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Over the past decade or so, there has been an increasing concern that the use of conventional synthetic pesticides may be having a detrimental effect not just on pollinators and other beneficial insects (Goulson et al., 2015; Regan et al., 2017), but also on insects in general (Sorg et al., 2013; Pisa et al., 2015; Leather, 2018; Main et al., 2018). In addition, the problem of insect resistance to insecticides is a serious problem, with almost 600 arthropod species‐resistant to one or more of the chemical groups commonly used in crop protection products (Sparks & Nauen, 2015). Aphids are particularly good at evolving resistance to insecticides, with the peach–potato aphid, Myzus persicae displaying six types of resistance (Simon & Peccoud, 2018). There is obviously a need to develop new crop protection products that are fully compatible with modern Integrated Pest Management approaches. Biopesticides based on entomopathogenic fungi have been used for many decades but their development and use has been hampered by legislation and, in some cases difficulties with formulation and delivery (Chandler et al., 2011).

On a certified organic field a trial of the hull-less oat variety Mina was conducted, sown after peas-sunflower mixture, maize for silage, and fallow. The aim of this experiment was to evaluate the effect of predecessors on the productivity and phytosanitary condition of hull-less oats in organic farming. The study was conducted in the period 2012 – 2014 under field conditions on leached, moderately loamy to slightly clayey smolniza at the Institute of Agriculture in Karnobat, Bulgaria, on a field certified for organic farming. The trial was conducted with spring hull-less oat, variety Mina. Predecessors – peas-sunflower mixture, maize for silage and fallow. Phytosanitary monitoring was conducted. The insect reporting was performed through direct investigation for plant pests. The weed reporting – species composition and density of weed infestation by a quantity-weight method, at the end of tillering and beginning of ear formation stage. Disease infestation was determined by walking through the plots during crop vegetation, by the route method, by inspection of the plants. The best predecessor for hull-less oats was fallow, followed by peas-sunflower mixture. The yield was high and the level of weed infestation was comparatively lower than after maize for silage. During the studied period a tendency for the effect of predecessor on disease infestation was not formed. The predecessors did not affect the species composition but mainly their density

During the period 2012 – 2014 in the Institute of Agriculture, Karnobat a field experiment was conducted with winter malting barley varieties Emon, Vanessa and Vicky. The influence of broadleaf (dicotyledonous) herbicides alone and in their combination with wild oat (monocotyledonous) in tillering stage of the crop was studied in optimal and double doses. The herbicide selectiveness was assessed according to the EWRS scale. Yields were reported after harvest. In variety Vanessa during the treatment with Derby Super, Granstar Super, Sekator OD and combination of Puma Super 7.5 EW + Sekator OD in optimal doses, the yield does not differ from the weed control. Variety Vicky endures well the treatment with optimal doses in all of the tested herbicides, except Husar Max. In treatment with double doses, only Granstar Super does not affect negatively the yield of grain. Comparing the data from ANOVA about the role of herbicides and year conditions on the malting barley varieties it can be concluded that the yield of variety Emon is the most stable in regard to herbicides applied in optimal doses (5%), followed by Vanessa (17%) and Vicky (18%). At application of the herbicides in double doses, their influence is increased – in variety Emon up to 15%, and in varieties Vanessa and Vicky – up to 23%.

During the period of 2013 – 2015 the influence of farming types (organic and biodinamic) on the phytosanitary status and yield of kamut was studied. Kamut is resistant to diseases and they are not a problem for growing it in an organic and biodynamic way. In both kinds of farming single numbers of five types of pests on kamut were recorded. Two of them were from Order Homoptera (Sitobion avenae L. and Rhopalosiphum maidis (Fitch)) and three from Hemiptera (Philaenus spumarius (L.), Eurygaster integriceps Put. and Aelia acuminata L.).The species diversity of the weeds was greater in biodynamic farming. Kamut yield from biodynamic farming was proven to exceed the organic one. The strength of effect of the type of farming factor was 83.57%.

Until recently, Penthaleus major (Dugès) has not been recognized as an economically significant pest for the cereal crops. After climatic changes, its population began to grow and inflict damages around the world. The aim of this study was to investigate its distribution in Bulgaria and establish whether it presents a danger to the cereal crops. In the autumn of 2015 and the spring of 2016, a monitoring survey was conducted to establish Penthaleus major (Dugès) with the cereal crops in Bulgaria. Over 60 sowed fields were investigated from all around the country. Samples were taken to identify the pest. It was established that Penthaleus major (Dugès) inflicted harm to the wheat in north-eastern (12-14 mites per stem) and south-eastern Bulgaria (6-8 mites per stem). Its density was under the threshold of economic harm. There was not found infestation of barley, rye, oat and triticale. On the field boundaries bordering the areas attacked by the mite were reported the following weeds: Capsella bursa pastoris (L.) Medic, Descurania sophia (L.) Welb. et Berth, Senecio spp., Sisymbrium orientale Torn., Taraxsacum officinale Weber, Anthemis spp., Bromus arvensis L., Eragrostis pilosa (L.) P.B. Lolium temulentum L., which can be habitat for Penthaleus major (Dugès).

Free-living amoebae (FLA) are phagocytic protozoa found in natural and engineered water systems. They can form disinfectant-resistant cysts, which can harbor various human pathogenic bacteria, therefore providing them with a means of environmental persistence and dispersion through water distribution and other engineered water systems. The association of FLA with human viruses has been raised, but the limited data on the persistence of infectious virions within amoebae leaves this aspect unresolved. Enteroviruses can cause a wide range of illness and replicate in human respiratory and gastrointestinal tracts, both of which could be exposed through contact with contaminated waters if virus detection and removal are compromised by virion internalization in free-living protozoa. This is especially problematic for high-risk contaminants, such as coxsackieviruses, representative members of the Enterovirus genus that are likely infectious at low doses and cause a variety of symptoms to a vulnerable portion of the population (particularly infants). To investigate Enterovirus persistence within free-living amoebae we co-cultured an infectious clinical coxsackievirus B5 (CVB5) isolate, with the commonly reported tap water amoeba Vermamoeba vermiformis , after which we tracked virus localization and persistence in co-culture over time through a combination of advanced imaging, molecular and cell culture assays. Our results clearly demonstrate that infectious CVB5 can persist in all life stages of the amoebae without causing any visible injury to them. We also demonstrated that the amoeba generated vesicles containing virions that were expelled into the bulk liquid surroundings, a finding previously described for FLA-bacteria interactions, but not for FLA and human pathogenic viruses. Therefore, our findings suggest that the ability of CVB5 to persist in V. vermiformis could be a novel waterborne risk pathway for the persistence and dispersion of infectious human enteric viruses through water systems.

We investigated characteristics of the F-waves in the upper limbs of patients suffering from primary torsion dystonia (PTD) by means of surface-electrode electromyography. Single electric stimulation was used to obtain optimum M-responses from the m. abductor pollicis brevis (median nerve) and m. abductor digiti minimi (ulnar nerve). Ten consecutive supramaximum electrical stimuli were applied to each nerve to obtain F-waves from the wrist. In general, the registered M-response latencies and amplitudes, as well as conduction velocities via all inspected nerves, demonstrated no significant deviations from the normal ranges. Nearly all investigated patients, except one, had normal F-wave minimal latencies. The mean amplitudes of F-waves from both median and ulnar nerves were higher than the average F-wave amplitudes described in the literature. The frequency of occurrence of F-waves in both median and ulnar nerves was greater than in the norm. According to our results, it can be concluded that the amplitude and, to some extent, frequency rather than the latency of F-waves are important in the studies of patients with PTD. Increased amplitudes and frequencies reveal changes in the excitability of alpha motoneurons, which could be accepted as a measure of a disturbed interneuronal balance probably caused by alterations in the suprasegmental control mechanisms related to PTD. Ми досліджували характеристики F-хвилі в нервах верхніх кінцівок пацієнтів, що страждали на первинну торсіонну дистонію (ПТД); використовували стандартну техніку електроміографії з відведенням поверхневими електродами. Застосовували поодинокі супрамаксимальні електричні стимули для отримання оптимальних М-відповідей m. abductor policis brevis (подразнення n. medianus) та m. abductor digiti minimi (подразнення n. ulnaris); F-хвилі відводили на рівні зап’ястка. В цілому зареєстровані латентні періоди та амплітуди М-відповідей, як і швидкості проведення по досліджених нервах, не демонстрували драматичних відхилень від нормальних діапазонів значень. Середні амплітуди F-хвиль y n. medianus та n. ulnaris були вищими, ніж описані в літературі. Частота реєстрації F-хвиль в обох нервах була вищою, ніж у нормі. Згідно з нашими результатами, амплітуда та (до деякої міри) частота реєстрації F-хвиль є параметрами, що заслуговують на увагу при обстеженні пацієнтів із ПТД. Вищі значення амплітуд та частоти виникнення F-хвиль вказують на зміни збудливості альфа-мотонейронів. Такі значення можуть розглядатись як показники дисбалансу в інтернейронних системах, вірогідно, пов’язані зі зрушеннями в механізмах супрасегментарного контролю при ПТД.

Biologically active point (BAP) ST36 is one of the most important and most commonly used points in the traditional Chinese medicine (TCM). A correlation between the location of acupuncture points and channels in humans and animals has been established. In the human ST36 is located on the stomach meridian - 3 cun (1 handbreadth) down and 1 fingerbreadth lateral to the anterior crest of the tibia, on the tibialis anterior muscle. The target of this study is to describe the histological structure of biologically active point (BAP) ST36 in the human by using the classic histological techniques. We observed normal histology structures in ST36 point in the human.

Cervical cancer is a serious medical and social issue as it affects women at active age and it is diagnosed too late. In Bulgaria morbidity and mortality show continuous increasing trend. The aim of this study is to compare the clinical performance of cytology and other alternative methods for cervical screening that could be used to assess the the cervix.This is a prospective study which included 317 patients aged between 18 and 65 years. Women were divided into four groups: I-st--cytology, Il-nd--visual inspection with acetic acid (VIA), III-th--visual inspection with Lugol's iodine (VILI) and IV-th--spectrophotometric analysis with TruScreen®. The results showed that the most appropriate screening method for cervical cancer remains cytology. In the absence of cytological laboratory or cytopathologist spectrophotometric analysis with TruScreen® can be used for primary cervical screening. Its main advantages are that it is a real time technique, user easy and it is well accepted by women. If TruScreen is not available in the gynecologist's practice it is possible to perform visual inspection with acetic acid (VIA).

Seventy-six promising bread winter wheat lines were investigated in relation to the allelic composition of grain storage proteins. The aim of the study was: i) to find out a possible relation between wheat quality and the separate low molecular loci and ii) to examine the potential of some of the existing Glu-A3 alleles to increase the quality. Five indices were investigated that covered almost all aspects of grain quality: sedimentation value, wet gluten content, dough stability, bread volume, quality index and valorimeter. The samples for quality analysis were from a 3-year period of investigation. Different statistical approaches were used to study the influence of Glu-A3 on the level of the indices. The LMW-GS were determined by SDS-PAGE (Payne et al. 1980). It was determined that locus Glu-A3 had the strongest influence on quality among the loci, that determine the low molecular glutenins. The Glu-A3 alleles influenced the end-use quality irrespective of the HMW-GS and LMW-GS composition background against which their effect was expressed. There were important variations among the separate alleles of Glu-A3 locus for their direct effect on end-used quality. Glu-A3f had strong positive effect on the end-use quality against the background of all HMW combinations. Glu-A3b had a similar positive effect. The Glu-A3b allele was connected with high quality in wheat but its effect was weaker than that of Glu-A3f and was not significant for some of the investigated indices.

Seventy-three common winter wheat varieties developed throughout the breeding history of the DAI were investigated for their diversity of allelic variants on storage proteins component composition in grain. The high- and low molecular weight protein structures were determined by the widely used SDS-PAGE method of Payne et al. (1980). The ratio between the individual alleles on the loci of high and low molecular weight glutenin was analyzed. The change in the HMW-score was followed according to the period when the respective varieties were developed. The configuration Glu-A1 b , GluB1 c , Glu-D1 d , which was established in about 45% of the investigated genotypes, was most frequent in the high-molecular variants of glutenin. Concerning the low-molecular weight glutenins in 21 out of the 73 investigated varieties, the combination Glu-A3 c , Glu-B3 b , Glu-D3 c was observed; it coincided with the spectrum of the widely used variety Bezostaya 1. Highest diversity was established in the allelic variants of Glu...

The development of the fetal aorta ends with the formation of the aortic arch which normally branches into three blood vessels: 1) a. brachiocephalica (a. innominata), which divides into the right subclavian artery (RSA) and the right carotid artery; 2) the left carotid artery; and 3) the left subclavian artery. Occasionally, RSA originates as a separate fourth branch of the aortic arch, passing behind the trachea with an oblique course to the right shoulder. This rare variant is called an aberrant right subclavian artery (ARSA) and is observed in approximately 2% of normal individuals. On the other hand, the reported incidence of ARSA varies between 25 and 37% in cases with Down syndrome and other chromosomal abnormalities.To evaluate the success rate of ultrasound visualization of the fetal RSA between 18 and 23 weeks of gestation and to establish the importance of the prenatal diagnosis of ARSA in the risk assessment for fetal chromosomal abnormalities in the second trimester.Three experienced sonographers scanned 992 fetuses in MC "Markovs", Sofia between 01.09.2013-01.06.2014 with Voluson 730 Expert (GE Healthcare) ultrasound equipment. Visualization of RSA was successful in 92.7% of cases. Overall, 17 cases with ARSA were diagnosed in the study period. ARSA was an isolated sonographic finding in 13 of them. The remaining 4 cases had additional pathology. In the first case ARSA was associated with a short femurand humerus, short nasal bone and borderline nuchal thickness without any other soft markers or structural abnormalities. Trisomy 21 was diagnosed after amniocentesis and the pregnancy was terminated at patient's request. In the second case ARSA was associated with severe polymalformation syndrome. Trisomy 18 was diagnosed by DNA analysis post abortem. In the third case ARSA was associated with an unilateral cleft lip and cleft palate. Abnormalities of the fetal karyotype and Di George syndrome were excluded by amniocentesis. The fourth case was associated with a single umbilical artery without any structural and chromosomal abnormalities. The pregnancy had a favourable perinatal outcome at term.Visualization of RSA and prenatal diagnosis of ARSA in the second trimester is relatively easy in experienced hands. The examination slightly prolongs the fetal morphology scan. Since there is an obvious association between ARSA and chromosomal fetal abnormalities, implementation of its sonographic evaluation in the protocol of fetal echocardiography in the second trimester is strongly recommended.

Background The past experience has taught the value of citizen participation but it has also highlighted the difficulties of mobilizing people. Identifying the barriers and facilitators of the citizen participation in health decision-making in the municipalities can contribute to more effective approach in influencing the local health policy-making process. Methods A mixed-method research design includes in-depth interviews with 23 health experts and active citizens and personal interviews with 328 …

Wheat quality is a complex feature determined by the level of various indices and dependent on a number of factors. It is defined by different interactions involving glutenin and gliadin composition and abiotic stresses. The efforts of the wheat breeders are directed towards combining a high level of the indices in the new varieties with a stable expression of these indices in different years and environments.

Obesity attracts large volumes of news coverage. This in turn has spawned academic studies investigating how news framing may affect views about causes of and solutions to obesity. We use key studies to demonstrate that although existing research has made valuable discoveries about how obesity is defined in various media outlets, some methodological and theoretical questions remain unaddressed. We argue that extant research has focused on one dimension of analysis--the problematization of obesity in news stories--precluding insights into the entire process of obesity communication. Drawing on framing and media studies research, we propose a multidimensional approach to shed more light on factors affecting the production of obesity news stories by journalists and how they may be received by audience members. Ways of moving research into this multidimensional direction are proposed, including analysis of journalistic news values, political leaning and style of media outlets, emotion-eliciting language, readers' comments and obesity-related news visuals. Knowledge resulting from the exploration of these dimensions of the issue of obesity can be used to improve strategies to inform and engage audience members.

To define the major sonographic findings used in the diagnosis and differential diagnosis of fetal abdominal cysts in the first trimester and to establish their clinical relevance to the perinatal outcome.A prospective longitudinal study of 5 antenatally detected cases of fetal abdominal cysts between 11-14 w.g. was performed in the University Hospital of Obstetrics and Gynecology "Maichin dom" and MC "Markovs", Sofia between Jan 2007 and Aug 2009. In all cases color flow mapping was used to differentiate the cystic structure from the fetal bladder by identifying the two umbilical arteries. All continuing pregnancies were carefully followed up sonographically at 14-16 w.g, 18-22 w.g. and 28-32 w.g., including with fetal echocardiography. Genetic amniocentesis was offered in all cases to exclude associated chromosomal abnormality. Termination of pregnancy was an option in all affected cases. Information about the perinatal outcome was ascertained by the hospital records, the referring physicians and/or the patients themselves.There were 5 cases of fetal abdominal cysts diagnosed between 11-14 w.g. during the study period (2--megacystis, 3--cystic structures from the gastro-intestinal tract). In one case of megacystis the patients opted for termination of pregnancy at 15 w.g. The second affected case was a male fetus from a twin pregnancy. The patient delivered at term by Cesarean section with a subsequent surgical treatment of the newborn. In one of the remaining three cases of fetal abdominal cysts the patients opted for termination of pregnancy at 12 w.g. The other two were followed up sonographically. Eventually, a complete resolution of the cystic structure was demonstrated. Both newborns had an uneventful perinatal outcome and were delivered at term with no complications in the early neonatal period.Megacystis is a common fetal abdominal cyst in early pregnancy. Abdominal cysts with other origin often resolve spontaneously or remain small in the second and third trimester. Thus, they usually have a good perinatal outcome. Nevertheless, some first trimester fetal abdominal cysts can be associated with structural abnormalities or other complications from the gastrointestinal tract.

Spina bifida is the most common abnormality of the fetal central nervous system. Prenatal diagnosis is usually made by ultrasound in the second or third trimester of pregnancy. However, first trimester detection of spina bifida is still a challenge. A new indirect ultrasound sign of open spina bifida between 11-13 6 weeks of gestation (w.g.) has been recently described. The marker is associated with an absence of intracranial translucency (IT) in the mid-sagittal plane. We present a case report of an open spina bifida detected at 13+2 weeks of gestation with an absent IT. The main ultrasound characteristics of normal and absent IT are described. In addition, the diagnostic role of three-dimensional (3D) transvaginal ultrasound is also discussed.

To describe the normal development of the embryonic central nervous system (CNS) using three-dimensional (3D) transvaginal (TV) ultrasound (US) between 7 and 10 w.g. and to compare the embryonic development visualized by 3D TV US with that of the classical embryology.A prospective longitudinal study was conducted over a period of 10 months with high-end ultrasound equipment (Voluson 730 Expert, GE Healthcare, U.S.). Thirty six pregnant women between 7 and 10 weeks of gestation (w.g.) were examined. In all cases a high-frequency 30 TV probe was used to acquire a 3D volume of the embryo, including the cranial pole. Subsequently, the acquired volume information was post-processed and analyzed with specialized software 4D View ver. 9.1 (GE Healthcare, U.S.). The duration of the examinations was about 15 minutes.Three-dimensional TV US allows adequate visualization of the embryonic CNS in accordance with the Carnegie stages from the classical embryology. In 7 w.g. it is possible to identify the diencephalon (future third ventricle), mesencephalon (future aqueductus Sylvii), rhombencephalon (future fourth ventricle), and the two hemispheres. In 8 w.g. the choroid plexus in the lateral ventricles, the fourth ventricle and the cerebellum can also be recognized. The developmental changes in the size, shape and relationship of the described structures can be progressively assessed in 9 and 10 w.g.Implementation of high-frequency 3D TV probes allows good visualization of the developing embryo, detailed anatomical description of all main cerebral structures, as well as adequate reconstruction of the brain ventricular system between 7 and 10 w.g. There is a good correlation between the embryonic development visualized by 3D TV U.S. and that of the classical embryology.

The first step in iron absorption requires the reduction of ferric iron to ferrous iron, a change that is catalyzed by duodenal ferric reductase. Iron deficiency is associated with high iron absorption, high ferric reductase activity, and high duodenal ascorbate concentrations in experimental animals, but it is not known whether a relation between reductase and ascorbate is evident in humans.The objective of the study was to assess the relation between ferric reductase activity in human duodenal biopsy specimens and ascorbate concentrations in iron-replete and iron-deficient subjects.Patients and control subjects were overnight-fasted adults presenting sequentially for upper gastrointestinal endoscopic investigation. Ferric reductase activity in duodenal biopsy specimens was assayed by using nitroblue tetrazolium. Ascorbate was assayed in duodenal biopsy specimens and plasma.Iron-deficient patients had significantly higher reductase activity (n = 6-9; P0.05) and duodenal (n = 20; P0.001) and plasma (n = 6; P0.001) ascorbate concentrations than did control subjects. Incubation of biopsy specimens with dehydroascorbate (to boost cellular ascorbate) increased reductase activity in the tissues that initially had normal activity (n = 9; P0.01) but inhibited reductase activity in the tissues that already had high reductase activity (n = 13; P0.001).Iron deficiency in humans is associated with increased duodenal ascorbate concentrations. This finding suggests that increased reductase activity is partly due to an increase in this substrate for duodenal cytochrome b reductase 1.

Immune-mediated segmental demyelination is the basic pathomorphological substrate of the Guillain-Barre syndrome (GBS). The aim of the study is to determine the diagnostic value of the conduction block in the early stage of GBS, as well as its changes during of the development of the disease. Sixteen patients with GBS were examined. Electroneurography (motor nerve conduction studies) was performed at interval from the third day of the onset till the first year. Partial CB in the early stage of the disease (range 0-15 days) was registered in 81,2% of the patients. In demyelinating forms of GBS partial CB was determined in 61% of the investigated nerves. It is the most often observed in peroneal nerves, followed by tibial, ulnar and median nerves in the same order. The maximal reduction of the amplitude of the CMAP (maximal CB) was registered before the 30th day from the onset of the disease with following recovery on the sixth month and first year. Partial CB is more often observed in the early phase of GBS, when it could be the only sign of demyelination. When patients reached a clinical plateau, progressive slowing of motor nerve conduction and increasing CB were registered. Proximal CB was revealed more often than distal CB, because of the typical initial localization of the process. In the early phase of GBS, proximal CB is most often found in lower limbs (in peroneal nerve, followed by tibial nerve). In patients with axonal damage, CB was more severe than in demyelinating group. Partial CB is an important diagnostic criterion for segmental demyelination, which helps for confirming the diagnosis of early GBS, when conduction velocity and other electrodiagnostic criteria for demyelination are normal.

The authors have suggested a hypothesis according to which the alimentary canal consists of the separate autonomous S-shaped functional structures possessing the antireflux and sphincter-like properties. The principle mentioned was used in 9 patients who had a "siphon" one-story invagination small-to-large intestinal anastomosis been created.

The authors subscribe to the standpoint that a "bile path" passes in biliodigestive anastomoses along the latero-posterior surface of the right hemi-circumference of the hepato-choledochus in the area where the choledocho-digestive anastomoses are constructed. A declivage (to this "bile path" in the hepato-choledochus) supraduodenal latero-lateral choledocho-duodeno-anastomosis is suggested. It is realized through latero-posterior choledochotomy and by oblique section of the duodenum in close proximity to its external edge. The stitches of the common bile duct needle are 2-2.5 mm apart from each other and from the end of the choledochotomy orifice and those of the--3-3.5 mm apart from each other and 6-7 mm from the end of the duodenotomy orifice. The sutures pass totally through the wall of the common bile duct and serous-muscular-submucosally (mucose-muscular-seriously) thorough the duodenal wall.

After a brief review of available data in the literature on the sections for surgical approach to the cervical segment of the thoracic duct, the authors made a comparative analysis, using time-honoured objective criteria on surgery, between the universal transverse cervical section (20 operated patients) for approach to the cervical segment of the thoracic duct and the oblique cervical section which they suggest (28 operated patients) it passes along the bisector of the angle formed between the thoracic pedicle of the sternocleidomastoid muscle and the upper edge of the left clavicle. It is concluded that the oblique cervical section for approach to the cervical segment of the thoracic duct is superior, with respect to accessibility and inflicted trauma.

A planar-magnetron system is used for dc reactive sputtering of Al in O2 + Ar atmosphere. It is shown that the electrophysical properties of so produced alumina (Al2O3) layers depend on the gas ratio mainly. By studying the index of refraction, the dielectric constant, the resistivity, the breakdown field, and the C–V characteristics it is found that the most stoichiometric layers are obtained at a partial pressure ratio, Po2/ArP, in the range of 0.45 to 0.65. The MAS structures show good interface properties only after annealing in N2 at 1000°C and in H2 at 450°C. Ein ebenes Magnetronsystem wird fur die reaktive Zerstaubung von Al in einer (O2 + Ar)- Atmosphare verwendet. Die elektrophysikalischen Eigenschaften der erzeugten Al2O3-Schichten hangen hauptsachlich vom Gaskonzentrationsverhaltnis ab. Aus den Untersuchungen des Brechungsindex, der Leitfahigkeit, der Dielektrizitatskonstante, der Durchschlagsspannung und der C–V-Kurven wird gefunden, das stochiometrische Schichten nur dann hergestellt werden konnen, wenn Po2/PAr im Bereich von 0,45 bis 0,65 liegt. MAS-Strukturen mit guten Grenzflacheneigenschaften werden nur nach Tempern in N2 bei 1000°C und in H2 bei 450°C erhalten.

Adsorption of CO on a Rh/NaY zeolite has been studied by the ESR method using carbon monoxide enriched in13C. A complex with one unpaired electron delocalized over a rhodium nucleus and a CO molecule is shown to form upon adsorption. The unpaired electron density on the CO molecule is found to be about 0.25.

The morphology of single crystal silicon and SiO2 surfaces etched in CF4 or CF4 + 5% O2 plasma as well as properties of MOS structures obtained by thermal oxidation of plasma etched Si are studied. The etched surfaces are rough and the shape and the size of the roughnesses depend mainly on the thickness of the removed layer and are different for Si and SiO2. The electrical properties of MOS structures fabricated on plasma etched Si surfaces can not be distinguished from those of reference samples, prepared on standard cleaned Si wafers. Die Morphologic der in CF4 oder in CF4 + 5% O2 Plasma-geatzten Si- und SiO2-Oberflachen wird untersucht. Die Oberflache nach dieser Behandlung wird rauh. Das Ausmas und die Gestalt der Rauhigkeiten hangen hauptsachlich von der Atztiefe ab, und sie sind verschieden fur Si- und SiO2- Oberflachen. Auserdem werden auch die elektrischen Eigenschaften der aus plasmageatzten Si- Scheiben und nachher durch thermische Oxidation hergestellten MOS-Strukturen untersucht. Die Eigenschaften solcher Strukturen unterscheiden sich nicht von Kontrollproben, die auf standardchemischgereinigten Si-Scheiben hergestellt werden.

A dc magnetron system for cathode sputtering with a spool-shaped cathode is described. In comparison with the cylindrical cathode, the spool-shaped cathode increases the intensity of the discharge by one order of magnitude for gas pressures of 10 −2 to 10 −3 torr. The main characteristics of the system are described.

Studies by ESR and optical spectroscopy of zeolites containing transition-metal ions are reviewed. The locations of transition-element ions introduced into zeolites of various types by cation exchange and identified by these techniques are generalised. It is shown that these methods give useful information on the accessibility of the ions by adsorbed molecules and on the electronic structure of the complexes formed by the interaction between adsorbed molecules and transition-metal ions. The properties of these complexes are discussed. 122 references.

The oxidation kinetics of Si in oxygen rf plasma in a planar reactor is investigated. It is found that the dependence of the oxide layer thickness on oxidation time is characterized by a rapid initial region described by the Mott-Cabrera law, followed by a linear region. The influence of glow discharge parameters on the oxidation process is investigated. It is concluded that the active oxidizing particle is elemental oxygen. Die Oxidationskinetik von Si im HF-Sauerstoffplasma eines planaren Reaktors wird untersucht. Es wird festgestellt, das die Abhangigkeit der Oxidschichtdicke von der Oxidationszeit durch einen steilen Anfangsbereioh, der nach dem Gesetz von Mott-Cabrera beschrieben wird, und einem nachfolgenden linearen Bereioh charakterisiert wird. Der Einflus der Entladungsparameter auf den Oxidationsvorgang wird untersucht. Es wird gefolgert, das das aktive Oxidationsteilchen atomarer Sauerstoff ist.