Syntheses and magnetic properties of substituted bis-indacenyl bi-metallic complexes & application / Síntesis y propiedades magnéticas de complejos bimetálicos de bis-indacenilo sustituido y su aplicación / Sínteses e propriedades magnéticas de complexos bimetálicos bis-indaceníli-cossubstituídos e aplicação

Abstract Organometallic compounds, Bis (2,4,6,8 teramethyl-indacenyl) di Iron (1), Bis (2,4,6,8 teramethyl s-indacenyl) mono iron, mono cobalt (2), and Bis (2,6 diethyl-4,8-dimethyl-s-indacenyl) di cobalt (3) were synthesised by means of salt elimination strategy, using Fe(II) and Co(II) salts. The compounds were characterised through spectroscopic and electrochemical methods. Magnetic measurements were carried out by Physical Property Measurement System (PPMS). Mossbauer spectroscopic data reveals that in all compounds, surprisingly, Iron is in +3 oxidation state. DFT calculations have been carried out to understand the change in the oxidation state of a metal. DFT study confirms the electron transfer nature of ligand to metal. Cyclic voltametric study on these compounds shows a large separation (ΔE>800mV) between two oxidation peaks confirming the strong interaction between the metal centres. Magnetic measurements on these organometallic compounds reveals that they exhibit a ferrimagnetic behaviour at temperatures below 40 K.

Resumen En este trabajo se sintetizaron los compuestos organometálicos Bis (2,4,6,8 terametil-indacenil) férrico (1), Bis (2,4,6,8 terametil s-indacenil) ferroso, cobaltoso (2) y Bis (2,6 dietil-4,8-dimetil-s-indacenil) di cobalto (3) mediante la estrategia de eliminación de sales, utilizando sales de Fe(II) y Co(II).Los compuestos se caracterizan por métodos espectroscópicos y electroquímicos. Las mediciones magnéticas se llevaron a cabo mediante el sistema de medición de propiedades físicas (PPMS). Los datos espectroscópicos Mossbauer revelan que, en todos los compuestos, sorprendentemente, el hierro se encuentra en el estado de oxidación +3. También se realizaron cálculos DFT para comprender el cambio en el estado de oxidación de los metales. El estudio DFT confirmó la naturaleza de transferencia de electrones del ligando al metal. El estudio voltamperométrico cíclico de estos compuestos muestra una gran separación (ΔE>800mV) entre los dos picos de oxidación que confirman la fuerte interacción entre los centros metálicos. Las mediciones magnéticas de estos compuestos organometálicos revelan que presentan un comportamiento ferrimagnético a temperaturas inferiores a 40 K.

Resumo Compostos organometálicos, Bis (2,4,6,8 terametil-indacenil) di ferro (1), Bis (2,4,6,8 terametil s-indacenil) mono ferro, mono cobalto (2) e Bis (2,6 dietil-4,8-dimetil-s-indacenil) di cobalto (3) foram sintetizados por estratégia de eliminação de sal, utilizando sais de Fe(II) e Co(II). Os compostossão caracterizados por métodos espectroscópicos e eletroquímicos. As medições magnéticas foram realizadas pelo Sistema de Medição de Propriedades Físicas (PPMS). Os dados espectroscópicos Mossbauerrevelam que em todos os compostos, surpreendentemente, o ferro está em +3 estado de oxidação.Os cálculos do DFT foram realizados para entender a mudança no estado de oxidação de um metal. O estudo DFT confirma a natureza da transferência de elétrons do ligante para o metal. O estudovoltamétrico cíclico dessescompostosmostrauma grande separação (ΔE>800mV) entre dois picos de oxidação confirmando a forteinteração entre os centros metálicos. As medições magnéticas nestescompostos organometálicos revelam que eles apresentam um comportamento ferrimagnético a uma temperatura abaixo de 40 K.

Ingestión de múltiples imanes en pediatría: ¿emergencia endoscópica o quirúrgica?

La ingesta de cuerpos extraños es común en población pediátrica. La mayoría de cuerpos extraños tienen un comportamiento benigno y suelen ser eliminados sin generar mayor morbimortalidad. En relación a la ingesta de imanes, se ha incrementado su frecuencia, a tal punto que en la actualidad representa un problema de salud pública en población pediátrica. La ingesta de un solo imán no genera ningún riesgo, pero la ingestión de 2 o más de estos, o incluso de imanes y metales de forma sucesiva se considera una emergencia ya que estos pueden atraerse entre sí pudiendo provocar cuadros graves de obstrucción intestinal, sangrado, fístulas, perforación e incluso necrosis intestinal. Presentamos 2 pacientes en edad pediátrica, que ingirieron múltiples imanes, en estos casos resaltamos la variedad en la presentación clínica, así como las complicaciones presentadas en relación a un diagnóstico tardío.

Ingestion of foreign bodies is common in the pediatric population. Most foreign bodies have a benign behavior and are usually eliminated without generating greater morbidity and mortality. In relation to the intake of magnets, its frequency has increased to the point that it currently represents a public health problem in the pediatric population. The ingestion of a single magnet does not generate any risk, but the ingestion of 2 or more of these, or even of magnets and metals in succession is considered an emergency since they can attract each other and can cause serious symptoms of intestinal obstruction, bleeding, fistulas, perforation and even intestinal necrosis. We present 2 pediatric patients, who ingested multiple magnets, in these cases we highlight the variety in the clinical presentation, as well as the complications presented in relation to a late diagnosis.

Accidental multiple magnet ingestion by an adult: a case report

Accidental multiple magnetic foreign body ingestion although common in children is rare in adults. Multiple magnetic foreign body ingestion possess a definitive risk of causing intestinal perforation, volvulus or fistulas and requires early surgical intervention even in apparently asymptomatic individuals to prevent catastrophic complications. We report a case of an 18 year old male with a history of accidental simultaneous ingestion of two semi-circular shaped magnets along with a nail. The peculiarity of the case being that despite the magnets being simultaneously ingested, one was in the stomach and the other in the jejunum adhered to each other through the transverse colon mesentery causing pressure necrosis of the adjoining wall with the patient being asymptomatic.

Ingesta de cuerpos extraños magnéticos en la edad pediátrica. Caso clínico de localización y extracción endoscópica con ayuda de un imán / Ingestion of magnetic foreign bodies during the paediatric age. Case report, location and endoscopic extraction aided by a magnet

La ingesta accidental de más de un imán puede producir complicaciones graves. Los protocolos actuales recomiendan la extracción endoscópica de ser posible. El objetivo de este trabajo es presentar un caso clínico de una ingesta de dos imanes y la técnica endoscópica de extracción. Niño de 11 años que acudió a Urgencias tras la ingesta de dos imanes, asintomático. En la radiografía de abdomen, se identificaron dos cuerpos extraños radiopacos, aparentemente unidos, en la cámara gástrica. Se realizó una endoscopía bajo anestesia general en quirófano. Para facilitar la extracción, se colocó, encima de la pared abdominal, a nivel gástrico, un imán de neodimio. En la endoscopía, se observaron dos pequeños imanes localizados y fijados en la cara anterior del estómago. Una vez localizados, se retiró el imán externo y se procedió a su extracción con cesta

The ingestion of more than one magnet can cause multiple complications. Current protocols recommend endoscopic extraction if possible. We report a patient who swallowed two magnets and the endoscopic extraction technique. An 11-yearold boy presented at the Emergency Room after ingesting two small magnets, being asymptomatic. In the abdominal x-ray two radiopaque bodies were identified at the gastric chamber, apparently together. A gastroscopy was done in the operating room under general anaesthesia. To enable the extraction, a neodymium magnet was placed externally at the abdominal wall. In the endoscopic image, the two magnets were fixed to the anterior gastric wall. Once located, the neodymium magnet was removed and the two magnets were retrieved with an endoscopic basket.

Microstomia: Difficult Proposition to Rehabilitate

Introduction: The rehabilitation of microstomia patientspresents difficulties during fabrication of denture as themaximal mouth opening is inadequate. This condition mayresult from the surgical treatment of orofacial cancer, cleft lip,trauma, burns, Plummer–Vinson syndrome or scleroderma.The reduced mouth opening also leads to difficulty in speech,mastication and psychological problems secondary to facialdisfigurement.Case report: It is often difficult to apply conventional clinicalprocedures to fabricate prosthesis for patients who demonstratelimited mouth opening, since it is difficult to follow theprotocol of fabrication of prosthesis and also insertion andremoval of one-piece prosthesis into the oral cavity. Thepresent case report focuses on rehabilitation of microstomiausing sectional prosthesis and intraoral magnets with whichenabled easier and competent removal and insertion by thepatient.Conclusion: The sectional denture attached by the magnetcan be more comfortably removed and inserted by the patientwith reduced mouth opening. It is simple and cost-effectivemethod for rehabilitation of microstomia patient.

Portable Low-Cost MRI System Based on Permanent Magnets/Magnet Arrays

Portable low-cost magnetic resonance imaging (MRI) systems have the potential to enable “point-of-care” and timely MRI diagnosis, and to make this imaging modality available to routine scans and to people in underdeveloped countries and areas. With simplicity, no maintenance, no power consumption, and low cost, permanent magnets/magnet arrays/magnet assemblies are attractive to be used as a source of static magnetic field to realize the portability and to lower the cost for an MRI scanner. However, when taking the canonical Fourier imaging approach and using linear gradient fields, homogeneous fields are required in a scanner, resulting in the facts that either a bulky magnet/magnet array is needed, or the imaging volume is too small to image an organ if the magnet/magnet array is scaled down to a portable size. Recently, with the progress on image reconstruction based on non-linear gradient field, static field patterns without spatial linearity can be used as spatial encoding magnetic fields (SEMs) to encode MRI signals for imaging. As a result, the requirements for the homogeneity of the static field can be relaxed, which allows permanent magnets/magnet arrays with reduced sizes, reduced weight to image a bigger volume covering organs such as a head. It offers opportunities of constructing a truly portable low-cost MRI scanner. For this exciting potential application, permanent magnets/magnet arrays have attracted increased attention recently. A magnet/magnet array is strongly associated with the imaging volume of an MRI scanner, image reconstruction methods, and RF excitation and RF coils, etc. through field patterns and field homogeneity. This paper offers a review of permanent magnets and magnet arrays of different kinds, especially those that can be used for spatial encoding towards the development of a portable and low-cost MRI system. It is aimed to familiarize the readers with relevant knowledge, literature, and the latest updates of the development on permanent magnets and magnet arrays for MRI. Perspectives on and challenges of using a permanent magnet/magnet array to supply a patterned static magnetic field, which does not have spatial linearity nor high field homogeneity, for image reconstruction in a portable setup are discussed.

Foreign Body Removal in Children Using Foley Catheter or Magnet Tube from Gastrointestinal Tract / 대한소아소화기영양학회지

Foreign body (FB) ingestion of children is a common pediatric emergency requiring medical attention. Pediatric emergency physicians and gastroenterologists often encounter nervous and distressed situations, because of children presenting with this condition in the common clinical practice. When determining the appropriate timing and indications for intervention, physicians should consider multiple patient- and FB-related factors. The utilization of a flexible endoscopy is considered safe and effective to use in these cases, with a high success rate, for the effective extraction of FBs from the gastrointestinal tract of a child. Additionally, a Foley catheter and a magnet-attached Levin tube have been used for decades in the case of FB removal. Although their use has decreased significantly in recent times, these instruments continue to be used for several indications. Using a Foley catheter for this purpose does not require special training and does not necessarily require sedation of the patient or fluoroscopy, which serve as advantages of utilizing this method for foreign object retrieval. An ingested magnet or iron-containing FB can be retrieved using a magnet-attached tube, and can be effective to retrieve an object from any section of the upper gastrointestinal tract that can be reached. Simple and inexpensive devices such as Foley catheters and magnet-attached tubes can be used in emergencies such as with the esophageal impaction of disk batteries if endoscopy cannot be performed immediately (e.g., in rural areas and/or in patients presenting at midnight in a facility, especially in those without access to endoscopes or emergency services, or in any situation that warrants urgent removal of a foreign object).

Non-Surgical Management of Gastroduodenal Fistula Caused by Ingested Neodymium Magnets / 대한소아소화기영양학회지

Foreign body ingestions pose a significant health risk in children. Neodymium magnets are high-powered, rare-earth magnets that is a serious issue in the pediatric population due to their strong magnetic force and high rate of complications. When multiple magnets are ingested, there is potential for morbidity and mortality, including gastrointestinal fistula formation, obstruction, bleeding, perforation, and death. Many cases require surgical intervention for removal of the magnets and management of subsequent complications. However, we report a case of multiple magnet ingestion in a 19-month-old child complicated by gastroduodenal fistula that was successfully treated by endoscopic removal and supportive care avoiding the need for surgical intervention. At two-week follow-up, the child was asymptomatic and upper gastrointestinal series obtained six months later demonstrated resolution of the fistula.

The influence of the number and the type of magnetic attachment on the retention of mandibular mini implant overdenture

PURPOSE: The aim of this study was to compare the retention of mini implant overdenture by the number, the type of magnetic attachment, and the directions of applied dislodging force. MATERIALS AND METHODS: The experimental groups were designed by the number and type of magnetic attachment. Twenty samples were tested with Magden implants. Each attachment was composed of the magnet assembly in overdenture sample and the abutment keeper in a mandibular model. Dislodging forces were applied to the overdenture samples (50.0 mm/min) in 3 directions. The loading was repeated 10 times in each direction. The values of dislodging force were analyzed statistically using SPSS at 95% level of confidence. RESULTS: The retentive force of group 2 was greater than that of group 1 in both types of attachment in every direction (P < .05). Oblique retentive force of flat type magnetic attachment was higher than that of cushion type attachment in both groups (P < .05). In group 1, oblique retentive force showed the highest and anterior-posterior retentive force showed the lowest value in both attachment types (P < .05). In group 2, both types of attachment showed the lowest retentive force with anteriorposterior direction of dislodging force (P <.05). CONCLUSION: Proper retentive properties for implant overdenture were obtained, regardless of the number and type of magnetic attachment. In both types of magnetic attachment, the greater retentive force was attained with more implants. Oblique retentive force of flat type magnetic attachment was greater than that of cushion type. Among all subgroups, anterior-posterior retentive force was the lowest among three different directions of dislodging force.

Prótesis nasal implantosoportada. Reporte de un caso clínico / Implant-supported nasal prosthesis. Clinical case report

Un reto en el tratamiento integral de pacientes con defectos faciales, es la reconstrucción con fines funcionales y estéticos, que conlleva a la elección de la rehabilitación y material a utilizar en cada caso. Los implantes extraorales juegan un papel importante en el soporte protésico, influyendo en los aspectos psicológicos, funcionales y estéticos, aportando al paciente una mejor calidad de vida. El objetivo de este trabajo es rehabilitar estética y funcionalmente, y mejorar la calidad de vida del paciente ofreciéndole, una prótesis nasal implantosoportada.

In our days, functional and esthetic reconstruction is one of the problems most frequently encountered when treating patients with facial defects. This reconstruction entails to choose among rehabilitation materials to use in each case. Extra-oral implants play an important role in prosthetic support, they bear influence into esthetic, functional and psychological aspects, granting better quality of life to the patient. The aim of the present study was to functionally and esthetically rehabilitate the patient as well as improve his quality of life with the use of an implant-supported nasal prosthesis.

Application of Different Types of Magnet Retention Systems in the Prosthetic Practice.

The magnetic systems as retention units in overdentures are especially used in dental prosthetics designed ​​on the appropriate endodontically treated dental root. With the rapid development of materials and technology their application with overdentures on implants is enabled. In dentistry for a long time magnets made ​​from alloys of aluminium - nickel - cobalt have been used with open field. Their success was limited because these magnets are susceptible to corrosion in contact with saliva and because their retention force is weaker than that retention offered by the mechanical attachments. The preparation of the magnets from alloys of rare earth elements samarium and neodymium enabled greater magnetic force per unit size. Also a new generation of containers allows laser welding with which the protection of the magnetic units from salivary corrosion has been improved. The interest in such attachments is growing which is justified, because the magnets, unlike mechanical attachments have the potential of unlimited duration and may be superior to either mechanical ball or bar attachments in achieving retention for overdentures. Moreover, the magnetic unit provides little resistance to lateral displacement, with which the impact of potentially damaging lateral forces on the retention tooth or implant is reduced.

Underestimated risks of rare-earth magnet ingestion in children: when does it need surgery?

This review discusses an underestimated risk of rare-earthmagnet (henceforth, magnet) ingestion in children and its surgical indication. Due to the ubiquity of magnets, the incidence of magnet ingestion has rapidly increased. While most foreign body ingestions show spontaneous passage, multiple magnet ingestion requires surgery in 30%-70% of the cases. Multiple magnets can attract each other across the bowel wall, leading to pressure necrosis, and subsequently, fistula, perforation, obstruction or volvulus. After recognizing magnet ingestion, the number of magnets should be checked using radiographs. In case of multiple magnet ingestion, surgery should be promptly considered.

Magnets in Orthodontics: An Overview.

Magnetic force is an essential ingredient of nature. The electron and the atom are the smallest magnets. The magnetic moment of the atom is caused by its own spin or by orbital motion of its electrons. Magnets have been used in the dentistry for many years, most commonly to aid in the retention of dentures and over dentures as well as obturators. In orthodontics, they have been used for treatment of unerupted teeth, for tooth movement along arch wire, for expansion, fixed retention, in correction of anterior open bite and in functional appliances.

Early treatment of anterior open bite: Comparison of the vertical and horizontal morphological changes induced by magnetic bite-blocks and adjusted rapid molar intruders / 대한치과교정학회지

OBJECTIVE: This prospective clinical study aims to determine the differences between two treatment modalities for anterior open bite in growing patients. The treatment modalities involved the use of magnetic bite-blocks (MBBs) or rapid molar intruders (RMIs) applied with posterior bite-blocks. METHODS: Fifteen consecutive patients with a mean age of 11.2 (standard deviation [SD] = 1.6) years and a mean open bite of -3.9 mm were treated with MBBs. Another 15 consecutive patients with a mean age of 10.9 (SD = 1.8) years and a mean open bite of -3.8 mm were treated with RMIs applied on bite-blocks. Cephalometric radiographs were obtained before (T1) and immediately after appliance removal (T2). The treatments lasted four months, during which the appliances were cemented to the teeth. The morphological changes were measured in each group and compared using logistic regression analysis. RESULTS: The MBB group exhibited significantly greater decreases in SNA angle, ANB angle, overjet, and maxillary incisor angle (p < 0.05). The MBBs induced greater effects on the maxilla and maxillary dentition. The MBBs restrained maxillary forward growth and retracted the maxillary incisors more effectively than did the RMIs. Consequently, changes in the intermaxillary relationships and overjets were more distinct in the MBB group. CONCLUSIONS: The anteroposterior differences between the appliances suggest that MBBs should be preferred for the treatment of patients with Class II open bites and maxillary incisor protrusions.

Eficacia de los imanes permanentes multipolares en el tratamiento del dolor crónico en pacientes con osteoartrosis generalizada / Effectiveness of the multipolar permanent magnets in the treatment of chronic pain in patients with generalized osteoarthrosis

Se efectuó un estudio longitudinal y controlado de 100 pacientes con osteoartrosis generalizada, atendidos en el Servicio de Medicina Natural y Tradicional del Hospital Provincial Docente Clinicoquirúrgico "Saturnino Lora Torres" de Santiago de Cuba, desde enero hasta diciembre del 2010, a fin de evaluar la eficacia de los imanes permanentes multipolares en el tratamiento del dolor crónico en los afectados. Estos imanes se ubicaron y fijaron en diferentes puntos de acupunturas para aliviar la dolencia. Los niveles de dolor se cuantificaron mediante la Escala Visual Análoga, por sexo y rango de edades; se evaluaron a los 0, 30, 60 y 90 días durante la terapia. Se demostró la factibilidad del uso de los imanes permanentes multipolares en el alivio del dolor de los pacientes con osteoartrosis generalizada por ser simples, seguros, eficaces y no inducir efectos adversos en el organismo.

A longitudinal and controlled study of 100 patients with generalized osteoarthrosis, assisted in the Service of Natural and Traditional Medicine of "Saturnino Lora Torres" Clinical Surgical Teaching Provincial Hospital in Santiago de Cuba was carried out from January to December, 2010, in order to evaluate the effectiveness of the multipolar permanent magnets in the treatment of the chronic pain in those affected. These magnets were placed and fixed in different acupuncture points to reduce pain. The pain levels were quantified by means of the Analogue Visual Scale, by sex and age range; they were evaluated at the 0, 30, 60 and 90 days during the therapy. The feasibility of the use of the multipolar permanent magnets was demonstrated in the relief of pain of the patients with generalized osteoarthrosis as they are simple, sure, effective and induce no adverse effects in the organism.

Rehabilitation of a mandibular segmental defect with magnet retained maxillofacial prosthesis.

Resection or loss of a portion of the mandible can result in a variety of functional, cosmetic and psychological deficits that are dependent on the extent of the defect, the concomitant therapy and the timing of rehabilitative efforts. These impairments greatly affect the patient's Quality of life (QOL). The thrust in cancer care is not simply on survival but on rehabilitation, which aims to improve multiple impairments and QOL. This article describes a case of a 58-year-old female with segmental resection of the anterior mandible, extending to lower lip, resulting in a large intraoral as well extra oral defect. Prosthodontics rehabilitation was done using a two-piece intra oral and extra oral prosthesis oriented to each other using magnets. Use of magnets for retaining the extra oral prosthesis simplifies the clinical and laboratory phase enhancing patient's comfort and psychological morale.

A Case of Small Bowel Fistulas Caused by Multiple Magnet Ingestion: Usefulness of Ultrasonography

Foreign body ingestion is a common problem in the pediatric population and the majority of such cases occur between the ages of six months and three years. Most objects pass uneventfully through the gastrointestinal tract; however, ingestion of multiple magnets can cause serious gastrointestinal complications through interaction with each other across the bowel wall. In these situations, radiologic evaluation is imperative for proper treatment. This is a case report on ingestion of 32 magnets in a 10-year-old boy. We diagnosed a small bowel fistula caused by ingestion of multiple magnets using sonography, which showed hyperechoic magnetic foreign bodies attached together penetrating the thickened neighbouring jejunum.

Jejuno-jejunal fistula induced by magnetic necklace ingestion / 대한외과학회지

We describe the case of a 19-year-old mentally challenged woman who developed jejuno-jejunal fistula following ingestion of a magnetic necklace. This case report demonstrates the necessity of prompt treatment when the ingested intestinal foreign body is suspected to be multiple magnets, even if there are no sharp edges; and even when it seems the object could be evacuated spontaneously. Ingested magnets are capable of attracting each other across the bowel wall, leading to serious intestinal complications such as pressure necrosis, perforation, fistula formation, or intestinal obstruction.

Testing and analysis of the magnetic sources of permanent magnet wafers for magnetotherapy / 中华物理医学与康复杂志

Objective To explore the magnetic properties of permanent magnet wafers commonly used in magnetotherapy to provide a basis for the scientific and rational use of sources of magnetism.Methods A magnetometer was used to measure the magnetic induction intensities of the N and S polar centers of eight groups of magnet wafers (axial magnetization) with nominal magnetic induction intensities of 6 mT, 10 mT, 20 mT, 30 mT, 60 mT,100 mT, 200 mT and 350 mT.Results There were some differences between the nominal values and the measured mean magnetic induction intensities. In a few groups the differences were close to 20％. There were also differences within the same group. The magnetic induction intensities of the two polar surfaces were not always equal for the same magnet, and there were large differences among individual magnets.Conclusions The intensities of magnetic sources must be measured before use to ensure the consistency of magnetic induction intensities in therapeutic applications.

A Case of Gastro-colic Fistula with Peritonitis Due to Ingested Magnets / 대한소화기내시경학회지

The ingestion of a foreign body is common in children. But in adults, especially in those who have a mental illness, dysphagia, and consciousness disorders often occur. If a patient ingests more than two magnets, he can develop numerous complications such as bowel necrosis, perforation, and fistula formation. Here we report a case of a 32-year-old patient with gastro-colic fistula and peritonitis following ingestion of multiple magnets. In accidental ingestion of multiple magnets, early exploration should be considered.