Improved Operation of Chloralkaline Reversible Cells with Mixed Metal Oxide Electrodes Made Using Microwaves

This study focuses on the synthesis of mixed metal oxide anodes (MMOs) with the composition Ti/RuO2Sb2O4Ptx (where x = 0, 5, 10 mol) using hybrid microwave irradiation heating. The synthesized electrodes were characterized using scanning electron microscopy, X-ray energy-dispersive analysis, X-ray diffraction, cyclic voltammetry, and electrochemical impedance spectroscopy. These electrodes were then evaluated in both bulk electrolytic and fuel cell tests within a reversible chloralkaline electrochemical cell. The configurations using the electrodes Ti/(RuO2)0.7-(Sb2O4)0.3 and Ti/(RuO2)66.5-(Sb2O4)28.5-Pt5 presented lower onset potential for oxygen and chlorine evolution reactions and reduced resistance to charge transfer compared to the Ti/(RuO2)63-(Sb2O4)27-Pt10 variant. These electrodes demonstrated notable performance in reversible electrochemical cells, achieving Coulombic efficiencies of up to 60% when operating in the electrolytic mode at current densities of 150 mA cm-2. They also reached maximum power densities of 1.2 mW cm-2 in the fuel cell. In both scenarios, the presence of platinum in the MMO coating positively influenced the process. Furthermore, a significant challenge encountered was crossover through the membranes, primarily associated with gaseous Cl2. This study advances our understanding of reversible electrochemical cells and presents possibilities for further exploration and refinement. It demonstrated that the synergy of innovative electrode synthesis strategies and electrochemical engineering can lead to promising and sustainable technologies for energy conversion.

A neural network based model for urban noise prediction

Noise is a global problem. In 1972 the World Health Organization (WHO) classified noise as a pollutant. Since then, most industrialized countries have enacted laws and local regulations to prevent and reduce acoustic environmental pollution. A further aim is to alert people to the dangers of this type of pollution. In this context, urban planners need to have tools that allow them to evaluate the degree of acoustic pollution. Scientists in many countries have modeled urban noise, using a wide range of approaches, but their results have not been as good as expected. This paper describes a model developed for the prediction of environmental urban noise using Soft Computing techniques, namely Artificial Neural Networks (ANN). The model is based on the analysis of variables regarded as influential by experts in the field and was applied to data collected on different types of streets. The results were compared to those obtained with other models. The study found that the ANN system was able to predict urban noise with greater accuracy, and thus, was an improvement over those models. The principal component analysis (PCA) was also used to try to simplify the model. Although there was a slight decline in the accuracy of the results, the values obtained were also quite acceptable.

Fuzzy techniques for environmental-impact assessment in the mineral deposit of Punta Gorda (Moa, Cuba)

An Environmental-Impact Assessment (EIA) makes it possible to determine whether or not a project is compatible with nature, and thus whether the project qualifies to be executed. The Environmental-Impact Assessment is intended to establish a balance between the development of human activities and the environment. In this work, an Environmental-Impact Assessment of the mineral deposit of Punta Gorda (Moa, Cuba) is made, using fuzzy techniques. Two previous works have been combined: an appropriate linguistic model built with fuzzy techniques, providing a framework for handling qualitative and quantitative variables, and an environmental-impact assessment carried out according to a classical methodology.

[Malignant catatonia as paradigm of neuropsychiatric disease]

Catatonia is a large neuropsychiatric syndrome with multiple etiologies (psychiatric disorder, cerebral structural lesion, systemic disease, secondary to drugs and toxic agents) and varied clinical manifestations (cognitive and behavioral disorders, motor and speech disorders and vegetative disorders). The presence of disautonomy means a situation having vital risk, that requires immediate therapeutic intervention. A 22 year old woman was admitted due to a picture of stupor, fever, maintained postures, rigidity, seizures and tachycardia and hypertension episodes; this picture initiated four weeks earlier, with psychotic and affective symptoms and she slowly developed speech and motor activity impairment. Initially, she had been treated with neuroleptics, anticholinergics and antidepressants. The CT, MRI and CSF studies were normal. The EEG revealed diffuse slow waves and right frontotemporal paroxystic activity Laboratory determinations showed elevation of CK, coinciding with the vegetative disorder phase. The picture resolved progressively in two months, after receiving 19 sessions of electroshock therapy. In all the patients, and above all in those who receive neuroleptics, with symptoms suggesting catatonia, the presence of disautonomy should be considered as an alarm situation, which would make it necessary to discontinue the neuroleptics and to adopt special control. Electroshock therapy is the most effective therapeutic option in the situation of malignant catatonia.

[Inverted metamorphopsia: an alteration in the perception of a special situation of objects]

OBJECTIVES

This study describes the characteristics of six patients who consulted because of episodes of perceptive alteration of extrapersonal space consisting in an inversion of the situation of objects although without changes in shape or size (inverted metamorphopsia).

PATIENTS

Six patients (4 males and 2 females) who presented episodes of inverted metamorphopsia were studied: 4 referred right-left inversion (axial plane), 1 upwards-downwards (saggital plane) and 1 inclination of environment (clockwise movement). None had any alteration in the perception of their own bodies during the episodes which lasted from 3 minutes to 1 hour, reporting from 1 to 40 episodes. The most notable antecedents were: traumatism and forced cervical posture (2), arterial hypertension (3), migraine (2), hyperlipemia (2) and protuberantial ischemia (1).

RESULTS

Intercritical neurologic exploration was normal. MR study showed leukoaraiosis (4), protuberantial paramedian infarctions (1) and was normal in one case of basilar migraine. Study of vestibular function (performed in 4 cases) did not show alterations. Three patients received antiepileptic drugs (1 carbamazepine and 2 gabapentin) with favorable response.

CONCLUSIONS

Inverted metamorphopsia is a paroxistic phenomenon which transduces a dysfunction of the posterior parietal cortex or its afferences (propioceptive, vestibular, retinian). The causes may be multiple (traumatism, migraine, ischemia). Antiepileptic drugs may have a therapeutic role in the cases with multiple episodes.

[Malignant prolactinoma with intra- and extracranial metastasis: clinico-radiologic study]

Malignant prolactinomas are very rare pituitary neoplasms which can be identified not from the hystopathologic nor neuroimaging aspects but only retrospectively from the presence of distant metastases. A 32-year-old male patient was diagnosed of a pituitary prolactinoma because of bitemporal hemianopsia on the basis of cranial MRI aspect and raised blood prolactin level. Visual signs improved under bromocriptine treatment but after surgical and X-ray therapies patient developed paralysis of V and XII left cranial nerves and suffered from medulocerebelous angle, vertebrae, spinal epidural space, lung, liver, suprarenal and femoral metastases. Patient died 3 years after the diagnosis time. Prolactin levels raised 2000 ng/ml. This is the first case of malignant prolactinoma described in the spanish literature and the more large one in number of metastatic localizations between the malignant prolactinomas from the literature. These kind of neoplasms can be partially ameliorated under X-ray and bromocriptine treatment but there is not, by the moment, a curative chemotherapy.

[Isolated hemi-ataxia as a sign of mesencephalic lacunar infarction]

INTRODUCTION

Lesions of the dento-rubro-thalamo-cortical pathway may cause homolateral or contralateral hemiataxia, depending on whether they are found above or below the decussation which occurs at the level of the inferior colliculus. Most mesencephalic infarctions causing hemiataxia also show oculomotor involvement with nuclear or fascicular lesions of the third cranial nerves. This was not seen in the case we report.

CLINICAL CASE

We describe the case of a diabetic patient with a permanent right appendicular hemiataxia, without oculomotor involvement, caused by a lacunar infarct shown on MR imaging which was situated in the antero-external part of the left superior mesencephalum.

CONCLUSIONS

This case helps to clarify the topography of the thalamic radiations of the mesencephalic calotte, including the decussated superior dento-rubro-thalamic pathway to the red nucleus. Involvement of this, situated in the mesencephalic lateral vascular territory causes contralateral hemiataxia.

[Coma associated with migraine]

INTRODUCTION

Basilar migraine is a particular form of migraine with an aura in which crises of headache are accompanied by symptoms of dysfunction in the vertebro-basilar territory, including alteration of consciousness in the form of stupor or coma.

CLINICAL CASES

We report four patients, three men of 14, 17 and 83 years of age and one woman of 21. All had previous histories of migraine and presented with transitory episodes of coma. During the coma, the woman woke up spontaneously with intense bulimia. In the three men, it was seen, on injecting flumazenil, that the state of consciousness and the EEG returned to normal transiently. Neuroimaging studies (CT and MR) were normal in all patients.

CONCLUSIONS

Migraine-coma is an exceptional, emergency condition in which structural, infectious, toxic and metabolic pathology of the Central Nervous System should be ruled out. As well as in patients with basilar migraine, the association of migraine and coma may also be seen in patients with familial hemiplegic migraine and CADASIL and MELAS syndromes. It may be that gabaergic mechanisms are involved in the theoretical dysfunction of the ascending reticular activating system causing alteration of consciousness, since in the three patients in whom flumazenil was injected, there was a response.

[Balantidiasis in a rural community from Bolivar State, Venezuela]

Balantidium coli is the etiologic agent of balantidiasis, an infrequent zoonose of worldwide distribution. The objective of the present study was to determine the clinical and epidemiological aspects of balantidiasis in a rural community in the Bolivar State in Venezuela. Fifty persons and 12 pigs were evaluated. Fecal samples were analyzed by direct examination and by the methods of Faust and Willis. The global rate of intestinal parasitoses detected was 88.0% for the human population and 83.3% for the pigs. The prevalence of human and porcine balantidiais was 12.0% (6/50) and 33.3% (4/12), respectively. The disease was only detected in children, all of them with multiple parasites and with clinical manifestations. Deficient environmental sanitation, absence of basic services in the dwellings, low socioeconomic level, and the presence of pigs infected with B. coli are the factors that explain and maintain the conditions favorable to the transmission of balantidiasis in the population studied.

[From writer's cramp to butcher's spasms: a case of interprofessional dystonia]

INTRODUCTION

Occupational or professional dystonia is a focal motor dystonic disorder which affect motor programs necessaries for the exercise of the patient's profession. Clinical case. A patient with writer's cramp in the childhood presented at the age of 22 years a new dystonia, which we name 'butcher's spasm', giving rise to a laboral incapacity. Neurological exam was normal except for right arm distal (writer's cramp) and proximal dystonias (butcher's cramp), with intentional tremor in the upper extremities. We classified, after complementary exams, the disease as idiopathic.

CONCLUSIONS

Idiopathic focal dystonias can progress to segmentary or multifocal dystonias, and, in exceptional cases as ours, can interfere with two different professional activities.

[Long chronic course of hemiparkinson-plus with l-dopa maintained response]

OBJECTIVE AND CLINICAL CASE: We describe and present a video film of a patient with a hemiparkinsonian illness associated with hemidystonia and pyramidalism, which responded to continuous L-Dopa treatment for twenty years, with no fluctuation or deterioration at the end of the dose-effect. CT and MR studies were normal.

CONCLUSIONS

The characteristics of this case with probable static unilateral dysfunction, basically presynaptic, of the nigrostriate via, make it reasonable to include it in the hemiparkinson-hemiatrophy group.

[Clinical pseudo-peripheral presentation of cerebral lesions]

Small size cerebral lesions, located strategically, can determine the presence of sensitive and motor signs limited to a part of an extremity, clinically suggesting peripheral nervous system affectation, determining erroneous diagnostic and therapeutic decisions. We present 5 patients initially diagnosed of peripheral nervous system pathology, which were finally diagnosed of cerebral lesions (2 lacunar infarcts, multiple sclerosis, progressive multifocal leucoencephalopaty, multicentric astrocytoma). In all, clinical examination disclosed incongruous distribution of the sensitive manifestations and myotatic reflexes were present. CT studies were normal in three patients whereas MRI showed lesions in all cases. Lesions were smaller than 1.5 cm in diameter (greater in the case of multicentric astrocytoma), and were subcortically located in the opposite cerebral hemisphere to the affected extremity. Sensitivomotor signs restricted to an extremity not concordant with a nervous or radicular distribution and with presentation of myotatic reflexes, make it necessary to look for a central nervous system lesion. Lesion will be located in the opposite cerebral hemisphere and MRI will be the elective complementary exam.

Senile chorea: a multicenter prospective study

Senile chorea (SC) is characterized by the presence of late onset, generalized chorea with no family history and no dementia. It is unclear whether it is a distinct clinical entity or represents late onset Huntington's disease (HD) with an undetected family history. In order to clarify this issue, we carried out a prospective, multicenter study of suspected cases of SC. Since 1994 we identified six cases that met clinical criteria for SC. Their study included routine lab tests, cerebral MRI, neuropsychological assessment, and lastly gene IT15 analysis. An abnormal expansion of the (CAG)n repeat was found in three patients. Although there were no criteria for dementia, most neuropsychological tests revealed mild to moderate deficits, particularly in visuospatial and prefrontal tasks, m all six patients, those that were finally diagnosed as having late onset "sporadic" HD, but also in patients that finally had SC. This study provides further evidence on the existence of SC; however, the distinction from late onset "sporadic" HD seems not to be possible on clinical grounds unless a genetic study is carried out. Some cases of suspected "SC" have late onset "sporadic" HD.

[Autoscopy and multiple sclerosis]

A female patient with clinically defined multiple sclerosis presented episodes of audiovisual hallucinations in the form of projections of her own body image speaking to her. EEG and EEG-Holter studies were normal. MRI revealed multiple areas of hypersignals in white matter, particularly in both temporal lobes. The episodes remitted with carbamazepine therapy. We postulate that this phenomenon of autoscopy, which is unusual in multiple sclerosis, may be related to a mechanism of ephaptic transmission in the temporal lobe that is inhibited by carbamazepine, or it may be related to seizure.

[Pseudotumor cerebri secondary to cerebral venous defects not identified by magnetic resonance]

Pseudotumour cerebri is the name of a syndrome characterized by headache and papilloedema, with normal cerebral CT/MR studies and CSF with a high pressure and normal laboratory findings. We describe four patients who fulfilled the diagnostic criteria of this condition (including normal 0.5T MR studies). They all had cerebral angiograms showing minor abnormalities localized to the level of the superior longitudinal sinus. All improved on treatment with anticoagulants and steroids. In view of these findings we consider that in cases of pseudotumour cerebri without a clear aetiological factor, an angio MR study should be done, or if this technique is not available, a cerebral angiogram should be done, to exclude cerebral venous drainage defects.

[Hemiballismus heralding thrombosis of the basilar artery]

We present a patient with top-of-the-basilar syndrome that was preceded by hemiballismus and progressed to coma and tetraplegia. Magnetic resonance imaging showed extensive infarction in the basilar artery territory. Cerebral angiography confirmed basilar artery obstruction. The patient died in spite of anticoagulation therapy.

Acute respiratory failure as the first sign of Arnold-Chiari malformation associated with syringomyelia

We report a rare case of acute respiratory failure in a previously asymptomatic patient showing clinical signs of inferior cranial nerve palsy together with weakness and muscular atrophy of the upper limbs. Magnetic resonance imaging revealed Arnold-Chiari malformation associated with platybasia, basilar impression, syringomyelia and Klippel-Feil syndrome. Episodes of apnoea required tracheostomy and recurred upon tentative closure of the tracheostome, but remitted upon decompression of the posterior fossa. This case involved both obstructive mechanisms and dysfunction of the respiratory centre. Patients with respiratory failure not explained by pulmonary pathology should be checked for underlying neurological disease.

Acute respiratory failure as the first sign of Arnold-Chiari malformation associated with syringomyelia

We report a rare case of acute respiratory failure in a previously asymptomatic patient showing clinical signs of inferior cranial nerve palsy together with weakness and muscular atrophy of the upper limbs. Magnetic resonance imaging revealed Arnold-Chiari malformation associated with platybasia, basilar impression, syringomyelia and Klippel-Feil syndrome. Episodes of apnoea required tracheostomy and recurred upon tentative closure of the tracheostome, but remitted upon decompression of the posterior fossa. This case involved both obstructive mechanisms and dysfunction of the respiratory centre. Patients with respiratory failure not explained by pulmonary pathology should be checked for underlying neurological disease.

[Syndromes of continuous muscular activity: report of a central case (stiff-man) and a peripheral case (neuromyotonia) associated with neuroborreliosis]

We describe two cases of continuous muscular activity: one which is central (the stiff-man syndrome), and another which is peripheral (neuromiotony), the latter in a patient suffering from diabetic neuropathy and with positive Borrellia burgdorferi serology in the bloodstream, as well as CSF. Both cases reacted favourably to medical treatment. In the first case botulinic toxin was used as a simultaneous treatment for focal pseudodystonia in one foot. Response was good.

[Disorders of neuronal migration: clinical and radiological signs in 21 patients]

We describe 21 patients affected by neuronal migration disorders. The main clinical manifestations were epilepsy, hemiparesis with hemiatrophy and psychomotor retardation. The neuronal migration disorders most frequently diagnosed were various forms of heterotopia and schizencephaly. Magnetic resonance imaging was more sensitive and specific that computed tomography in the diagnosis of these disorders. Schizencephaly correlates well with hemiparesis and hemiatrophy, as does nodular heterotopia with focal epilepsy and diffuse neuronal migration disorders with severe encephalopathies.

Multiple sclerosis and hypertrophic demyelinating neuropathy

Images

[CT vs MRI in the diagnosis of acute stroke]

70 patients who had suffered an acute stroke (52 ischaemic and 18 haemorrhagic) were studied with CT and MR, performing both techniques during the first week of disease and correlating the findings with the clinical data. MR proved superior in the detection of ischaemic infarcts, specially those in the posterior territory and with a small size; it was also superior to CT in the detection of leukoaraiosis and the demonstration of vascular obstructions. CT failed to detect a small brain stem haemorrhage secondary to bleeding of a cavernoma, while its performance was similar to that of MR in the remaining cases. In all patients with intracerebral haemorrhages, including two who were examined on the first day, an area of increased density was evidenced in the T1 sequences. It is concluded that CT, due to its greater availability and easiness of performance, must be maintained as first choice in acute stroke in order to differentiate haemorrhage from ischaemia, while MR may provide additional information in selected cases.

Clear cell squamous cell carcinoma. A histologic, immunohistologic, and ultrastructural study

Squamous cell carcinomas (SCCs) usually show a standard histopathologic picture only varying with regard to their degree of differentiation. The authors describe a case of clear cell SCC that was studied by light and electron microscopy. The clear cells showed an empty cytoplasm that was periodic acid-Schiff and alcian blue negative. By electron microscopy these cytoplasms consisted of empty spaces and were not surrounded by membranes, which would be consistent with lipid vacuoles. The differential diagnosis of this uncommon variant of SCC requires consideration of other clear cell tumors.

Cavernomas of the central nervous system: clinical and neuroimaging manifestations in 47 patients

Forty seven cases of central nervous system cavernous angioma (21 males and 26 females) are described. The main clinical signs were epilepsy and brainstem syndromes. Digital subtraction intra-arterial angiography, when used, failed to reveal cavernoma. CT detected many of the lesions, but the most successful supplementary diagnostic procedure was MRI which produces highly characteristic images of cavernous angioma. The diagnosis of cavernous angioma was confirmed in the 18 cases in which the tumour was removed surgically.

[Hypertensive encephalopathy: contribution of magnetic resonance]

We report a patient with hypertensive encephalopathy and we analyze his clinical and neurological imaging peculiarities. Computed tomography showed hypodense corticosubcortical lesions, whereas magnetic resonance scan disclosed extensive, wholly reversible enhanced signal lesions due to cerebral edema.

Trichogenic trichoblastoma. An unusual neoplasm of hair germ

Tumors of hair germ are a very rare group of primary cutaneous neoplasms that have been divided into two groups: epithelial and mesenchymal. Epithelial neoplasms of hair germ are further subdivided into those that are purely epithelial (trichoblastomas) and into epithelial neoplasms with mesenchymal components that may cause inductive changes toward the earliest phase of hair follicle differentiation (trichoblastic fibroma) or a more advanced and complete hair follicle formation (trichogenic trichoblastoma). We herein report an ulcerated trichogenic trichoblastoma whose epithelial and mesenchymal components recapitulated the formation of numerous primitive dermal papillae of the hair bulb because there were numerous strands of small polygonal epithelial cells that delimited areas of a dense and abundantly cellular connective tissue in a hair papilla-like pattern.