Discontinuous resistance change and domain wall scattering in patterned NiFe wires with a nanoconstriction

A nonlinear current-voltage (I-V) characteristic was observed in patterned NiFe wires with a central "bow-tie" point contact constriction. By passing a dc current through the wire, a sharp resistance drop was obtained for current densities in the range of 1.1-1.4 x 10(7) A/cm(2). This is attributed to current-induced domain wall drag, resulting in displacement of a domain wall away from the constriction. A maximum current-induced resistance change of 0.079% was obtained for a 100-nm constriction, which is comparable with the magnetoresistance due to domain wall scattering in NiFe

Solving the electrical control of magnetic coercive field paradox

The ability to tune magnetic properties of solids via electric voltages instead of external magnetic fields is a physics curiosity of great scientific and technological importance. Today, there is strong published experimental evidence of electrical control of magnetic coercive fields in composite multiferroic solids. Unfortunately, the literature indicates highly contradictory results. In some studies, an applied voltage increases the magnetic coercive field and in other studies the applied voltage decreases the coercive field of composite multiferroics. Here, we provide an elegant explanation to this paradox and we demonstrate why all reported results are in fact correct. It is shown that for a given polarity of the applied voltage, the magnetic coercive field depends on the sign of two tensor components of the multiferroic solid: magnetostrictive and piezoelectric coefficient. For a negative applied voltage, the magnetic coercive field decreases when the two material parameters have the same sign and increases when they have opposite signs, respectively. The effect of the material parameters is reversed when the same multiferroic solid is subjected to a positive applied voltage

Quantum-Information Theoretic Properties of Nuclei and Trapped Bose Gases

Fermionic (atomic nuclei) and bosonic (correlated atoms in a trap) systems are studied from an information-theoretic point of view. Shannon and Onicescu information measures are calculated for the above systems comparing correlated and uncorrelated cases as functions of the strength of short range correlations. One-body and two-body density and momentum distributions are employed. Thus the effect of short-range correlations on the information content is evaluated. The magnitude of distinguishability of the correlated and uncorrelated densities is also discussed employing suitable measures of distance of states i.e. the well known Kullback-Leibler relative entropy and the recently proposed Jensen-Shannon divergence entropy. It is seen that the same information-theoretic properties hold for quantum many-body systems obeying different statistics (fermions and bosons).Comment: 24 pages, 9 figures, 1 tabl

Problems in diagnosis and surgical treatment of the retroperitoneal non-pancreatogenic phlegmons

Catedra de Chirurgie, FEC MF, Universitatea de Stat de Medicină și Farmacie ”N. Testemițanu”, Chișinău, Moldova, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Supurațiile ale spațiului retroperitoneal sunt o problemă medico-chirurgicală neobișnuită cu un tablou clinic vag, care prezintă o provocare în aprecierea diagnosticului. Debutul insidios și evoluție ocultă ale acestei patologii sunt urmate de un diagnostic întârziat și drenaj neadecvat, astfel pentru flegmon retroperitoneal sunt caracteristice morbiditatea și mortalitatea considerabile. Anterior au fost publicate studii privind detaliile anatomice ale spațiilor extraperitoneale, dar mai puțina atenție a fost acordată metodelor de diagnostic și tehnicilor chirurgicale de drenaj. Prezentăm o trecere în revistă a 15 de cazuri de inflamații suruprative retroperitoneale nonpancreatogene care s-au manifestat ca entitate clinică principală. În aspect etiologic pacienții s-au repartizat în 5 grupe: psoitele purulente – 4, abcesele retroperitoneale apendiculare - 4, perinefritele purulente - 3, colecții retroperitoneale în urma osteolizei - 3 (ostemielita hematogenă, postraumatică, tuberculoza osoasă), hematom postraumatic retroperitoneal infectat – 1 caz. Trei pacienți (16,7 %) au decedat în perioada postoperatorie precoce. Complicații au survenit la 40 % pacienți. Letalitatea și rata înaltă de complicații au fost asociate cu perioada îndelungată de la debut până la diagnostic pozitiv (> 5 zile) și cu hemocultura pozitivă. Există o corelație între tipuri de complicații și sursa de infecție retroperitoneală. Computer tomografia este metoda cea mai informativă în diagnosticul supurațiilor abdominale extraperitoneale. În cazuri selecte drenajul ecoghidat poate fi folosit ca un gest chirurgical inițial. Descriem tehnica operatorie în dependență de topografia procesului purulent retroperitoneal. Este propus un plan de diagnostic și tratament pentru fiecare grup etiologic.Retroperitoneal space inflammation is an unusual surgical problem with vague clinical presentation, which presents a diagnostic challenge. An insidious onset and occult evolution of illness marked by diagnostic delay, inadequate drainage, and considerable morbidity and mortality is common. Papers regarding anatomic detailing of the extraperitoneal spaces have been published, but less attention has been focused on diagnostic and drainage techniques.We report an analysis of 15 cases of retroperitoneal suppurations which acted as main clinical manifestation. According to etiology of inflammation patients were distributed into 5 groups: psoas abscesses – 4 cases, retroperitoneal appendical abscesses – 4 cases, purulent perinephritis -3, retroperitoneal collections caused by osteolysis – 3 patients (hematogenic, posttraumatic or tuberculous) and one case of infected posttraumatic hematoma.Three patients (16,7 %) died in the early postoperative period. Rate of complications was 40 %. High lethality and postoperative morbidity were associated with positive blood cultures and delayed diagnosis (> 5 days). There is a correlation between the type of complications and etiology of the retroperitoneal phlegmon. Computed tomography is the most informative diagnostic method for the extraperitoneal purulent collections. Echoguided drainage in selected cases appears to be a useful initial approach. The operative technique dependent on the retroperitoneal purulent collection topography is described. A diagnostic and treatment plan is proposed for each etiologic group

Intraperitoneal single-layer and double-layer polypropylene mesh integrated in rectus abdominis sheath in repair of large and recurrent incisional hernias

Chirurgie generală, Spitalul Clinic Republican, Chișinău, Moldova, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introducere. În tratamentul chirurgical al eventrațiilor postoperatorii mari și recidivante au fost aplicate diferite tehnici de plastii cu utilizarea materialelor sintetice, care au scopul de a reduce substanțial rată de recidive. Prezentăm o tehnică nouă de plastie cu plasă din polipropilen.Materiale şi metode. Panglicile 3-4 cm lungime sunt croite din marginile plasei. Omentul se fixează la distanța de marginea defectului de foița peritoneală parietală acoperind viscerele. Plasa se poziționează intraperitoneal. În plastia într-un plan panglicele plasei se trec bont prin marginea laterală a muşchiului rect abdominal. În plastie în două planuri panglicile plasei din al doilea stat se trec bont la mijlocul mușchilor recți abdominali. Capetele exteriorizate ale plasei ancorează pe suprafața tecii anterioare a recților abdominali. Utilizând această metodică au fost operați 116 pacienți cu eventrații postoperatorii mari în perioada februarie 2005 şi aprilie 2010 (65 pacienți cu eventrații recidivante). Complicațiile intra- şi postoperatorii au fost întregistrate prospectiv şi analizate retrospectiv.Rezultate. Recidive de eventrații, complicații gastrointestinale, fistule intestinale sau decese nu au fost înregistrate în perioada de urmărire. Seroamele ale plăgilor postoperatorii au fost înregistrate la 12 (10,34 %) pacienți. Nici un pacient nu a avut supurația plăgii postoperatorii. Concluzii. Tehnica propusă prezintă o alternativă sigură şi realizabilă pentru pacienți cu eventrații mari şi recidivante. Această metodă exclude posibilitatea de migrare a plasei din locul de inserție, scade rata de recidive şi nu este asociată cu complicații serioase.Background. There are different techniques of incisional hernia repair using prosthetic materials, which have lowered the recurrence rate. We present a new method of incisional hernia surgery using polypropylene mesh. Methods and materials. Stripes 3-4 cm long are cut out at the margins of the polypropylene mesh. Then the mash is placed intraperitoneally upon the greater omentum, fixed thoroughly to the anterior abdominal wall. Prepared stripes are bluntly guided through the lateral margins of the rectus abdominis muscle and fasten to the anterior wall of the rectus abdominis sheath. In the double-layer variant strips from the second layer of the mesh are guided through the middle of the rectus abdominis. Using this technique we performed 116 open abdominal wall incisional hernia repairs between February 2005 and April 2010 (65 of them with recurrent hernia). Intra- and postoperative complications were registered prospectively and retrospectively analyzed. Results. There were no hernia recurrences during the follow-up period, gastrointestinal complications, fistulas, or deaths. Seromas occurred postoperatively in 5 patients (8,9%). None of the patients developed surgical site infections. Conclusions. The proposed technique is a safe and feasible alternative procedure in patients with large primary or recurrent incisional hernias. This method completely excludes the possibility of migration of the mesh from the place of insertion, reduces the rate of recurrence, and is not associated with serious complications

Gastroesophageal reflux disease with complicated evolution

SCR, Catedra Chirurgie FEC MF, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introducere. BRGE a devenit una din cele mai frecvente patologii ale tubului digestiv ale secolului XXI, care aproximativ în 80-90% dintre cazuri evoluează pe fundalul unei hernii hiatale şi constituie o problemă dintre cele mai actuale, înregistrând o frecvenţă de 5-10% la populaţia examinată. Material şi metode: Într-un termen de 15 ani în clinica chirurgie FEC MF au fost trataţi 357 pacienţi cu BRGE. La 123 (34,45%) pacienţi au fost depistate diferite complicaţii ale BRGE. Între cele mai frecvente au fost complicaţiile tractului digestiv: • Ulcere ale esofagului şi joncţiunii eso-gastrice • Stenoze • Esofag Barrett • Cancer esofagian şi joncţiunii esogastrice. Complicaţiile bronhopulmonare între complicaţiile extradigestive au fost cele mai frecvente fiind determinate de bronşită cronică obstructivă şi astmul bronşic. În această perioadă în clinică au fost implementate în practică schemele conceptuale de tratament ale BRGE ce vizează diferite faze de evoluţie ale BRGE. Concluzii. Depistarea precoce a BRGE precum şi antrenare pe scara largă a tratamentului multimodal al BRGE poate micşora considerabil rata complicaţiilor BRGE în general precum şi ameliorează considerabil rezultatele tratamentului medicochirurgical imediate şi la distanţă. Introduction. GERD has become one of the most common diseases of the digestive tract of the XXI century, which about 80-90% of cases develops on the basis of a hiatal hernia and is one of the most recent issue, recording a rate of 5-10% of the population examined. Material and methods: In the period of 15 years in the department of surgery CEM were treated 357 patients with GERD. Were detected various complications of GERD in 123 (34.45%) patients and among the most frequent were complications of digestive tract: • Ulcers of the esophagus and esophageal-gastric junction • Stenosis • Barrett’s Esophagus • Cancer of esophagus and esophageal-gastric junction. Broncho-pulmonary complications between extradigestive complications were the most frequent being caused by chronic obstructive bronchitis and bronchial asthma. During this period in clinical practice have been implemented in the treatment of GERD conceptual schemes aimed at different stages of evolution of GERD. Conclusions. Early detection of GERD as well as training on a large scale multimodal treatment of GERD can significantly decrease the overall rate of GERD complications and significantly improves the immediate and remote results, of conservative and surgical treatment.Introduction. GERD has become one of the most common diseases of the digestive tract of the XXI century, which about 80-90% of cases develop on the basis of a hiatal hernia and is one of the most recent issues, recording a rate of 5-10% of the population examined. Material and methods: In the period of 15 years in the department of surgery CEM were treated 357 patients with GERD. Were detected various complications of GERD in 123 (34.45%) patients and among the most frequent were complications of the digestive tract: • Ulcers of the esophagus and esophageal-gastric junction • Stenosis • Barrett’s Esophagus • Cancer of the esophagus and esophageal-gastric junction. Broncho-pulmonary complications between extra digestive complications were the most frequent being caused by chronic obstructive bronchitis and bronchial asthma. During this period in clinical practice have been implemented in the treatment of GERD conceptual schemes aimed at different stages of evolution of GERD. Conclusions. Early detection of GERD as well as training on a large-scale multimodal treatment of GERD can significantly decrease the overall rate of GERD complications and significantly improves the immediate and remote results, of conservative and surgical treatment

The principles of surgical treatment of giant hiatal hernias

Secția chirurgie generală, Spitalul Clinic Republican, Catedra chirurgie FECMF, USMF “Nicolae Testemițanu”, Chișinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Hernia hiatală (HH) esofagiană este o problemă actuală cu incidența globală înaltă, de aproximativ 5-10%. Conform clasificării anglo-americane (Shackelford, 1978) sunt patru tipuri de hernii hiatale. Literatura actuală face tot mai frecvent referire la HH tip IV – voluminoase sau gigante. Se consideră, că prezența în torace a cel puțin 1/3 din stomac definește termenul de HH voluminoasă. Tactica tratamentului chirurgical depinde de mărimea acestei hernii. Scopul: Determinarea criteriilor de încadrare a herniilor hiatale în noțiunea herniei gigante și elucidarea tacticii chirurgicale în funcție de volumul și tipul herniei hiatale. Material și metode: În Clinica noastră timp de 10 ani (2004-2014) au fost operați 42 de pacienți cu HH voluminoase, dintre care 35 de cazuri pe cale laparoscopică. Intervenția chirurgicală a inclus următoarele etape: disecția joncțiunii esogastrice, crurorafia combinată și fundoplicatura. Plasa sintetică a fost aplicată în 14 cazuri, 9 cazuri au fost rezolvate laparoscopic și 5 cazuri prin laparotomie. La toți pacienții operați s-au confirmat HH gigante subtotale cu diametrul hiatusului esofagian >5 cm, prezența în torace a cel puțin 1/3 din stomac. În 40 de cazuri evoluția postoperatorie a fost favorabilă și a decurs fără complicații, la 2 pacienți s-a constatat recidivă de HH. Concluzii: În HH voluminoase se recomandă aplicarea frenorafiei combinate pentru evitarea deformării traectului esofagian. Cura herniei hiatale cu plasă sintetică, efectuată laparoscopic, este metoda electivă în tratamentul HH mari cu deteriorarea pilierilor diafragmatici. În HH gigante cu diametrul hiatusului esofagian >5 cm utilizarea plasei sintetice este recomandată pentru evitarea recidivilor.Introduction: Hiatal hernia (HH) is a current problem with a high overall incidence of 5-10%. According to Anglo-American classification there are four types of hiatal hernias. Newer literature very often mentions type IV of HH – giant hernias. The presence of 1/3 stomach in the thorax is considered giant HH. Policy of surgical treatment depends on size of this hernia. Aim: Determination of criteria which reflects notion of giant HH and elucidation of surgical tactics depending on the volume and type of HH. Material and methods: In the period of 10 years (2004-2014) in our department were operated 42 patients with giant HH, 35 of them by laparoscopic way. Surgical intervention included following steps: gastro-esophageal junction dissection, combined cruroraphy and fundoplication. Synthetic mesh was used in 14 cases, 9 cases of which were solved by laparoscopic way and 5 cases by laparotomy. In all operated cases were confirmed giant HH with diameter of esophageal hiatus >5 cm and presence of 1/3 stomach in the thorax. Postoperative period was favorable without complications in 40 cases; recurrence of HH was detected in 2 patients. Conclusions: Combined cruroraphy is recommended in giant HH to avoid deformation of esophagus path. Cure of HH with synthetic mesh, performed by laparoscopic way, is the elective method in the treatment of giant HH with diaphragmatic pillars damage. The use of synthetic mesh in giant HH with diameter of esophageal hiatus >5 cm is advisable to avoid the recurrence of them

Simultaneous dynamic electrical and structural measurements of functional materials

A new materials characterization system developed at the XMaS beamline, located at the European Synchrotron Radiation Facility in France, is presented. We show that this new capability allows to measure the atomic structural evolution (crystallography) of piezoelectric materials whilst simultaneously measuring the overall strain characteristics and electrical response to dynamically (ac) applied external stimuli

Dielectric constants of bulk ferroelectric PZTmeasured by terahertz time-domain spectroscopy

The complex permittivity of bulk ceramic ferroelectric of nominal composition PbZr0.4Ti0.6O3 was measured in the range 0.2–2 THz using transmission time-domain spectroscopy. The results indicate strong absorption and dispersion in this frequency range as often seen in highly disordered and polar materials. The results are compared to equivalent thin film data in the literature, and significant differences in the real and imaginary permittivity suggest that substrate clamping and degree of polarisation of the ferroelectric thin film materials affect dielectric properties even at these high frequencies

Unified treatment of spin torques using a coupled magnetisation dynamics and three-dimensional spin current solver

A three-dimensional spin current solver based on a generalised spin drift-diffusion description, including the bulk and interfacial spin Hall effects, is integrated with a magnetisation dynamics solver. The resulting model is shown to simultaneously reproduce the spin-orbit torques generated using the spin Hall effect, spin pumping torques generated by magnetisation dynamics in multilayers, as well as the spin transfer torques acting on magnetisation regions with spatial gradients, whilst field-like and spin-like torques are reproduced in a spin valve geometry. Two approaches to modelling interfaces are analysed, one based on the spin mixing conductance and the other based on continuity of spin currents where the spin dephasing length governs the absorption of transverse spin components. In both cases analytical formulas are derived for the spin-orbit torques in a heavy metal / ferromagnet bilayer geometry, showing in general both field-like and damping-like torques are generated. The limitations of the analytical approach are discussed, showing that even in a simple bilayer geometry, due to the non-uniformity of the spin currents, a full three-dimensional treatment is required. The model is further applied to the analysis of the spin Hall angle in Pt by reproducing published experimental ferromagnetic resonance data in the bilayer geometry