bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of rotating stall characteristics in a centrifugal pump impeller at low flow rates
Authors: Zhou Peijian , Wang Fujun , Mou Jiegang
Published: June 2017

Purpose

Rotating stall is an unsteady flow phenomenon that causes instabilities and low efficiency in pumps. The purpose of this paper is to investigate the rotating stall characteristics and unsteady behavior of stall cells in a centrifugal pump impeller at low flow rates.

Design/methodology/approach

A developed large eddy simulation with dynamic mixed nonlinear model is performed to evaluate the unsteady flow in a centrifugal pump impeller. The rotating stall flow field through the centrifugal pump impeller is analyzed under three typical flow rates. Frequency spectrum analysis are carried out on the series of pressure fluctuation to get the rotating stall characteristics. The size and intensity of stall cells are also analyzed using time-averaged vorticity and static pressure.

Findings

The rotating stall cell first occurs in the suction side of the blade and exhibits an obvious life cycle including decay mergence, shedding, growing and development with a low frequency. With the decrease of flow rate, the amplitude of pressure fluctuations in the impeller tends to be larger, the propagated speed of stall cells and rotating stall frequency tends to be smaller, but the number of cells remains unchanged. The size of stall cells increases as the flow rate decreases, but intensity changes is very little.

Originality/value

The rotating stall characteristics in a centrifugal pump impeller under low flow rates are presented first using a developed large eddy simulation approach.
All that glitters is not gold
Authors: Church Allan H. , Del Giudice Matthew , Margulies Alyson
Published: June 2017

Purpose

Formal assessment and development of executives have become standard practices in organizations. There is a need, however, to determine what levers are available to maximize the impact and return on investment of initiatives. The purpose of this paper is to present outcomes and learnings from a multi-method approach to evaluating behavior change following the implementation of PepsiCo’s Senior Leader Development Center, a comprehensive process designed to accelerate capability at the executive level.

Design/methodology/approach

Learnings are presented based on analyses from three independent data sources collected throughout the 18-month program: behavioral change ratings from managers, direct reports, and peers via a 360 survey; attitudinal measures from participants’ post-program completion; and third-party observations by an internal facilitator.

Findings

Overall, findings indicate that while program rigor and content do matter as baseline components, principles of participant engagement and commitment emerged as most essential to delivering programs with sustained impact.

Research limitations/implications

This case is based on leaders in a high-touch multi-trait multi-method assessment and development program in one organization. Additional research is needed to explore in other settings.

Practical implications

Results and implications are organized by each of the four key stages of the assessment and development process: conduct data-based assessments, deliver feedback and insights, build the development plan, and take action to implement the plan. Findings and recommendations for practice regarding each stage are discussed.

Originality/value

Few case studies or applied research exist that focus on the execution and outcomes associated with senior executive assessment and development programs in major corporations. This paper offers findings regarding the overall impact of such a program and key learnings from its sustained effort in a complex multi-national organization. The discussion and implications in this paper may directly influence how other organizations design and manage future talent management interventions with similar types of senior-level populations.
An integrative model of trust and leadership
Authors: Hasel Markus C. , Grover Steven L.
Published: June 2017

Purpose

The purpose of this paper is to examine the interplay between different streams of trust and leadership and their impact on motivation and performance. The model answers recent calls for a better understanding of underlying mechanisms in these interactions.

Design/methodology/approach

The authors drew from contemporary leadership and trust theories to develop ten propositions teasing out how specific person- and role-oriented leadership behaviors interact with calculus-, identification-, knowledge-based trust, motivation, and performance.

Findings

The model accentuates the complexity of the interactions between trust, leadership, and follower outcomes. It guides future empirical research to unravel these intricate relations and accentuates their complexity.

Research limitations/implications

The ten propositions act as guidelines in mastering the complex art of leadership by understanding how behaviors affect followers. An important limitation originates in the detailed analysis of leadership and trust. Focusing on specific leadership behaviors and trust types leaves further scope for future research into additional behaviors and cofounding variables to arrive at a more holistic picture of the underlying mechanisms that make or break an effective leader.

Originality/value

Contemporary theories on leadership and trust frequently view the different streams as overall constructs in lieu of multi-faceted phenomena. The model is a first of its kind in that it fuses contemporary leadership and trust theory to develop a set of propositions based on specific interactions between leadership behaviors and different forms of trust.
Pharmacokinetics and pharmacodynamics of bococizumab, a monoclonal antibody to PCSK9, after single subcutaneous injection at three sites [NCT 02043301]
Authors: Wang Ellen Q. , Plotka Anna , Salageanu Joanne , Sattler Catherine , Yunis Carla
Published: June 2017

Aim

To characterize the single‐dose pharmacokinetics (PK) and pharmacodynamics (PD) of bococizumab, a monoclonal antibody inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9), administered subcutaneously (s.c.) to the abdomen, thigh, or upper arm (NCT02043301).

Methods

Seventy‐five adults with low‐density lipoprotein cholesterol (LDL‐C) ≥130 mg/dL and not on background lipid‐lowering therapy were randomized (1:1:1) to a single 150‐mg s.c. dose of bococizumab administered to the abdomen, thigh, or upper arm. Blood samples for bococizumab and lipids were collected for 12 weeks postdose.

Results

Plasma bococizumab concentration‐time profiles and PK parameters were generally similar across injection sites. Mean maximum observed concentration (Cmax) ranged from 8.14 to 11.9 μg/mL, and area under the concentration‐time curve (AUCinf) ranged from 160.3 to 198.9 µg∙day/mL. The median time to Cmax (Tmax) ranged from 4.25 to 6.93 days. Similar LDL‐C concentration‐time profiles were observed across injection sites, with mean (% coefficient of variation) maximum reductions in LDL‐C of −57.5% (15.8), −57.0% (25.9), and −55.0% (24.1) for the abdomen, thigh, and upper arm, respectively. Adverse events (AEs) were mostly mild and generally similar across injection sites. Commonly reported AEs were upper respiratory tract infection (9.3%), headache (6.7%), and injection site reaction (6.7%). One serious AE was reported (ischemic colitis), which was not considered related to study drug.

Conclusions

Similar PK profiles and robust LDL‐C reductions were observed following a single 150‐mg s.c. injection of bococizumab administered to the abdomen, thigh, or upper arm in untreated subjects with LDL‐C ≥130 mg/dL. Bococizumab was generally well tolerated following a single 150‐mg s.c. administration in this subject population.
Laparoscopic surgery for sigmoid colon cancer after multiple operations including urinary diversion with Indiana pouch: A case report
Authors: Iwamoto Kazuya , Takahashi Hidekazu , Haraguchi Naotsugu , Nishimura Junichi , Hata Taishi , Matsuda Chu , Yamamoto Hirofumi , Mizushima Tsunekazu , Doki Yuichiro , Mori Masaki
Published: June 2017

A 73‐year‐old man with lower abdominal pain was diagnosed at our hospital with sigmoid colon cancer. He had previously undergone radical cystectomy with Indiana pouch construction and gastrectomy to treat bladder cancer and gastric cancer, respectively. We performed a laparoscopic Hartmann's operation with Japanese D3 lymph node dissection. We observed severe adhesion in the abdominal cavity; adhesions between the urostomy and sigmoid colon were particularly severe. The tumor had invaded to the distal rectum, which had adhered to the pubic bone and the previously reconstructed urinary pouch. By performing careful and persistent laparoscopic dissection, we completed the operation without damaging the urostomy and with no remnant tumor tissue (R0). The postoperative course was uneventful, and the patient was doing well with no evidence of cancer recurrence 1 year after surgery.
SET/I2PP2A overexpression induces phenotypic, molecular, and metabolic alterations in an oral keratinocyte cell line
Authors: Sobral Lays M. , Coletta Ricardo D. , Alberici Luciane C. , Curti Carlos , Leopoldino Andréia M.
Published: June 2017

The multifunctional SET/I2PP2A protein is known to be overexpressed in head and neck squamous cell carcinoma. However, SET has been reported to have apparently conflicting roles in promoting cancer cell survival under oxidative stress conditions and preventing invasion and metastasis, complicating efforts to understand the contribution of SET to carcinogenesis. In the present study, we overexpressed SETin a spontaneously immortalized oral keratinocyte cell line (NOK‐SI SET) and demonstrated that SET upregulation alone was sufficient to transform cells. In comparison with NOK‐SI cells, NOK‐SI SET cells demonstrated increased levels of phosphorylated Akt, c‐Myc and inactive/phosphorylated Rb, together with decreased total Rb protein levels. In addition, NOK‐SI SET cells presented the following: (a) a spindle‐cell shape morphology compared with the polygonal morphology of NOK‐SI cells; (b) loss of mesenchymal stem cell markers CD44 and CD73, and epithelial cell markers CD71 and integrin α6/β4; (c) the ability to form xenograft tumors in nude mice; and (d) increased mitochondrial respiration accompanied by decreased ROSlevels. Overall, our results show that SEToverexpression promotes morphological and oncogenic cell transformation of an oral keratinocyte cell.
Increased renal concentrating ability after long‐term oral desmopressin lyophilisate treatment contributes to continued success for monosymptomatic nocturnal enuresis
Authors: Ikeda Hirokazu , Watanabe Tsuneki , Isoyama Keiichi
Published: June 2017

Objectives

To investigate renal concentrating ability after long‐term fast‐melting oral desmopressin lyophilisate treatment in children with monosymptomatic nocturnal enuresis.

Methods

The present retrospective study involved 58 children (43 boys, 15 girls; aged 6–12 years) with nocturnal enuresis receiving oral desmopressin lyophilisate. After treatment for 4 weeks with a complete response, patients were placed on a reduced dose of 120 μg on alternate days. Moring urine osmolality was measured using urine samples obtained after medication and non‐medication dry nights. Patients who experienced ≥1 wet nights/month during alternate‐day oral desmopressin lyophilisate treatment or within 6 months after its cessation were assigned to the relapse group, whereas those who experienced <1 wet night/month were assigned to the continued success group.

Results

The continued success and relapse groups included 41 and 17 patients, respectively. The mean duration of treatment was 18.5 and 18.3 months in the continued success group and relapse group, respectively. There was no significant difference in morning urine osmolality after medication nights between the continued success and relapse groups; however, morning urine osmolality after non‐medication nights was significantly higher in the continued success group than in the relapse group (P < 0.0001). Similarly, nocturnal urine volume was significantly higher in the relapse group than in the continued success group (P = 0.046).

Conclusions

These results suggest that patients receiving long‐term oral desmopressin lyophilisate treatment develop increased nocturnal renal concentrating ability, which results in sustained dryness even after treatment cessation.
Recent progress in immunotherapy for urological cancer
Authors: Obara Wataru , Kato Renpei , Kato Yoichiro , Kanehira Mitsugu , Takata Ryo
Published: June 2017

Cancer immunotherapy for urological tumors had made progress for several decades, but recent advances in immunotherapy, as therapeutic vaccines or immune checkpoint inhibitors, have drastically changed the present treatment strategy. Recently, nivolumab and atezolizumab have been approved by the Food and Drug Administration for treatment of urological cancers. Additional immune checkpoint inhibitors and vaccines are being tested in clinical trials. Despite advances in these therapeutic modalities, benefits are limited to a subset of patients. New agents and novel combinations will also continue to create new immunotherapy strategies. Further development of biomarkers for predicting response is required to achieve optimal efficacy with these therapeutic interventions.
Optimal policy and the role of social contacts in a search model with heterogeneous workers
Authors: Stupnytska Yuliia , Zaharieva Anna
Published: June 2017

This paper develops a search model with heterogeneous workers and social networks. High‐ability workers are more productive and have a larger number of professional contacts. Firms can choose between a vacancy in the regular market and a job opening in the referral market. The model predicts that a larger number of social contacts is associated with a larger wage gap between high‐ and low‐ability workers and a larger difference in the unemployment rates. The net welfare gain of referrals is estimated at 1.2%. There are three reasons for the inefficiency of the decentralized equilibrium. First is the traditional search externality described by Hosios. Second, firms share their profits with workers, whereas the social optimum implies that full surplus should be given to firms in the referral market. This inefficiency can be internalized by means of referral subsidies. Third, there is the “pooling inefficiency” in the regular market. If high‐ability workers are sufficiently more productive they impose a positive externality on low‐ability workers and should be rewarded by positive transfers. On the contrary, if productivity differences are small, high‐ability workers achieve unreasonably high wages by referring each other and reduce employment chances of low‐ability workers. In this latter case, high‐ability workers should be penalized. If optimal policy is implemented the net welfare gain of referrals rises up to 1.8%.
A case of presumed autoimmune subepidermal blistering dermatosis treated with oclacitinib
Authors: Aymeric Estelle , Bensignor Emmanuel
Published: June 2017

Background

Autoimmune subepidermal blistering dermatoses (ASBD) are a group of severe autoimmune dermatoses rarely described in dogs. Their treatment usually necessitates the long term use of medications potentially associated with adverse effects. In humans, Janus Kinase (JAK) inhibitors have been demonstrated to be of value in some cases of autoimmune skin disease.

Hypothesis/Objectives

To evaluate oral oclacitinib, a JAK‐1 predominant inhibitor, in one case of ASBD in a dog.

Case report

A 5‐year‐old German shepherd cross‐bred dog was presented with an acute onset of ulcerative and blistering skin lesions on the face, oral cavity, lateral trunk and limbs. Associated systemic signs were not seen. A clinical diagnosis of ASBD was supported by the finding of subepidermal clefts and visualization of the epidermal basement membrane zone at the bottom of the clefts on histopathological examination. Treatment was initiated with prednisolone at 1.2 mg/kg twice daily. Because of severe adverse effects and relapse, when the prednisolone dose was reduced, oclacitinib therapy was administered at 0.5 mg/kg twice a day. A complete resolution of clinical signs was noted after one month and no relapse was observed after twelve months of treatment. No adverse effects were reported.

Conclusion

The use of oclacitinib may be useful for the treatment of some autoimmune skin diseases in dogs. Further controlled studies are needed to confirm our findings.
PRODUCTION OF BIODIESEL FROM PALM OIL USING COCKLE SHELL WASTE AS HETEROGENEOUS CATALYST
Authors: Ngadi Norzita , Sulaiman Sulaiha , Abd Rahman Roshanida , Lani Nurul Saadiah
Published: June 2017

In this study, production of biodiesel from palm oil using cockle shell wastes as catalyst was carried out using transesterification reaction. The objectives of this study are to analyze and characterize calcium oxide (CaO) from cockle shell wastes and to determine the catalytic activity of derived shell catalyst towards the percentage yield of biodiesel produced. The effect of methanol to oil ratio, reaction time and reaction temperature were investigated. The types of esters content in biodiesel and the functional group presence in catalyst were determined using FTIR and GC-MS analysis. The results showed that the optimum condition for cockle shell wastes achieved maximum yield of biodiesel (78.05%) is at reaction temperature 50°C within 1 hour with 9:1 methanol to oil ratio. Meanwhile for commercial CaO, the maximum yield is 73.95% at 60°C within 3 hours for 3:1 methanol to oil ratio. From the result obtained, this indicated that cockle shell wastes have potential to substitute commercial CaO as catalyst in transesterification reaction.
Mobile-assisted Language Learning (MALL) for ESL Learners: A Review of Affordances and Constraints
Authors: Hashim Harwati , Md. Yunus Melor , Amin Embi Mohamed , Mohamed Ozir Nor Azwa
Published: June 2017

Nowadays, mobile technology is changing the landscape of language learning and is seen as the next frontier being researched for its potential in enhancing the teaching and learning of English language.  The portability of mobile devices is believed to bring new methods that can shape learning styles and pedagogies which could become more personalised and allow learners to learn on the move; thus, enhance English language teaching and learning.  This creates the potential for significant change in the teaching and learning of English as Second Language (ESL). Taking mobile learning as the setting within which developments in Mobile-assisted Language Learning (MALL) may be understood, this paper offers reflections on what Mobile-assisted Language Learning (MALL) has potentially offered and the constraints that might be faced by the English as Second Language (ESL) learners when using MALL.  Above all, it was a challenging issue to cover learning tasks by using a mobile device particularly in learning English as Second Language (ESL).  Nevertheless, mobile devices which are popular among students are motivational tools to be used in education as well as various learning activities.  This was proven by many researchers who have shown the positive outcomes.  Hence, we should admit that mobile devices are finding their way into classrooms in the student’s pockets, and we have to ensure that educational practice can include this mobile technology in effective and productive ways particularly for English as Second Language (ESL) learning.
Sīrah Of The Prophet’s Early Life In Musnad of Aḥmad: An Analytical Study Of Qurʿānic References In Sīrah Nabawiyyah
Authors: Azmi Ahmad Sanusi
Published: June 2017

Reviews of early Muslim sources confirm that some verses of the Qur’ān have been perceived by Muslim scholars as direct references to the narratives of the Prophet’s early life. These selected verses are deemed to contain information about Muḥammad’s genealogy, birth, childhood and other aspects of his youth.  Modern scholars have, however, argued about the appropriateness and authority of these Qur’ānic references as being the true bearers of information of the Prophet’s biography. Since the ḥadīth is regarded as an authoritative exegetical tool employed to explore more deeply the meaning of the Qur’ān, and one of which contains a vast source of information about the Prophet’s life, it is indispensable to analyse the works of ḥadīth and its scholars’ views on the narratives of sīra nabawiyya. This study aims to explore the narratives of the Prophet’s early life in Musnad of Aḥmad and analyse Aḥmad’s perspective regarding Quranic references to the Prophet’s early life. The study is qualitative in nature in which the researcher utilised both critical and analytical approached as its methodology. The study in its finding espouses that the rarity of Qur’ānic reference to Muḥammad’s early life in Musnad of Aḥmad, an enormous inventory of ḥadīth of the ninth century, indicates one scholar’s views about Muḥammad’s early life. It is obvious that Aḥmad make no connection between the Quran and the narratives of the Prophet’s early life, even though verses that are widely used by the author of sīra as an allusion to Muḥammad’s early life.
Alternative Evolutionary Pathways for Drug-Resistant Small Colony Variant Mutants in
Staphylococcus aureus
Authors: Cao Sha , Huseby Douglas L. , Brandis Gerrit , Hughes Diarmaid
Published: June 2017

Staphylococcus aureus
is known to generate small colony variants (SCVs) that are resistant to aminoglycoside antibiotics and can cause persistent and recurrent infections. The SCV phenotype is unstable, and compensatory mutations lead to restored growth, usually with loss of resistance. However, the evolution of improved growth, by mechanisms that avoid loss of antibiotic resistance, is very poorly understood. By selection with serial passaging, we isolated and characterized different classes of extragenic suppressor mutations that compensate for the slow growth of small colony variants. Compensation occurs by two distinct bypass mechanisms: (i) translational suppression of the initial SCV mutation by mutant tRNAs, ribosomal protein S5, or release factor 2 and (ii) mutations that cause the constitutive activation of the SrrAB global transcriptional regulation system. Although compensation by translational suppression increases growth rate, it also reduces antibiotic susceptibility, thus restoring a pseudo-wild-type phenotype. In contrast, an evolutionary pathway that compensates for the SCV phenotype by activation of SrrAB increases growth rate without loss of antibiotic resistance. RNA sequence analysis revealed that mutations activating the SrrAB pathway cause upregulation of genes involved in peptide transport and in the fermentation pathways of pyruvate to generate ATP and NAD
+
, thus explaining the increased growth. By increasing the growth rate of SCVs without the loss of aminoglycoside resistance, compensatory evolution via the SrrAB activation pathway represents a threat to effective antibiotic therapy of staphylococcal infections.

IMPORTANCE
Small colony variants (SCVs) of
Staphylococcus aureus
are a significant clinical problem, causing persistent and antibiotic-resistant infections. However, SCVs are unstable and can rapidly evolve growth-compensated mutants. Previous data suggested that growth compensation only occurred with the loss of antibiotic resistance. We have used selection with serial passaging to uncover four distinct pathways of growth compensation accessible to SCVs. Three of these paths (reversion, intragenic suppression, and translational suppression) increase growth at the expense of losing antibiotic resistance. The fourth path activates an alternative transcriptional program and allows the bacteria to produce the extra ATP required to support faster growth, without losing antibiotic resistance. The importance of this work is that it shows that drug-resistant SCVs can evolve faster growth without losing antibiotic resistance.
POEMS syndrome: a rare cause of exudative ascites and chronic peripheral neuropathy
Authors: Al-Mayoof Omar , AL Sughaiyer Hana , Abuomar Wuroud , Khan Maria
Published: June 2017

POEMS syndrome (Peripheral neuropathy, Organomegaly, Endocrinopathy, M protein, Skin changes) is a rare plasma cell disorder with multisystem involvement

A 40-year-old man with a chronic history of unexplained peripheral neuropathy , presented with exudative ascites.He was found to have an incidental osteolytic lesion of the sacrum proven to be a plasmacytoma. Immunoelectrophoresis for monoclonal protein was negative.

In addition, the patient was found to have hepatosplenomegaly, erectile dysfunction, hyperprolactinaemia and hypothyroidism.

The patient, was given steroid along with lenalidomide, and showed a good clinical response.
A dirty cause of vancomycin-mediated Henoch-Schonlein purpura: oxygen tubing is not a foley
Authors: Shah Nikhil H , Kline Kristopher P , Shukla Manas K
Published: June 2017

A 59-year-old male presented with methicillin-resistantStaphylococcus aureusbacteraemia from a prostatic abscess and was treated with vancomycin. Two weeks into his treatment course, he developed severe joint pains, abdominal pain with bloody, mucinous stools and a diffuse palpable purpuric rash on his extremities. Biopsy of the rash showed IgA immune-complex deposition consistent with Henoch-SchÃ¶nlein purpura. After treatment with glucocorticoids, his symptoms resolved completely. Vancomycin is an extremely commonly used antibiotic with certain well-known adverse effects. Henoch-SchÃ¶nlein purpura, a vasculitis involving abdominal pain, arthralgias and palpable purpura, is a much less common side effect, as seen in this patient. Given that vancomycin is widely used internationally, clinicians should be aware of the risks entailed by its use.
Successful conservative management of a permanent pacemaker pocket infection: a less invasive approach
Authors: Keeley Alexander James , Hammersley Daniel , Dissanayake Madhava
Published: June 2017

We present a successful conservative management strategy for a frail elderly patient with a cardiac resynchronisation pacemaker who presented with evidence of anEnterobacter cloacaepacemaker pocket infection. A device washout and debridement procedure was performed, with reburial of the device in a new prepectoral pocket and creation of a closed-loop continuous antibiotic infusion into the infected pacemaker pocket. This was followed by a 6-week course of ambulatory intravenous antibiotic therapy. This conservative management strategy avoided the need for a more invasive and high-risk full device extraction, which the patient clearly stated he did not wish to have. Up-to-date consensus management guidelines recommend extraction of the entire implanted system in this situation; however, in this case we demonstrate an alternative conservative management option, which may be suitable for frail elderly and comorbid patients or for patients who decline device extraction.
Le Striga gesnerioides et son hôte, le niébé : interaction et méthodes de lutte
Authors: Dubé Marie-Pier , Olivier Alain
Published: June 2017

Cowpea (Vigna unguiculata (L.) Walp.) is an important legume crop in subsaharian Africa. However, its cultivation is threatened by the parasitic weed Striga gesnerioides (Willd.) Vatke, which causes considerable yield losses. Striga gesnerioides is an obligate parasite with low photosynthetic activity. Its seeds germinate in response to specific germination stimulants exuded by host roots. After germination, an haustorium is formed through differentiation of the radicular apex. A vascular connection is subsequently established, allowing the parasitic weed to absorb water and nutrients that are essential for its development. Control of S. gesnerioides is difficult to achieve because of the intimate association between the parasitic weed and its host. The use of resistant cowpea cultivars, in combination with appropriate cultural practices, is probably the easiest and most effective method to control S. gesnerioides and achieve long term reduction of its seed bank in the soil.Key words: germination, interaction, control methods, cultivar resistance, Striga gesnerioides, Vigna unguiculata.
Seed germination characteristics of Halogeton glomeratus
Authors: Khan M Ajmal , Gul Bilquees , Weber Darrell J
Published: June 2017

Halogeton glomeratus (Bieb.) C.A. Mey, an annual forb in the family Chenopodiaceae, is widely distributed in the inland salt deserts of western North America. Experiments were conducted to determine the effects of NaCl and temperature on seed germination and the recovery of germination responses after transfer to distilled water. Seeds of H. glomeratus were germinated at various temperature regimes (515°C, 1020°C, 1030°C, 1525°C, 2030°C, and 2535°C), and salinities (0, 200, 400, 600, 800, and 1000 mM NaCl) in a 12 h dark : 12 h light photoperiod. Increases in NaCl concentration progressively inhibited seed germination, and this inhibition was more substantial in the dark than in the photoperiod treatment. Seed germination at concentrations higher than 800 mM NaCl was low (10%). Cooler temperatures significantly inhibited germination in all treatments. A temperature regime of high night (25°C) and high day (35°C) temperatures led to higher germination. Rate of germination decreased with an increase in salinity and was highest at 2535°C and lowest at 515°C temperature regimes. Seeds were transferred from salt solution to distilled water after 20 days, and those from high salinities recovered quickly at all temperature regimes. Recovery germination percentages from the highest salinity treatment varied from 51 to 100% at various temperature regimes.Key words: Great Basin desert, Halogeton glomeratus, halophyte, recovery of seed germination, salt deserts, temperature regime.
Action de l'acide 2,4-dichlorophénoxyacétique et de l'acide 2,4,5- trichlorophénoxyacétique sur la croissance des filets staminaux du Zea mays. Etude de l'activité saccharasique et des modifications ultrastructurales des parois cellulaires au cours de leur allongement
Authors: Ngoc K. A. Ha
Published: June 2017

not available
Origine et degrés de ploïdie des méristèmes racinaires régénérés in vitro sur des disques foliaires issus de plantes haploïdes, diploïdes et tétraploïdes de Nicotiana tabacum (variétés 'Wisconsin 38' et 'Xanthi')
Authors: Brossard-Chriqui Dominique
Published: June 2017

In order to define the relation existing between the ploidy levels of the regenerated root meristems and those of the initial explants in vitro cultures of foliar discs arising from tobacco plants of different kinds of ploidy levels have been performed on the gelified medium of Murashige and Skoog modified with addition of sucrose, glutamine and indoleacetic acid. Under such conditions, numerous roots were always initiated. Foliar discs were excised from two varieties of Nicotiana tabacum L., each variety possibly being under two forms: cv. Wisconsin 38: haploid (n) androgenetic plants, diploid (2n) plants arising from seeds; cv. Xanthi: diploid (2n) plants arising from seeds, tetraploid (4n) plants previously regenerated in vitro.The histological origin of the neoformed roots was established, then the DNA contents were measured by means of a microspectrophotometer. For every kind of initial explant, ploidy levels were successively examined at the level of the apical meristem of the mother plant, in the foliar explants, and in the neoformed root meristems. Regenerated roots arose from the perifascicular cells of the leaf veins, dedifferentiation being induced by the auxin. Root meristems were directly formed without any previous callus. DNA contents in the vegetative shoot apices of the mother plants revealed their haploid, diploid, or tetraploid condition, but polyploid nuclei were found in the leaves. On the contrary, ploidy levels of the regenerated root meristems were always analogous to those of the apical meristems of the mother plants. The significance of these results in regard to the determinism of adventitious rhizogenesis was discussed.
Le développement en cultures pures in vitro des mycosymbiotes des lichens
Authors: Lallemant Richard
Published: June 2017

The mycosymbiont of Pertusaria pertusa was cultivated from ascospores or conidiospores. On Sabouraud agar, a nematothallus forms a multilobed, conidia-producing vesicle. Some mycelian filaments grow away from it and initiate "sclerotial structures." On maltea 2%, only a mycelian sheet was obtained. On the Lilly and Barnett medium such a mycelian sheet generates a hollow structure. The mycosymbiont of the Xanthoria parietina was cultivated from one ascospore or from conidiospores. On maltea 2%, a mycelian sheet is formed, then a nematothallian structure, generating a swollen, hollow, conidiogenous formation. On the Lilly and Barnett medium, the hollow structure is progressively filled with new hyphae. On the Sabouraud agar, the vesiculous structure becomes more structured; it can bear young apothecial primordia. It gives rise to small tongue-shaped lobes resembling young thallus lobes. The mycosymbiont ofthe Lecidea parasema could be cultivated on Sabouraud agar. A mycelium is formed which is then transformed into a nematothallus. On it appear concentric crown-shaped protuberances. The cultures of Lobaria pulmonaria and Lobaria laetevirens form a mycelian sheet which is transformed into a nematothallus. On Sabouraud agar this generates a vesiculous structure. Under intense light a sclerotic structure is formed. So, the mycosymbiont of the lichens has a great morphogenic plasticity; the phycosymbiont plays a fundamental role in the symbiotic union, leading to the formation of a pseudocladomian lichen thallus.
Growth and development at cold-hardening temperatures. Pigment and benzoquinone accumulation in winter rye
Authors: Krol Marianna , Huner Norman P. A.
Published: June 2017

Accumulation of chlorophyll, the carotenoids (β-carotene, lutein, violaxanthin, and neoxanthin), and the benzoquinones (plastoquinone A and α-tocopherol) were monitored in 'Puma' rye as a function of leaf ontogeny at warm and cold-hardening temperatures. Although the kinetics of accumulation differed among the leaves of warm-grown plants, the initial and maximum levels of the pigments and benzoquinones expressed on a leaf area basis did not differ significantly among the first four leaves of the main culm. In contrast, the third and fourth leaf of cold-grown plants, which developed completely at the low temperature, generally exhibited initial and maximum pigment and benzoquinone levels 60–300% greater than was observed for leaf 1 and 2 of cold-grown plants, which were completely or partially developed at the warm temperature regime. This resulted in pigment and benzoquinone levels which were 1.6- to 3-fold greater in the plants grown at cold-hardening temperatures than those grown at the warm temperature, when expressed on a per unit leaf area basis. However, when pigment accumulation was calculated on a chlorophyll basis, the benzoquinone content of leaves that developed solely at cold-hardening temperatures exhibited a 1.7-fold increase over the same leaves developed at warm temperatures. Carotenoids did not exhibit this trend. Calculations based on chlorophyll/carotenoid content and dry weight accumulation indicated that leaves that were developed at cold-hardening temperatures appeared to produce more dry matter per unit of photosynthetic pigments than the same leaves that were developed at nonhardening temperatures.
The latitudinal inventory of 137Cs in vegetation and topsoil in northern Canada, 1980
Authors: Hutchison-Benson E. , Svoboda J. , Taylor H. W.
Published: June 2017

The latitudinal distribution of fallout 137Cs in Canada has been determined along a transect extending from 50° to 82° N in 1980. The 137Cs content of lichens, bryophytes, and cushionlike vascular species was measured at 16 sites between Brandon, Manitoba, and Alert, Ellesmere Island. Lichen species were shown to be the most effective biological monitors of 137Cs deposition because of their specific morphology, longevity, and slow growth rates. Dry, exposed ridges were the sites of the highest 137Cs retention by plants. 137Cs levels in vegetation followed a bell-shaped distribution along the transect and the maximum accumulation was measured in samples collected between 60° and 70° N (10 nCi m−2 at 63° N) (1 Ci = 37 GBq). This distribution is the combined result of the original latitudinal deposition of 137Cs, the expired portion of its physical half-life, and the efficiency of biotic and abiotic removal processes along the studied corridor. It is suggested that the long-term implications of 137Cs in the northern food chain ought to be followed and studied more closely in the light of the data presented.
The ultrastructure of dwarf mistletoe (Arceuthobium spp.) sinker cells in the region of the host secondary vasculature
Authors: Alosi M. Carol , Calvin Clyde L.
Published: June 2017

Sinker cells showed ultrastructural similarities in three species of Arceuthobium on three different hosts despite differences in season of collection and fixation. All species had abundant osmiophilic lipid bodies, plastids with prolamellarlike bodies, mitochondria with large nucleoids, chromocentric nuclei, and peculiar saccules associated with plasmodesmatal fields. Xylem may not be continuous through sinkers. Apoplastic continuity between host and parasite is afforded by fused cellulosic cell walls. Pitlike wall thinnings and "half-plasmodesmata" are found between juxtaposed host and parasite cells. One-sided, imperforate sieve pores were noted between a sieve cell and a contiguous sinker cell. However, symplastic isolation of the host and parasite seems likely. Therefore, nutrients may be absorbed from the common host–parasite apoplast. Mobilization of nutrients out of the endophytic system to the aerial shoots is thought to be facilitated by differential starch storage in the parasite body.
The photosensitization of the plant pathogen Fusarium culmorum by phenylheptatriyne from Bidens pilosa
Authors: Bourque G. , Arnason J. T. , Madhosingh C. , Orr W.
Published: June 2017

The photosensitization of the cereal pathogen Fusarium culmorum by phenylheptatriyne (PHT), a naturally occurring acetylene of Bidens pilosa L. (Asteraceae), was investigated. PHT strongly inhibited germination of macroconidia (mean effective concentration (EC50) = 1.7 ppm) and growth of mycelia (EC50 = 5.6 ppm) of F. culmorum in the presence of near-ultraviolet radiation. Photosensitization of macroconidia was found to be fungicidal and was not reversed after repeated washings in PHT-free media. Photosensitization was less apparent in germ tube elongation in liquid media. However, nonphotosensitizing growth inhibition was observed in these trials. Endogenous levels of PHT in Bidens pilosa were highest (up to 450 μg/g fresh weight) in all plant parts during the seedling stage and declined during vegetative growth. The concept that PHT acts as a preinfectional inhibitor to F. culmorum is discussed.
Induction de la synthèse de la δ-aminolévulinate déshydratase des cotylédons de radis étiolés ou cultivés sous lumière rouge lointain par l'érythromycine
Authors: Huault Claude , Bruyant Philippe , Balangé Alain-Pierre
Published: June 2017

Erythromycin stimulates the de novo synthesis of δ-aminolevulinate dehydratase of radish cotyledons in both far-red light and darkness and blocks the enzyme accumulation in the etioplast. Density labelling experiments using erythromycin and cycloheximide demonstrate that δ-aminolevulinate dehydratase is encoded by the nuclear genome and that its synthesis is controlled by the etioplast.
Litter fall of epiphytic macrolichens in two old Picea abies forests in Sweden
Authors: Esseen Per-Anders
Published: June 2017

The seasonal and annual variation in the litter fall of epiphytic lichens and tree litter was studied over a period of 2 to 3 years at two forested hills in the eastern part of central Sweden. Litter fall was measured using traps and for one species, Usnea longissima, by collecting specimens present on the ground. Total litter fall amounted to 2.5 and 2.8 tons ha−1 year−1 of which lichens constituted 4.6 and 5.7% at the two sites. Lichen litter fall was highest during the period from late autumn to the beginning of summer. Both the lichens and the tree litter showed significant between-year differences. Usnea longissima had an annual turnover of 7.0 and 10.0% of the standing crop at the two sites. The thallus length distribution of U. longissima was positively skewed. It is concluded that dispersal of thallus fragments by wind evidently plays an important role for many of the filamentous lichens studied. It is suggested that U. longissima disperses over a much shorter distance than Alectoria sarmentosa and Bryoria spp. within a forest stand.
Divisions cellulaires au niveau de l'épiderme de l'hypocotyle du lin (Linum usitatissimum) cultivé in vitro
Authors: Sqalli M. , Chlyah H.
Published: June 2017

A study of the initiation and propagation of cell divisions in the epidermis of flax hypocotyl segments cultured in vitro was made using surface observations (light and scanning electron microscopes) as well as transverse and longitudinal sections. Epidermal cells were of two types: long, narrow cells and short, wide cells. The latter, less numerous, rarely participated in cell division. Nuclear activation and the first mitoses appeared very early (after 4–8 h of culture). Cell division began in isolated cells and spread progressively to surrounding cells arranged transversely. At 24 h, approximately 50 cells in division or newly divided were observed on an epidermal strip of 10 × 2 mm composed of about 8000 original cells. At 48 h, about 110 cells had divided forming 22 division centers; 26 prophase, 10 metaphase, and 7 telophase figures were observed. The mean number of original cells which participated in the formation of a cell division center was three at 12 h, five at 72 h, with no increase thereafter. The percentage of cells in mitosis or already divided remained low (1.9%) in relation to the total number of epidermal cells. For 22 division centers, only 7 would participate in vegetative bud formation.
Early stages of infection of resistant and susceptible sunflower seedlings by three races of Plasmopara halstedii
Authors: Gray A. Bruce , Sackston W. E.
Published: June 2017

Resistance in sunflower (Helianthus annuus L.) to downy mildew (Plasmopara halstedii (Farl.) Berl. et de Toni) is conditioned by a series of Pl. genes. Races 1 (European race), 2 (Red River race), and 3 (a new North American race encountered in the Red River valley in 1980) formed similar infection structures on inoculated seedlings whether susceptible or resistant to races 1 and 2; all cultivars tested were susceptible to race 3. The zoospores encysted and produced germ tubes and appressoria on the roots and hypocotyls. Penetration occurred and mycelium and haustoria developed in both compatible and incompatible host–pathogen combinations. Resistance did not appear to involve a hypersensitive reaction occurring prior to penetration.
Dégradation de l'acide malique par Botrytis cinerea
Authors: Donèche Bernard , Roux Françoise , Ribéreau-Gayon Pascal
Published: June 2017

During the growth of Botrytis cinerea on grape must, malic acid is actively oxidized by malic dehydrogenase. Some properties of this constitutive enzyme are described. In the absence of glucose, malic acid metabolism results in an equivalent accumulation of oxalic acid. In the presence of glucose, malic acid degradation is much slower, but the glucose is completely oxidized by the reactions of the Krebs cycle. Citric acid production in Czapek solution and in grape must differs according to strains of Botrytis cinerea; it depends mainly on glucose metabolism and is not directly related to malic acid degradation.
Longevity and persistence of alder west of the tree line on the Seward Peninsula, Alaska
Authors: Wilson Brayton F. , Patterson 111 William A. , O'Keefe John F.
Published: June 2017

We measured alder plants (Alnus viridis ssp. crispa (Aiton) Turrill) in stands on 11 sites on the Seward Peninsula. Of the plants measured in detail, 70% had multiple stems (largest difference in stem age on a plant was 67 years), 54% had small epicormic shoots, and 59% had partially prostrate stems that could layer. The oldest stems were 35–114 years on alpine tundra, 47–48 years on river cuts, 36 years on moist tundra, and 16–33 years on floodplain. This species appeared to be reproducing by means of seedlings on 8 of 11 sites. Alder pollen percentages in surface samples from seven small ponds were negatively correlated with distance to alder stands. Pollen and 14C analysis of sediments from a pond near one sample stand showed that alder pollen percentages had decreased over the past 3600 years, but that alder had persisted in the area during this period. Estimates of potential plant age, dependent on assumptions about the production and survival of new stems, ranged from 100 years to unlimited age. The maximum age of stands is at least 100–200 years, but could be up to the 3600 years shown by a continuous pollen record and 14C analysis.
Hop tree (Ptelea trifoliata) in Canada: population and reproductive biology of a rare species
Authors: Ambrose John D. , Kevan Peter G. , Gadawski Randy M.
Published: June 2017

In Canada, Ptelea trifoliata L. (Rutaceae) is restricted in its natural distribution primarily to the Lake Erie shoreline. Although it is locally successful as a colonizing species, it appears inhibited from either exploiting a large area of shoreline habitat or extending its range inland. The morphological descriptions of the hop tree's sexual expression have been ambiguous; however, our observations show this species to be clearly dioecious, with only about 2% of the otherwise male plants producing a few hermaphroditic flowers, and fruit. The sex ratio is strongly skewed toward the males, which produce more and showier inflorescences than female plants. Despite this, the insect visitation rates are not significantly different between the sexes. For pollination, the hop tree is a polyphilic generalist, dependent on a diverse array of insects, including short-tongued bees, wasps, and flies. It is totally dependent on wind-dispersed seeds for establishment, lacking the ability to grow clonally. In a dioecious species of disturbed habitats, this is exceptional.
The species-specific effects of sublethal concentrations of cadmium on freshwater phytoplankton communities in a Canadian Shield lake
Authors: Reinke Danny C. , DeNoyelles Jr. Frank
Published: June 2017

The species-specific responses of natural phytoplankton communities to low cadmium concentrations were measured in Lake 239 (Experimental Lakes Area, northwestern Ontario). Both in situ and laboratory 5-L continuous-flow cultures, and 5-L and 100-mL cultures were used. Asterionella formosa, Dinobryon sertularia, and Dinobryon bavaricum showed dramatic negative sensitivity to low cadmium concentrations (5–100 μg/L), while Rhabdoderma gorskii and Elakatothrix sp. consistently increased in numbers at the same cadmium concentrations. In all experiments, some species exhibited no apparent effect to cadmium addition as measured by cell counts. The "bottle effect" of each technique was evaluated by comparing the community similarity valves of the control cultures to the lake samples and showed the in situ continuous cultures to be most similar to the lake followed by the laboratory continuous cultures, the in situ 5-L batch cultures, the 5-L laboratory cultures, and the 100-mL batch cultures. Replicate cadmium cultures, all techniques, were more similar to each other than the lake samples. The similarity of the cadmium cultures to the lake sample or control cultures decreased with increased cadmium concentration and incubation time.