Model for curvature-driven pearling instability in membranes

A phase-field model for dealing with dynamic instabilities in membranes is presented. We use it to study curvature-driven pearling instability in vesicles induced by the anchorage of amphiphilic polymers on the membrane. Within this model, we obtain the morphological changes reported in recent experiments. The formation of a homogeneous pearled structure is achieved by consequent pearling of an initial cylindrical tube from the tip. For high enough concentration of anchors, we show theoretically that the homogeneous pearled shape is energetically less favorable than an inhomogeneous one, with a large sphere connected to an array of smaller spheres.

Nonrelativistic bound states at finite temperature. II. Muonic hydrogen

We illustrate how to apply modern effective field-theory techniques and dimensional regularization to factorize the various scales, which appear in QED bound states at finite temperature. We focus here on the muonic hydrogen atom. Vacuum polarization effects make the physics of this atom at finite temperature very close to that of heavy quarkonium states. We comment on the implications of our results for these states in the quark gluon plasma. In particular, we estimate the effects of a finite-charm quark mass in the dissociation temperature of bottomonium.

Failure of surgical treatment in 115 infected total hip arthroplasties - analysis of a 12-year prosthetic joint cohort study (1999-2010)

Infection of total hip arthroplasties (THA) leads to significant long-termmorbidity and high healthcare costs. We evaluated the differentreasons for treatment failure using different surgical modalities in a12-year prosthetic joint infection cohort study.Method: All patients hospitalized at our institution with infected THAwere included either retrospectively (1999-2007) or prospectively(2008-2010). THA infection was defined as growth of the same microorganismin ≥2 tissue or synovial fluid culture, visible purulence, sinustract or acute inflammation on tissue histopathology. Outcome analysiswas performed at outpatient visits, followed by contacting patients,their relatives and/or treating physicians afterwards.Results: During the study period, 117 patients with THA were identified.We exclude 2 patients due to missing data. The median age was69 years (range, 33-102 years); 42% were women. THA was mainlyperformed for osteoarthritis (n = 84), followed by trauma (n = 22),necrosis (n = 4), dysplasia (n = 2), rheumatoid arthritis (n = 1), osteosarcoma(n = 1) and tuberculosis (n = 1). 28 infections occurred early(≤3 months), 25 delayed (3-24 months) and 63 late (≥24 months aftersurgery). Infected THA were treated with (i) two-stage exchange in59 patients (51%, cure rate: 93%), (ii) one-stage exchange in 5 (4.3%,cure rate: 100%), (iii) debridement with change of mobile parts in18 (17%, cure rate: 83%), (iv) debridement without change of mobileparts in 17 (14%, cure rate: 53% ), (v) Girdlestone in 13 (11%, curerate: 100%), and (vi) two-stage exchange followed by removal in 3(2.6%). Patients were followed for a mean of 3.9 years (range, 0.1 to 9years), 7 patients died unrelated to the infected THA. 15 patients (13%)needed additional operations, 1 for mechanical reasons (dislocationof spacer) and 14 for persistent infection: 11 treated with debridementand retention (8 without change and 3 with change of mobile parts)and 3 with two-stage exchange. The mean number of surgery was 2.2(range, 1 to 5). The infection was finally eradicated in all patients, butthe functional outcome remained unsatisfactory in 20% (persistentpain or impaired mobility due to spacer or Girdlestone situation).Conclusions: Non-respect of current treatment concept leads totreatment failure with subsequent operations. Precise analysis of eachtreatment failures can be used for improving the treatment algorithmleading to better results.

Carbono orgânico total, biomassa microbiana e atividade enzimática do solo de áreas agrícolas, florestais e pastagem no médio Vale do Paraíba do Sul (RJ)

Características do solo, como o carbono orgânico total (COT), a biomassa microbiana e a atividade enzimática, são influenciadas por diversos fatores e têm sido apontadas como indicadores adequados de alterações provocadas por diferentes sistemas de uso e manejo do solo. O objetivo deste trabalho foi avaliar o COT, a biomassa microbiana e a atividade enzimática de um Cambissolo Háplico Tb distrófico típico de áreas agrícolas, florestais e de pastagem, no Médio Vale do Paraíba do Sul (RJ). Os sistemas avaliados foram: agricultura anual (AgAn); agricultura perene (AgP); pasto; floresta secundária em estádio inicial de sucessão (FSEI); floresta secundária em estádio médio de sucessão (FSEM); e floresta secundária em estádio avançado de sucessão (FSEA). Foram coletadas amostras de terra na camada de 0-5 cm, em duas épocas distintas (úmida e seca), e analisados o COT e as propriedades biológicas: C da biomassa microbiana - CBM; N da biomassa microbiana - NBM; respiração basal - RB; quociente metabólico - qCO2; quociente microbiano - qMIC; e atividade das enzimas arilsulfatase, β-glicosidase e fosfatase ácida. As áreas agrícolas apresentaram redução no COT e nas propriedades biológicas (atividade enzimática e carbono e nitrogênio da biomassa microbiana) do solo quando comparadas ao pasto e às áreas florestais. Com as análises de componentes principais, foi possível separar os sistemas agrícolas e os sistemas florestais e de pasto. Observou-se que, em ambas as épocas, a FSEM e o pasto estiveram associados ao COT e à maioria das variáveis biológicas, ao contrário dos sistemas agrícolas.

n=1/4 domain-growth universality class: Crossover to the n=1/2 class

The kinetic domain-growth exponent is studied by Monte Carlo simulation as a function of temperature for a nonconserved order-parameter model. In the limit of zero temperature, the model belongs to the n=(1/4 slow-growth unversality class. This is indicative of a temporal pinning in the domain-boundary network of mixed-, zero-, and finite-curvature boundaries. At finite temperature the growth kinetics is found to cross over to the Allen-Cahn exponent n=(1/2. We obtain that the pinning time of the zero-curvature boundary decreases rapidly with increasing temperature.

Yields, plant characteristics, total N and fibre composition of timothy cultivars grown at two latitudes

Selostus: Timoteilajikkeiden sadot, kasvuominaisuudet sekä typpi- ja kuitupitoisuus kahdella leveysasteella

Patient-perceived health-related quality of life during recovery after total hip arthroplasty – a 6-month follow-up study

Potilaiden käsitys terveyteen liittyvästä elämänlaadusta lonkan tekonivelleikkauksen jälkeisenä toipumisaikana – kuuden kuukauden seurantatutkimus Tässä kaksivaiheisessa seurantatutkimuksessa tarkasteltiin potilaiden käsitystä terveyteen liittyvästä elämänlaadusta lonkan tekonivelleikkauksen jälkeisenä toipumisaikana. Tutkimuksen ensimmäisessä vaiheessa tarkoituksena oli sekä kuvailla potilaiden kokemuksia potilaana olosta, saamastaan hoidosta ja terveyspalveluorganisaatiosta että analysoida aikaisempien tutkimusten perusteella leikkauksen tuloksia potilaan kannalta. Toisessa vaiheessa tarkoituksena oli arvioida potilaiden kokemaa elämänlaatua leikkauksen jälkeen, ja sitä vaikuttivatko primaaritulokset (fyysinen toimintakyky, kipu, ahdistus) tai taloudelliset seuraukset (potilaiden itsensämaksamat kustannukset, palvelujen käyttö) terveyteen liittyvään elämänlaatuun. Tutkimuksen tavoitteena oli löytää mahdolliset kriittiset ajankohdat tai tekijät, jotka saattavat hidastaa toipumista ja siten huonontaa potilaiden elämänlaatua. Tätä tietoa voidaan käyttää hoitotyössä kun suunnitellaan sopivaa hoitoa ja tukea toipumisajalle. Tutkimuksen ensimmäisessä vaiheessa primaarileikkaukseen tulevat potilaat (n = 17) kuvailivat teemahaastatteluissa kokemuksiaan kahdesti leikkauksen jälkeen. Haastatteluaineisto analysoitiin induktiivisella sisällönanalyysilla. Lisäksi 17 tutkimusartikkelista analysoitiin deduktiivisella sisällönanalyysilla leikkauksen tuloksia potilaalle, tuloksiin vaikuttavia tekijöitä ja käytetyt tutkimusmetodit. Toisessa vaiheessa primaari- tai revisioleikkaukseen tulevat potilaat (n = 100) arvioivat leikkauksen tuloksia kuuden kuukauden ajan leikkauksen jälkeen: terveyteen liittyvää elämänlaatua, primaarituloksia ja taloudellisia seurauksia. Aineisto kerättiin erilaisilla mittareilla: Sickness Impact Profile, Finnish Version, Stait-Trait Anxiety Inventory, ja Numeric Rating Scale. Lisäksi käytettiin tätä tutkimusta varten tehtyjä kyselylomakkeita: Fyysinen toimintakyky-mittari, Palvelujen käyttö-mittari ja Kustannusmittari. Tutkimuksen toiseen vaiheen tulokset analysoitiin tilastollisilla menetelmillä. Potilaiden terveyteen liittyvä elämänlaatu parani ja kipu lievittyi leikkauksen jälkeen ja fyysinen toimintakyky lisääntyi toipumisaikana. Positiivisista muutoksista huolimatta potilaat kokivat ahdistusta samassa määrin kuin ennen leikkaustakin. Palvelujen käyttö vaihteli toipumisajan kuluessa ja potilaiden maksamissa kustannuksissa oli suuria vaihteluita. Fyysisen toimintakyvyn lisääntyminen ja kivun lieveneminen paransivat terveyteen liittyvää elämänlaatua. Sen sijaan huonompi elämänlaatu toipumisaikana oli yhteydessä suurempaan palvelujen käyttöön, kun taas kustannuksilla ei ollut yhteyttä elämänlaatuun. Potilaiden ominaispiirteet tulisi ottaa enemmän huomioon suunniteltaessa sopivaa leikkauksenjälkeistä hoitoa ja tukea. Potilaat tarvitsevat yksilöllisiä ohjeita, sillä monet taustatekijät (esim. ikä, sukupuoli, preoperatiivinen kipu, siviilisääty, ja leikkaustyyppi) vaikuttavat toipumiseen.

Variação diurno-noturna do potencial mátrico e gradiente de potencial total da água no solo

O potencial mátrico em solos não saturados é um importante componente do potencial total e, portanto, deve ser medido da melhor forma possível. Este trabalho teve por objetivo avaliar a influência da temperatura do solo sobre o potencial mátrico e o gradiente de potencial total, durante a redistribuição da água num Latossolo Vermelho-Amarelo, em Piracicaba, SP, a partir de dados coletados por tensiometria. Em uma parcela circular de 3 m de diâmetro, foram instalados 10 tensiômetros com transdutor de tensão, modelo SWT3 da Delta-T, nas profundidades de 0,10; 0,15; 0,20; 0,25; 0,30; 0,35; 0,40; 0,45; 0,50; e 0,55 m, com os quais foram obtidos os potenciais mátricos para essas profundidades e o gradiente de potencial total, (ΔΦm/Δz)+1, para a profundidade de 0,25 m, com Δz de 0,1; 0,2; e 0,3 m, utilizando os tensiômetros instalados nas profundidades de 0,20 e 0,30; 0,15 e 0,35; e 0,10 e 0,40 m para ΔΦm, respectivamente. Na mesma parcela, foram também instalados termopares tipo T na superfície e nas profundidades 0,025; 0,050; e 0,075 m de solo. Ambas as leituras dos tensiômetros e termopares foram armazenadas em um Datalogger, Modelo DL2, da Delta-T, a idênticos intervalos de tempo. As avaliações detectaram oscilações na leitura do potencial mátrico da água no solo ao longo do dia e nos efeitos diferenciados nos tensiômetros instalados em profundidades diferentes, ocasionando oscilações também no gradiente de potencial total da água no solo. Os melhores horários para a realização das leituras dos tensiômetros são nas primeiras sete horas do dia ou após às 18 h.

Accurate and efficient simulation of multiphase flow in a heterogeneous reservoir by using error estimate and control in the multiscale finite-volume framework

The multiscale finite-volume (MSFV) method is designed to reduce the computational cost of elliptic and parabolic problems with highly heterogeneous anisotropic coefficients. The reduction is achieved by splitting the original global problem into a set of local problems (with approximate local boundary conditions) coupled by a coarse global problem. It has been shown recently that the numerical errors in MSFV results can be reduced systematically with an iterative procedure that provides a conservative velocity field after any iteration step. The iterative MSFV (i-MSFV) method can be obtained with an improved (smoothed) multiscale solution to enhance the localization conditions, with a Krylov subspace method [e.g., the generalized-minimal-residual (GMRES) algorithm] preconditioned by the MSFV system, or with a combination of both. In a multiphase-flow system, a balance between accuracy and computational efficiency should be achieved by finding a minimum number of i-MSFV iterations (on pressure), which is necessary to achieve the desired accuracy in the saturation solution. In this work, we extend the i-MSFV method to sequential implicit simulation of time-dependent problems. To control the error of the coupled saturation/pressure system, we analyze the transport error caused by an approximate velocity field. We then propose an error-control strategy on the basis of the residual of the pressure equation. At the beginning of simulation, the pressure solution is iterated until a specified accuracy is achieved. To minimize the number of iterations in a multiphase-flow problem, the solution at the previous timestep is used to improve the localization assumption at the current timestep. Additional iterations are used only when the residual becomes larger than a specified threshold value. Numerical results show that only a few iterations on average are necessary to improve the MSFV results significantly, even for very challenging problems. Therefore, the proposed adaptive strategy yields efficient and accurate simulation of multiphase flow in heterogeneous porous media.

Einfluss von L-Carnitin-supplementierter total parenteraler Ernährung (TPE) auf die postoperative Fett- und Stickstoff-Utilisation [Effect of L-carnitine supplemented total parenteral nutrition on postoperative lipid and nitrogen utilization].

During episodes of trauma carnitine-free total parenteral nutrition (TPN) may result in a reduction of the total body carnitine pool, leading to a diminished rate of fat oxidation. Sixteen patients undergoing esophagectomy were equally and randomly divided and received isonitrogenous (0.2 gN/kg.day) and isocaloric (35 kcal/kg.day TPN over 11 days without and with L-carnitine supplementation (12 mg/kg.day). Compared with healthy controls, the total body carnitine pool was significantly reduced in both groups prior to the operation. Without supplementation carnitine concentrations were maintained, while daily provision of carnitine resulted in an elevation of total carnitine mainly due to an increase of the free fraction. Without supplementation the cumulative urinary carnitine losses were 11.5 +/- 6.3 mmol corresponding to 15.5% +/- 8.5% of the estimated total body carnitine pool. Patients receiving carnitine revealed a positive carnitine balance in the immediate postoperative phase, 11.1% +/- 19.0% of the infused carnitine being retained. After 11 days of treatment comparable values for respiratory quotient, plasma triglycerides, free fatty acids, ketone bodies, and cumulative nitrogen balance were observed. It is concluded that in the patient population studied here carnitine supplementation during postoperative TPN did not improve fat oxidation or nitrogen balance.

Vacuum decay in quantum field theory

We study the contribution to vacuum decay in field theory due to the interaction between the long- and short-wavelength modes of the field. The field model considered consists of a scalar field of mass M with a cubic term in the potential. The dynamics of the long-wavelength modes becomes diffusive in this interaction. The diffusive behavior is described by the reduced Wigner function that characterizes the state of the long-wavelength modes. This function is obtained from the whole Wigner function by integration of the degrees of freedom of the short-wavelength modes. The dynamical equation for the reduced Wigner function becomes a kind of Fokker-Planck equation which is solved with suitable boundary conditions enforcing an initial metastable vacuum state trapped in the potential well. As a result a finite activation rate is found, even at zero temperature, for the formation of true vacuum bubbles of size M-1. This effect makes a substantial contribution to the total decay rate.