PubMed Health⌕ Search

Biomedical subjects

A Henning

Publications and source records attributed to A Henning.

At least 19 recordsLinked to original sources
PubMed2003

Scale-up of anaerobic digestion of the biowaste fraction from domestic wastes.

In the City of Karlsruhe/Germany anaerobic digestion of 7200 ta(-1) of separately collected biowaste has proven its feasibility at an organic loading rate (OLR) of up to 8.5 kg CODm(-3)d(-1). An extension of biowaste collection over the whole city area would increase the amount of biowaste to 12,000 ta(-1), leading to an OLR of the existing anaerobic reactor of up to 15 kg CODm(-3)d(-1). To test, whether the increased amount of biowaste could be stabilized in the existing plant, biowaste suspensions were digested in a laboratory reactor at a maximum OLR, that exceeded the future OLR of the full-scale plant. The laboratory reactor was started with effluent of the full-scale biowaste digester. Like in full-scale, biowaste suspension from the hydropulper was added in a fed-batch mode. The elimination of organic material (measured as COD, chemical oxygen demand) and the volumetric gas production were linearly increasing with the OLR from 4.3 to 19 kg CODm(-3)d(-1). Thus, safe operation of the full-scale plant at an OLR of 15 kg CODm(-3)d(-1) should be possible, leaving still some reserve capacity. To determine the metabolic reserves for fatty acid degradation during digestion at an OLR of 10 kg CODm(-3)d(-1), digester effluent was supplemented with either 40 mmoll(-1) acetate, propionate, i-butyrate or n-butyrate. Results of these batch assays indicated a rapid degradation of all fatty acids and fatty acid conversion rates, that would allow a stable anaerobic fermentation at 15 kg CODm(-3)d(-1)OLR. On the basis of the laboratory results the OLR of the full-scale methane reactor was increased to 15 kg CODm(-3)d(-1). After 7 months, results of full-scale digestion were still consistent with the previously obtained laboratory results.

Bacteria, Anaerobic↗
PubMed2000

Ripple formation through an interface instability from moving growth and erosion sources

The propagation of material interfaces is investigated under the action of a localized moving source which deposits or removes material. Among others the latter process applies to beam cutting techniques. We develop a Kuramoto-Sivashinsky-type model and find a new type of ripple forming mechanism. This theory offers a new explanation for the occurrence of striation patterns which often degrade the quality of cutting edges.

Journal Article↗
PubMed2000

[Organ shortage in transplant centers--approaches to a solution from the economic viewpoint].

In the article the regulations of the German transplantation law, which came into force on 1 December 1997, are considered from an economic perspective. First, the essential regulations of the law are described and then analyzed with respect to economic aspects. The law regulates in particular the administration of the demand surplus for organs. This could be reduced by rationing the demand or by increasing the supply. Apart from the medical features economic attributes such as cost effectiveness are also applicable as criteria for rationing. In addition, the method of the quality-adjusted life-years (QALYs) is introduced and described on the basis of the results of a study about costs and benefits of liver transplantation. To increase the organ supply the authorities in Germany have so far established information campaigns and made appeals to the public. In contrast, an organ donation club the allocation of donors is made considering if and when the recipient declared his readiness to organ donation. In this way the willingness to donate his own organs could be sanctioned positively and an additional incentive for supply could be set.

Cost-Benefit Analysis↗
PubMed2000

Randomized controlled trial of anterior-chamber intraocular lenses in Nepal: long-term follow-up.

Most of the estimated 20 million people who are blind with cataracts live in rural areas of developing countries, where expert surgical resources are scarce. We have studied the use of multiflex open-loop anterior-chamber intraocular lenses (ACIOL) in high-volume low-cost surgery. Between 1992 and 1995, a total of 2000 people attending Lahan Eye Hospital, Nepal, with bilateral cataracts reducing vision to < or = 6/36 were randomly allocated to receive intracapsular extraction (ICCE) with aphakic spectacles, or ICCE with an ACIOL. We re-examined the cohort (1305/2000, 65%) between November 1996 and April 1997 and report the findings in this article. There were 13 new cases of poor visual outcome (best corrected vision < 6/60) arising after one year: 9 in the ACIOL group and 4 in the control group; odds ratio 2.1 (95% confidence interval, 0.59-9.55). The causes of poor outcome were as follows: ACIOL group--retinal detachment (4 cases), cystoid macular oedema (2), epiretinal membrane (1), age-related macular degeneration (1), and late endophthalmitis (1); control group--retinal detachment (2 cases), late endophthalmitis (1), and primary open-angle glaucoma with age-related macular degeneration (1). In rural areas of developing countries, well-manufactured multiflex open-loop ACIOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction.

Adult↗
PubMed1999

[Not Available].

Explore the source record for details and available documents.

Cataract↗
PubMed1998

Circadian plasma leptin levels in patients with anorexia nervosa: relation to insulin and cortisol.

In anorexia nervosa, underweight results from a loss of body mass due to a restricted energy intake. Circulating leptin levels have been shown to be low in the acute stage of the disorder. We studied diurnal secretion characteristics of leptin, insulin and cortisol in a study group of anorectic patients prior to refeeding, a second study group of anorectic patients after initiation of refeeding and study groups of healthy underweight and normal-weight controls. Spontaneous secretion of leptin, insulin and cortisol was measured by drawing blood samples every 2 h for 24 h. The temporal relationships between the diurnal secretion patterns of the three hormones were assessed by cross-correlation analysis in every study group. Plasma levels of leptin and cortisol were secreted with a specific circadian rhythmicity and displayed an intricate temporal relationship in anorectic patients. Semistarvation in the non-refed patients was associated with (1) exceedingly low plasma leptin levels, (2) a qualitative alteration in the circadian rhythm of leptin and cortisol levels and (3) an alteration in the temporal coupling between cortisol and leptin. In contrast, in the patients who had gained weight, leptin levels were higher; furthermore, the diurnal pattern of leptin and the temporal relationship between leptin and cortisol were similar to controls. Increments in insulin secretion preceded those of leptin by 4-6 h in both anorectic patients and in controls. Leptin levels increased 4 h prior to those of cortisol in controls and in refed patients, whereas in the non-refed patients cortisol increased prior to leptin. Thus, anorexia nervosa leads to pronounced, albeit reversible changes in the secretion dynamics of leptin and cortisol.

Adult↗
PubMed1998

Comorbidity of diabetes and eating disorders. Does diabetes control reflect disturbed eating behavior?

OBJECTIVE: This multicenter study was designed to explore the prevalence of clinical and subclinical eating disorders (EDs), the extent of intentional omission of insulin and oral antidiabetic agents, and its relationship to glycemic control in an inpatient and outpatient population of men and women with type 1 and type 2 diabetes. RESEARCH DESIGN AND METHODS: Data have been collected from 12 diabetes medical centers in two German cities. In a questionnaire and interview-based study, a sample of male and female patients (n = 341 type 1, n = 322 type 2) was assessed for the following eating disorders: anorexia nervosa, bulimia nervosa, binge eating disorder, and eating disorder not otherwise specified. For lack of interview data of several patients meeting the screening criteria, prevalence ranges were calculated. RESULTS: The overall prevalence range of current EDs was 5.9-8.0% (lifetime prevalence 10.3-14.0%). When patients were stratified according to type 1 and type 2 diabetes, there was no difference in prevalence of EDs. However, the distribution of the EDs was different in both types of diabetes, with a predominance of binge eating disorder in the type 2 diabetes sample. Type 1 (5.9%) and type 2 (2.2%) diabetic patients reported deliberate omission of hyperglycemic drugs (insulin or oral agents) in order to lose weight. Compared with control subjects, neither the presence of EDs nor insulin omission influenced diabetic control. CONCLUSIONS: There seems to be no difference in prevalence rates of EDs in both types of diabetes; however, distribution of EDs is different. The findings suggest that neither EDs nor insulin omission are necessarily associated with poor control of glycemia. Binge eating disorder seems to precede type 2 diabetes in most patients and could be one of the causes of obesity that often precedes type 2 diabetes.

Adolescent↗
PubMed1998

[Not Available].

Explore the source record for details and available documents.

Cataract↗
PubMed1996

Evidence for the presence of a large keratan sulphate proteoglycan in the human uterine cervix.

Profound changes occur in the uterine cervix during pregnancy. In particular, the extracellular matrix of the connective tissue is remodelled extensively. To elucidate the mechanisms involved in this process, we have analysed the proteoglycan pattern in the human cervix from pregnant and non-pregnant women. Proteoglycans of the cervix tissue specimen were extracted with 4 M guanidine hydrochloride and precipitated with 80% ethanol. Purification of proteoglycans was performed by several chromatographic steps. Characterization of proteoglycans was done by SDS/PAGE before and after digestion with glycosaminoglycan-specific enzymes. Proteoglycans were detected by combined Alcian Blue/silver staining or, after blotting of biotin-labelled proteoglycans on to poly(vinylidene difluoride) membrane, with peroxidase-conjugated avidin or by the use of keratan sulphate- or decorin-specific monoclonal antibodies. In contrast with previous reports, where only chondroitin/dermatan sulphate proteoglycans have been found in the uterine cervix, we have shown in the present study the existence of a large keratan sulphate proteoglycan with an M(r) > 220,000 in cervix samples from non-pregnant and pregnant women. This proteoglycan showed a strong reaction with the keratan sulphate-specific monoclonal antibody 5D4 and could be degraded by keratanases. The size of the core protein of this keratan sulphate proteoglycan was estimated to be about M(r) 220,000.

Cervix Uteri↗
PubMed1993

[Factors influencing the vitamin A concentration in the liver of cattle].

Nineteen long-term individual- and group-feeding experiments with 180 male calves, 338 growing bulls, 302 heifers, and 344 dairy cows were carried out in order to measure the influence of feeding (straw, silages or green fodder as roughages) and different vitamin-A supplies (0-40,000 IU per 100 kg body weight per day in growing cattle or 0-120,000 IU per dairy cow per day) on liver vitamin-A concentration. All together, 2,127 biopsies from livers were taken for retinol analysis. At the end of six growth experiments animals were slaughtered. Liver vitamin-A concentration of calves depends on their term at birth and is associated with the carotene intake of their mothers. The carotene content of feeds and the vitamin-A supply are the most important influencing factors on liver vitamin-A concentration of growing and lactating cattle. On the average, livers of calves fed with colostrum contained 100-200 IU, those of growing cattle fed with grass and legumes or with silages contained 200-300 or 100-200 IU resp., and those of cows fed with green fodder or silage contained 300-600 or 100-300 IU vitamin A resp. per g fresh liver. There were also values outside of the variations mentioned above. The vitamin-A storage capacity of liver and the effects of oral and parenteral vitamin-A supply to depleted calves and growing cattle were also tested.

Aging↗
PubMed1993

[Itinerant and established oculists of the 18th century].

BACKGROUND: The formation of scientific surgery in the 18th century was associated by the development of ophthalmology as a special branch of medicine and accompanied with a large number of more or less qualified oculists. A lot of them travelled practising throughout Europe, propagating their profession by handbills, announcements and booklets. In 1748 Frederick II of Prussia appointed Joseph Hillmer (born about 1720) from Vienna, who was a contemporary of John Taylor (1703-1772) as oculist and charlatan, an ordinary professor for ophthalmiatrics at the Berlin Collegium Medico-Chirurgicum. In 1752 C. E. Eschenbach, in the course of critizing Taylor's charlatanism, had called his century the "Okulisten-seculum". By the way many documents on travelling oculists have been delivered, first of all as to the English oculist, but the most important in medical and historical view concerning Hillmer. MATERIAL AND METHODS: Researches on 25 oculist, based on documents and newspapers from 1558 to 1806 (especially concentrated upon Berlin as Hillmer's residence) reveal the transformation of the ancient ophthalmiatry into ophthalmology. RESULTS: There have been resident oculists before the 18th century; their small number corresponded to the poor demographical situation at the time. For the last reason they practised partially travelling. Local medical authorities reglemented them by permission for practising within a given time. CONCLUSIONS: Many propagandistic publications about oculistic charlatans, mainly from their own hand, might make us believe, above all the early ophthalmology would have been characterized by travelling oculists, because their respectable and resident colleagues are documented less impressive, for the reason that they have not made as much propaganda, as charlatans made.

Cataract Extraction↗
PubMed1992

[Not Available].

Explore the source record for details and available documents.

Expeditions↗
PubMed1991

[Complications following cataract incision 1751].

In 1751 the oculist Joseph Hillmer was expelled as charlatan from Petersburg by an expert opinion, which was founded on 125 case reports on his Russian clients, amongst them 60 suffering from cataracts, which had been couched on 80 eyes. Beside 82% of failures these case reports on cataract-couching contain postoperative complications, epicritically symptomatic for today's clinical pictures, which have been etiologically unknown in 1751. At least five eyes suffered postoperatively blindness by supposed detachment of the retina. The experts believed Hillmer's unexact, rough handling of the cataract needle to have been the reason. No less than 18 cases were complicated post operationem by secondary glaucomata, which ended at least twice as absolute glaucoma. We also recognize acute glaucoma, caused by couching the cataract. Secondary glaucomata were associated with severe iridocyclitis. In three cases there are indications of sympathetic ophthalmia. The experts seem to have been well acquainted with that threat to the untreated second eye. We are enabled to recognize a vitreous hemorrhage and an abscess in vitreum. No less than 21 times the couched crystalline lenses had set up again, in one case repeatedly after having been couched a second time.

Cataract Extraction↗
PubMed1991

Radiation-induced effects in multiprogrammable pacemakers and implantable defibrillators.

Twenty-three multiprogrammable pacemakers and four implantable cardioverter defibrillators (ICDs) containing either complementary metal-oxide semiconductor (CMOS) or CMOS/Bipolar integrated circuit (IC) technology were exposed to 6-MV photon and 18-MeV electron radiation at various dose levels. Of the 17 pacemakers exposed to photon radiation eight failed before 50 Gy, whereas four of the six pacemakers exposed to electron radiation failed before 70 Gy. Photon scatter doses were well tolerated. For the ICDs detection and charging time increased with accumulated radiation dose, the charging time increased catastrophically at less than 50 total pulses delivered when compared with the charging time of six implanted ICDs. Sensitivity and output energy delivered by the ICD pulse were constant during the test. It was found that devices using the shorter channel length IC technology (i.e., 3 microns CMOS) were per se harder to ionizing radiation than the devices using larger channel length IC technologies (i.e., either 8 microns CMOS or combined 5 microM CMOS/20 V Bipolar). In fact, none of the devices based on 3 microns CMOS IC technology failed before 76 Gy, which is above the highest dose level (70 Gy) normally used in radiation oncology treatments.

Electric Countershock↗
PubMed1991

[The effectiveness of oral and parenteral vitamin A doses in growing cattle with different vitamin A supplies].

The effect of one single oral or parenterally administered dose of 1 million IU vitamin A on the vitamin A depot in the liver and on blood plasma vitamin A concentrations was investigated in 3 individual feeding experiments with involvement of 18 and 24 calves or 24 fattening bulls. 50% of all animals in each of the 3 experiments received feed without any vitamin A through 108 or 112 or 209 days, prior to vitamin A administration, or received 10.000 IU/100 kg live weight and day. Parenteral vitamin A administration in either group yielded rise in blood plasma from 0.06--0.35 to 26.2--30.2 mumol/l, after 1 or 2 days. The maximum value measured after oral administration was 1.9 mumol/l. Most of the plasma values had returned to normal (0.6--12. mumol/l) within 14 days from administration. Oral and parenteral vitamin A doses, after 14 days, caused significant rise in vitamin A concentrations in the liver (from 15.5 to 82.5), with the increase resulting from parenteral administration (from 13.7 to 99.1) being clearly higher than that resulting from oral administration (from 17.3 to 65.9 mumol/kg fresh liver tissue). The same trends were recorded from recovery of vitamin A from the liver (26.8% after parenteral administration versus 15.0% in the wake of oral doses). Storage in and recovery from vitamin-A depleted animals were below values recorded from young cattle with sufficient vitamin A supply. These findings are likely to confirm that one single parenteral vitamin A administration was of clearly higher effectiveness, as compared to oral application.

Administration, Oral↗