ABSTRACT
In the southeastern part of Turkey, two earthquakes measuring 7.7 and 7.8 on the Richter scale occurred within 9 h on 6 February 2023, causing 120,000 injuries and over 50,000 deaths. Evacuees were transferred to various secondary and tertiary hospitals as the health system and hospitals in the affected region were affected by the earthquake. Injuries were mostly caused by blunt trauma and/or prolonged bruising under rubble. The severity and pattern of traumatic injuries in earthquake victims differed from other trauma patients who were not affected by an earthquake. In addition to traumatic injuries that affected multiple body regions and systems, patients who were trapped under debris for long periods of time were also frequently found to have crush syndrome. Pulmonary thromboembolism and hypoxic-ischaemic brain injury were observed in some patients. In this review, we present the imaging findings of traumatic injuries in earthquake victims, emphasising the earthquake-related distinct injury types.
Subject(s)
Crush Syndrome , Earthquakes , Wounds, Nonpenetrating , Humans , Turkey/epidemiology , Crush Syndrome/complications , SurvivorsABSTRACT
OBJECTIVE: The exact pathophysiology of meconium passage into the amniotic fluid is unknown, but it is frequently associated with fetal hypoxia. The mean platelet volume (MPV) seems to be a marker of platelet production and consumption and may be related to the severity of some diseases associated with bone marrow, hypoxia, and perinatal infections. We aimed to investigate the association between MPV levels and meconium-stained amniotic fluid (MSAF) in infants. PATIENTS AND METHODS: MPV, serum-reactive protein and hemoglobin levels, and leukocyte and thrombocyte counts were measured in 106 infants with MSAF and a comparison group of 78 healthy control infants. RESULTS: The mean MPV values of the infants with MSAF were statistically significantly lower than those of the control group (p < 0.001). There was no statistically significant difference in the hemoglobin levels or leukocyte and thrombocyte counts in the study group compared to the control group (p > 0.05). There was also no statistically significant difference in the MPV levels of the infants with meconium aspiration syndrome (MAS) compared to the infants with MSAF without MAS (p = 0.107). The optimal cut-off value for the MPV was 9.90 fl (area under the curve [AUC: 0.788]) in the infants with MSAF, with a sensitivity of 78.1% and specificity of 74.3%. CONCLUSIONS: Our data suggest that the MPV levels of infants with MSAF were significantly lower than those of healthy infants. This might be associated with a hypoxic process. However, the MPV levels of infants with MSAF and MAS were statistically similar. Thus, the MPV level could not be used to detect patients with or without severe disease.
Subject(s)
Amniotic Fluid/metabolism , Mean Platelet Volume , Meconium , Biomarkers/metabolism , Female , Humans , Infant , Infant, Newborn , Meconium Aspiration Syndrome , PregnancySubject(s)
Dermoscopy , Histiocytoma, Benign Fibrous/pathology , Microscopy, Confocal/methods , Adult , Female , Humans , Young AdultABSTRACT
BACKGROUND/OBJECTIVE: Reflectance confocal microscopy (RCM) is a noninvasive, objective imaging technique that provides in vivo, high-resolution skin imaging. We sought to assess epidermal and dermal changes associated with the psoriasis and its treatment with RCM before the treatment and at weeks 4 and 8 of the treatment. MATERIAL AND METHODS: This is an investigator-blinded, internal-controlled, follow-up study. A total of 25 patients with plaque psoriasis were included in the study. The RCM evaluation criteria were defined on the basis of the histopathological diagnostic criteria for psoriasis. The clinical severity of the psoriasis was evaluated using the Psoriasis Area Severity Index (PASI). RESULTS: The RCM findings which were correlated with the PASI can be used to follow up the patient's response to treatment have been identified as follows: the acanthosis, the number of spongiotic sites, the number of regular/irregular honeycomb-like sites, the number of epidermal inflammatory cells, the number of focal microabscesses, the total epidermal thickness, the number of nonedge dermal papillae, the length of the papillary dermis, the number of dermal inflammatory cells, and the vascularization in the papillary dermis (P < 0.05). CONCLUSION: This is the first study with a large group of patients to perform a noninvasive assessment with RCM of the response of psoriasis to different treatments: phototherapy, systemic and topical treatment. Micrometric and morphometric changes occurring in the psoriatic tissue during the 8-week treatment period were identified by in vivo RCM in a noninvasive manner. RCM is capable of monitoring of treatment response in psoriasis.
Subject(s)
Dermoscopy/methods , Microscopy, Confocal/methods , Microscopy, Interference/methods , Psoriasis/pathology , Psoriasis/therapy , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Single-Blind Method , Skin/pathology , Treatment Outcome , Young AdultABSTRACT
BACKGROUND: The characteristic vascular patterns of nonpigmented skin tumors have been established by dermoscopy. Recently, in vivo reflectance confocal microscopy (RCM) has become an established method for the noninvasive examination of skin tumors. OBJECTIVES: Determination of the value of RCM on the vascularity of nonpigmented skin tumors. METHODS: One hundred and twenty two tumoral lesions have been evaluated by RCM in terms of their vascular structures. They were classified in five groups as basal cell carcinoma (BCC), seborrheic keratosis (SK), squamous cell carcinoma (SCC)/keratoacanthoma, actinic keratosis (AK)/Bowen disease and others. Vascular morphologies were investigated as curved linear, straight linear, branching, tubular/canalicular, round and polymorphic vessels in six types. LIMITATIONS: Relatively, small number of patients with some tumor subgroups is limitation. Larger prospective studies are required before firm conclusions can be drawn. RESULTS: Excellent compliance was obtained in interobserver analysis. Branching vessels had a high predictive value for basal cell carcinoma (BCC) with RCM (P < 0.001). Also vascular polymorphism was more frequently (69.4%) seen in malignant nonpigmented tumors (P < 0.05) than benign nonpigmented tumors (30.6%). Furthermore, vessels with opposite flows had high predictive value for malignant tumors (P < 0.05) compared with benign tumors. CONCLUSION: Vascular properties can be evaluated in the diagnosis of nonpigmented tumoral skin lesions via RCM.
Subject(s)
Dermoscopy/methods , Microscopy, Confocal/methods , Neovascularization, Pathologic/pathology , Skin Neoplasms/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Image Enhancement/methods , Male , Middle Aged , Neovascularization, Pathologic/classification , Observer Variation , Pigmentation Disorders/pathology , Reproducibility of Results , Sensitivity and Specificity , Skin Neoplasms/classification , Young AdultABSTRACT
BACKGROUND/PURPOSE: Increased interest in antiaging methods, mandates a development of reliable noninvasive technique to assess skin aging. In this study, we aimed to determine the effects of photoaging at histopathologic resolution by means of reflectance confocal microscopy. METHOD: The sun-exposed malar area, the anterior aspect of ear lobule, and the sun-protected posterior aspect of ear lobule had been evaluated in 120 volunteers from different age groups over 10 previously reported and new confocal parameters for skin aging. RESULT: The sun-exposed areas revealed more frequent irregular honeycomb pattern, polycylic papillary contours, coarse collagen, huddled collagen, curled bright structures with higher epidermal thickness, and furrow depth values. However, the incidence of thin reticulated collagen and the number of dermal papillae were statistically higher on the sun-protected posterior aspect of ear lobule. CONCLUSION: Reflectance confocal microscopy is a reliable diagnostic technique for evaluation of skin photoaging with objective criteria. With the new emerging compact models it is possible to scan even the least accessible body parts with no discomfort to the patient, which offers the possibility to assess the effect of antiaging applications and to identify early signs of solar damage in cosmetically sensitive areas.
Subject(s)
Aging/physiology , Dermoscopy/methods , Microscopy, Confocal/methods , Microscopy, Interference/methods , Skin Aging/physiology , Skin/cytology , Adult , Aged , Aged, 80 and over , Female , Humans , Image Interpretation, Computer-Assisted/methods , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Skin/radiation effects , SunlightABSTRACT
BACKGROUND: Reflectance confocal microscopy (RCM) has been recently shown to be effective for measuring the Demodex mite density. OBJECTIVES: To compare and demonstrate the advantages and disadvantages of standardized skin surface biopsy (SSSB) and RCM for measuring the density of Demodex mites. MATERIALS AND METHODS: Forty-eight patients (30 female, 18 male) and 47 healthy controls (30 female, 17 male) were enrolled in the study. The patients diagnoses were pityriasis folliculorum (n = 40), papulopustulary rosecea (n = 7) and erythema-telengiectatic rosacea (n = 1). The area with the most intense erythema on the right cheek was selected for imaging with RCM (VivaScope 3000) and SSSB. RESULTS: Forty-two patients demonstrated high Demodex density [(Dd) > 5 mites/cm(2) ] with SSSB (85.7%). RCM identified demodicosis in 48 patients (100%). The mean Dd measured with RCM (409.8 ± 209.2) was significantly higher than SSSB (15.33 ± 18.1) (P < 0.001). In the patients, RCM demonstrated the mean number of mites 40.90 ± 20.9 and 4.11 ± 6.4 in the controls per 10 mm(2) area. The corresponding mean number of 2.63 ± 0.77 mites was detected in the infested follicles per area of view compared to a mean of 0.77 ± 0.98 mites in the infested follicles in the controls (P < 0.001). CONCLUSION: Reflectance confocal microscopy is a fast, direct and noninvasive method for Demodex-associated diseases and it is superior to SSSB for Demodex mite detection.
Subject(s)
Microscopy, Confocal/methods , Microscopy, Interference/methods , Mite Infestations/pathology , Mite Infestations/parasitology , Mites/cytology , Skin/pathology , Skin/parasitology , Adult , Animals , Biopsy/methods , Dermoscopy/methods , Female , Humans , Male , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Articular cartilage experiences significant mechanical loads during daily activities. Healthy cartilage provides the capacity for load bearing and regulates the mechanobiological processes for tissue development, maintenance, and repair. Experimental studies at multiple scales have provided a fundamental understanding of macroscopic mechanical function, evaluation of the micromechanical environment of chondrocytes, and the foundations for mechanobiological response. In addition, computational models of cartilage have offered a concise description of experimental data at many spatial levels under healthy and diseased conditions, and have served to generate hypotheses for the mechanical and biological function. Further, modeling and simulation provides a platform for predictive risk assessment, management of dysfunction, as well as a means to relate multiple spatial scales. Simulation-based investigation of cartilage comes with many challenges including both the computational burden and often insufficient availability of data for model development and validation. This review outlines recent modeling and simulation approaches to understand cartilage function from a mechanical systems perspective, and illustrates pathways to associate mechanics with biological function. Computational representations at single scales are provided from the body down to the microstructure, along with attempts to explore multiscale mechanisms of load sharing that dictate the mechanical environment of the cartilage and chondrocytes.
Subject(s)
Cartilage/physiology , Models, Biological , Animals , Biomechanical Phenomena , Humans , Joints/physiology , Muscle, Skeletal/physiologyABSTRACT
OBJECTIVES: The aim of this study is to evaluate the views of cancer patients on patient rights in the context of the right to information and autonomy according to articles related to the issue in the "Patient Rights Regulation". METHODS: The research was conducted among cancer patients in the medical oncology department of a research and practice hospital using a random sampling method between June and September 2005. Data were collected during face-to-face interviews using a questionnaire. RESULTS: There was a high rate of positive response to the items that the patients have the right to be informed (86.5%), that the physician should inform the patient on the diagnosis and the treatment (92.3%) and that the physician is obliged to inform the patient (76.9%). Only 43.3% of the patients stated that the patient has the right to refuse the treatment recommended by the physician. The participants mostly agreed that the patient should participate in decisions about the treatment and that patient consent should be given (78.8%). CONCLUSIONS: There are extensive efforts in Turkey towards making patient rights a significant supportive component of health services. For patient rights to become a natural part of medical practice it is necessary to give priority to education of both patients and physicians about patient rights and to lay emphasis on an ethical approach in the patient-physician relationship.
Subject(s)
Attitude to Health , Patient Rights/ethics , Personal Autonomy , Physician-Patient Relations/ethics , Truth Disclosure/ethics , Adolescent , Adult , Aged , Aged, 80 and over , Demography , Female , Humans , Male , Middle Aged , Neoplasms/psychology , Patient Participation/psychology , Patient Rights/legislation & jurisprudence , Surveys and Questionnaires , TurkeyABSTRACT
In medical practice and research it is necessary to consider the rights of the researcher or physician and of the subject or patient, to conform to scientific standards and to examine the appropriateness with respect to laws and moral values. Research ethics committees have an important role to play in ensuring the ethical standards and scientific merit of research on human subjects. Research of no scientific value is also against ethical principles. To obtain valid and reliable results from biomedical research, it is a scientific and ethical obligation to make use of the science of statistics. Therefore, for research to be evaluated using biostatistics intensively from ethical and scientific points of view, a biostatistics expert is necessary on research ethics committees. Developments in Turkey are used as examples.
Subject(s)
Ethics Committees, Research/organization & administration , Human Experimentation/ethics , Research/standards , Biometry , Data Interpretation, Statistical , Guidelines as Topic , Human Experimentation/standards , Humans , Social ResponsibilityABSTRACT
AIM: To evaluate the accuracy of the Root ZX (J Morita Corp., Kyoto, Japan) and Tri Auto ZX (J Morita Corp.) devices for measuring root canal length in primary teeth with and without apical resorption. METHODOLOGY: Thirty-four extracted human primary molar teeth with resorption and 19 primary teeth without resorption were collected. After endodontic access preparation, the actual lengths of the teeth were determined. The teeth were then embedded in an alginate model to determine the electronic working length measurement. Statistical evaluation was completed using Student's t-tests. RESULTS: For the Root ZX, there was no significant difference between those teeth with root resorption and those without. However, for the Tri Auto ZX, there was a significant difference in the electronic measurements between those teeth with root resorption and those without (P < 0.05). Significant differences were found amongst the measurements of the two apex locators (P < 0.05). For root canals with resorption, the respective accuracy rates (within +/-0.5 mm) of Root ZX and Tri Auto ZX were 83.33% and 89.47%; within +/-1 mm, the Root ZX and Tri Auto ZX demonstrated 98.95% and 100% accuracy, respectively. For root canals with no resorption, the percentage of measurements within +/-0.5 mm of the apical construction was 89.28% for the Root ZX and 80.35% for the Tri Auto ZX. The accuracy within +/-1 mm of the Root ZX and the Tri Auto ZX was 98.22% and 100%, respectively. CONCLUSION: Within the limitations of this laboratory study, the presence of resorption affected the performance of the Tri Auto ZX more than the Root ZX.
Subject(s)
Dental Pulp Cavity/anatomy & histology , Odontometry/instrumentation , Root Canal Preparation/instrumentation , Root Resorption/pathology , Tooth Apex/anatomy & histology , Tooth, Deciduous/anatomy & histology , Dental Instruments , Electronics, Medical , Humans , Molar/anatomy & histology , Tooth Apex/pathologyABSTRACT
AIM: To determine the influence of various irrigating solutions on the accuracy of the electronic apex locator facility in the Tri Auto ZX handpiece. METHODOLOGY: One hundred and forty teeth with single canals and mature apices, scheduled for extraction for either periodontal or prosthetic reasons in 76 patients were used. Following informed written consent local anaesthesia was administered, access cavities were prepared and pulp tissue removed. The teeth were then randomly divided into seven groups according to the irrigating solutions used. The root canal length measurements were completed using the Tri Auto ZX handpiece with automatic reverse function in the presence of one or other of the following solutions: 0.9% saline, 2.5% NaOCl, 3% H(2)O(2), 0.2% chlorhexidine, 17% EDTA, Ultracaine D-S or in the absence of an irrigating solution (control). Files were immobilized in the access cavity with composite resin. After extraction, the apical regions of the teeth were exposed and the file tips examined under a stereomicroscope. Distances between the file tips and the apical constriction were measured (mm) and analysed using a one-way anova and post hoc Tukey test. RESULTS: Mean distances from the apical constriction to the file tip were longer in the 0.9% saline group (P<0.05). There was no statistically significant difference on file tip position between the other solutions. CONCLUSIONS: Tri Auto ZX gave reliable results with all irrigating solutions apart from in the presence of 0.9% saline.
Subject(s)
Dental High-Speed Equipment , Odontometry/instrumentation , Root Canal Irrigants/adverse effects , Tooth Apex , Adolescent , Adult , Aged , Analysis of Variance , Female , Humans , Male , Middle AgedABSTRACT
BACKGROUND: Finite element (FE) analysis has shown promise for the evaluation of elastomeric foam personal protection devices. Although appropriate representation of foam materials is necessary in order to obtain realistic simulation results, material definitions used in the literature vary widely and often fail to account for the multi-mode loading experienced by these devices. This study aims to provide a library of elastomeric foam material parameters that can be used in FE simulations of complex loading scenarios. METHOD OF APPROACH: Twelve foam materials used in footwear were tested in uni-axial compression, simple shear and volumetric compression. For each material, parameters for a common compressible hyperelastic material model used in FE analysis were determined using: (a) compression; (b) compression and shear data; and (c) data from all three tests. RESULTS: Material parameters and Drucker stability limits for the best fits are provided with their associated errors. The material model was able to reproduce deformation modes for which data was provided during parameter determination but was unable to predict behavior in other deformation modes. CONCLUSIONS: Simulation results were found to be highly dependent on the extent of the test data used to determine the parameters in the material definition. This finding calls into question the many published results of simulations of complex loading that use foam material parameters obtained from a single mode of testing. The library of foam parameters developed here presents associated errors in three deformation modes that should provide for a more informed selection of material parameters.
Subject(s)
Elastomers/chemistry , Finite Element Analysis , Cellulose/chemistry , Computer Simulation , Humans , Polyethylene/chemistry , Polyurethanes/chemistry , Shoes , Stress, MechanicalABSTRACT
AIM: To compare in vitro two different fibre placement techniques on reinforcement of root-filled molar teeth with mesio-occluso-distal (MOD) cavities. METHODOLOGY: Fifty sound extracted human mandibular molars were used (n = 10). Group 1 served as control. From group 2-5, endodontic access and standard MOD cavities were prepared. Following root canal treatment, group 2 was kept unrestored. In groups 3 and 4, the teeth were restored with composite resin (AP-X; Kuraray, Japan). A groove was prepared on occlusal surface of the finished restorations in group 4 from buccal to lingual direction. Polyethylene woven fibre (Ribbond; Seattle, WA, USA) was inserted in the groove in combination with flowable resin that was cured for 20 s and covered with composite resin. Cavity surfaces were covered with flowable resin in group 5, and polyethylene fibre was placed into the bed of resin in a buccal to lingual direction before the composite restoration was placed. All specimens were stored in 100% humidity at 37 degrees C for 24 h. Compressive loading of the teeth was performed by a universal testing machine at a crosshead speed of 0.5 mm min(-1) until failure. The data were recorded in Newton and submitted to anova and Tukey post hoc test. RESULTS: The mean load necessary to fracture the samples in each group was: G1: 1671.57 +/- 131.54(a); G2: 375.21 +/- 34.30(b); G3: 749.47 +/- 124.54(c); G4: 1224.36 +/- 132.17(d); G5: 926.88 +/- 118.28(e). Different superscript letters demonstrate significant difference between groups. CONCLUSIONS: Polyethylene fibre use over or under MOD composite restorations significantly increased fracture strength. However, when the fibre was placed on the occlusal surface of the restoration in buccal to lingual direction, significantly higher fracture resistance was observed.
Subject(s)
Dental Materials/chemistry , Dental Restoration, Permanent/methods , Polyethylenes/chemistry , Root Canal Therapy , Composite Resins/chemistry , Dental Cavity Preparation/classification , Dental Stress Analysis , Humans , Materials Testing , Methacrylates/chemistry , Molar , Resin Cements/chemistry , Stress, Mechanical , Surface Properties , Tooth Fractures/physiopathologyABSTRACT
As an element, carbon is rather unique and offers a range of rare opportunities for the design and fabrication of zero-, one-, two-, and three-dimensional nanostructured novel materials and coatings such as fullerenes, nanotubes, thin films, and free-standing nano-to-macroscale structures. Among these, carbon-based two-dimensional thin films (such as diamond and diamond-like carbon (DLC)) have attracted an overwhelming interest in recent years, mainly because of their exceptional physical, chemical, mechanical, electrical, and tribological properties. In particular, certain DLC films were found to provide extremely low friction and wear coefficients to sliding metallic and ceramic surfaces. Since the early 1990s, carbon has been used at Argonne National Laboratory to synthesize a class of novel DLC films that now provide friction and wear coefficients as low as 0.001 and 10(-11)-10(-10) mm(3) N(-1) m(-1), respectively, when tested in inert or vacuum test environments. Over the years, we have optimized these films and applied them successfully to all kinds of metallic and ceramic substrates and evaluated their friction and wear properties under a wide range of sliding conditions. In this paper, we will provide details of our recent work on the deposition, characterization, and tribological applications of near-frictionless carbon films on glass and ceramic substrates. We will also provide chemical and structural information about these films and describe the fundamental tribological mechanisms that control their unusual friction and wear behaviour.
ABSTRACT
AIM: To evaluate the effect of using flowable composite with or without leno woven ultra high modulus polyethylene fibre reinforcement on fracture resistance of root filled mandibular molars with mesio-occlusodistal (MOD) preparations. METHODOLOGY: Sixty sound extracted human mandibular molars were randomly assigned to five groups (n = 12). Group 1 did not receive any preparation. From groups 2 to 5, the teeth were root filled and MOD preparations were created. Group 2 remained unrestored. Group 3 was restored with a dentine bonding system (DBS; SE Bond, Kuraray, Japan) and composite resin (CR) (AP-X; Kuraray). In group 4, flowable composite resin (Protect Liner F; Kuraray) was used before restoring teeth with CR. In group 5, leno woven ultra high modulus polyethylene ribbon fibre (Ribbond, Seattle, WA, USA) was inserted into the cavities in a buccal to lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens were stored in 100% humidity at 37 degrees C for 1 day. Compressive loading of the teeth was performed using a universal testing machine at a crosshead speed of 0.5 mm min(-1). The mean load necessary to fracture the samples were recorded in newtons (N) and were subjected to analysis of variance (ANOVA) and Tukey post-hoc test. RESULTS: The mean load necessary to fracture the samples in each group were (in N): group 1: 1676.75 +/-154.63(a), group 2: 376.51 +/- 37.36(b), group 3: 733.23 +/- 133.33(c), group 4: 786.48 +/- 145.34(c), group 5: 943.63 +/- 121.15(d). There were statistically significant differences between the groups annotated with different letters. CONCLUSIONS: (i) Use of flowable composite resin under composite restorations had no effect on fracture resistance of root filled molar teeth with MOD preparations, (ii) use of polyethylene ribbon fibre under composite restorations in root filled teeth with MOD preparations significantly increased fracture strength.
Subject(s)
Composite Resins , Dental Cavity Lining/methods , Dental Restoration, Permanent/methods , Polyethylenes , Tooth Fractures/prevention & control , Tooth, Nonvital , Analysis of Variance , Compressive Strength , Dental Cavity Preparation , Dental Stress Analysis , Dentin-Bonding Agents , Humans , Materials Testing , Methacrylates , Molar , Random Allocation , Resin CementsABSTRACT
The purpose of this in vitro study was to evaluate the effect of gutta-percha solvents on the microhardness and the roughness of human root dentine. Forty-five recently extracted human mandibular anterior teeth were used. The teeth were sectioned longitudinally, embedded in acrylic resin and polished. Ninety specimens were divided into three groups containing 30 teeth each. In group 1, the specimens were treated with chloroform for 15 min. In group 2, the specimens were treated with halothane for 15 min. In group 3, distilled water was used and this group was served as control. All groups were then divided into two subgroups of 15 specimens each. The specimens, in groups 1a, 2a and 3a, were submitted to Vicker's microhardness indentations. Groups 1b, 2b and 3b were used for determination of the roughness of root dentine. The data were recorded as Vicker's numbers and Ra, mum for roughness test. The results were then analysed by one-way ANOVA and post hoc Tukey tests. The results indicated that chloroform and halothane did not affect the microhardness and the roughness of root dentine (P > 0.05).
Subject(s)
Dentin , Gutta-Percha , Solvents , Tooth Root , Hardness , Humans , Surface PropertiesABSTRACT
The NIST watt balance experiment is being completely rebuilt after its 1998 determination of the Planck constant. That measurement yielded a result with an approximately 1×10(-7) relative standard uncertainty. Because the goal of the new incarnation of the experiment is a ten-fold decrease in uncertainty, it has been necessary to reexamine many sources of systematic error. Hysteresis effects account for a substantial portion of the projected uncertainty budget. They arise from mechanical, magnetic, and thermal sources. The new experiment incorporates several improvements in the apparatus to address these issues, including stiffer components for transferring the mass standard on and off the balance, better servo control of the balance, better pivot materials, and the incorporation of erasing techniques into the mass transfer servo system. We have carried out a series of tests of hysteresis sources on a separate system, and apply their results to the watt apparatus. The studies presented here suggest that our improvements can be expected to reduce hysteresis signals by at least a factor of 10-perhaps as much as a factor of 50-over the 1998 experiment.