bluuebunny/crossref_metadata_2025 huggingface dataset:
L-Tryptophan Production by Auxotrophic and Analogue Resistant Mutants of Aureobacterium flavescens
Authors: Roy A. , Mukhopadhyay S.K.
Published: May 2011

A number of tyrosine plus phenylalanine double auxotrophic mutants were isolated by N-methyl-N-nitro-N-nitrosoguanidine (MNNG) treatment of a locally isolated strain of Aureobacterium flavescens of which 11A39 and 11A17 were selected on the basis of their tryptophan production in a mineral salt medium over other isolated mutant strains. The mutational block in the aromatic amino acid biosynthetic pathway of the selected double auxotrophs were determined. By controlling pH of the production medium to near neutrality, the active growth period could be extended up to 72 h and more tryptophan was accumulated compared to pH unregulated culture where the active growth ceased after 48 h. Further improvement of the tryptophan production has been achieved by stepwise isolation of a mutant strain resistant to the tryptophan analogues p-fluorotryptophan (FT) and 5-methyl tryptophan (MT) from the 11A39. Demand for L-tryptophan as food additive and therapeutic agent is increasing day by day throughout the World, particularly in the underdeveloped and developing countries like India. Still to date India depends on other countries for L-tryptophan. The aim of this work is to develop a potent high yielding, feed back insensitive mutant strain and optimization of its medium pH for maximum production of tryptophan.
Evidence-Based Pharmacotherapy for Pediatric Obsessive-Compulsive Disorder and Chronic Tic Disorders
Authors: De Nadai Alessandro S. , Storch Eric A. , Mcguire Joseph F. , Lewin Adam B. , Murphy Tanya K.
Published: June 2011

In recent years, much progress has been made in pharmacotherapy for pediatric obsessive-compulsive disorder (OCD) and chronic tic disorders (CTDs). What were previously considered relatively intractable conditions now have an array of efficacious medicinal (and psychosocial) interventions available at clinicians' disposal, including selective serotonin reuptake inhibitors, atypical antipsychotics, and alpha-2 agonists. The purpose of this review is to discuss the evidence base for pharmacotherapy with pediatric OCD and CTDs with regard to efficacy, tolerability, and safety, and to put this evidence in the context of clinical management in integrated behavioral healthcare. While there is no single panacea for these disorders, there are a variety of medications that provide considerable relief for children with these disabling conditions.
What Works for Patients in Outpatient Treatment for Alcohol Addiction? An Explorative Study into Clients’ Evaluation of Subjective Factors and Therapy Satisfaction
Authors: Frick Katrin M. , Loessl Barbara , Brueck Rigo K. , Kriston Levente , Jaehne Andreas , Riemann Dieter , Gann Horst , Batra Anil , Wodarz Norbert , Mann Karl F. , Berner Michael M.
Published: May 2011

This explorative survey investigated clients’ evaluation of therapy elements and other supportive factors within a randomized controlled trial. The treatment of patients with alcohol dependence consisted of pharmacotherapy (acamprosate/naltrexone/placebo) and biweekly medical management (MM). Forty-nine study participants were surveyed with a questionnaire to measure both the patients’ satisfaction with the therapy and the subjective assessment of treatment elements and supportive factors.

Study participants were highly satisfied with the treatment. The supportive factors previously identified by Orford et al 1 were confirmed. ‘Pharmacotherapy’ was rated significantly less effective than ‘MM’ and ‘global study attendance’ ( P < 0.001). The significant differences in the evaluation of treatment elements point to a preference for regular low-key contacts rather than for medication. Such contacts based on MM could be a useful intervention in clinical care, and its effectivity should be examined more closely in further research.
Asymptotic isoperimetry on groups and uniform embeddings into Banach spaces
Authors: Tessera Romain
Published: June 2011

We characterize the possible asymptotic behaviors of the compression associated to a uniform embedding into some

L^p

-space, with

1< p<\infty

, for a large class of groups including connected Lie groups with exponential growth and word-hyperbolic finitely generated groups. In particular, the Hilbert compression exponent of these groups is equal to 1. This also provides new and optimal estimates for the compression of a uniform embedding of the infinite 3-regular tree into some

L^p

-space. The main part of the paper is devoted to the explicit construction of affine isometric actions of amenable connected Lie groups on

L^p

-spaces whose compressions are asymptotically optimal. These constructions are based on an asymptotic lower bound of the

L^p

-isoperimetric profile inside balls. We compute the asymptotic behavior of this profile for all amenable connected Lie groups and for all

1\leq p<\infty

, providing new geometric invariants of these groups. We also relate the Hilbert compression exponent with other asymptotic quantities such as volume growth and probability of return of random walks.
Rational connectedness modulo the non-nef locus
Authors: Broustet Amaël , Pacienza Gianluca
Published: June 2011

It is well known that a smooth projective Fano variety is rationally connected. Recently Zhang [Z2] (and later Hacon and McKernan [HM] as a special case of their work on the Shokurov RC-conjecture) proved that the same conclusion holds for a klt pair

(X,\Delta)

such that

-(K_X+\Delta)

is big and nef. We prove here a natural generalization of the above result by dropping the nefness assumption. Namely we show that a klt pair

(X,\Delta)

such that

-(K_X+\Delta)

is big is rationally connected modulo the non-nef locus of

-(K_X+\Delta)

. This result is a consequence of a more general structure theorem for arbitrary pairs

(X,\Delta)

with

-(K_X+\Delta)

pseff.
The Khovanov width of twisted links and closed 3-braids
Authors: Lowrance Adam M.
Published: June 2011

Khovanov homology is a bigraded

ℤ

-module that categorifies the Jones polynomial. The support of Khovanov homology lies on a finite number of slope two lines with respect to the bigrading. The Khovanov width is essentially the largest horizontal distance between two such lines. We show that it is possible to generate infinite families of links with the same Khovanov width from link diagrams satisfying certain conditions. Consequently, we compute the Khovanov width for all closed 3-braids.
Pharmacokinetics of Oral Sitamaquine Taken with or without Food and Safety and Efficacy for Treatment of Visceral Leishmaniais: A Randomized Study in Bihar, India
Authors: Sundar Shyam , Sinha Prabhat K. , Dixon Susan A. , Buckley Renata , Miller Ann K. , Mohamed Khadeeja , Al-Banna Mahir
Published: June 2011

This randomized, open-label study of patients in India with visceral leishmaniasis (VL) investigated the effect of food on sitamaquine and desethyl-sitamaquine pharmacokinetics. Patients were randomized to receive oral sitamaquine, 2 mg/kg/day, once a day for 21 days across four cohorts (n = 41) (fasted/fed, fed/fasted, fed/fed, and fasted/fasted) over two periods (days 1−10 and 11−21), or intravenous amphotericin B (AmB), 1 mg/kg every other day for 30 days (n = 20). Mean day 21 pharmacokinetics across the four cohorts were sitamaquine, area under curve (AUC)(0−τ) = 6,627−8,903 ng.hr/mL, AUC(0−16) = 4,859−6,633 ng.hr/mL, maximum plasma concentration (Cmax) = 401−570 ng/mL, apparent terminal half-life (t1/2) = 18.3−22.8 hr, time to reach Cmax (tmax) = 3.5−6 hr; and desethyl-sitamaquine, AUC(0−τ) = 2,307−3,163 ng.hr/mL, Cmax = 109−154 ng/mL, t1/2 = 23.0−27.9 hr, tmax = 2−10 hr, with no significant food effect. On-therapy adverse events were observed for sitamaquine in 4 (10%) of 41 patients and for AmB in 17 (85%) of 20 patients. The final clinical cure (day 180) was 85% (95% confidence interval = 70.8–94.4%) for sitamaquine and 95% (95% confidence interval = 75.1–99.9) for AmB. Sitamaquine can be taken regardless of food intake, was generally well tolerated, and showed potential efficacy in patients with visceral leishmaniasis.
Diagnosis of Gestational, Congenital, and Placental Malaria in Colombia: Comparison of the Efficacy of Microscopy, Nested Polymerase Chain Reaction, and Histopathology
Authors: Campos Ivón M. , Uribe Mary L. , Cuesta Carolina , Franco-Gallego Alexander , Carmona-Fonseca Jaime , Maestre Amanda
Published: June 2011

The technical capability of different methods to diagnose Plasmodium in maternal peripheral blood, placenta, and umbilical cord blood has not been assessed in Colombia and seldom explored in other malaria-endemic regions. We designed a study to compare the technical and the operational-economical performances of light microscopy (LM), nested polymerase chain reaction (nPCR), and histopathology (HP). In maternal blood, LM had 41% sensitivity and 100% specificity and in placental blood, 35% and 100%, respectively, compared with nPCR. In placental tissue, LM had 33% sensitivity and 95% specificity; and nPCR 47% and 77%, respectively; compared with HP. Light microscopy had the best operational-economical qualification. We concluded that nPCR and HP performed better compared with LM, but field implementation of these two techniques remains a problem. Therefore, LM is recommended as the gold standard for diagnosis of gestational malaria and placental blood infection in the field.
A Patient with Erythema Nodosus Leprosum and Chagas Cardiopathy: Challenges in Patient Management and Review of the Literature
Authors: Trindade Maria Ângela B. , Carvalho Noemia B. , Belfort Elaini C. , Pagliari Carla , Gakiya Erika , Sakai-Valente Neusa Y. , Benard Gil , Shikanai-Yasuda Maria A.
Published: June 2011

We report a patient with severe multi-bacillary leprosy complicated by recurrent episodes of erythema nodosum necrotisans that required thalidomide and/or corticosteroids during follow-up. Although the patient was from an area to which Chagas disease is endemic, this diagnosis was initially missed and was only investigated when heart failure developed in the patient. The difficulties of managing erythema nodosum necrotisans and heart failure concomitantly and those involved in excluding the diagnosis of acute myocarditis caused by reactivation of Chagas disease secondary to the immunosuppressive regimen are discussed. Other potential causes for the heart failure and possible interactions between the two diseases and their treatments are discussed. We also reviewed the literature for the association between leprosy and Chagas disease, both of which are highly endemic in Brazil. This case emphasizes the importance of searching for subclinical co-infections in leprosy patients because reactions frequently develop during specific treatment in these patients, and these reactions require prolonged therapy with immunosuppressive drugs.
Efficacy of a Tetravalent Chimeric Dengue Vaccine (DENVax) in Cynomolgus Macaques
Authors: Osorio Jorge E. , Brewoo Joseph N. , Silengo Shawn J. , Arguello John , Moldovan Ioana R. , Tary-Lehmann Magdalena , Powell Tim D. , Livengood Jill A. , Kinney Richard M. , Huang Claire Y.-H. , Stinchcomb Dan T.
Published: June 2011

Three tetravalent formulations of chimeric dengue (DENVax) viruses containing the pre-membrane and envelope genes of serotypes 1–4 expressed by the attenuated DENV-2 PDK-53 genome were tested for safety, immunogenicity, and efficacy in cynomolgus macaques (Macaca fascicularis). Subcutaneous injection of the DENVax formulations was well-tolerated. Low levels of viremia of only one of the four vaccine viruses were detected yet virus neutralizing antibody titers were induced against all four dengue virus serotypes after one or two administrations of vaccine. All animals immunized with the high-dose formulation were protected from viremia, and all immunized animals were completely protected from DENV-3 and DENV-4 challenge. A lower dose of DENVax formulation partially protected animals from DENV-1 or DENV-2 challenge. In contrast, all control animals developed high levels of viremia for multiple days after challenge with DENV 1–4. This study highlights the immunogenicity and efficacy of the tetravalent DENVax formulations in nonhuman primates.
Endemic Tegumentary Leishmaniasis in Brazil: Correlation between Level of Endemicity and Number of Cases of Mucosal Disease
Authors: Bedoya-Pacheco Sandro J. , Araujo-Melo Maria H. , Valete-Rosalino Claudia M. , Pimentel Maria Inês F. , Conceição-Silva Fátima , Schubach Armando O. , Marzochi Mauro C. A.
Published: June 2011

The purpose of this study was to establish a correlation between the endemic level of tegumentary leishmaniasis in different regions of Brazil during 2002–2009 and the number of cases of mucosal or mucocutaneous leishmaniasis. The proportion of mucosal leishmaniasis was inversely correlated with prevalence of infection. In areas with a lower infection prevalence, the proportion of mucosal leishmaniasis increased (P < 0.05). The hypothesis of an Amazonian origin and dissemination through human migration is considered. Our results show that in regions with lower prevalence and endemically younger, the proportion of cases that evolve to the mucosal form is higher than in regions with higher prevalence and endemically older.
A Laboratory-Based Surveillance System for Wuchereria bancrofti in Togo: A Practical Model for Resource-Poor Settings
Authors: Mathieu Els , Dorkenoo Ameyo , Otogbe Felix K. J. , Budge Philip J. , Sodahlon Yao K.
Published: June 2011

One goal of the Global Program to Eliminate Lymphatic Filariasis (GAELF) is interruption of disease transmission through annual mass drug administration (MDA) in areas where LF prevalence is greater than 1%. After MDAs are completed, the World Health Organization (WHO) recommends a period of passive surveillance before final certification of LF elimination is achieved. Guidelines for such a surveillance system have yet to be developed. This paper describes a surveillance system launched in Togo in 2006. The system uses existing laboratories with technicians on call at night who, among other activities, prepare nocturnal thick blood smears for malaria diagnosis that can also be used for LF diagnosis. During its first 2 years (2006–2007), the system provided geographically disperse sampling nationwide, and 1 of 750 people residing in Togo was tested. Over the same period, the system detected two cases of LF, both from areas previously considered non-endemic. This system could be a cost-effective, sustainable model for WHO-mandated passive surveillance after cessation of MDA.
Repeat Blood Culture Positive for B. pseudomallei Indicates an Increased Risk of Death from Melioidosis
Authors: Limmathurotsakul Direk , Wuthiekanun Vanaporn , Wongsuvan Gumphol , Pangmee Sukanya , Amornchai Premjit , Teparrakkul Prapit , Teerawattanasook Nittaya , Day Nicholas P. J. , Peacock Sharon J.
Published: June 2011

Melioidosis, a bacterial infection caused by Burkholderia pseudomallei, is notoriously difficult to cure despite appropriate antimicrobial therapy and has a mortality rate of up to 40%. We demonstrate that a blood culture positive for B. pseudomallei taken at the end of the first and/or second week after hospitalization for melioidosis is a strong prognostic factor for death (adjusted odds ratio = 4.2, 95% confidence interval = 2.1–8.7, P < 0.001 and adjusted odds ratio = 2.6, 95% confidence interval = 1.1–6.0, P = 0.03, respectively). However, repeat cultures of respiratory secretions, urine, throat swabs, or pus/surface swabs provide no prognostic information. This finding highlights the need for follow-up blood cultures in patients with melioidosis.
Molecular Identification of Trichinella papuae from a Thai Patient with Imported Trichinellosis
Authors: Intapan Pewpan M. , Chotmongkol Verajit , Tantrawatpan Chairat , Sanpool Oranuch , Morakote Nimit , Maleewong Wanchai
Published: June 2011

Previously, we reported the presence of imported trichinellosis in a Thai worker returning from Malaysia, who presented with progressive generalized muscle hypertrophy and weakness after eating wild boar meat. This work analyzed a partial small subunit of a mitochondrial ribosomal RNA gene of Trichinella larvae isolated from the patient. The results showed complete identity with a mitochondrial RNA gene of Trichinella papuae (GenBank accession no. EF517130). This is the first report of imported trichinellosis in Thailand caused by T. papuae. It is possible that T. papuae is widely distributed in the wildlife of Southeast Asia.
A Cluster of Cutaneous Leishmaniasis Associated with Human Smuggling
Authors: Cannella Anthony P. , Nguyen Bichchau M. , Piggott Caroline D. , Lee Robert A. , Vinetz Joseph M. , Mehta Sanjay R.
Published: June 2011

Cutaneous leishmaniasis (CL) is rarely seen in the United States, and the social and geographic context of the infection can be a key to its diagnosis and management. Four Somali and one Ethiopian, in U.S. Border Patrol custody, came to the United States by the same human trafficking route: Djibouti to Dubai to Moscow to Havana to Quito; and then by ground by Columbia/Panama to the United States - Mexico border where they were detained. Although traveling at different times, all five patients simultaneously presented to our institution with chronic ulcerative skin lesions at different sites and stages of evolution. Culture of biopsy specimens grew Leishmania panamensis. Soon thereafter, three individuals from East Africa traveling the identical route presented with L. panamensis CL to physicians in Tacoma, WA. We document here the association of a human trafficking route and new world CL. Clinicians and public health officials should be aware of this emerging infectious disease risk.
Human Ocular Infection with Dirofilaria repens (Railliet and Henry, 1911) in an Area Endemic for Canine Dirofilariasis
Authors: Otranto Domenico , Brianti Emanuele , Gaglio Gabriella , Dantas-Torres Filipe , Azzaro Salvatore , Giannetto Salvatore
Published: June 2011

Dirofilaria repens, which is usually found in canine subcutaneous tissues, is the main causative agent of human dirofilariasis in the Old Word. However, a relationship between animal and human cases of dirofilariasis caused by D. repens in a given area has never been demonstrated. The uneven distribution of D. repens in provinces in Sicily, Italy represented the foundation for this study. We report a human case of ocular infection with D. repens from Trapani Province, where canine dirofilariasis is endemic. The nematode was morphologically and molecularly identified and surgical removal of the parasite was documented. The relationship between the prevalence of D. repens in dogs and the occurrence of human cases of ocular dirofilariasis is discussed on the basis of a review of the historical literature.
Therapeutic Efficacies of Artemisinin-Based Combination Therapies in Nigerian Children with Uncomplicated Falciparum Malaria during Five Years of Adoption as First-Line Treatments
Authors: Gbotosho Grace O. , Sowunmi Akintunde , Happi Christian T. , Okuboyejo Titilope M.
Published: June 2011

The therapeutic efficacies of 3-day regimens of artesunate-amodiaquine and artemether-lumefantrine during 5 years of adoption as first-line treatments were evaluated in 811 ≤ 12-year-old malarious children. Compared with artemether-lumefantrine, amodiaquine-artesunate significantly reduced the proportion of children with fever and parasitemia 1 day after treatment (day 1; P < 0.008 for both). The proportion of parasitemic children on day 2 and gametocytemia on presentation and carriage reduced significantly over the years (P < 0.000001 and P < 0.03, respectively; test for trend). Overall efficacy was 96.5% (95% confidence interval [CI] = 94.5–98.6) and remained unchanged over the years (P = 0.87; test for trend). Kinetics of parasitemias after treatments were estimated by a non-compartmental model. Declines of parasitemias were monoexponential, with a mean elimination half-life of 1.09 hours (95% CI = 1.0–1.16). Parasitemia half-lives and efficacy were similar for both regimens and in all ages. Artesunate-amodiaquine and artemether-lumefantrine remain efficacious treatments of uncomplicated falciparum malaria in Nigerian children 5 years after adoption.
Herpes Labialis in Patients with Russell's Viper Bite and Acute Kidney Injury: A Single Center Experience
Authors: Waikhom Rajesh , Sapam Ranjeeta , Patil Krishna , Jadhav Jaya Prada , Sircar Dipankar , Roychowdhury Arpita , Dasgupta Sanjay , Pandey Rajendra
Published: June 2011

Snake bite is an important health hazard in tropical countries and is associated with significant morbidity and mortality. Herpes labialis is a common ailment caused by the Herpes simplex virus. There is no published data showing any association between the snake bite and development of Herpes labialis. Here, we present a series of patients who developed Herpes labialis after Russell's viper bite and had acute kidney injury. We attempted to find whether snake bite is an immunosuppressed state and whether it could have pre-disposed the patients to the development of these lesions.
Antibody Responses and Avidity of Naturally Acquired Anti-Plasmodium vivax Duffy Binding Protein (PvDBP) Antibodies in Individuals from an Area with Unstable Malaria Transmission
Authors: Zakeri Sedigheh , Babaeekhou Laleh , Mehrizi Akram Abouie , Abbasi Maryam , Djadid Navid Dinparast
Published: June 2011

Plasmodium vivax remains an important cause of morbidity outside Africa, and no effective vaccine is available against this parasite. The P. vivax Duffy binding protein (PvDBP) is essential during merozoite invasion into erythrocytes, and it is a target for protective immunity against malaria. This investigation was designed to evaluate naturally acquired antibodies to two variant forms of PvDBP-II antigen (DBP-I and -VI) in malaria individuals (N = 85; median = 22 years) who were living in hypoendemic areas in Iran. The two PvDBP-II variants were expressed in Escherichia coli, and immunoglobulin G (IgG) isotype composition and avidity of naturally acquired antibodies to these antigens were measured using enzyme-linked immunosorbent assay (ELISA). Results showed that almost 32% of the studied individuals had positive antibody responses to the two PvDBP-II variants, and the prevalence of responders did not differ significantly (P > 0.05; χ2 test). The IgG-positive samples exhibited 37.03% and 40.8% high-avidity antibodies for PvDBP-I and PvDBP-VI variants, respectively. Furthermore, high-avidity IgG1 antibody was found in 39.1% of positive sera for each examined variant antigen. The avidity of antibodies for both PvDBP variant antigens and the prevalence of responders with high- and intermediate-avidity IgG, IgG1, and IgG3 antibodies were similar in patients (P > 0.05; χ2 test). Moreover, the prevalence of IgG antibody responses to the two variants significantly increased with exposure and host age. To sum up, the results provided additional data in our understanding of blood-stage immunity to PvDBP, supporting the rational development of an effective blood-stage vaccine based on this antigen.
Blastocystis sp. Subtype 4 is Common in Danish Blastocystis-Positive Patients Presenting with Acute Diarrhea
Authors: Stensvold Christen Rune , Christiansen Dorte Bang , Olsen Katharina Elisabeth Pribil , Nielsen Henrik Vedel
Published: June 2011

Fecal samples from 444 Danish patients presenting with acute diarrhea were tested for Blastocystis and positive samples were subtyped to investigate the prevalence and subtype distribution of Blastocystis in this patient group. A total of 25 patients (5.6%) were positive, and 19 of these patients (76.0%) were positive for Blastocystis sp. ST4. Because the relative prevalence of ST4 in other patients presenting with other types of diarrhea (persistent, travel-related, and human immunodeficiency virus-related) in Denmark is low, the role of Blastocystis sp. ST4 in the etiology of acute diarrhea should be investigated further.
Tuberculosis-Associated Chronic Kidney Disease
Authors: de Oliveira Jobson Lopes , da Silva Junior Geraldo Bezerra , Daher Elizabeth De Francesco
Published: June 2011

Extrapulmonary tuberculosis (TB) account for approximately 15–20% of TB cases in immunocompetent patients. The genitourinary system is the third most commonly affected site. We report the case of a 20-year-old man admitted with fever, chills, dry cough, right flank pain, and oliguria who developed renal function loss. The pyelogram evidenced silence of the right kidney, and the abdominal and pelvic magnetic resonance showed significant dilation of the right pyelocaliceal system and proximal ureter. Biopsies of renal cortex and retroperitoneal lymph nodes showed caseous granuloma consistent with TB. Treatment was started with rifampicin, isoniazid, pyrazinamide, and ethambutol, and the patient presented a favorable outcome but with non-dialytic chronic kidney disease. This case illustrates a case of chronic kidney disease secondary to TB in a young, otherwise healthy man.
Disseminated Cutaneous Leishmaniasis Resembling Post-Kala-Azar Dermal Leishmaniasis Caused by Leishmania donovani in Three Patients Co-Infected with Visceral Leishmaniasis and Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome in Ethiopia
Authors: Gelanew Tesfaye , Hurissa Zewdu , Diro Ermias , Kassahun Aysheshm , Kuhls Katrin , Schönian Gabriele , Hailu Asrat
Published: June 2011

We report paired strains of Leishmania parasites, one from the viscera and the other from skin lesions that were isolated from three patients with visceral leishmaniasis and disseminated cutaneous leishmaniasis that were co-infected with human immunodeficiency virus. The causative parasites were characterized by polymerase chain reaction–restriction length polymorphism of the ribosomal DNA internal transcribed spacer 1 and by a panel of multilocus microsatellite markers. We demonstrated that the causative agent was Leishmania donovani in all cases, irrespective of the phenotype of the disease. The paired strains from viscera and skin lesions of the same patients showed genetic identity across the 14 microsatellite markers investigated. These findings demonstrate that the skin lesions in these human immunodeficiency virus–positive patients with visceral leishmaniasis were caused by dissemination of viscerotropic L. donovani parasites as a consequence of severe immunosuppression. However, in all three patients, rapid clearance of the skin lesions was observed after antimonial therapy.
Enteric Pathogens Associated with Childhood Diarrhea in Tripoli-Libya
Authors: Rahouma Amal , Klena John D. , Krema Zaineb , Abobker Abdalwahed A. , Treesh Khalid , Franka Ezzedin , Abusnena Omar , Shaheen Hind I. , El Mohammady Hanan , Abudher Abdulhafid , Ghenghesh Khalifa Sifaw
Published: June 2011

Stool samples from children < 5 years of age with diarrhea (N = 239) were examined for enteric pathogens using a combination of culture, enzyme-immunoassay, and polymerase chain reaction methods. Pathogens were detected in 122 (51%) stool samples; single pathogens were detected in 37.2% and co-pathogens in 13.8% of samples. Norovirus, rotavirus, and diarrheagenic Escherichia coli (DEC) were the most frequently detected pathogens (15.5%, 13.4%, and 11.2%, respectively); Salmonella, adenovirus, and Aeromonas were detected less frequently (7.9%, 7.1%, and 4.2%). The most commonly detected DEC was enteroaggregative E. coli (5.4%). Resistance to ≥ 3 antimicrobials was observed in 60% (18/30) of the bacterial pathogens. Salmonella resistance to ciprofloxacin (63.1%) has become a concern. Enteric viral pathogens were the most significant causative agents of childhood diarrhea in Tripoli. Bacterial pathogens were also important contributors to pediatric diarrhea. The emergence of ciprofloxacin-resistant Salmonella represents a serious health problem that must be addressed by Libyan health authorities
A numerical study of mountain waves in the upper troposphere and lower stratosphere
Authors: Mahalov A. , Moustaoui M. , Grubišić V.
Published: June 2011

Abstract. A numerical study of mountain waves in the Upper Troposphere and Lower Stratosphere (UTLS) is presented for two Intensive Observational Periods (IOPs) of the Terrain-induced Rotor Experiment (T-REX). The simulations use the Weather Research and Forecasting (WRF) model and a microscale model that is driven by the finest WRF nest. During IOP8, the simulation results reveal presence of perturbations with short wavelengths in zones of strong vertical wind shear in the UTLS that cause a reversal of momentum fluxes. The spectral properties of these perturbations and the attendant vertical profiles of heat and momentum fluxes show strong divergence near the tropopause indicating that they are generated by shear instability along shear lines locally induced by the primary mountain wave originating from the lower troposphere. This is further confirmed by results of an idealized simulation initialized with the temperature and wind profiles obtained from the microscale model. For IOP6, we analyze distributions of O3 and CO observed in aircraft measurements. They show small scale fluctuations with amplitudes and phases that vary along the path of the flight. Detailed comparisons between these fluctuations and the observed vertical velocity show that the behavior of these short fluctuations is due not only to the vertical motion, but also to the local mean vertical gradients where the waves evolve, which are modulated by larger variations. The microscale model simulation results show favorable agreement with in situ radiosonde and aircraft observations. The high vertical resolution offered by the microscale model is found to be critical for resolution of smaller scale processes such as formation of inversion layer associated with trapped lee waves in the troposphere, and propagating mountain waves in the lower stratosphere.
Source apportionment of arsenic in atmospheric dust fall out in an urban residential area, Raipur, Central India
Authors: Balakrishna G. , Pervez S. , Bisht D. S.
Published: June 2011

Abstract. The components and quantities of atmospheric dust fallout have been reported to be the pollution indicator of large urban areas. The multiplicity and complexity of sources of atmospheric dusts in urban regions has put forward the need of source apportionment of these sources indicating their contribution to specific environmental receptor. The study presented here is focused on investigation of source contribution estimates of Arsenic in urban dust fallout in an urban-industrial area, Raipur, India. Source-receptor based representative sampling plan using longitudinal study design has been adopted. Six sampling sites have been identified on the basis of land use for development plan of anthropogenic activities and factors related to the transportation and dispersion pattern of atmospheric dusts. Source apportionment has been done using Chemical Mass Balance (CMB 8). Good fit parameters and relative source contribution has been analyzed and documented. Dominance of coal fired industries sources on arsenic levels measured at selected ambient residential receptors compared to line sources has been observed. Road-traffic has shown highest contribution of dust at indoor houses and out door-street automobile exhaust has shows highest contribution for arsenic. The results of CMB output and regression data of source-receptor dust matrices have shown comparable pattern.
Sources and production of organic aerosol in Mexico City: insights from the combination of a chemical transport model (PMCAMx-2008) and measurements during MILAGRO
Authors: Tsimpidi A. P. , Karydis V. A. , Zavala M. , Lei W. , Bei N. , Molina L. , Pandis S. N.
Published: June 2011

Abstract. Urban areas are large sources of organic aerosols and their precursors. Nevertheless, the contributions of primary (POA) and secondary organic aerosol (SOA) to the observed particulate matter levels have been difficult to quantify. In this study the three-dimensional chemical transport model PMCAMx-2008 is used to investigate the temporal and geographic variability of organic aerosol in the Mexico City Metropolitan Area (MCMA) during the MILAGRO campaign that took place in the spring of 2006. The organic module of PMCAMx-2008 includes the recently developed volatility basis-set framework in which both primary and secondary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA emission inventory is modified and the POA emissions are distributed by volatility based on dilution experiments. The model predictions are compared with observations from four different types of sites, an urban (T0), a suburban (T1), a rural (T2), and an elevated site in Pico de Tres Padres (PTP). The performance of the model in reproducing organic mass concentrations in these sites is encouraging. The average predicted PM1 organic aerosol (OA) concentration in T0, T1, and T2 is 18 μg m−3, 11.7 μg m−3, and 10.5 μg m−3 respectively, while the corresponding measured values are 17.2 μg m−3, 11 μg m−3, and 9 μg m−3. The average predicted locally-emitted primary OA concentrations, 4.4 μg m−3 at T0, 1.2 μg m−3 at T1 and 1.7 μg m−3 at PTP, are in reasonably good agreement with the corresponding PMF analysis estimates based on the Aerosol Mass Spectrometer (AMS) observations of 4.5, 1.3, and 2.9 μg m−3 respectively. The model reproduces reasonably well the average oxygenated OA (OOA) levels in T0 (7.5 μg m−3 predicted versus 7.5 μg m−3 measured), in T1 (6.3 μg m−3 predicted versus 4.6 μg m−3 measured) and in PTP (6.6 μg m−3 predicted versus 5.9 μg m−3 measured). The rest of the OA mass (6.1 μg m−3 and 4.2 μg m−3 in T0 and T1 respectively) is assumed to originate from biomass burning activities and is introduced to the model as part of the boundary conditions. Inside Mexico City (at T0), the locally-produced OA is predicted to be on average 60 % locally-emitted primary (POA), 6 % semi-volatile (S-SOA) and intermediate volatile (I-SOA) organic aerosol, and 34 % traditional SOA from the oxidation of VOCs (V-SOA). The average contributions of the OA components to the locally-produced OA for the entire modelling domain are predicted to be 32 % POA, 10 % S-SOA and I-SOA, and 58 % V-SOA. The long range transport from biomass burning activities and other sources in Mexico is predicted to contribute on average almost as much as the local sources during the MILAGRO period.
Retrievals of chlorine chemistry kinetic parameters from Antarctic ClO microwave radiometer measurements
Authors: Kremser S. , Schofield R. , Bodeker G. E. , Connor B. J. , Rex M. , Barret J. , Mooney T. , Salawitch R. J. , Canty T. , Frieler K. , Chipperfield M. P. , Langematz U. , Feng W.
Published: June 2011

Abstract. Key kinetic parameters governing the partitioning of chlorine species in the Antarctic polar stratosphere were retrieved from 28 days of chlorine monoxide (ClO) microwave radiometer measurements made during the late winter/early spring of 2005 at Scott Base (77.85° S, 166.75° E). During day-time the loss of the ClO dimer chlorine peroxide (ClOOCl) occurs mainly by photolysis. Some time after sunrise, a photochemical equilibrium is established and the ClO/ClOOCl partitioning is determined by the ratio of the photolysis frequency, J, and the dimer formation rate, kf. The values of J and kf from laboratory studies remain uncertain to a considerable extent, and as a complement to these ongoing studies, the goal of this work is to provide a constraint on that uncertainty based on observations of ClO profiles in the Antarctic. First an optimal estimation technique was used to derive J/kf ratios for a range of Keq values. The optimal estimation forward model was a photochemical box model that takes J, kf, and Keq as inputs, together with a priori profiles of activated chlorine (ClOx = ClO+2×ClOOCl), profiles of ozone, temperature, and pressure. JPL06 kinetics are used as a priori in the optimal estimation and for all other chemistry in the forward model. Using the more recent JPL09 kinetics results in insignificant differences in the retrieved value of J/kf. A complementary approach was used to derive the optimal kinetic parameters; the full parameter space of J, kf, Keq and ClOx was sampled to find the minimum in differences between measured and modelled ClO profiles. Furthermore, values of Keq up to 2.0 times larger than recommended by JPL06 were explored to test the sensitivity of the J/kf ratio to changes in Keq. The results show that the retrieved J/kf ratios bracket the range of 1.23 to 1.97 times the J/kf value recommended by JPL06 over the range of Keq values considered. The retrieved J/kf ratios lie in the lower half of the large uncertainty range of J/kf recommended by JPL06 and towards the upper portion of the smaller uncertainty range recommended by JPL09.
Characteristics of PM2.5 speciation in representative megacities and across China
Authors: Yang F. , Tan J. , Zhao Q. , Du Z. , He K. , Ma Y. , Duan F. , Chen G. , Zhao Q.
Published: June 2011

Abstract. Based on PM2.5 chemical data sets from literature and from our surface observations, chemical species and reconstructed speciation of PM2.5 in representative Chinese megacities and across China were compared to draw insights into the characteristics of PM2.5 speciation. PM2.5 mass concentrations and speciation compositions varied substantially over geographical regions in China. Near six-fold variations in average PM2.5 concentrations (34.0–193.4 μg m−3) across China were found with high PM2.5 levels (>100 μg m−3) appearing in the cities in the northern and western regions and low levels (<40 μg m−3) in the remote forest area (Changbai Mountain) and in Hong Kong. The percentages of the sum of sulfate, nitrate and ammonium, organic matter, crustal material, and elemental carbon in PM2.5 mass ranged 7.1–57 %, 17.7–53 %, 7.1–43 %, and 1.3–12.8 %, respectively. At both urban and rural sites in the eastern region, the sum of sulfate, nitrate and ammonia typically constituted much higher fractions (40–57 %) of PM2.5 mass, indicative of more local formation/production and regional transport of the secondary aerosols, thus more intensive characteristic of "complex atmospheric pollution" compared to the western region. Organic matter had significant contribution to PM2.5 over all the sites. Organic matter plus sulfate, nitrate, and ammonia accounted for 53–90 % of PM2.5 mass across China. PM2.5 speciation across China was also characterized by high content of crustal material, which was usually at more than ~10 μg m−3 level or shared ~10 % of PM2.5 mass in urban areas, due to transported desert dust and locally induced dust. In four representative megacities (i.e. Beijing, Chongqing, Shanghai, and Guangzhou), PM2.5 mass and major components (except sulfate) were at higher levels than those in US continental east by one order of magnitude. Distinct differences in nitrate and sulfate levels and their mass ratio [NO3−]/[SO42−] imply that mobile sources are likely more important in Guangzhou, whereas in Chongqing it is stationary (coal combustion) sources. The observed intra-city variations in PM2.5 mass and speciation indicate that both local emissions and regional transportation contributed significantly to high fine particle loadings in Beijing, while local contribution likely played a predominant role in Chongqing. During the ten-year period from 1999 through 2008 in urban Beijing, both the sum of sulfate, nitrate, and ammonia and [NO3−]/[SO42−] ratio exhibited steadily increasing trends, implying that the characteristic of "complex atmospheric pollution" and the contribution from mobile sources were being enhanced.
Parameterisation and impact of aerosol uptake of HO2 on a global tropospheric model
Authors: Macintyre H. L. , Evans M. J.
Published: June 2011

Abstract. HO2 is an important atmospheric trace gas, whose sink to aerosol is poorly understood yet significant. Previous parameterisations of the rate of uptake have been limited by the lack of laboratory studies. This paper creates a parameterisation for γHO2 based on the available laboratory studies. The calculated global mean γHO2 is 0.028, significantly lower than previous work (0.2). Modelled concentrations of HO2 show significant regional sensitivity to the value of γHO2 (up to +106 % at the surface with the parameterisation of γHO2 in this work as compared with a value of 0.2), but global sensitivity is small (+3.2 %). The modelled response in O3 is also highly regional, being up to +27 % at the surface over China, and only +0.3 % globally (with the parameterisation of γHO2 in this work as compared with a value of 0.2). The impact of γHO2 on sulfate is more complex, with up to +16 % over China and −5 % over high latitudes, resulting in a global change of +1.2 % (with the parameterisation of γHO2 in this work as compared with a value of 0.2). Uncertainty in the reaction mechanism and hence products (previously assumed to be H2O2) impacts the processing of sulfur and hence aerosol loads. Further laboratory studies are desirable to constrain the rate of reaction and to elucidate the reaction mechanism and products.
ARIS-Campaign: intercomparison of three ground based 22 GHz radiometers for middle atmospheric water vapor at the Zugspitze in winter 2009
Authors: Straub C. , Murk A. , Kämpfer N. , Golchert S. H. W. , Hochschild G. , Hallgren K. , Hartogh P.
Published: June 2011

Abstract. This paper presents the Alpine Radiometer Intercomparison at the Schneefernerhaus (ARIS), which took place in winter 2009 at the high altitude station at the Zugspitze, Germany (47.42° N, 10.98° E, 2650 m). This campaign was the first direct intercomparison between three new ground based 22 GHz water vapor radiometers for middle atmospheric profiling with the following instruments participating: MIRA 5 (Karlsruhe Institute of Technology), cWASPAM3 (Max Planck Institute for Solar System Research, Katlenburg-Lindau) and MIAWARA-C (Institute of Applied Physics, University of Bern). Even though the three radiometers all measure middle atmospheric water vapor using the same rotational transition line and similar fundamental set-ups, there are major differences between the front-ends, the backends, the calibration concepts and the profile retrieval. The spectrum comparison shows that all three radiometers measure spectra without severe baseline artifacts and that the measurements are in good general agreement. The measurement noise shows good agreement to the values theoretically expected from the radiometer noise formula. At the same time the comparison of the noise levels shows that there is room for instrumental and calibration improvement, emphasizing the importance of low elevation angles for the observation, a low receiver noise temperature and an efficient calibration scheme. The comparisons of the retrieved profiles show that the agreement between the profiles of MIAWARA-C and cWASPAM3 with the ones of MLS is better than 0.3 ppmv at all altitudes. MIRA 5 has a dry bias of approximately 0.5 ppm below 0.1 hPa with respect to all other instruments. The profiles of cWASPAM3 and MIAWARA-C could not be directly compared because the vertical region of overlap was too small. The comparison of the time series at different altitude levels show a similar evolution of the H2O volume mixing ratio (VMR) for the ground based instruments as well as the space borne sensor MLS.
Progress in turbulence detection via GNSS occultation data
Authors: Cornman L. B. , Goodrich R. K. , Axelrad P. , Barlow E.
Published: June 2011

Abstract. The increased availability of radio occultation (RO) data offers the ability to detect and study turbulence in the Earth's atmosphere. An analysis of how RO data can be used to determine the strength and location of turbulent regions is presented. This includes the derivation of a model for the power spectrum of the log-amplitude and phase fluctuations of the permittivity (or index of refraction) field. The bulk of the paper is then concerned with the estimation of the model parameters. Parameter estimators are introduced and some of their statistical properties are studied. These estimators are then applied to simulated log-amplitude RO signals. This includes the analysis of global statistics derived from a large number of realizations, as well as case studies that illustrate various specific aspects of the problem. Improvements to the basic estimation methods are discussed, and their beneficial properties are illustrated. The estimation techniques are then applied to real occultation data. Only two cases are presented, but they illustrate some of the salient features inherent in real data.
An aircraft based three channel broadband cavity enhanced absorption spectrometer for simultaneous measurements of NO3, N2O5 and NO2
Authors: Kennedy O. J. , Ouyang B. , Langridge J. M. , Daniels M. J. S. , Bauguitte S. , Freshwater R. , McLeod M. W. , Ironmonger C. , Sendall J. , Norris O. , Nightingale R. , Ball S. M. , Jones R. L.
Published: June 2011

Abstract. A three channel broadband cavity enhanced absorption spectroscopy (BBCEAS) instrument has been developed for airborne measurements of atmospheric trace gases involved in night-time oxidation chemistry and air quality. The instrument was deployed on board the Facility for Airborne Atmospheric Measurements BAe 146-301 atmospheric research aircraft during the Role of Nighttime Chemistry in Controlling the Oxidising Capacity of the Atmosphere (RONOCO) measurement campaigns between December 2009 and January 2011. In its present configuration (i.e. specifications of the cavity optics and spectrometers) the instrument is designed to measure NO3, N2O5 (by detection of NO3 after thermal dissociation of N2O5), H2O and NO2 by characterising the wavelength dependent optical attenuation within ambient samples by molecular absorption around 662 nm (NO3 and H2O) and 445 nm (NO2). This paper reports novel advancements in BBCEAS instrumentation including a refined method for performing BBCEAS mirror reflectivity calibrations using measurements of the phase delay introduced by the optical cavities to amplitude modulated radiation. Furthermore, a new methodology is introduced for fitting the strong but unresolved transitions of water vapour, which is required for accurate retrieval of water absorption features from the 662 nm absorption band used to measure NO3 concentrations. The paper also details the first example of airborne measurements of NO3, N2O5 and NO2 over Europe from a flight over the North Sea and Thames Estuary on the night of the 20 July 2010, one of the most polluted days of the RONOCO summertime flying period. As part of this analysis, the performance of the BBCEAS instrument is assessed by comparing airborne NO2 measurements to those reported concurrently by a photolytic chemiluminescence based detector.