bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification and partial characterization of a ‘short' insectotoxin‐like peptide from the venom of the scorpion Parabuthus schlechteri
Authors: Tytgat Jan , Debont Tom , Rostoll Karin , Müller Gert J. , Verdonck Fons , Daenens Paul , van der Walt Jurg J. , Possani Lourival D.
Published: July 2002

A disulfide‐rich, low‐molecular‐mass toxin‐like peptide has been isolated from Parabuthus schlechteri venom using gel filtration, ion exchange, and reversed phase chromatography. Partial characterization of this peptide reveals a relationship with four‐disulfide bridge proteins belonging to the family of ‘short' insectotoxins (44% residue identity). In recognition hereof, the peptide was named PBITx1 (sITx10). Our work also reports on the deduced sequences of two other ‘short' insectotoxins from Buthus eupeus, I3 and I4, and it provides a consensus sequence and nomenclature for all known ‘short' insectotoxins. Finally, sequence similarities with K+ channel blockers (charybdotoxin, κ‐conotoxin), and a Cl− channel blocker (chlorotoxin) are highlighted.
A second mechanism of respiratory control
Authors: Kadenbach Bernhard , Arnold Susanne
Published: July 2002

According to the chemosmotic hypothesis, ATP is synthesized in mitochondria, bacteria and chloroplasts via the proton motive force Δp, the energy‐rich intermediate of electron transport and photosynthetic phosphorylation. The general applicability of the chemosmotic hypothesis, however, was disputed until present. In particular the relationship between the rate of respiration and Δp in mitochondria was found variable, depending on the experimental conditions. Recently, a new mechanism of respiratory control was found, based on binding of ATP or ADP to subunit IV of cytochrome c oxidase, which is independent of Δp and could explain many previous results contradicting the chemosmotic hypothesis.
Energetics of the proposed rate‐determining step of the glyoxalase I reaction
Authors: Feierberg Isabella , Cameron Alexander D. , Åqvist Johan
Published: July 2002

The proposed rate‐limiting step of the reaction catalyzed by glyoxalase I is the proton abstraction from the C1 carbon atom of the substrate by a glutamate residue, resulting in a high‐energy enolate intermediate. This proton transfer reaction was modelled using molecular dynamics and free energy perturbation simulations, with the empirical valence bond method describing the potential energy surface of the system. The calculated rate constant for the reaction is approximately 300–1500 s−1 with Zn2+, Mg2+ or Ca2+ bound to the active site, which agrees well with observed kinetics of the enzyme. Furthermore, the results imply that the origin of the catalytic rate enhancement is mainly associated with enolate stabilization by the metal ion.
ADP‐ribosylation factor (ARF)‐like 4, 6, and 7 represent a subgroup of the ARF family characterized by rapid nucleotide exchange and a nuclear localization signal
Authors: Jacobs Stephan , Schilf Christiane , Fliegert Frank , Koling Susanne , Weber Yvonne , Schürmann Annette , Joost Hans-Georg
Published: July 2002

The novel ARF‐like GTPase ARL7 is a close relative of ARL4 and ARL6 (71% and 59% identical amino acids). A striking characteristic of these GTPases is their basic C‐terminus which, when fused to the C‐terminus of green fluorescent protein (GFP), targets the constructs to the nucleus of transfected COS‐7 cells. Full length ARL4 was detected in both nuclear and extranuclear compartments, whereas a construct of ARL4 lacking its C‐terminus was excluded from the nucleus. Nucleotide exchange rates of recombinant ARL4, ARL6 and ARL7 were similar and appeared considerably higher than those of other members of the ARF family (ARF1, ARP). It is concluded that ARL4, ARL6 and ARL7 form a subgroup within the ARF family with similar, possibly nuclear, function.
p68 Sam is a substrate of the insulin receptor and associates with the SH2 domains of p85 PI3K
Authors: Sánchez-Margalet Víctor , Najib Souad
Published: July 2002

The 68 kDa Src substrate associated during mitosis is an RNA binding protein with Src homology 2 and 3 domain binding sites. A role for Src associated in mitosis 68 as an adaptor protein in signaling transduction has been proposed in different systems such as T‐cell receptors. In the present work, we have sought to assess the possible role of Src associated in mitosis 68 in insulin receptor signaling. We performed in vivo studies in HTC‐IR cells and in vitro studies using recombinant Src associated in mitosis 68, purified insulin receptor and fusion proteins containing either the N‐terminal or the C‐terminal Src homology 2 domain of p85 phosphatidylinositol‐3‐kinase. We have found that Src associated in mitosis 68 is a substrate of the insulin receptor both in vivo and in vitro. Moreover, tyrosine‐phosphorylated Src associated in mitosis 68 was found to associate with p85 phosphatidylinositol‐3‐kinase in response to insulin, as assessed by co‐immunoprecipitation studies. Therefore, Src associated in mitosis 68 may be part of the signaling complexes of insulin receptor along with p85. In vitro studies demonstrate that Src associated in mitosis 68 associates with the Src homology 2 domains of p85 after tyrosine phosphorylation by the activated insulin receptor. Moreover, tyr‐phosphorylated Src associated in mitosis 68 binds with a higher affinity to the N‐terminal Src homology 2 domain of p85 compared to the C‐terminal Src homology 2 domain of p85, suggesting a preferential association of Src associated in mitosis 68 with the N‐terminal Src homology 2 domain of p85. This association may be important for the link of the signaling with RNA metabolism.
Spatial gradients of cellular phospho‐proteins
Authors: Brown Guy C. , Kholodenko Boris N.
Published: July 2002

If a protein is rapidly phosphorylated and dephosphorylated at separate cellular locations and protein diffusion is slow, then a spatial gradient of the phosphorylated form of the protein may develop within the cell. We have estimated the potential size of such gradients using measured values of protein diffusion coefficients and protein kinase and phosphatase activities. We analysed two different cellular geometries: (1) where the kinases is located on the plasma membrane of a spherical cell and the phospatase is distributed homogenously in the cytoplasm and (2) where the kinase is located on one planar membrane and the phosphatase on a second parallel planar membrane. The estimated gradients of phospho‐proteins were potentially very large, which has important implications for cellular signalling.
Is the protein/lipid hydrophobic matching principle relevant to membrane organization and functions?
Authors: Dumas Fabrice , Lebrun Maria Chantal , Tocanne Jean-François
Published: July 2002

Biological membranes are complex and well‐organized multimolecular assemblies composed of a wide variety of protein and lipid molecular species. If such a diversity in protein and lipid polar headgroup structures may easily be related to a large panel of functions, the wide dispersion in acyl chain length and structure which the lipids display is more difficult to understand. It is not required for maintaining bilayer assembly and fluidity. Direct information on the lateral distribution of these various molecular species, on their potential specificity for interaction between themselves and with proteins and on the functional implications of these interactions is also still lacking. Because hydrophobic interactions play a major role in stabilizing membrane structures, we suggest considering the problem from the point of view of the matching of the hydrophobic surface of proteins by the acyl chains of the lipids. After a brief introduction to the hydrophobic matching principle, we will present experimental results which demonstrate the predictive power of the current theories and then, we will introduce the new and important concept of protein/lipid sorting in membranes. Finally, we will show how the hydrophobic matching condition may play a key role in the membrane organization and function.
Involvement of the cAMP/protein kinase A pathway and of mitogen‐activated protein kinase in the anti‐proliferative effects of anandamide in human breast cancer cells
Authors: Melck Dominique , Rueda Daniel , Galve-Roperh Ismael , De Petrocellis Luciano , Guzmán Manuel , Di Marzo Vincenzo
Published: July 2002

Anandamide (ANA) inhibits prolactin‐ and nerve growth factor (NGF)‐induced proliferation of human breast cancer cells by decreasing the levels of the 100 kDa prolactin receptor (PRLr) and the high affinity trk NGF receptor, respectively, and by acting via CB1‐like cannabinoid receptors. However, the intracellular signals that mediate these effects are not known. Here, we show that, in MCF‐7 cells: (i) forskolin and the mitogen‐activated protein kinase (MAPK) kinase inhibitor PD098059 prevent, and the protein kinase A inhibitor RpcAMPs mimics, the inhibitory effects of ANA on cell proliferation and PRLr/trk expression and (ii) ANA inhibits forskolin‐induced cAMP formation and stimulates Raf‐1 translocation and MAPK activity, in a fashion sensitive to the selective CB1 antagonist SR141716A. ANA stimulation of MAPK was enhanced by inhibitors of ANA hydrolysis. Forskolin inhibited MAPK and ANA‐induced Raf‐1 translocation. These findings indicate that, in MCF‐7 cells, ANA inhibits adenylyl cyclase and activates MAPK, thereby exerting a down‐regulation on PRLr and trk levels and a suppression of cell proliferation.
Identification of glucose 6‐phosphate dehydrogenase deficiency in a population with a high frequency of thalassemia
Authors: Tagarelli Antonio , Piro Anna , Bastone Loredana , Tagarelli Giuseppe
Published: July 2002

High frequencies of both thalassemia trait (5.2%) and glucose 6‐phosphate dehydrogenase (G6PD) deficiency for only males (1.3%) have been observed in the Calabrian population. The G6PD activity measurement was carried out on 1239 samples of whole blood from Calabrian subjects of both sexes (age range 10–55) by a differential pH‐metry technique which was quite suitable to determine the G6PD deficiency in mass screenings. The analyzed subjects showed: only the thalassemia trait; or only the G6PD deficiency; or only the total iron serum deficiency; or G6PD deficiency associated with the thalassemia trait or with the total iron serum deficiency. The G6PD heterozygous subjects have an enzymatic activity which is masked by both the thalassemia trait and the total iron serum deficiency. In a population showing high frequencies of both thalassemia trait and G6PD deficiency, the comparison of G6PD activity of heterozygous subjects also affected with the thalassemia trait is more reliable if referred to the enzymatic activity of the carriers of the latter inherited anomaly rather than to G6PD activity of normal subjects.
Improving obstetric care at the district hospital, Ekpoma, Nigeria
Authors: Ande B , Chiwuzie J , Akpala W , Oronsaye A , Okojie O , Okolocha C , Omorogbe S , Onoguwe B , Oikeh E ,   (The Benin PMM Team)
Published: July 2002

Preliminary studies: Facility reviews and focus group discussions revealed several factors at the district hospital contributing to maternal deaths in Ekpoma District, Nigeria. Interventions: In response, the necessary equipment for the operating theater, labor suite and laboratory were repaired or purchased. A blood bank and standby generator were repaired. Drugs and consumable material were purchased and a revolving fund established. Refresher courses were held for medical officers, nursing staff and laboratory technicians. At a later stage, community interventions focused on improving access and reducing delay in seeking care. Results: The number of cesarean sections performed increased from zero in 1990–1991 to between seven and 13/year in the period 1992–1995. The number of women with major obstetric complications seen at the hospital increased from seven in 1990 (5% of obstetric admissions) to a high of 29 (20% of obstetric admissions) in 1993. These gains were not sustained, however. In 1995, only 12 women with complications (9% of obstetric admissions) were seen. Costs: The cost of improvements was approximately US $12 800, of which 41% was paid by the government and the rest by the project. Conclusions: Improving obstetric care at the district hospital can increase use by women with complications. However, sociopolitical and economic problems can hamper success. © 1997 International Federation of Gynecology and Obstetrics
Upgrading obstetric care at a secondary referral hospital, Ogun State, Nigeria
Authors: Olukoya A.A , Ogunyemi M.A , Akitoye C.O , Abudu O , Tijani M.A , Epoyun A.O , Ahabue C.E , Shaba O ,   (The Lagos PMM Team)
Published: July 2002

Preliminary studies: A 1991 inventory at the State Hospital, Ota, in Ogun State, Nigeria, showed inadequate surgical equipment, drugs, blood and power supply. A time–motion study indicated substantial delays in receiving obstetric care. Interventions: In 1994, medical officers and midwives were given refresher courses in emergency obstetric skills. In 1995, the surgical theater, labor ward and laboratory were provided with the necessary supplies and equipment. A reliable electrical supply was set up, but problems were encountered in establishing blood services. Subsequent community interventions focused on improving access and reducing delay in seeking care. Results: The annual number of women with complications seen, which had been declining — from 123 in 1992 to 55 in 1994 — increased to 91 in 1995. Case fatality rate (CFR) due to major direct obstetric complications did not change appreciably, i.e. it was 6.6% in 1995, as compared with 7.3%, 8.3% and 7.3% for the years 1992–1994, respectively. Costs: The cost of hospital improvements was approximately US $46 000. Conclusions: The facility improvements were completed only recently in mid‐1995. It is hoped that improved services will result in reductions in CFR and motivate more women with complications to seek hospital care, despite difficult economic conditions prevailing in Nigeria. © 1997 International Federation of Gynecology and Obstetrics
Upgrading obstetric care at the health center level, Juaben, Ghana
Authors: Djan J.O , Kyei‐Faried S , Twum S , Danquah J.B.O , Ofori M , Browne E.N.L ,   (The Kumasi PMM Team)
Published: July 2002

Preliminary studies: Inventory and observations at Juaben Teaching Health Center (JTHC) revealed an inability to treat obstetric complications. Women with complications needed to be referred to other institutions, resulting in delays. Interventions: During 1993 and 1994, an operating theater and blood bank were established and equipped, the maternity refurbished, and a revolving drug fund created. A physician was posted and trained in obstetrics, and midwives were trained in life‐saving skills. A running water supply was established. Subsequent community interventions focused on improving access and reducing the delay in seeking care. Results: The number of women with complications coming for care increased almost three‐fold, from 26 in 1993 to 73 in 1995 and the proportion of these who were referred for treatment dropped from 42 to 14%. Surgical obstetric procedures performed at JTHC increased from 23 in 1993 to 90 in 1995. Midwives performed 32% of manual removals, 58% of vacuum extractions and 98% of episiotomy repairs. No deaths occurred among the women treated. Costs: The cost of improvements was approximately US $30 000, mostly for equipment and supplies. Forty percent came from project funds, 36% from non‐governmental organizations (NGOs), 15% from government and 9% from community members. The salary of the new physician cost an additional $4700 annually. Conclusions: Modest improvements can increase the provision and utilization of emergency obstetric care. Collaboration with NGOs, government and the community can be beneficial. © 1997 International Federation of Gynecology and Obstetrics
Mobilizing the community to utilize obstetric services, Cross River State, Nigeria
Authors: Olaniran N , Offiong S , Ottong J , Asuquo E , Duke F ,   (The Calabar PMM Team)
Published: July 2002

Preliminary studies: Twenty‐one focus groups and a survey in two rural communities revealed socioeconomic and cultural barriers to utilization of emergency obstetric services. Interventions: To facilitate the use of services, 20 community educators were trained and an education campaign was conducted beginning in 1994. Educational activities emphasized the need for women with obstetric complications to use obstetric services at two local health facilities and one teaching hospital. Communities were also mobilized to set up loan and transport programs. Results: Awareness of obstetric complications increased in both communities and for all complications: increases ranged from 5% (for obstructed labor) to 63% (for hemorrhage). Fourteen of 39 project communities established new loan programs (six communities already had them). Loans were granted in only nine communities. Transport systems were established in nine communities. Referrals to the teaching hospital of women with major obstetric complications from two health facilities in the study area increased from three in 1990 to 11 in 1995 in one community and from four to eight in the other. Costs: The cost of the mobilization activities was approximately US $6500. Conclusion: Community education and mobilization can help increase awareness of obstetric complications. © 1997 International Federation of Gynecology and Obstetrics
Community education to encourage use of emergency obstetric services, Kebbi State, Nigeria
Authors: Bello Gummi F , Hassan M , Shehu D , Audu L ,   (The Sakoto PMM Team)
Published: July 2002

Preliminary studies: Focus group discussions and a mini‐survey in Kebbi State, Nigeria, revealed poor knowledge of obstetric complications, lack of confidence in health services, and cultural barriers to seeking care. Interventions: After upgrading services in emergency obstetric facilities, the team began community education to encourage utilization. Messages focused on recognition and need for prompt treatment of complications, and addressed men's role as decision‐makers. Beginning in 1992, messages were disseminated through weekly meetings with community opinion leaders, video shows, posters and handbills. Results: A post‐intervention mini‐survey showed knowledge gains of over 30% among women and men. The increase was greatest (59% increase among women and 55% among men) on the need for prompt care for women with obstetric complications. However, utilization of emergency obstetric services did not increase. At Maiyama Maternity Center, referrals declined from 18 in 1992 to four in 1995. At Jega Health Center, referrals remained relatively stable at 20–30/year, but the number of women with major obstetric complications treated declined from 234 in 1992 to 136 in 1995. At Birnin Kebbi Specialist Hospital, the referral center, the number of women with complications treated declined from 200 in 1990 to 152 in 1995. Costs: The cost of community education was approximately US $9500, of which 15% was contributed by the community. Conclusions: Increased awareness of the signs of obstetric complications and the need for prompt treatment among community women and men did not result in greater utilization of emergency obstetric services at the facilities studied. © 1997 International Federation of Gynecology and Obstetrics
Community motivators promote use of emergency obstetric services in rural Sierra Leone
Authors: Kandeh H.B.S , Leigh B , Kanu M.S , Kuteh M , Bangura J , Seisay A.L ,   (The Freetown/Makeni PMM Team)
Published: July 2002

Preliminary studies: An appraisal of government health facilities documented generally poor conditions, a shortage of drugs and supplies, and inadequate skills among staff. Focus group discussions in the community revealed a lack of knowledge about obstetric complications and difficulty in reaching health facilities. Interventions: Improvements were made in services at primary health units (PHUs) through May 1993. Community motivators were trained in June and provided with bicycles and raingear in September 1993. Among their duties were community education, formation of village action groups for emergency transport and facilitation of referral for women with obstetric complications. Results: Between August 1992 and December 1995, women with major complications seen at the PHUs increased from nine to 16 per month, with fluctuations due to disruptions in services and civil strife. The proportion of women with complications who were referred by the community motivators diminished over time, dropping from 24% to 1% over the first two years (1993–1994) and then recovering somewhat to 10% in the final period of observation. Costs: The cost of this intervention was approximately US$5082, with about half coming from the project and the rest from the government (44%) and the community (8%). Conclusions: The project improved utilization of the PHUs by women with complications, indicating that once services are of acceptable quality, many women will use them. The contribution of the motivators was positive, though smaller than expected. © 1997 International Federation of Gynecology and Obstetrics
Promoting the use of obstetric services through community loan funds, Bo, Sierra Leone
Authors: Fofana P , Samai O , Kebbie A , Sengeh P ,   (The Bo PMM Team)
Published: July 2002

Preliminary studies: Focus group discussions revealed that a lack of funds often contributed to a delay for women receiving treatment for obstetric complications. Interventions: Improvements were made in health facilities and transport, then, beginning in 1992, meetings were held to mobilize communities to establish emergency loan funds. Per capita levies were set and repayment was enforced by the most paramount chief of the area. Funds were managed by existing village development committees and loans were granted to women who could not pay hospital bills immediately. Results: Of the six chiefdoms contacted, two successfully established loan funds. Utilization of Bo Government Hospital by women with complications from the two chiefdoms with loan funds increased from five in 1992 to 12 in 1993. Utilization from other chiefdoms remained basically unchanged. Of women from loan fund chiefdoms, half paid their hospital bills in full and one‐third paid in part. Costs: The cost of community mobilization was about US $472. Conclusions: The establishment of loan funds depended on strong community leadership and required substantial mobilization efforts. Where community loan funds are established, utilization of emergency obstetric care may increase. © 1997 International Federation of Gyneology and Obstetrics
Molecular heterogeneity of hCG β — related glycoproteins and the clinical relevance in trophoblastic and non‐trophoblastic tumors
Authors: Nishimura R. , Koizumi T. , Yokotani T. , Taniguchi R. , Morisue K. , Yoshimura M. , Hiranmoy D. , Yamaguchi S. , Nakagawa T. , Hasegawa K. , Yasui H.
Published: July 2002

We analyzed immunoreactive hCG/hCG β (IR‐β) in the sera and urine of patients with trophoblastic diseases and non‐trophoblastic tumors by using enzyme immunoassays (EIAs) specific for intact hCG, free hCG β, and β‐core fragment of hCG (β‐CF). In trophoblastic diseases, while intact hCG and free hCG β were contained in both serum and urine, the β‐CF could be detected only in the urine of the patients. The relative contribution of the β‐CF to the total urinary IR‐β accounted for about 30–50% in normal early pregnancy and hydatidiform mole, and more than 60% in choriocarcinoma. We conclude that intact hCG should be measured in the serum rather than in the urine as a tumor marker for trophoblastic dieseases, and suggested that the ratios of intact hCG, free hCG β, and β‐CF to each other may be useful indices in the differential diagnosis of trophoblastic diseases. Ectopic IR‐β was also investigated in the sera and urine of the patients with cervical, endometrial, ovarian, lung, and bladder carcinomas. We found that even when IR‐β could not be detected in the serum, the urine of the same patients with cancer often contained the significant amounts of IR‐β. The chromatographic study indicated that these urinary IR‐β were essentially attributed to β‐CF, leading to the evaluation of urinary β‐CF as a tumor marker. The positive rated of urinary β‐CF were 48% for cervical, 38% for endometrial, and 84% for ovarian, 40% for lung, and 42% for bladder carcinomas. We conclude that ectopic production of hCG β by non‐trophoblastic tumors is not a rare phenomenon and it can be recognized as a tumor marker when β‐CF is measured in urine of the patients.
c‐Mos and cyclin B/cdc2 connections during Xenopus oocyte maturation
Authors: Castro Anna , Peter Marion , Lorca Thierry , Mandart Elisabeth
Published: July 2002

Summry— Fully‐grown G2 arrested Xenopus oocytes can be induced to enter and progress into meiotic cell cycle by progesterone stimulation. This process is termed oocyte maturation. An early response to progesterone is the synthesis of the onco‐protein c‐Mos, defined as the candidate initiator of Xenopus oocyte maturation, which triggers the MAPK cascade, MPF activation and promotes CSF activity. Here we review our current knowledge on the synthesis, activation and functions of c‐Mos in connection with MPF activation during maturation. We also discuss our recent results concerning the dispensability of cyclin B degradation in meiosis I‐meiosis II transition and the stabilization of c‐Mos through its direct phosphorylation by cyclin B/cdc2.
Cell alignment is induced by cyclic changes in cell length: studies of cells grown in cyclically stretched substrates
Authors: Neidlinger‐Wilke C. , Grood E. S. , Wang J. H.‐C. , Brand R. A. , Claes L.
Published: July 2002

Many types of cells, when grown on the surface of a cyclically stretched substrate, align away from the stretch direction. Although cell alignment has been described as an avoidance response to stretch, the specific deformation signal that causes a cell population to become aligned has not been identified. Planar surface deformation is characterized by three strains: two normal strains describe the length changes of two initially perpendicular lines and one shear strain describes the change in the angle between the two lines. The present study was designed to determine which, if any, of the three strains was the signal for cell alignment. Human fibroblasts and osteoblasts were grown in deformable, rectangular, silicone culture dishes coated with ProNectin, a biosynthetic polymer containing the RGD ligand of fibronectin. 24 h after plating the cells, the dishes were cyclically stretched at 1 Hz to peak dish stretches of 0% (control), 4%, 8%, and 12%. After 24 h of stretching, the cells were fixed, stained, and their orientations measured. The cell orientation distribution was determined by calculating the percent of cells whose orientation was within each of eighteen 5° angular intervals. We found that the alignment response was primarily driven by the substrate strain which tended to lengthen the cell (axial strain). We also found that for each cell type there was an axial strain limit above which few cells were found. The axial strain limit for fibroblasts, 4.2 ± 0.4% (mean ± 95% confidence), was lower than for osteoblasts, 6.4 ± 0.6%. We suggest that the fibroblasts are more responsive to stretch because of their more highly developed actin cytoskeleton. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Apolipoprotein E-ε4frequency in deficit schizophrenia
Authors: Thibaut F , Van der Elst A , Campion D , Martin C , Coron B , Dollfus S , Frebourg TH , Petit M
Published: July 2002

The apolipoprotein E (ApoE) genotype has been found to affect the expression of several neuropsychiatric disorders. We determined ApoE genotype frequencies and their relationship to primary negative symptoms in 61 non-deficit and 45 deficit schizophrenic patients, and compared them with 98 control subjects. No difference was observed when genotype or allele frequencies were compared between the three groups. Our data do not support a role for ApoE in the phenotypic expression of schizophrenia.
Control over Light Soaking Effect in All‐Inorganic Perovskite Solar Cells
Authors: Wu Xiao , Ma Junjie , Qin Minchao , Guo Xinlu , Li Yuhao , Qin Zhaotong , Xu Jianbin , Lu Xinhui
Published: April 2021

Light soaking (LS) has been reported to positively influence the device performance of perovskite solar cells (PSCs), which, however, could be potentially harmful to the loaded devices due to the unstable output. There are very few reports on controls over the LS effect, especially in all‐inorganic PSCs. In this study, a remarkable LS induced performance enhancement of CsPb(I1−xBrx)3 based PSCs is presented. In situ grazing‐incidence wide‐angle X‐ray scattering measurements quantize the temperature increase under illumination and reveal a radiative heating‐induced lattice expansion. The device curing time is shortened with the increased Br/I ratio, evidently correlated with their distinct mobility and activation energy. It is suggested that LS could promote the migration of halide ions, giving rise to notable defect passivation and thus device improvements. Based on these understandings, an effective means is proposed to suppress the LS effect, which is to incorporate slightly over‐stochiometric PbI2 in precursor, and a champion PCE of 18.14% in all‐inorganic PSCs with significantly reduced device curing time is obtained.
Van Der Waals Heterostructures Based on Atomically‐Thin Superconductors
Authors: Boix‐Constant Carla , Mañas‐Valero Samuel , Córdoba Rosa , Coronado Eugenio
Published: April 2021

Van der Waals heterostructures (vdWHs) allow the assembly of high‐crystalline 2D materials in order to explore dimensionality effects in strongly correlated systems and the emergence of potential new physical scenarios. In this work, the feasibility of integrating 2D materials in‐between 2D superconductors is illustrated. In particular, the fabrication and electrical characterization of vertical vdWHs based on air‐unstable atomically‐thin transition metal dichalcogenides formed by NbSe2/TaS2/NbSe2 stacks, with TaS2 being the insulator 1T‐TaS2 or the metal 2H‐TaS2, is presented. Phase transitions as 1T‐TaS2 charge density wave and NbSe2 superconductivity are detected. An enhancement of the vdWH resistance due to Andreev reflections is observed below the superconducting transition temperature of the NbSe2 flakes. Moreover, in the NbSe2 superconducting state, the field and temperature dependence of the normalized conductance is analyzed within the Dynes’ model and the overall behavior is consistent with the Bardeen–Cooper–Schrieffer theory. This vdWH approach can be extended to other 2D materials, such as 2D magnets or topological insulators, with the aim of exploring the new emergent properties that may arise from such combinations.
Nutritive and non‐nutritive effects of compost on organic dryland wheat in Utah
Authors: Adeleke Kareem A. , Atoloye Idowu A. , Creech J. Earl , Dai Xin , Reeve Jennifer R.
Published: April 2021

Organic dryland wheat (Triticum aestivum L.) is an important crop in Utah and the intermountain western United States; however, growers face numerous challenges maintaining yield, grain quality, soil fertility, and health. Wheat yields in the West are severely constrained by lack of rainfall, so dryland organic wheat farmers generally do not grow cover crops due to the risk of subsequent crop failure or apply soil amendments due to the inability to recoup application costs in the short term. Compost may have significant non‐nutritive as well as nutritive effects on soil processes, however, potentially changing calculations of perceived costs vs. benefits. The goal of this study was to quantify the effects of a one‐time compost application on soil health, yield, and crop quality in an organic dryland wheat–fallow system in northern Utah. Four rates of compost, applied once, (0, 12.5, 25, and 50 Mg ha−1 dry weight, DW) were compared to anhydrous ammonia (50 kg N ha−1) applied at planting. Mineralizable C, microbial biomass, and phosphatase enzyme activity increased significantly at all compost rates, while available soil P increased at the 25 and 50 Mg ha−1 rates and total soil N at the 50 Mg ha rate−1. Soil moisture was generally no different between treatments. Wheat yield was significantly greater 3 yr after application at the 50 Mg ha−1 compost rate only, with no response to conventional fertilizer. A lack of yield response to conventional fertilizer suggests that non‐nutritive benefits of improved soil health were responsible for improved yields at the high compost rate.
Horizontal equity in the design of Australian family payments for newborns
Authors: Taylor Matthew
Published: April 2021

Equity and efficiency are important evaluative criteria in tax and transfer policy. While matters of vertical equity receive more attention, horizontal equity is widely regarded as an important design principle. This is especially true in the design of family payments and has traditionally been interpreted as requiring universal – rather than targeted – payments to families on the basis the number, and ages, of dependent children. The focus of this paper is the horizontal equity of Australian family payments made specifically to the families of newborns. Under current policy, these families may receive maternity payments (the Newborn Supplement and Newborn Upfront Payment) or Parental Leave Pay (PLP), the former, a means‐tested birth grant; and the latter, a government‐funded paid maternity leave payment. Eligibility for PLP is largely contingent upon the birth mother providing a specific level of pre‐birth labour supply known as the “work test”. This paper uses microsimulation modelling to demonstrate the variation in the level of payment provided by the Australian Government under both programmes. It finds significant variation in the level of payment made both within and between families where the mother meets the PLP work test and finds higher levels of payment flowing to families where the mother is eligible for PLP. It concludes with a discussion of Australia's retreat from the provision of family payments on a universal basis with an emphasis on the equity–efficiency trade‐offs inherent to the PLP work test.
Highly sensitive and selective fluorescence sensing and imaging of Fe3+ based on a novel nitrogen‐doped graphene quantum dots
Authors: Wu Dongming , Qu Chaojie , Wang Jizhong , Yang Ran , Qu Lingbo
Published: April 2021

A novel nitrogen‐doped graphene quantum dots (N‐GQDs) with a green fluorescence emission was synthesized through microwave method using citric acid and semicarbazide hydrochloride as reactants. The as‐synthesized N‐GQDs exhibited good stability, excellent water solubility, and negligible cytotoxicity. Due to intermolecular charge transfer, ferric ion (Fe3+) has a strong quenching effect on the N‐GQDs. Fluorescence quenching has a linear relationship with the Fe3+ concentration in the range 0.02–12 μM. The detection limit was 1.43 nM. What is more, it is worth mentioning that the obtained N‐GQDs showed high selectivity and sensitivity towards Fe3+. Under the optimum conditions, the addition of 10‐fold copper ions and 100‐fold other metal ions had no influence on the detection of Fe3+ (0.8 μM), which indicated a higher sensitivity compared with that of the reported methods. Due to their excellent properties, the obtained N‐GQDs was successfully applied for sensing and imaging Fe3+ in water samples and HeLa cells.
On a parallel spark workflow for frequent itemset mining based on array prefix‐tree
Authors: Niu Xinzheng , Wu Peng , Wu Chase Q. , Hou Aiqin , Qian Mideng
Published: April 2021

Extracting frequent itemsets from datasets is an important problem in data mining, for which several mining methods including FP‐Growth have been proposed. FP‐Growth is a classical frequent itemset mining method, which generates pattern databases without candidates. Many improvements have been made in the literature due to the high time complexity and memory usage of FP‐Growth. However, most of them still suffer from performance issues on large datasets. In this paper, we design an auxiliary structure, Array Prefix‐Tree (AP‐Tree), and propose a new algorithm, Array Prefix‐Tree Growth (APT‐Growth), which is further parallelized as a Spark workflow, referred to as PAPT‐Growth. Based on a density threshold, we incorporate an adaptive algorithm selection process into PAPT‐Growth to ensure its running time performance. We conduct extensive experiments on different thresholds and multiple datasets, and experimental results show the performance superiority of PAPT‐Growth in comparison with several state‐of‐the‐art methods such as PFP, YAFIM, and DFPS. The analysis on density reveals a changing point, which justifies the necessity and validity of adaptive algorithm selection.
Effects of Endplate Assembly on Cold Start Performance of Proton Exchange Membrane Fuel Cell Stacks
Authors: Wei Lin , Liao Zihao , Mohmed Dafalla Ahmed , Suo Zhenbang , Jiang Fangming
Published: April 2021

A proton exchange membrane fuel cell (PEMFC) stack has two endplate assemblies (EAs) to stabilize the multilayered structure and distribute the preload evenly on each cell. Thermal inertia of and heat loss through the EA are crucial factors for developing novel thermal and water management strategies for PEMFC stacks. Herein, a 3D multidisciplinary transient model is established to assess the effects of EAs on the cold start performance of PEMFC stacks. The underlying mechanism linked to the EA effects is revealed through the analysis of temperature distribution, current density distribution, ice formation, and water balance calculation. The predicted results show that the EA has a significant impact on temperature and ice distributions in the end cell, thus negatively affecting the end cell performance. It is found that the smaller water diffusivity caused by the lower temperature in end cells results in more ice accumulation in the middle of cathode catalyst layer (CCL). The temperature of the end cells is greatly influenced by the thermal mass of the bus plate. For a low start‐up temperature of −30 °C, the impact of EA becomes more significant and the end cell is completely filled up by ice and therefore shuts down.
Alkali modified Abies bornmulleriana cones as a costeffective biosorbent for enhanced removal of Pb (II) ions, and its comparison with normal biosorbent: Isotherm, kinetic, and thermodynamic parameters
Authors: Oguz Ensar
Published: April 2021

The purpose of this investigation is the increase the biosorption efficiency and capacity in the removal of Pb (II) ions using Abies bornmulleriana cones modified with NaOH. The biosorption capacity of Pb (II) ions decreased in the presence of Cu (II), Cd (II), Ni (II), and Co (II) ions. Brunauer, Emmett, and Teller surface area and pore volume of the NB and MB after the biosorption decreased by (4.37 m2 g−1 and 0.00154 cm3 g−1) and (0.41 m2 g−1 and 0.00014 cm3 g−1), respectively. The pseudo‐second‐order kinetic gave the best fit to the biosorption data (R2 0.97, 0.97). The biosorption data for the NB and MB fitted well to Dubinin–Radushkevitch (D–R) isotherm due to the high R2 values (0.97, 0.97), and the maximum biosorption capacities were determined as 24.42 and 43.67 mg g−1, respectively. The change of free energy, enthalpy, and entropy of the biosorption for the NB and MB were determined as [(−2.10 kJ mol−1, 14.72 kJ mol−1, and 0.057 kJ mol−1 K−1) and (−7.04 kJ mol−1, 121 kJ mol−1, and 0.438 kJ mol−1 K−1)], respectively. The NB and MB regeneration with 0.1 N HNO3 showed that the biosorption and desorption processes were reversible.
Frequent breakpoints of focal deletion and uniparental disomy in 22q11.1 or 11.2 segmental duplication region reveal distinct tumorigenesis in rhabdoid tumor of the kidney
Authors: Haruta Masayuki , Arai Yasuhito , Okita Hajime , Tanaka Yukichi , Takimoto Tetsuya , Kamijo Takehiko , Oue Takaharu , Souzaki Ryota , Taguchi Tomoaki , Kuwahara Yasumichi , Chin Motoaki , Nakadate Hisaya , Hiyama Eiso , Ishida Yasushi , Koshinaga Tsugumichi , Kaneko Yasuhiko
Published: April 2021

SMARCB1 is mutated in most rhabdoid tumors (RTs) developing in the kidney (RTK) and various other organs. Focal deletions found in patients with 22q11.2 deletion syndrome show breakpoints within clusters of segmental duplications (SDs), and those in some RTs show breakpoints in the 22q11‐q12 region. SDs are known to cause focal deletion mediated by non‐allelic homologous recombination. The present study identified SMARCB1 alterations in all 30 RTKs, using SNP array CGH, MLPA, and sequence analyses. Twenty‐eight tumors had a total of 51 breakpoints forming focal 22q deletion and/or uniparental disomy (22qUPD), and the other two had compound mutation with no breakpoints in 22q. Twenty‐four (47.1%) of the 51 breakpoints were within SDs, and occurred in 16 (53.3%) of the 30 tumors. The association of breakpoints with SDs was found not only in focal deletion, but also in 22qUPD, indicating that SDs mediate the first and second hits (focal deletion) and the second hit (22qUPD) of SMARCB1 alteration. Of the 51 breakpoints, 14 were recurrent, and 10 of the 14 were within SDs, suggesting the presence of hotspots in the 22q11.2 region. One recurrent breakpoint outside SDs resided in SMARCB1, suggesting inactivation of the gene by out‐of‐frame fusion. The association between SDs and focal deletion has been reported in two other types of cancer. RTKs may be the third example of SD‐associated tumors. Thus, the present study indicated that RTKs exploit genomic instability in the 22q11.1‐11.2 SDs region, and 22qUPD caused by mitotic recombination may also be mediated by SDs.
Intergenerational health mobility: Magnitudes and Importance of Schools and Place
Authors: Fletcher Jason , Jajtner Katie M.
Published: April 2021

This paper broadens the literature on intergenerational persistence of socioeconomic status to consider individual, family, and spatial variation in intergenerational health mobility in the United States. Using a school‐based representative panel (Add Health), we report overall health persistence of 0.17 with higher mobility in Hispanic families. We find large variation by place; intergenerational health persistence estimates range between 0 and 0.5, with similarly large ranges for absolute upward and downward health mobility. School‐ and contextual‐level correlates indicate local race/ethnicity composition, proportion of single parents, and average mother's education may be related to observed variation in intergenerational health mobility.
Long‐term hydrology and aquatic biogeochemistry data from H. J. Andrews Experimental Forest, Cascade Mountains, Oregon
Authors: Johnson Sherri L. , Henshaw Don , Downing Greg , Wondzell Steve , Schulze Mark , Kennedy Adam , Cohn Greg , Schmidt Stephanie A. , Jones Julia A.
Published: April 2021

The H. J. Andrews Experimental Forest (HJA) encompasses the 6400 ha Lookout Creek watershed in western Oregon, USA. Hydrologic, chemistry and precipitation data have been collected, curated, and archived for up to 70 years. The HJA was established in 1948 to study the effects of harvest of old‐growth conifer forest and logging‐road construction on water quality, quantity and vegetation succession. Over time, research questions have expanded to include terrestrial and aquatic species, communities and ecosystem dynamics. There are nine small experimental watersheds and 10 gaging stations in the HJA, including both reference and experimentally treated watersheds. Gaged watershed areas range from 8.5 to 6242 ha. All gaging stations record stage height, water conductivity, water temperature and above‐stream air temperature. At nine of the gage sites, flow‐proportional water samples are collected and composited over 3‐week intervals for chemical analysis. Analysis of stream and precipitation chemistry began in 1968. Analytes include dissolved and particulate species of nitrogen and phosphorus, dissolved organic carbon, pH, specific conductance, suspended sediment, alkalinity, and major cations and anions. Supporting climate measurements began in the 1950s in association with the first small watershed experiments. Over time, and following the initiation of the Long Term Ecological Research (LTER) grant in 1980, infrastructure expanded to include a set of benchmark and secondary meteorological stations located in clearings spanning the elevation range within the Lookout Creek watershed, as well as a large number of forest understory temperature stations. Extensive metadata on sensor configurations, changes in methods over time, sensor accuracy and precision, and data quality control flags are associated with the HJA data.
Plants versus streams: Their groundwater‐mediated competition at “El Morro,” a developing catchment in the dry plains of Argentina
Authors: Jobbágy Esteban G. , Lorenzo Santiago , Buono Nicolás , Páez Ricardo , Diaz Yésica , Marchesini Victoria , Nosetto Marcelo D.
Published: April 2021

Our understanding of how groundwater mediates evapotranspiration/streamflow partitioning is still fragmented and catchment studies under changing vegetation conditions can provide a useful frame for integration. We explored this partition in a flat sedimentary dry catchment in central Argentina in which the replacement of native vegetation with rainfed crops was accompanied by the abrupt formation of groundwater‐fed streams by subsurface erosion (i.e., sapping) episodes. Historical records indicated widespread water table rises (~0.3 m y−1 on average). Groundwater level and stream baseflow fluctuated seasonally with minima in the warm rainy season, indicating that evaporative discharge rather than rainfall shapes saturated flows. Diurnal groundwater level fluctuations showed that plant uptake was widespread where water tables are shallow (<3 m) but restricted to deep‐rooted Prosopis forests where they are deep (7–10 m). MODIS and LANDSAT NDVI revealed a long‐term greening for native vegetation, new wetlands included, but not for croplands, suggesting more limited evapotranspiration‐groundwater level regulation under agriculture. Close to the deepest (20 m) and most active incisions, groundwater level and greenness declined and stream baseflow showed no seasonal fluctuations, hinting decoupling from evapotranspiration. Intense ecological and geomorphological transformations in this catchment exposed the interplay of five mechanisms governing evapotranspiration/streamflow partition including (a) unsaturated uptake and both (b) riparian and (c) distributed uptake from the saturated zone by plants, as well as (d) deepening incisions and (e) sediment deposits over riparian zones by streams. Acknowledging the complex interplay of these mechanisms with groundwater is crucial to predict and manage future hydrological changes in the dry plains of South America.