAMP and E1a. While the cooperation seems to play no role in E1a action, integrity of the −150 CCAAT is necessary for ATF‐2 and cAMP efficient activation in a cell‐specific manner. These results show that the CRE and CCAAT elements function as a ‘composite element’ and establish a cell‐specific function for CRE‐CCAAT synergy.
Phosphorylation of the skeletal muscle glycogen‐targetting subunit of protein phosphatase 1 in response to adrenaline in vivo
Authors: Walker Kay S. , Watt Peter W. , Cohen Philip
Published: July 2002

The protein GM, which targets protein phosphatase 1 (PP1) to the glycogen particles and sarcoplasmic reticulum (SR) of striated muscles, is known to be phosphorylated at Ser48 and Ser67 in vitro by adenosine 3′,5′ cyclic monophosphate‐dependent protein kinase (PKA) and at Ser48 by MAP kinase‐activated protein kinase‐1 (MAPKAP‐K1, also called p90 RSK). The phosphorylation of Ser48 increases the rate at which the glycogen‐associated PP1.GM complex dephosphorylates (activates) glycogen synthase, but the phosphorylation of Ser67 has the opposite effect, suppressing the activity of PP1 toward glycogen‐bound substrates. The phosphorylation of Ser67 overrides the activating effect of Ser48 phosphorylation because it dissociates PP1 from GM. Here, we use two phospho‐specific antibodies to demonstrate that the SR‐associated form of GM, as well as the glycogen‐associated form of GM, becomes phosphorylated at Ser48 and Ser67 in response to adrenaline, supporting the view that the PKA‐mediated regulation of the PP1.GM complex plays a role in the adrenergic control of glycogen metabolism and SR function. In contrast, Ser48 is not phosphorylated significantly in response to insulin, and neither is Ser67. Thus the phosphorylation of GM at Ser48 by MAPKAP‐K1 or other insulin‐stimulated protein kinases is not involved in the activation of glycogen synthase by insulin.
Developing a network: the PMM process
Authors: Kamara A
Published: July 2002

Since 1988, the Prevention of Maternal Mortality (PMM) Network has developed, implemented and evaluated projects that focus directly on prevention of maternal deaths. The Network, which consists of 11 multidisciplinary teams in West Africa and one at Columbia University, grew from discussions between the Carnegie Corporation of New York and researchers at Columbia School of Public Health. Its goals are: to strengthen capacities in developing countries; to provide program models for preventing maternal deaths; and to inform policymakers about the importance of maternal mortality. This paper describes the development and functioning of the Network. The initial steps included identifying interested partners in Africa and encouraging them to form multidisciplinary teams. Each African team received two grants: one to perform a needs assessment and then another to develop and implement projects based on the results. The Columbia team provided technical assistance in a variety of ways, including site visits, workshops and correspondence. Teams tested program models and reported findings both to local policymakers and in international fora. Collaboration with government and community leaders helped facilitate progress at all stages. At the PMM Network Results Conference in 1996, the teams decided to continue their work by forming the Regional PMM (RPMM) Network, an entirely African entity. © 1997 International Federation of Gynecology and Obstetrics
Hysteroscopic endometrial ablation without endometrial preparation
Authors: Yin C.S , Wei R.Y.‐C , Chao T.‐C , Chan C.‐C
Published: July 2002

Objective: To study the effectiveness of endometrial ablation by hysteroscopic resection without prior medical preparation for the treatment of women with persistent menorrhagia. Method: From January 1996 to January 1997, a total of 170 women with persistent menorrhagia and/or dysmenorrhea and who underwent hysteroscopic endometrial resection were included in the study. A thorough suction curettage was done before the procedure. The operation was conducted through a continuous flow hysteroscopic resectoscope with electrosurgery while the patient was under intravenous general anesthesia. The distention fluid used was 5% dextrose with a gravity feed infusion system consisting of a 2‐l bag between 1 and 1.5 m above the uterine cavity. After the procedure, the patients’ conditions were followed for at least 6–18 months by telephone interview or at our clinic. Results: A total of 127 women were available for a follow‐up period of at least 6 months. Operative complications were 3%; three women had fever and received oral antibiotics; no uterine perforation occurred; one case of post‐operative bleeding was controlled by intrauterine balloon inflation; the average operation time was 21 min; The mean fluid deficit was 435 ml. Ninety‐nine out of 127 women (78%) had adequately controlled menorrhagia (18.1% had amenorrhea, 42.5% hypomenorrhea and 17.3% had normal menstrual flow), while 27 women (21.2%) were failed due to unchanged or heavier menstrual flow after surgery. Eleven (40%) out of the 27 failed cases had myoma with menorrhagia, whereas only five women (5%) out of the 99 adequately treated women had myomas (P<0.05). Thirty‐eight (54%) out of the 70 women with severe dysmenorrhea reported either lessening dysmenorrhea or no dysmenorrhea after the surgery. A total of 76 women (60%) were satisfied with the procedure. A second surgical procedure, either a resection or hysterectomy, was necessary in 13 women (10%) after ablation (seven received repeated ablations and six underwent hysterectomy). Conclusion: Endometrial ablation without endometrial suppression is a cheap, effective and acceptable procedure for treatment in women with persisted persistent menorrhagia.
Abnormal urodynamic findings after radical hysterectomy or pelvic irradiation for cervical cancer
Authors: Lin H.H , Sheu B.C , Lo M.C , Huang S.C
Published: July 2002

Objective: To assess urodynamic study results in patients with cervical cancer who had received radical hysterectomy or pelvic irradiation or radical hysterectomy with pelvic irradiation. Methods: Forty‐two patients with stage IB cervical cancer after radical hysterectomy (group A), 11 patients at stage IB or IIA after pelvic irradiation (group B), 15 patients at stage IB or IIA after both radical hysterectomy and pelvic irradiation (group C) and 17 patients at stage IB before treatment (group D) as control were recruited for urodynamic examination. The evaluations for each case included a 20‐min pad test, uroflowmetry, both filling and voiding cystometry, and stress urethral pressure profile. ANOVA method with Bonferroni test and Pearson χ2‐test were utilized for statistical analysis. Results: The mean ages in sequential groups A, B, C and D were 52.9±10.2, 62.5±13.5, 49.8±11.7 and 49.4±12.5 years (P=0.02), respectively. The occurring frequency of either detrusor instability or low bladder compliance was 57%, 45%, 80% and 24%, respectively. Each group revealed decreased bladder capacity as 268.4±102.8, 164.1±62.9, 233.5±73.9 and 293.0±47.2 ml (P<0.0001). However, the frequency of abdominal strain voiding was 100% in groups A, B and C as compared to 0% in group D (P<0.01), and the frequency of abnormal residual urine (>50 ml) was 41%, 27%, 40% and 24%. Although each case showed a poor pressure transmission ratio (<100%), the frequency of positive pad test in each group was 81%, 46%, 100% and 18% (P<0.001). The functional urethral length decreased in each group and was 2.6±0.8, 2.3±0.8, 2.5±0.8 and 2.9±0.6 cm, but there were no significant differences in maximal urethral pressure or urethral closure pressure among the four groups. Conclusions: Our data show that abnormal urodynamic findings pre‐exist in patients with cervical cancer before treatment especially in bladder storing function, and that these findings may worsen, or that new abnormal findings may happen after radical hysterectomy or pelvic irradiation, or both.
Traditional birth attendants and their practices in the State of Pernambuco rural area, Brazil, 1996
Authors: Carvalho I , Chacham A.S , Viana P
Published: July 2002

Objective: To obtain socioeconomic information about TBAs in the State of Pernambuco and information concerning their practices. Method: Statistical analysis of the answers to structured questionnaires applied to 127 TBAs. Results: The results of a survey with 127 TBAs conducted in the rural area of the State of Pernambuco (Brazil) is presented in this paper. TBAs in rural Pernambuco are a group of basically old and very poor and uneducated women. Most of them learned to attend births by themselves or by helping another TBA. Thirty percent learned midwifery in hospital delivery rooms, helping doctors and nurses. How the TBAs learned to help births seemed to be the most influential factor on the kind of practices they use. TBAs who learned from other TBAs from the community seem to have the least interventionist approach, followed by the TBAs who learned by themselves. They are more likely to perform more home births and avoid practices such as shaving the pubic hair, vaginal exams, artificial rupture of the membranes, episiotomy and early cord clamping. Conclusion: The way women learned midwifery is the most important determinant of their practice.
Pushing the frontiers of science: reflections on an Institute of Medicine study
Authors: Rosenfield Allan
Published: July 2002

A women‐centered contraceptive research agenda was the focus of a 1996 Institute of Medicine Committee report. Priority was given to research on methods that act as a chemical or physical barrier to conception and to STDs including HIV; to menses inducers and once‐per‐month methods; and to male contraceptive methods. Much progress has been made since the 1996 report. This paper summarizes this progress. New research has been developed in the three priority areas, collaboration activities have been developed between the public and private sectors, and emergency contraception has been introduced to the US. Controversies are discussed in relation to immunocontraception, stem cell research and fetal tissue research. Finally there is a brief report on the lessons to be learned from the experience of the introduction of the implant, Norplant, in the US.
Treatment of Mental Disorders in Psychiatric Services
Authors: Widlöcher D
Published: July 2002

Health care policies are subject to scientific and economic constraints. It is necessary to develop research and evaluation policies, particularly in mental health services. In the area of drug treatment, new methodologies in phase II studies, and a true research program of phase IV, are needed. Furthermore, evaluation of practices needs new scientific programs. This last point is also relevant for psychotherapies. Comparative studies about criteria of indications must be developed.
Post-communist political studies: ten years later, twenty years behind?
Authors: Kubicek Paul
Published: July 2002

The collapse of communism has led to a number of different research agendas in post-communist political studies. These include political culture, “transitology,” nationalism, institutionalism, and political economy. This article critically reviews these approaches, comparing them to the more general lines of research in comparative politics. It asks what contribution each is making, and argues that a political economy perspective may be the most interesting and revealing for post-communist societies.
The Inner Asian anomaly: Mongolia’s democratization in comparative perspective
Authors: Fish M. Steven
Published: July 2002

Following the demise of Soviet-type regimes most countries of postcommunist Inner Asia either experienced initial political openings followed by reversion to authoritarianism or moved directly from one type of harsh authoritarianism to another. Mongolia is exceptional. The extent of political opening there during the 1990s far exceeded anything seen in any neighboring country and the gains of the early post-Soviet period were maintained instead of reversed. This paper investigates the causes of Mongolia’s relative success and argues that the absence of several factors that are often regarded as propitious for democratization has actually facilitated Mongolia’s democratization. The experience of postcommunist Inner Asia casts doubt on some arguments current in thinking on regime change.
The myth of equilibrium: winner power, fiscal crisis and Russian economic reform
Authors: Robinson Neil
Published: July 2002

It has become common to describe Russia as a state that has only achieved partial reform due to the influence of powerful economic forces, the ‘winners’ of economic reform, and to assume that the Russian state lacks autonomy. This paper questions how far reform in Russia has been compromised by the power of winners. The failure of economic reform between 1992 and 1998 is explained as a policy response by state officials unable to manage tendencies towards fiscal crisis because of the state’s general helplessness in managing the Russian economy, rather than as a surrender of sovereignty to economic interests.
The lncRNA ‘UCA1’ modulates the response to chemotherapy of ovarian cancer through direct binding to miR‐27a‐5p and control of UBE2N levels
Authors: Wambecke Anaïs , Ahmad Mohammad , Morice Pierre‐Marie , Lambert Bernard , Weiswald Louis‐Bastien , Vernon Mégane , Vigneron Nicolas , Abeilard Edwige , Brotin Emilie , Figeac Martin , Gauduchon Pascal , Poulain Laurent , Denoyelle Christophe , Meryet‐Figuiere Matthieu
Published: June 2021

Ovarian cancer (OC) is the leading cause of death in patients with gynecologic cancers. Due to late diagnosis and resistance to chemotherapy, the 5‐year survival rate in patients with OC is below 40%. We observed that UCA1, a lncRNA previously reported to play an oncogenic role in several malignancies, is overexpressed in the chemoresistant OC cell line OAW42‐R compared to their chemotherapy‐sensitive counterpart OAW42. Additionally, UCA1 overexpression was related to poor prognosis in two independent patient cohorts. Currently, the molecular mechanisms through which UCA1 acts in OC are poorly understood. We demonstrated that downregulation of the short isoform of UCA1 sensitized OC cells to cisplatin and that UCA1 acted as competing endogenous RNA to miR‐27a‐5p. Upon UCA1 downregulation, miR‐27a‐5p downregulated its direct target UBE2N leading to the upregulation of BIM, a proapoptotic protein of the Bcl2 family. The upregulation of BIM is the event responsible for the sensitization of OC cells to cisplatin. In order to model response to therapy in patients with OC, we used several patient‐derived organoid cultures, a model faithfully mimicking patient’s response to therapy. Inhibition of UBE2N sensitized patient‐derived organoids to platinum salts. In conclusion, response to treatment in patients with OC is regulated by the UCA1/miR‐27a‐5p/UBE2N axis, where UBE2N inhibition could potentially represent a novel therapeutic strategy to counter chemoresistance in OC.
Dosimetric impact of using a commercial metal artifact reduction tool in carbon ion therapy in patients with hip prostheses
Authors: Zhao Jingfang , Wang Weiwei , Shahnaz Kambiz , Wu Xianwei , Mao Jingfang , Li Ping , Zhang Qing
Published: June 2021

The study investigated the dosimetric impact of an iterative metal artifact reduction (iMAR) tool on carbon ion therapy for pelvic cancer patients with hip prostheses. An anthropomorphic pelvic phantom with unilateral and bilateral hip prostheses was used to simulate pelvic cancer patients with metal implants. The raw data obtained from phantom CT scanning were reconstructed with a regular filtered back projection (FBP) algorithm and then corrected with iMAR. The phantom without hip prosthesis was also scanned and used as a reference ground truth (GT). The CT images of three prostate and four sarcoma patients with unilateral hip prosthesis were also reconstructed by FBP and iMAR algorithm and compared. iMAR algorithm reduced the metal artifacts and the maximum WEPL deviation in phantom images from −19.1 to −0.4 mm. However, the CT numbers cannot be retrieved using iMAR for periprosthetic bone materials, eventually leading to a WEPL deviation of −3.6 mm. The use of iMAR improved large discrepancies in DVHs of PTVs and the gamma index between FBP and GT images but increased the difference in the bladder DVH for bilateral hip prostheses due to newly introduced artifacts. In the patient study, the discrepancies of dose distribution were small on iMAR images when compared with FBP images for most cases, except for two sarcoma cases where gamma analysis failed and dose coverage in 98% of the PTV maximally reduced due to large volume of dark metal artifacts. iMAR reduced the metal artifacts and improved dose distribution accuracy in carbon ion radiotherapy for pelvic cancer. However, the residual and newly introduced artifacts, especially with bilateral hip prostheses, may potentially increase WEPL inaccuracy and dose uncertainty. The use of iMAR has the potential to improve carbon ion treatment planning of pelvic cancer but should be used with caution.
Evaluation of deep learning for COVID‐19 diagnosis: Impact of image dataset organization
Authors: Kim Ga Young , Kim Jae Yong , Kim Chae Hyeon , Kim Sung Min
Published: June 2021

Introduction

Coronavirus disease 2019 (COVID‐19) has spread all over the world showing high transmissibility. Many studies have proposed diverse diagnostic methods based on deep learning using chest X‐ray images focusing on performance improvement. In reviewing them, this study noticed that evaluation results might be influenced by dataset organization. Therefore, this study identified whether the high‐performance values can prove the clinical application potential.

Methods

This study selected chest X‐ray image databases which have been widely applied in previous studies. One database includes images for COVID‐19, while the others consist of normal and pneumonia images. Then, the COVID‐19 classification model was designed and trained on diverse database compositions and evaluated using confusion matrix‐based metrics. Also, each database was analyzed by graphical representation methods.

Results

The performance was significantly different according to dataset composition. Overall, higher performance was identified on the dataset organized with different databases for each class, compared with the dataset from same database. Also, there were significant differences in the image characteristics between different databases.

Conclusions

The experimental results indicate that model may be trained based on differences of the image characteristics between databases and not on lesion features. This shows that evaluation metrics can be influenced by dataset organization, and high metric values would not directly mean the potential for clinical application. These emphasize the importance of suitable dataset organization for applying COVID‐19 diagnosis methods to real clinical sites. Radiologists should sufficiently understand about this issue as actual user of these methods.
Effect of Bonding Temperature on Microstructure and Mechanical Properties of 304L/Zircaloy‐4 Diffusion‐Bonded Joints with Ni/Ta Hybrid Interlayer
Authors: Wang Zhen , Guo Yangyang , Ren Lingbao , Quan Gaofeng , Liu Yan , Pan Houhong
Published: June 2021

Diffusion bonding of stainless steel 304 L and zircaloy‐4 (Zr‐4) in solid state is conducted using Ni and Ta as the hybrid interlayer at the bonding temperature of 850−1000 °C for the bonding time of 30 min under the bonding pressure of 6 MPa in vacuum. The effect of the bonding temperature on the microstructure and the mechanical properties of the joints is investigated. The microstructure analysis is conducted by a scanning electron microscope, energy dispersive spectroscopy, and X‐ray diffraction. The mechanical properties of the joints are measured by a shear test and microhardness test. The results show that Ni3Ta intermetallic compounds are formed at the Ni/Ta interface, and the solid solution of Zr and Ta appears at the Ta/Zr‐4 interface. In the meantime, the maximum shear strength reaches 194 MPa and the highest hardness value across the interface of joints is 356 HV in the Ni3Ta layer.
Long‐Lived Liquid Marbles for Green Applications
Authors: Saczek Joshua , Yao Xiaoxue , Zivkovic Vladimir , Mamlouk Mohamed , Wang Dan , Pramana Stevin S. , Wang Steven
Published: June 2021

Liquid marbles allow for quantities of various liquids to be encapsulated by hydrophobic particles, thus ensuring isolation from the external environment. The unique properties provided by this soft solid has allowed for use in a wide array of different applications. Liquid marbles do however have certain drawbacks, with lifetime and robustness often being limited. Within this review, particle characteristics that impact liquid marble stability are critically discussed, in addition to other factors, such as internal and external environments, that can be engineered to achieve a robust long‐lived liquid marble. New emerging applications, which will benefit from this improvement, are explored such as unconventional computing, cell mimicry, and soft lithography. Incorporation of liquid marbles and liquid crystal technologies shows promise in utilizing structural color for optical display applications, and within green and environmental applications, liquid marble technology is increasingly adapted for use in energy conversion, heavy metal recovery, CO2 capture, and oil removal.
High‐Performance Flow Alkali‐Al/Acid Hybrid Fuel Cell for High‐Rate H2 Generation
Authors: Zhang Mengtian , Li Hao , Cai Pingwei , Chen Kai , Wen Zhenhai
Published: June 2021

Hydrogen (H2) has been utilized as a versatile feedstock or promising energy carrier in a variety of fields, yet the implementation of high‐rate H2 production presents a grand challenge for its readily accessible application. Herein, a newly alkali‐Al/acid hybrid fuel cell (3AHFC) that shows the capability of rapidly producing H2 upon delivering a considerably high energy density is reported, which is set up by paring Al anode in alkaline anolyte with acidic catholyte and a relatively cheap nanohybrid of Ru nanoparticle decorating crumpled reduced graphene oxide (Ru/c‐rGO) as cathode catalysts. It is demonstrated that the 3AHFC can release a power density of up to 240.6 mW cm−2 with a Faradic efficiency of approaching 99% for fast H2 generation (300 mA cm−2). Such hybrid electrolyte H2‐generation fuel cell can also be extended for either seawater anolyte or metallic Mg anode, presenting great promise for the practice feasibility of on‐site H2 production for applications in tough or even extreme environments.
Electric Current Aligning Component Units during Graphene Fiber Joule Heating
Authors: Cheng Yi , Cui Guang , Liu Changhao , Liu Zhetong , Yan Longge , Liu Bingyao , Yuan Hao , Shi Pengcheng , Jiang Jun , Huang Kewen , Wang Kun , Cheng Shuting , Li Junliang , Gao Peng , Zhang Xinfang , Qi Yue , Liu Zhongfan
Published: June 2021

Joule heating is featured with an extremely high rising rate of temperature with hundreds of kelvin per second, which has shown superiorities of high efficiency and energy conservation in graphene fabrication. Herein, we design a dynamic joule heating system for continuous synthesis of graphene fibers with ultrashort high‐temperature (≈2000 °C), treating time (≈20 min), and low electric energy consumption (≈2000 kJ m−1). During the joule heating fabrication, the current flowing through the fibers can manipulate the configuration of graphene sheets, the basic component units of fiber, and induce their alignment. Theoretical simulations reveal that graphene sheets tend to rotate towards the current direction under the current induced electric field for the highest stability with the lowest electric free energy and zero rotation torque. Therefore, the electrical and mechanical performances of as‐fabricated graphene fibers can be further improved in comparison with thermally annealed graphene fibers without applying current.
Interfacial Nucleation Seeding for Electroluminescent Manipulation in Blue Perovskite Light‐Emitting Diodes
Authors: Shen Yang , Wu Hai‐Yan , Li Yan‐Qing , Shen Kong‐Chao , Gao Xingyu , Song Fei , Tang Jian‐Xin
Published: June 2021

Efficient and stable blue emission of perovskite light‐emitting diodes (PeLEDs) is a requisite toward their potential applications in full‐color displays and solid‐state lighting. Rational manipulation over the entire electroluminescence process is promising to break the efficiency limit of blue PeLEDs. Herein, a facile device architecture is proposed to achieve efficient blue PeLEDs for simultaneously reducing the energetic loss during electron‐photon conversion and boosting the light outcoupling. Effective interfacial engineering is employed to manipulate the perovskite crystallization nucleation, enabling highly compact perovskite nanocrystal assemblies and suppressing the trap‐induced carrier losses by means of interfacial hydrogen bonding interactions. This strategy contributes to a high external quantum efficiency (EQE) of 12.8% for blue PeLEDs emitting at 486 nm as well as improved operational stability. Moreover, blue PeLEDs reach a peak EQE of 16.8% with the incorporation of internal outcoupling structures for waveguided light, which can be further raised to 27.5% by integrating a lens‐based structure for substrate‐mode light. These results verify the validity of this strategy in producing efficient and stable blue PeLEDs for practical applications.
Industry‐Scale and Environmentally Stable Ti3C2Tx MXene Based Film for Flexible Energy Storage Devices
Authors: Liao Leiping , Jiang Degang , Zheng Kun , Zhang Maozhuang , Liu Jingquan
Published: June 2021

MXenes, 2D transition metal carbides, and nitrides have attracted tremendous interest because of their metallic conductivity, solution processability, and excellent merits in energy storage and other applications. However, the pristine MXene films often suffer from poor ambient stability and mechanical properties that stem from their polar terminal groups and weak interlayer interactions. Here, a heteroatom doping strategy is developed to tailor the surface functionalities of MXene, followed by the addition of large‐sized reduced graphene oxide (rGO) as conductive additives to achieve a scalable production of S, N‐MXene/rGO (SNMG‐40) hybrid film with high mechanical strength (≈45 MPa) and energy storage properties (698.5 F cm−3). Notably, the SNMG‐40 film also demonstrates long‐term cycling stability (≈98% capacitance retention after 30 000 cycles), which can be maintained under ambient condition or immersed in H2SO4 electrolyte for more than 100 days. The asymmetric supercapacitor (aMGSC) based on SNMG‐40 film shows an ultrahigh energy density of 22.3 Wh kg−1, which is much higher than those previously reported MXene‐based materials. Moreover, the aMGSC also provides excellent mechanical durability under different deformation conditions. Thus, this strategy makes MXene materials more competitive for real‐world applications such as flexible electronics and electromagnetic interference shielding.
An Activatable Probe with Aggregation‐Induced Emission for Detecting and Imaging Herbal Medicine Induced Liver Injury with Optoacoustic Imaging and NIR‐II Fluorescence Imaging
Authors: Sun Lihe , Ouyang Juan , Ma Yunqing , Zeng Zhuo , Zeng Cheng , Zeng Fang , Wu Shuizhu
Published: June 2021

Whilte herbal medicines are widely used for health promotion and therapy for chronic conditions, inappropriate use of them may cause adverse effects like liver injury, and accurately evaluating their hepatotoxicity is of great significance for public health. Herein, an activatable probe QY‐N for diagnosing herbal‐medicine‐induced liver injury by detecting hepatic NO with NIR‐II fluorescence and multispectral optoacoustic tomography (MSOT) imaging is demonstrated. The probe includes a bismethoxyphenyl‐amine‐containing dihydroxanthene serving as electron donor, a quinolinium as electron acceptor, and a butylamine as recognition group and fluorescence quencher. The hepatic level of NO reacts with butylamine, thereby generating the activated probe QY‐NO which exhibits a red‐shifted absorption band (700–850 nm) for optoacoustic imaging and generates strong emission (910–1110 nm) for NIR‐II fluorescence imaging. QY‐NO is aggregation‐induced‐emission (AIE) active, which ensures strong emission in aggregated state. QY‐N is utilized in the triptolide‐induced liver injury mouse model, and experimental results demonstrate the QY‐N can be activated by hepatic NO and thus be used in detecting herbal‐medicine‐induced liver injury. The temporal and spatial information provided by three‐dimensional MSOT images well delineates the site and size of liver injury. Moreover, QY‐N has also been employed to monitor rehabilitation of liver injury during treatment process.
Heteroepitaxial β‐Ga2O3 on Conductive Ceramic Templates: Toward Ultrahigh Gain Deep‐Ultraviolet Photodetection
Authors: Alfaraj Nasir , Li Kuang‐Hui , Alawein Meshal , Kang Chun Hong , Braic Laurentiu , Zoita Nicolae Catalin , Kiss Adrian Emil , Ng Tien Khee , Ooi Boon S.
Published: June 2021

This article investigates the ultrahigh sensitivity and DUV photodetection capability of a hybrid oxide‐nitride stack comprising β‐Ga2O3 layers grown heterogeneously on a conductive ceramic crystal. The ceramic crystal, namely a TiN interlayer, which acts as a lattice template, was heteroepitaxially grown on bulk MgO. Because β‐Ga2O3 is a monoclinic phase crystal, it is conjectured that its nucleation and growth process on cubic phase TiN is entropic in nature, whereby the two unit cell configurations of the β‐Ga2O3 crystal, exhibiting rotational twin domains, grew alternately side by side in a semiperiodic manner on TiN while maintaining a single crystal phase. This film formation mechanism contributed to the introduction of additional defects in the β‐Ga2O3 lattice (Taylor's dislocations in addition to growth‐induced vacancies). The fabricated DUV photodetectors based on the resulting metal‐semiconductor junction heterodiodes exhibited an average peak spectral responsivity of 276.72 A W−1 and fast decay constants in the order of 500 ms in the ultraviolet‐C regime, with true solar‐blind characteristics manifested by ultraviolet‐to‐visible rejection ratios of up to 2 × 103 and illuminating power density of around 70 μW cm−2. The crystallographic orientation relationships between the TiN and β‐Ga2O3 crystals, as well as the lattice fit and dislocation types, are revealed and examined.
Physics and Applications of High‐β Micro‐ and Nanolasers
Authors: Deng Hui , Lippi Gian Luca , Mørk Jesper , Wiersig Jan , Reitzenstein Stephan
Published: June 2021

Micro‐ and nanolasers are emerging optoelectronic components with many properties still to be explored and understood. On the one hand, they make it possible to address fundamental physical questions in the border area between classical physics and quantum physics, on the other hand, they open up new application perspectives in many areas of photonics. This progress report provides an overview of the exciting developments from conventional semiconductor lasers toward nanoscale lasers, whose function relies on increased light–matter interaction in low‐mode‐volume resonators and unconventional gain concepts. The latest advances in the physical understanding of light emission from high‐β lasers, in which a large part of the spontaneous emission is coupled into the laser mode, are highlighted. In the limit of β = 1, this leads to thresholdless lasing and it is shown that quantum optical characterization is required to fully explore the underlying emission processes. In addition, emerging nanolaser concepts based on Fano resonators, topological photonics, and 2D materials are presented. Open questions, future prospects, and application scenarios of high‐β lasers in integrated photonics, quantum nanophotonics, and neuromorphic computing are discussed.
Relationship between Multivalent Cation Charge Carriers and Organic Solvents on Nanoporous Carbons in 4 V‐Window Magnesium Ion Supercapacitors
Authors: Moon Seongbak , Lee Sang Moon , Lim Hyung‐Kyu , Jin Hyoung‐Joon , Yun Young Soo
Published: June 2021

Multivalent charge carriers with a smaller ionic radius exhibit strong ionic interactions with solvent molecules. This can lead to unusual characteristics that typically are not observed in conventional monovalent charge carriers. Herein, the capacitive Mg ion storage behavior on nanoporous carbons is investigated within different solvent systems. A larger multivalent charge carrier, Ca ions, and alkali cations with different ionic radii are used as a comparison. In addition, the effects of nanopores on solvated Mg ion physisorption are observed in two types of nanoporous carbon, namely typical microporous carbon and ultramesoporous carbon (MEC). The oxidation stability of dimethoxyethane (DME) solvent is significantly improved by forming a solvation complex with Mg ions, while the destabilization effect of DME induced by anions is suppressed by the Mg ion charge carriers. The use of MEC as an active electrode material in a Mg ion‐DME electrolyte system leads to high electrochemical performance of the Mg ion supercapacitor over a wide range of operating voltages. A high‐performance 4 V Mg ion supercapacitor with charge‐injected symmetric MEC‐based electrodes is evaluated, where excellent specific energy and power densities of ≈106 W h kg−1 and ≈11870 W kg−1, respectively, are achieved.
Effect of Antisolvent Application Rate on Film Formation and Photovoltaic Performance of Methylammonium‐Free Perovskite Solar Cells
Authors: An Qingzhi , Vieler Leonie , Goetz Katelyn P. , Telschow Oscar , Hofstetter Yvonne J. , Buschbeck Robin , Taylor Alexander D. , Vaynzof Yana
Published: June 2021

The poor stability of perovskite solar cells that are based on methylammonium (MA)‐containing compositions has triggered immense interest in the development of MA‐free alternatives such as the double‐cation mixed‐halide Cs
x
FA1–x
Pb(I1–x
 + Br
x
)3 composition (CsFA perovskites). Although efficient solar cells based on this composition have been reported, many aspects related to the film formation of CsFA perovskites remain unclear. Herein, the influence of the antisolvent application rate on the properties and device performance of MA‐free perovskite solar cells are investigated. It is found that when applied slowly, all six of the investigated antisolvents result in high‐quality films and devices reaching a maximum power conversion efficiency of 20.7%. However, fast application leads to incomplete film coverage, and consequently no functional solar cells, for three of these antisolvents. It is demonstrated that this is related to the inefficacy of these antisolvents in triggering the crystallization of the perovskite layer and a simple test is offered that can aid researchers to identify whether other antisolvents will favor fast or slow antisolvent application.
Highly Cyclable All‐Solid‐State Battery with Deposition‐Type Lithium Metal Anode Based on Thin Carbon Black Layer
Authors: Suzuki Naoki , Yashiro Nobuyoshi , Fujiki Satoshi , Omoda Ryo , Shiratsuchi Tomoyuki , Watanabe Taku , Aihara Yuichi
Published: June 2021

A thin carbon black (CB) layer on a metal current collector is used as a substrate of a deposition‐type Li metal anode for a sulfide‐based all‐solid‐state battery (ASSB). In this ASSB, the capacity of the CB layer is set to ≈5–10% of the cathode. Therefore, the anode soon overcharges and a large proportion of the Li ions precipitate as Li metal on the anode during the charging process, thus this precipitated Li works as a Li metal anode. This CB‐based anode effectively suppresses short circuit of the cell, and an ASSB with this anode has shown an excellent cycle property of over 150 cycles with good capacity retention. From measurements involving cross‐sectional scanning electron microscopy, deposited Li metal layer at the CB/Ni interface is observed. It is also found that the addition of metal particles in the CB‐based anode drastically improves cell performance by extending the cycle life. An ASSB with an Ag/CB‐based anode is operated over 700 cycles at 3 mA cm−2 current density (0.5 C) with a capacity retention of ≈86% after 700 cycles.