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1.
Adv Mater ; 35(8): e2209598, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36482790

ABSTRACT

Organic bulk heterojunction photodiodes (OPDs) attract attention for sensing and imaging. Their detectivity is typically limited by a substantial reverse bias dark current density (Jd ). Recently, using thermal admittance or spectral photocurrent measurements, Jd has been attributed to thermal charge generation mediated by mid-gap states. Here, the temperature dependence of Jd in state-of-the-art OPDs is reported with Jd down to 10-9  mA cm-2 at -0.5 V bias. For a variety of donor-acceptor bulk-heterojunction blends it is found that the thermal activation energy of Jd is lower than the effective bandgap of the blends, by ca. 0.3 to 0.5 eV, but higher than expected for mid-gap states. Ultra-sensitive sub-bandgap photocurrent spectroscopy reveals that the minimum photon energy for optical charge generation in OPDs correlates with the dark current thermal activation energy. The dark current in OPDs is attributed to thermal charge generation at the donor-acceptor interface mediated by intra-gap states near the band edges.

2.
Adv Mater ; 34(11): e2110053, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34965005

ABSTRACT

Perovskite-based multijunction solar cells are a potentially cost-effective technology that can help surpass the efficiency limits of single-junction devices. However, both mixed-halide wide-bandgap perovskites and lead-tin narrow-bandgap perovskites suffer from non-radiative recombination due to the formation of bulk traps and interfacial recombination centers which limit the open-circuit voltage of sub-cells and consequently of the integrated tandem. Additionally, the complex optical stack in a multijunction solar cell can lead to losses stemming from parasitic absorption and reflection of incident light which aggravates the current mismatch between sub-cells, thereby limiting the short-circuit current density of the tandem. Here, an integrated all-perovskite tandem solar cell is presented that uses surface passivation strategies to reduce non-radiative recombination at the perovskite-fullerene interfaces, yielding a high open-circuit voltage. By using optically benign transparent electrode and charge-transport layers, absorption in the narrow-bandgap sub-cell is improved, leading to an improvement in current-matching between sub-cells. Collectively, these strategies allow the development of a monolithic tandem solar cell exhibiting a power-conversion efficiency of over 23%.

3.
J Orofac Orthop ; 83(5): 291-306, 2022 Sep.
Article in English | MEDLINE | ID: mdl-34142175

ABSTRACT

AIMS: Orthodontic care and its effectiveness have increasingly become the focus of political and public attention in the recent past. Therefore, this multicenter cohort study aimed to report about the effectiveness of orthodontic treatments in Germany and to identify potential influencing factors. METHODS: A total of 586 patients from seven German study centers were screened for this cohort study, of which 361 patients were recruited at the end of their orthodontic treatment. Of these, 26 patients had missing study models and/or missing treatment information. Thus, 335 participants were included. The severity of malocclusion was rated using the Peer Assessment Rating (PAR) Index at baseline (T0) retrospectively and-prospectively-after the retention period (T1). Practitioner-, treatment- and patient-related information were analyzed in order to detect potential predictive factors for treatment effectiveness. RESULTS: Study participants (202 female and 133 male) were on average 14.8 (standard deviation [SD] ± 6.1) years old at start of active treatment. Average PAR score at T0 was 25.96 (SD ± 10.75) and mean posttreatment PAR score was 3.67 (SD ± 2.98) at T1. An average decrease of total PAR score by 22.30 points (SD ± 10.73) or 83.54% (SD ± 14.58; p < 0.001) was detected. Furthermore, 164 treatments (49.1%) were categorized as 'greatly improved' but only 3 treatments (0.9%) as 'worse or no different'; 81.5% of all cases finished with a high-quality treatment outcome (≤5 PAR points at T1). Logistic regression analyses detected staff experience as a significant predictive factor for high-quality results (odds ratio 1.27, p = 0.001, 95% confidence interval 1.11-1.46). CONCLUSION: The improvement rate among this selected German cohort indicated an overall very good standard of orthodontic treatment. Staff experience proved to be a predictive factor for high-quality results.


Subject(s)
Malocclusion , Orthodontics, Corrective , Quality of Health Care , Cohort Studies , Female , Germany/epidemiology , Humans , Male , Malocclusion/diagnosis , Malocclusion/epidemiology , Malocclusion/therapy , Retrospective Studies , Treatment Outcome
4.
Nat Commun ; 12(1): 7277, 2021 Dec 14.
Article in English | MEDLINE | ID: mdl-34907190

ABSTRACT

Metal halide perovskite photodiodes (PPDs) offer high responsivity and broad spectral sensitivity, making them attractive for low-cost visible and near-infrared sensing. A significant challenge in achieving high detectivity in PPDs is lowering the dark current density (JD) and noise current (in). This is commonly accomplished using charge-blocking layers to reduce charge injection. By analyzing the temperature dependence of JD for lead-tin based PPDs with different bandgaps and electron-blocking layers (EBL), we demonstrate that while EBLs eliminate electron injection, they facilitate undesired thermal charge generation at the EBL-perovskite interface. The interfacial energy offset between the EBL and the perovskite determines the magnitude and activation energy of JD. By increasing this offset we realized a PPD with ultralow JD and in of 5 × 10-8 mA cm-2 and 2 × 10-14 A Hz-1/2, respectively, and wavelength sensitivity up to 1050 nm, establishing a new design principle to maximize detectivity in perovskite photodiodes.

5.
Sci Rep ; 11(1): 23066, 2021 11 29.
Article in English | MEDLINE | ID: mdl-34845282

ABSTRACT

The effect of respiratory infectious diseases on STEMI incidence, but also STEMI care is not well understood. The Influenza 2017/2018 epidemic and the COVID-19 pandemic were chosen as observational periods to investigate the effect of respiratory virus diseases on these outcomes in a metropolitan area with an established STEMI network. We analyzed data on incidence and care during the COVID-19 pandemic, Influenza 2017/2018 epidemic and corresponding seasonal control periods. Three comparisons were performed: (1) COVID-19 pandemic group versus pandemic control group, (2) COVID-19 pandemic group versus Influenza 2017/2018 epidemic group and (3) Influenza 2017/2018 epidemic group versus epidemic control group. We used Student's t-test, Fisher's exact test and Chi square test for statistical analysis. 1455 patients were eligible. The daily STEMI incidence was 1.49 during the COVID-19 pandemic, 1.40 for the pandemic season control period, 1.22 during the Influenza 2017/2018 epidemic and 1.28 during the epidemic season control group. Median symptom-to-contact time was 180 min during the COVID-19 pandemic. In the pandemic season control group it was 90 min (p = 0.183), and in the Influenza 2017/2018 cohort it was 90 min, too (p = 0.216). Interval in the epidemic control group was 79 min (p = 0.733). The COVID-19 group had a door-to-balloon time of 49 min, corresponding intervals were 39 min for the pandemic season group (p = 0.038), 37 min for the Influenza 2017/2018 group (p = 0.421), and 38 min for the epidemic season control group (p = 0.429). In-hospital mortality was 6.1% for the COVID-19 group, 5.9% for the Influenza 2017/2018 group (p = 1.0), 11% and 11.2% for the season control groups. The respiratory virus diseases neither resulted in an overall treatment delay, nor did they cause an increase in STEMI mortality or incidence. The registry analysis demonstrated a prolonged door-to-balloon time during the COVID-19 pandemic.


Subject(s)
Pandemics , ST Elevation Myocardial Infarction , COVID-19 , Epidemics , Humans , Incidence , Middle Aged
6.
ACS Appl Energy Mater ; 4(4): 3033-3043, 2021 Apr 26.
Article in English | MEDLINE | ID: mdl-34056551

ABSTRACT

Parasitic optical absorption is one of the root causes of the moderate efficiency of metal halide perovskite solar cells (PSCs) with an opaque substrate configuration. Here, we investigate the reduction of these optical losses by using thin (7-10 nm), undoped, thermally evaporated 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD), N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) (NPB), and tris(4-carbazoyl-9-ylphenyl)amine) (TCTA) hole transport layers (HTLs). Of these, NPB is found to offer the best compromise between efficiency and stability. In semitransparent n-i-p configuration PSCs with an indium tin oxide bottom and a MoO3/thin-Au/ZnS dielectric-metal-dielectric top electrode, NPB gives 14.9% and 10.7% efficiency for bottom and top illumination, respectively. The corresponding substrate-configuration PSC fabricated on an Au bottom electrode has 13.1% efficiency. Compared to a 14.0% efficient PSC with a thick spin-coated doped spiro-OMeTAD layer, the cell with NPB provides an improved short-circuit current density but has slightly lower open-circuit voltage and fill factor. Detailed analysis of the optical losses in the opaque devices demonstrates that evaporated NPB offers negligible parasitic absorption compared to solution-processed spiro-OMeTAD. The optical losses that remain are due to absorption and reflection of the transparent top electrode.

7.
Comput Methods Biomech Biomed Engin ; 24(3): 320-332, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33063557

ABSTRACT

In total knee arthroplasty (TKA), force is transmitted into the tibia by a combined plate-stem device along with cemented or cementless stem fixation. The present work analyzes this force transmission in finite element simulations with the main aim to avoid reported postsurgical bone density reduction as a consequence of a reduced tibial bone loading. In the numerical analysis different implant materials, stem/extension lengths and implant-to-stem interface conditions are considered, from a stiff fully cemented fixation to sliding contact conditions with a low friction coefficient. The impact of these variations on bone loading changes are measured by (i) decomposing the total force into parts mediated by the plate and by the stem and by (ii) post-surgery strain energy density (SED) deviations. Based on a bionics-inspired perspective on how nature in pre-operative conditions carries out force transfer from the knee joint into the tibia, a modified implant-bone interface is suggested that alters force transmission towards physiological conditions while preserving the geometries of the standard plate-stem endoprosthesis design. The key aspect is that the axial force is predominantly transmitted through the plate into proximal bone which requires a compliant bone-stem interface as realized by sliding friction conditions at a low friction coefficient. These interface conditions avoid stress shielding almost completely, preserve pre-surgery bone loading such that bone resorption is not likely to occur.


Subject(s)
Arthroplasty, Replacement, Knee , Knee Prosthesis , Metals/chemistry , Reoperation , Stress, Mechanical , Tibia/surgery , Female , Finite Element Analysis , Humans , Middle Aged , Prosthesis Design , Weight-Bearing
8.
Adv Mater ; 32(19): e2000270, 2020 May.
Article in English | MEDLINE | ID: mdl-32202010

ABSTRACT

Organic electrochemical transistors (OECTs) show great promise for flexible, low-cost, and low-voltage sensors for aqueous solutions. The majority of OECT devices are made using the polymer blend poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), in which PEDOT is intrinsically doped due to inclusion of PSS. Because of this intrinsic doping, PEDOT:PSS OECTs generally operate in depletion mode, which results in a higher power consumption and limits stability. Here, a straightforward method to de-dope PEDOT:PSS using commercially available amine-based molecular de-dopants to achieve stable enhancement-mode OECTs is presented. The enhancement-mode OECTs show mobilities near that of pristine PEDOT:PSS (≈2 cm2 V-1 s-1 ) with stable operation over 1000 on/off cycles. The electron and proton exchange among PEDOT, PSS, and the molecular de-dopants are characterized to reveal the underlying chemical mechanism of the threshold voltage shift to negative voltages. Finally, the effect of the de-doping on the microstructure of the spin-cast PEDOT:PSS films is investigated.

9.
J Mater Chem A Mater ; 6(16): 6882-6890, 2018 Apr 28.
Article in English | MEDLINE | ID: mdl-30009025

ABSTRACT

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is frequently used as hole transport layer in planar p-i-n perovskite solar cells. Here we show that processing of a metal halide perovskite layer on top of PEDOT:PSS via spin coating of a precursor solution chemically reduces the oxidation state of PEDOT:PSS. This reduction leads to a lowering of the work function of the PEDOT:PSS and the perovskite layer on top of it. As a consequence, the solar cells display inferior performance with a reduced open-circuit voltage and a reduced short-circuit current density, which increases sublinearly with light intensity. The reduced PEDOT:PSS can be re-oxidized by thermal annealing of the PEDOT:PSS/perovskite layer stack in the presence of oxygen. As a consequence, thermal annealing of the perovskite layer in air provides solar cells with increased open-circuit voltage, short-circuit current density and high efficiency.

10.
Med Eng Phys ; 2018 Jun 12.
Article in English | MEDLINE | ID: mdl-29773487

ABSTRACT

The present work proposes a simple, novel fixation concept for short stem hip endoprostheses, which preserves the pre-surgery force flow through femoral bone to an unprecedented extent. It is demonstrated by finite element analyses that a standard implant model endowed with minor geometrical changes can overcome bone loading reduction and can achieve almost physiological conditions. The numerical results underpin that the key aspect of the novel, so-called "collar cortex compression concept CO4" is the direct, almost full load transmission from the implant collar to the resected femur cortex, which implies that the implant stem must be smooth and therefore interacts mainly by normal contact with the surrounding bone. For a stem endowed with surface porosity at already small areas, it is mainly the stem which transmits axial forces by shear, whereas the collar shows considerable unloading, which is the standard metaphyseal fixation. Only in the latter case the implant-bone stiffness contrast induces stress shielding, whereas for CO4 stress shielding is avoided almost completely, although the implant is made of a stiff Ti-alloy. CO4 is bionics-inspired in that it mimics force transmission at implant-bone interfaces following the natural conditions and it thereby preserves pre-surgery bone architecture as an optimized solution of nature.

11.
Unfallchirurg ; 120(2): 122-128, 2017 Feb.
Article in German | MEDLINE | ID: mdl-26271220

ABSTRACT

BACKGROUND: Type II fractures of the odontoid process of the axis are the most common injury of the cervical spine in elderly patients. Only little evidence exists on whether elderly patients should be treated conservatively or surgically. MATERIAL AND METHODS: The mortality and survival probability of 51 patients were determined in a retrospective study. The range of motion, pain and the neck disability index were clinically investigated. RESULTS: Of the 51 patients 37 were treated surgically and 14 conservatively. The conservatively treated group showed a higher mortality (64 % vs. 32 %). Kaplan-Meier analysis revealed a median survival of the conservatively treated group of 29 months, whereby during the first 3 months of treatment this group showed a higher survival probability and afterwards the surgically treated group showed a higher survival probability. The clinical examination of 20 patients revealed limited range of motion of the cervical spine. Additionally, moderate levels of pain and complaints were recorded using the neck disability index. CONCLUSION: Fractures of the odontoid process pose a far-reaching danger for elderly patients. A balanced assessment of the general condition should be carried out at the beginning of treatment of these patients. In the early phase following trauma no differences were found with respect to survival rates but for long-term survival the operatively treated group showed advantages; however, these advantages cannot be causally attributed to the choice of therapy.


Subject(s)
Immobilization/statistics & numerical data , Neck Pain/mortality , Odontoid Process/injuries , Spinal Fractures/mortality , Spinal Fractures/therapy , Spinal Fusion/mortality , Aged , Aged, 80 and over , Comorbidity , Germany/epidemiology , Humans , Incidence , Male , Neck Pain/prevention & control , Odontoid Process/surgery , Pain, Postoperative/mortality , Pain, Postoperative/prevention & control , Retrospective Studies , Risk Factors , Spinal Fusion/statistics & numerical data , Survival Rate , Treatment Outcome
12.
Ann Oncol ; 27(10): 1916-22, 2016 10.
Article in English | MEDLINE | ID: mdl-27456299

ABSTRACT

BACKGROUND: Central venous catheter (CVC)-related bloodstream infections (CRBSI) are a frequent cause of morbidity and mortality in patients with chemotherapy-induced neutropenia. Chlorhexidine containing catheter securement dressings may prevent CRBSI. PATIENTS AND METHODS: A multicenter randomized, controlled trial was conducted at 10 German hematology departments. We compared chlorhexidine-containing dressings with non-chlorhexidine control dressings in neutropenic patients. The primary end point was the incidence of definite CRBSI within the first 14 days (dCRBSI14) of CVC placement. Secondary end points included combined incidence of definite or probable CRBSI within 14 days (dpCRBSI14), overall (dpCRBSI), incidence of unscheduled dressing changes and adverse events. RESULTS: From February 2012 to September 2014, 613 assessable patients were included in the study. The incidence of dCRBSI14 was 2.6% (8/307) in the chlorhexidine and 3.9% (12/306) in the control group (P = 0.375). Both dpCRBSI14 and dpCRBSI were significantly less frequent in the study group with dpCRBSI14 in 6.5% (20/307) of the chlorhexidine group when compared with 11% (34/306) in the control group (P = 0.047), and dpCRBSI in 10.4% (32/307) versus 17% (52/306), respectively (P = 0.019). The frequency of dressing intolerance with cutaneous and soft tissue abnormalities at the contact area was similar in both groups (12.4% and 11.8%; P = 0.901). CONCLUSIONS: Although the trial failed its primary end point, the application of chlorhexidine containing catheter securement dressings reduces the incidence of definite or probable CRBSI in neutropenic patients. CLINICAL TRIALS NUMBER: NCT01544686 (Clinicaltrials.gov).


Subject(s)
Catheter-Related Infections/prevention & control , Central Venous Catheters/adverse effects , Chlorhexidine/administration & dosage , Neutropenia/drug therapy , Adolescent , Adult , Aged , Aged, 80 and over , Bandages , Catheter-Related Infections/complications , Catheter-Related Infections/pathology , Female , Humans , Male , Middle Aged , Neoplasms/complications , Neoplasms/drug therapy , Neoplasms/pathology , Neutropenia/chemically induced , Neutropenia/pathology
13.
Z Gastroenterol ; 54(7): 642-6, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27429101

ABSTRACT

PURPOSE: To investigate the effect of an early contrast-enhanced computed tomography (CECT) on clinical course and complications of acute pancreatitis (AP). MATERIAL AND METHODS: 58 patients with AP who had at least one CECT examination were analyzed retrospectively. Laboratory as well as clinical data, and results from the assessment of disease severity (CT severity index (CTSI) and its modified (MCTSI) version) were analyzed. The primary endpoint was the development of severe complications, defined as death, respiratory failure, acute renal failure, and the need for invasive interventions. Patients were divided into two groups: an early group (CECT within the first 48 h after the onset of symptoms, n = 32) and a late group (CECT > 48 h after the onset of symptoms, n = 26). Multivariate regression analysis was performed to identify risk factors for severe complications. RESULTS: There were no statistically significant differences between both groups concerning baseline characteristics, CTSI, and MCTSI. Complications occurred more often in the early CECT group (p = 0.008). Multivariate logistic regression analysis identified an early CECT and a severe MCTSI as independent risk factors for the occurrence of severe complications (p = 0.02 and p = 0.002, respectively). CONCLUSION: CECT performed within the first 48 h after the onset of symptoms is associated with an unfavorable outcome in AP.


Subject(s)
Acute Kidney Injury/mortality , Early Diagnosis , Pancreatitis/diagnostic imaging , Pancreatitis/mortality , Respiratory Insufficiency/mortality , Tomography, X-Ray Computed/statistics & numerical data , Acute Disease , Acute Kidney Injury/diagnosis , Adult , Aged , Aged, 80 and over , Contrast Media , Disease Progression , Female , Germany/epidemiology , Humans , Length of Stay/statistics & numerical data , Male , Middle Aged , Pancreatectomy/mortality , Pancreatectomy/statistics & numerical data , Pancreatitis/surgery , Reproducibility of Results , Respiratory Insufficiency/diagnosis , Retrospective Studies , Risk Factors , Sensitivity and Specificity , Survival Rate , Young Adult
14.
Med Mycol ; 54(6): 576-83, 2016 Aug 01.
Article in English | MEDLINE | ID: mdl-26941254

ABSTRACT

UNLABELLED: Aspergillus spp.-related morbidity and mortality remains a major challenge in the management of neutropenic patients. Little is known about the impact of domestic Aspergillus spp. EXPOSURE: In this controlled prospective study, fungal spores were collected from homes of neutropenic patients. Cases were defined as patients with probable or proven controls as patients with no invasive pulmonary aspergillosis, while patients with possible disease were evaluated as a third group. Forty patients were enrolled and returned questionnaires on high-risk activities and mould exposure. A. fumigatus was detected in concentrations of 0 to 76 cfu/m(3) in every home. A. terreus was detected in nine (18%) homes. Mean Aspergillus spp. cfu/m(3) according to EORTC criteria were: proven/probable IA (15 patients) - 36; possible IA (12 patients) - 42; no IA (13 patients) - 42. Of the seven patients with self-reported moulded walls at home, four had probable and three had possible aspergillosis; the risk ratio of developing IA was 1.65 (95% CI: 1.25-2.17). In conclusion self-reported domestic mould exposure was associated with a high incidence of IA and may be a feasible tool for identifying high-risk patients. There was no correlation between domestic ambient-air spore counts and IA.


Subject(s)
Air Microbiology , Aspergillus/isolation & purification , Environmental Exposure , Hematologic Diseases/complications , Invasive Pulmonary Aspergillosis/epidemiology , Invasive Pulmonary Aspergillosis/etiology , Spores, Fungal/isolation & purification , Adult , Aged , Case-Control Studies , Colony Count, Microbial , Female , Humans , Incidence , Male , Middle Aged , Pilot Projects , Prospective Studies , Surveys and Questionnaires , Young Adult
15.
J Orofac Orthop ; 76(1): 30-40, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25613383

ABSTRACT

OBJECTIVE: Micro- and retrognathia of mandibular origin may lead to life-threatening respiratory problems in connection with glossoptosis immediately after birth. Prenatal screening for this malformation is therefore increasingly important. Today this is accomplished by predominantly subjective standards. Objective criteria have been proposed but have not become established. We therefore made an effort to develop indices that would identify major skeletal discrepancies or micrognathia in as straightforward a fashion as possible during routine prenatal sonography. MATERIALS AND METHODS: Series of fetal jaw sonograms (Toshiba Aplio MX®) were obtained in 313 women with normal pregnancies from weeks 19-29 of gestation. Upper- and lower-jaw landmarks were interactively located on screen and evaluated for reproducibility. Linear parameters representative of maxillary and mandibular length (SpA'-SpP' and Rami-SymMe) were measured and related to femur length and gestational age. Based on these data, indices for maxillary, and mandibular length were derived and analyzed. RESULTS: High correlations were identified for mandibular length both with gestational age (R = 0.845; R(2) = 0.713) and with femur length (correlation coefficients (R) = 0.839; coefficients of determination (R(2)) = 0.704). For maxillary length, the respective correlation coefficients were 0.691 (R(2) = 0.477) and 0.656 (R(2) = 0.430). Estimates of mandibular and maxillary length based on gestational age and femur length were obtained by regression analysis. The mean bimaxillary length ratio was 0.628 ± 0.043. CONCLUSION: Maxillary and mandibular growth can be objectively evaluated via indices. It is conceivable to develop this approach into a sensitive and reliable method of prenatal jaw screening for major skeletal anomalies and congenital malformations.


Subject(s)
Mandible/diagnostic imaging , Mandible/embryology , Micrognathism/diagnostic imaging , Retrognathia/diagnostic imaging , Ultrasonography, Prenatal/methods , Ultrasonography, Prenatal/standards , Anthropometry/methods , Female , Germany , Humans , Image Interpretation, Computer-Assisted/methods , Image Interpretation, Computer-Assisted/standards , Male , Mandible/abnormalities , Micrognathism/embryology , Reference Values , Reproducibility of Results , Retrognathia/embryology , Sensitivity and Specificity
16.
J Orofac Orthop ; 74(4): 275-86, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23807257

ABSTRACT

OBJECTIVES: In order to visualize and quantify the direction and extent of morphological upper-jaw changes in infants with unilateral cleft lip and palate (UCLP) during early orthodontic treatment, a three-dimensional method of cast analysis for routine application was developed. In the present investigation, this method was used to identify reaction patterns associated with specific cleft forms. MATERIALS AND METHODS: The study included a cast series reflecting the upper-jaw situations of 46 infants with complete (n=27) or incomplete (n=19) UCLP during week 1 and months 3, 6, and 12 of life. Three-dimensional datasets were acquired and visualized with scanning software (DigiModel®; OrthoProof, The Netherlands). Following interactive identification of landmarks on the digitized surface relief, a defined set of representative linear parameters were three-dimensionally measured. At the same time, the three-dimensional surfaces of one patient series were superimposed based on a defined reference plane. Morphometric differences were statistically analyzed. RESULTS: Thanks to the user-friendly software, all landmarks could be identified quickly and reproducibly, thus, allowing for simultaneous three-dimensional measurement of all defined parameters. The measured values revealed that significant morphometric differences were present in all three planes of space between the two patient groups. Patients with complete UCLP underwent significantly larger reductions in cleft width (p<0.001), and sagittal growth in the complete UCLP group exceeded sagittal growth in the incomplete UCLP group by almost 50% within the first year of life. CONCLUSION: Based on patients with incomplete versus complete UCLP, different reaction patterns were identified that depended not on apparent severities of malformation but on cleft forms.


Subject(s)
Aging/pathology , Cleft Lip/pathology , Cleft Lip/surgery , Cleft Palate/pathology , Cleft Palate/surgery , Imaging, Three-Dimensional/methods , Maxillofacial Development , Anatomic Landmarks/pathology , Cleft Lip/physiopathology , Cleft Palate/physiopathology , Dental Casting Technique , Female , Humans , Infant , Infant, Newborn , Male , Maxilla/growth & development , Maxilla/pathology , Reproducibility of Results , Sensitivity and Specificity , Treatment Outcome
17.
Cell Tissue Res ; 352(3): 509-21, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23430474

ABSTRACT

Mesenchymal stem cells have become extremely interesting for regenerative medicine and tissue engineering in the horse. Stem cell therapy has been proven to be a powerful and successful instrument, in particular for the healing of tendon lesions. We pre-differentiated equine adipose-tissue-derived stem cells (ASCs) in a collagen I gel scaffold by applying tensile strain, growth differentiation factors (GDFs) and various oxygen tensions in order to determine the optimal conditions for in vitro differentiation toward the tenogenic lineage. We compared the influence of 3% versus 21% oxygen tension, the use of GDF 5, GDF 6 and GDF 7 and the application of uniaxial tensile strain versus no mechanical stimulation on differentiation results as evaluated by cell morphology and by the expression of the tendon-relevant genes collagen I, collagen III, cartilage oligomeric matrix protein and scleraxis. The best results were obtained with an oxygen tension of 21%, tensile stimulation and supplementation with GDF 5 or GDF 7. This approach raises the hope that the in vivo application of pre-differentiated stem cells will improve healing and recovery time in comparison with treatment involving undifferentiated stem cells.


Subject(s)
Adipose Tissue/cytology , Cell Differentiation/drug effects , Growth Differentiation Factors/pharmacology , Oxygen/pharmacology , Stem Cells/cytology , Tendons/cytology , Tensile Strength/drug effects , Animals , Biomarkers/metabolism , Bioreactors , Cell Communication/drug effects , Cell Lineage/drug effects , Cell Shape/drug effects , Collagen Type I/pharmacology , Gels , Gene Expression Regulation/drug effects , Horses , Immunohistochemistry , Intercellular Junctions/drug effects , Intercellular Junctions/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Stem Cells/drug effects , Stem Cells/ultrastructure , Tissue Scaffolds
18.
J Mech Behav Biomed Mater ; 4(7): 1452-61, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21783155

ABSTRACT

Compressive behaviour of bovine cancellous bone and three open-cell metallic foams (AlSi7Mg (30 ppi and 45 ppi); CuSn12Ni2 (30 ppi)) has been studied using mechanical testing, micro-focus computed tomography and finite element modelling. Whilst the morphological parameters of the foams and the bone appear to be similar, the mechanical properties vary significantly between the foams and the bone. Finite element models were built from the CT images of the samples and multi-linear constitutive relations were used for modelling of the bone and the foams. The global responses of the bone and foam samples were reasonably well captured by the FE models, whilst the percentage of yielded elements as a measure of damage evolution during compression seems to be indicative of the micro-mechanical behaviour of the samples. The damage evolution and distribution patterns across the bone and the foams are broadly similar for the strain range studied, suggesting possible substitution of trabecular bones with appropriate foams for biomechanical studies.


Subject(s)
Biomimetic Materials , Bone and Bones/diagnostic imaging , Compressive Strength , Finite Element Analysis , Materials Testing , X-Ray Microtomography , Animals , Biomechanical Phenomena , Bone and Bones/physiology , Cattle , Metals
19.
Rofo ; 181(3): 220-9, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19229787

ABSTRACT

PURPOSE: To determine whether CTCA supplemented with CT flow measurements can be used to demonstrate and semiquantitatively evaluate poststenotic coronary blood flow in a porcine model. MATERIALS AND METHODS: In 10 thoracotomized pigs, transit time flow meter probes were attached to the aorta and left anterior descending artery (LAD) for real-time blood flow volumetry. A vascular silicone occluder was deployed around the LAD proximal to the probe to create medium-grade (MGS) and high-grade stenoses (HGS). The blood flow was measured by CT without vessel occlusion and distal to the stenoses. Time-density curves were generated from CT data. The curves were evaluated by calculating and cross-plotting the variables "slope of the density increase", "peak density" and "slope of the post-peak density decrease" from the LAD and aortic CT data. RESULTS: The flow in the LAD dropped to 41 % +/- 9 % (mean +/- SD) for MGS and 12 % +/- 6 % for HGS of the baseline. Coronary time-density curves plateaued proportional to luminal narrowing. Unimpaired flow could be differentiated statistically significant from poststenotic flow adjacent to MGS and HGS (p < 0.000 and p < 0.002, respectively). Flow adjacent to MGS and HGS was successfully differentiated for "slope of the density increase" and "slope of the post-peak density decrease" (p < 0.003 and p < 0.030, respectively). CONCLUSION: CT measurements allow semiquantitative evaluation of poststenotic coronary blood flow.


Subject(s)
Coronary Angiography/methods , Coronary Circulation/physiology , Image Processing, Computer-Assisted/methods , Models, Cardiovascular , Tomography, Spiral Computed/methods , Animals , Blood Flow Velocity/physiology , Blood Volume/physiology , Contrast Media , Coronary Angiography/instrumentation , Coronary Stenosis/diagnostic imaging , Coronary Stenosis/physiopathology , Equipment Design , Flowmeters , Iopamidol/analogs & derivatives , Sensitivity and Specificity , Swine , Tomography, Spiral Computed/instrumentation
20.
Ann Oncol ; 18(3): 479-84, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17272832

ABSTRACT

BACKGROUND: The following study was conducted to explore patients' information needs and preferences with a special focus on doctor-patient communication. PATIENTS AND METHODS: A 62-item questionnaire developed by a multidisciplinary team and validated in a phase-I study was given to breast cancer patients via the Internet (homepage) or in a hard copy version. RESULTS: A total of 617 patients responded, 552 on line and 65 via the hard copy questionnaire. The median age of the on-line group was 47 (21-85) and 55 (40-92) in the hard copy group. Sixty-five per cent of the patients were treated with the intention of achieving a cure and 35% of the patients had metastatic disease. The median length of the consultation communicating the information 'You have breast cancer' was 15 min (0-300). The most effective and patient-relevant source of information about the disease and the treatment options was consultation with the physician (84%). When asked to suggest areas for improvement, patients' most common answers were: more complementary therapies should be offered by the physician (54%); physicians should take more time to explain things (51%); and cooperation between the physicians involved in the patient's care should be improved (39%). The questions most relevant to patients were: 'Am I getting the right therapy?' (89%); 'How many patients with my condition does my doctor treat?' (46%) and 'Can I be enrolled into a trial?' (46%). An independent second opinion centre was desired by 94% of the respondents but only 20% knew of any such resource. CONCLUSIONS: This study underlines the need to give patients with breast cancer the full details on treatment options and cancer management. The results provide a suitable basis for a broader interdisciplinary discussion of the patient-physician relationship and should be useful in generating hypotheses for subsequent prospective studies.


Subject(s)
Attitude of Health Personnel , Breast Neoplasms/therapy , Health Knowledge, Attitudes, Practice , Patient Satisfaction , Physician-Patient Relations , Adult , Aged , Aged, 80 and over , Breast Neoplasms/psychology , Decision Making , Female , Germany , Health Care Surveys , Humans , Internet , Middle Aged , Patient Education as Topic , Patients/psychology , Referral and Consultation , Surveys and Questionnaires
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