Inverse Heat Transfer Analysis of Grinding, Part 1: Methods

Thermal analyses of the grinding process generally require assumptions concerning the distributions of the heat flux to the workpiece within the grinding zone and convective cooling outside the grinding zone. The present work is concerned with the use of inverse heat transfer methods to estimate the heat flux and convection heat transfer coefficient distributions on the workpiece surface during straight surface grinding from temperature measurements within the workpiece. In the present paper, three inverse heat transfer methods are developed: temperature matching, integral, and sequential methods. Each method is evaluated for accuracy and stability using simulated temperature data. The selection of the sampling frequency of the temperature measurements and location of the temperature sensor are found to be critical for both estimation accuracy and stability. In a second paper, these inverse heat transfer methods are applied to estimate the distributions of the heat flux and convection heat transfer coefficients on the workpiece surface for grinding of steels with aluminum oxide and CBN abrasive wheels.

Fluorescence resonance energy transfer reveals interleukin (IL)-1-dependent aggregation of IL-1 type I receptors that correlates with receptor activation

Fluorescence resonance energy transfer (FRET) was used to investigate whether interleukin-1 (IL-1) causes the aggregation of IL-1 type I receptors (IL-1 RI) at the cell surface. For these experiments, a noncompetitive anti-IL1 RI monoclonal antibody, M5, was labeled separately with a donor probe, fluorescein isothiocyanate, or with an acceptor carbocyanine probe, Cy3. Donor-labeled M5 and acceptor-labeled M5 were simultaneously bound to transfected mouse IL-1 RI on either C-127 mouse mammary carcinoma cells or on Chinese hamster ovary (CHO)-K1 cells, and the ratio of acceptor emission at 590 nm to donor emission at 525 nm (excitation at 488 and 514 nm) was monitored with flow cytometry as an indicator of FRET. Addition of a saturating concentration of human IL-1 alpha at 22 degrees C causes a time-dependent increase in FRET for both cell lines that indicates IL-1-dependent self-association of IL-1 RI. Binding of the IL-1 receptor antagonist at 22 degrees C causes little or no FRET for both cell lines, indicating a correlation between receptor aggregation and the ability of the ligand to stimulate a functional response. When donor-labeled and acceptor-labeled Fab fragments of M5 are used to monitor FRET, IL-1 alpha causes efficient energy transfer in the CHO-K1 cells at 22 degrees C, but not at 4 degrees C. In contrast, IL-1 alpha causes much less FRET at 22 degrees C in C-127 cells when the M5 Fab fragments are used instead of the intact bivalent M5. In a striking parallel, IL-1 alpha-dependent activation of prostaglandin E2 production depends on the bivalent M5 antibody in the C-127 cells, but is independent of this monoclonal antibody in the CHO-K1 cells. These results provide a strong correlation between the ability of IL-1 to cause the aggregation of IL-1 RI and the stimulation of a functional response.

Analysis of Transient Temperatures in Grinding

Temperatures generated in the workpiece during straight surface plunge grinding follow a transient behavior as the grinding wheel engages with and disengages from the workpiece, and throughout the entire grinding pass for workpieces which are shorter than needed to reach a quasi-steady state condition. In the present paper, a thermal model is developed for the transient temperature distribution under regular and creep-feed grinding conditions. Numerical results obtained using a finite difference method indicate that the workpiece temperature rises rapidly during initial wheel-workpiece engagement (cut in), subsequently reaches a quasi-steady state value if the workpiece is sufficiently long, and increases still further during final wheel-workpiece disengagement (cut out) as workpiece material is suddenly unavailable to dissipate heat. Cooling by a nozzle directed at the end face of the workpiece should significantly reduce the temperature rise during cut out.

Identification of a splice variant of the rat and human mineralocorticoid receptor genes

The sequence of a splice variant of the rat mineralocorticoid receptor (MR) gene is presented. A cDNA clone corresponding to rat MR was isolated from a rat brain cDNA library. Sequence analysis of the region corresponding to the DNA binding domain revealed the presence of a 12 base pair (bp) insertion. Analysis of mRNA from several rat tissues suggests that the variant is less abundant than the wild type in most tissues. The insertion variant is also a product of the human MR gene, the identical splice variant was also observed in human white blood cell mRNA. Unlike other splice variants reported for the MR, this variant alters the encoded protein by the addition of four amino acid residues in the DNA binding domain. The altered protein may influence the affinity of the MR for mineralocorticoid or glucocorticoid response elements.

Lack of association between HLA class II polymorphisms and essential hypertension in a Belgian population

The aim of the present study was to investigate whether the HLA class II polymorphisms contributes to the susceptibility to essential hypertension in the Belgian population. For this purpose we studied 120 hypertensive patients and 168 normotensive controls by means of a PCR-SSO assay. No significant difference in allele and genotype frequencies of the DRB and DPB1 loci could be found between the two groups. We concluded that essential hypertension as a multifactorial and heterogeneous disease cannot be associated with one of the HLA class II DRB and DPB1 alleles in Belgian patients.

[Comparison of toxic effects of brucite and aluminium-treated chrysotile on macrophage]

Toxicity of brucite and two kinds of chrysotile (Xinkang and Sichuan chrysotile) treated with aluminium chloride to alveolar macrophage from guinea pigs was compared in vitro. Results showed changes of toxicity, indicated as generation of O2-., increase in membrane lipid fluidity and leakage of intracellular potassium, etc., caused by aluminium-treated chrysotile, were significantly lower than those by bructite of same dose (P < 0.05 and P < 0.01, respectively), and changes of other toxic indicators, such as release of lactic dehydrogenase (LDH) and acid phosphatase (ACP) from macrophage and its mortality, were similar to those by brucite. It suggests aluminium chloride can be used to antagonize pathogenic bioactivity of chrysotile in practice.

TEL gene is involved in myelodysplastic syndromes with either the typical t(5;12)(q33;p13) translocation or its variant t(10;12)(q24;p13)

A t(5;12)(q33;p13) translocation is a recurrent chromosome abnormality in a subgroup of myeloid malignancies with features of both myeloproliferative disorders and myelodysplastic syndromes (MDSs). The molecular consequence of a t(5;12) is a fusion between the platelet-derived growth factor receptor-B gene on chromosome 5 and a novel ETS-like gene, TEL, on chromosome 12. We report on three patients with a t(5;12)(q33;p13) diagnosed as chronic myelomonocytic leukemia, and one case of a t(10;12)(q24;p13) in a progressive MDS, with eosinophilia and monocytosis. Involvement of the TEL gene in these chromosome translocations was investigated by fluorescence in situ hybridization (FISH) with cosmid probes containing selectively the 5' end or 3' end of TEL. Hybridization of these cosmids to the der(5)/der(10) or a der(12), respectively, demonstrated a rearrangement of TEL in both translocations, showing that the t(10;12) is a variant translocation of the t(5;12). Cloning of the fusion cDNA of one case of t(5;12) showed that the breakpoint occurred at the RNA level at exactly the same position as reported by Golub et al (Cell 77:307, 1994). In addition, the TEL gene on chromosome 12 could be localized between two probes previously mapped to 12p13, namely PRB1 and D12S178, leading to a better definition of the position of TEL in this chromosome region. Moreover, in the case involving chromosome 10, the breakpoint occurred between cKTN206 and cKTN312/LYT-10 at 10q24. Clinicohematological data in these studies as well as the restriction mapping of chromosomal breakpoints strongly suggest that (1) common features in MDSs involving the TEL gene are monocytosis and eosinophilia, (2) chromosomes other than no. 5 may be involved and at least a t(10;12)(q24;p13) variant chromosome translocation does exist in these MDSs, and (3) both standard and variant 12p/TEL translocations may be identified by FISH with appropriate probes.

Energy Partition to the Workpiece for Grinding with Aluminum Oxide and CBN Abrasive Wheels

An experimental investigation is reported of the energy partition to the workpiece for grinding of steels with aluminum oxide and cubic boron nitride (CBN) abrasive wheels. The energy input to the workpiece was obtained by measuring the temperature distribution in the workpiece using an embedded thermocouple technique and matching the results with analytically computed values. It was found that 60-75 percent of the grinding energy is transported to the workpiece as heat with an aluminum oxide abrasive wheel, as compared to only about 20 percent with CBN wheels. An analysis of the results indicates that the much lower energy partition to the workpiece with CBN can be attributed to its very high thermal conductivity whereby a significant portion of the grinding heat is transported to the abrasive instead of to the workpiece. The much lower energy partition to the workpiece with CBN wheels results in much lower grinding temperatures and a greatly reduced tendency for thermal damage to the workpiece.

Severe alport phenotype in a woman with two missense mutations in the same COL4A5 gene and preponderant inactivation of the X chromosome carrying the normal allele

The X-linked form of Alport disease, caused by mutations in the COL4A5 or the COL4A6 gene, usually leads to terminal renal failure in males, while affected females have a more variable and moderate phenotype. We detected in a female patient, with a severe Alport phenotype, two new missense mutations. One mutation (G289V) occurred in exon 15 and converted a glycine in a collagenous domain of COL4A5 to a valine. The second mutation, located in exon 46, substituted a cysteine proximal to the NC1 domain of COL4A5 for an arginine. In white blood cells and kidney both mutations were present on > 90% of the mRNA, while at the genomic level the patient was heterozygous for both mutations. The two mutations therefore occurred in the same COL4A5 allele. No mutation was found in the COL4A5 promoter region by sequencing nor was a major rearrangement of the normal allele detected. A skewed pattern of X inactivation was demonstrated in DNA isolated from the patient's kidney and white blood cells: > 90% of the X chromosomes with the normal COL4A5 allele was inactivated. It is suggested that this skewed inactivation pattern is responsible for the absence of detectable normal COL4A5 mRNA and hence the severe phenotype in this woman.

[Isolation and identification of enteric adenovirus in China]

Enteric adenovirus type 40/41 is considered to be the second major cause of gastroenteritis in young children. In this study fecal specimens 86-123 from diarrhea patients were isolated and examined in Grahm 293 cells. This induced cytopathic effect (CPE) at this cells. Viral particles were also found in fecal specimens and by electron microscopy. Examination of the isolate with Cambridge Biotech Adenoclone-Type 40/41 test kit indicated that it contained EAd. On the basis of the above studies, one strain of EAd was the first isolated virus in China.

Analysis of Energy Partition in Grinding

An analysis is presented for the fraction of the energy transported as heat to the workpiece during grinding. The abrasive grains and grinding fluid in the wheel pores are considered as a thermal composite which moves relative to the grinding zone at the wheel speed. The energy partition fraction to the workpiece is modeled by setting the temperature of the workpiece surface equal to that of the composite surface at every point along the grinding zone, which allows variation of the energy partition along the grinding zone. Analytical results indicate that the energy partition fraction to the workpiece is approximately constant along the grinding zone for regular down grinding, but varies greatly along the grinding zone for regular up grinding and both up and down creep-feed grinding. The resulting temperature distributions have important implications for selecting up versus down grinding especially for creep-feed operations.

A physical map of the region spanning the chromosome 12 translocation breakpoint in a mesothelioma with a t(X;12)(q22;p13)

We have constructed a physical map of a 4.6-cM region of human chromosome band 12p13.3 that contains a translocation breakpoint from a mesothelioma with a t(X;12)(q22;p13). The map contains a contig of 22 yeast artificial chromosomes (YACs), onto which we have placed 18 sequence tagged site (STS) markers, including seven genes: D12S370, FGF6, KCAN1, KCNA5, KCNA6, NTF3, and VWF. A second YAC contig, comprised of 22 YAC clones, was located distal to the mesothelioma breakpoint and contained 12 STS markers, including four genes (CACNL1A1, D12S380E, D12S381E, and D12S382E). Based on STS content and fluorescence in situ hybridization experiments, two stable, nonchimeric YAC clones were found that span the mesothelioma breakpoint. A long-range restriction map of an 800-kb region was constructed and used to refine the mesothelioma breakpoint to a region of approximately 100 kb, flanked by the potassium channel genes KCNA1 and KCNA5. The latter was confirmed by direct visual hybridization (DIRVISH) experiments, using cosmids isolated for markers flanking the breakpoint as probes.

Cloning and sequence of the Xenopus laevis homologue of the midkine cDNA

The Xenopus laevis (Xl) homologue of the midkine-encoding gene (MK) has been isolated and sequenced from a X. laevis cDNA library made from the head region of stage-22 embryo. The nucleotide and deduced amino-acid sequences show a high degree of conservation with the avian and mammalian MK and pleiotrophin (PTN) genes and gene products. Highly conserved domains may indicate important regions for the function of the MK and PTN proteins.

Lack of association between the I/D polymorphism of the angiotensin-converting enzyme gene and essential hypertension in a Belgian population

We tested the insertion/deletion (I/D) polymorphism of the ACE gene in 119 hypertensive patients and in 109 normotensive controls by means of the polymerase chain reaction (PCR). The allele and genotype frequencies of the I/D polymorphism in the ACE gene are essentially identical in both groups, regardless of age or sex. The I/D polymorphism of the ACE gene is thus not implicated in Belgian hypertensive patients.

Genetic study of indirect inguinal hernia

We performed a genetic analysis of 280 families with congenital indirect inguinal hernia ascertained in Shandong province. The multifactorial threshold model and segregation analysis were applied to these families to investigate the mode of inheritance of congenital indirect inguinal hernia. Our results indicate that congenital indirect inguinal hernia is not compatible with a multifactorial threshold model, and the frequent vertical transmission and high segregation ratio suggest autosomal dominant inheritance with incomplete penetrance and sex influence. Through further pedigree analysis of the multiple case families with at least two closely related affected members, we noted preferential paternal transmission of the disease gene, which might suggest the role of genomic imprinting in the aetiology of this condition.

Toxic effect of the bloom-forming Trichodesmium sp. (Cyanophyta) to the copepod Acartia tonsa

The toxicity of the marine cyanobacterium Trichodesmium sp. to the copepod Acartia tonsa was assessed in a series of experiments during a Trichodesmium bloom off the North Carolina coast in late October 1992. Healthy intact cells of Trichodesmium sp. were not toxic to A. tonsa and were ingested by A. tonsa when no other foods were available. However, homogenized Trichodesmium cells were toxic to A. tonsa, suggesting that Trichodesmium sp. contains certain type(s) of intracellular biotoxins. This hypothesis was consistent with the observed high mortality when A. tonsa was treated with aging Trichodesmium sp. cells or with filtered cell homogenate. The affected copepods showed weakness, recumbency, and reduced responsiveness. Many were observed to have distended intestines. Bioassays using aged Trichodesmium sp. cells and filtered homogenate demonstrated a dose-dependent effect on A. tonsa survival.

Differential splicing of COL4A5 mRNA in kidney and white blood cells: a complex mutation in the COL4A5 gene of an Alport patient deletes the NC1 domain

PCR conditions were optimized to amplify the COL4A5 cDNA from lymphoblasts and kidney tissue. Sequencing of the COL4A5 mRNA isolated from the kidney of an Alport syndrome patient revealed two differences with the published sequence. One divergence, the insertion of an 18 bp sequence between exon 11 and 10 of the COL4A5 mRNA added two Gly-X-Y triplets to the COL4A5 sequence and was subsequently found in the mRNA of four normal kidney mRNA samples. This sequence was absent in all white blood cell RNA samples sequenced by us, indicating tissue specific splicing with the presence of an additional exon in kidney COL4A5 mRNA. This finding of differential splicing of COL4A5 mRNA in kidney and white blood cells might affect the use of white blood cell mRNA for the analysis of Alport mutations. Second, a complex mutation was detected in the mRNA from the AS patient introducing a premature stop codon in the message, deleting part of the triple helical domain and the complete NC domain. The mother of the patient was shown to be heterozygous for this mutation.

Site-specific methylation inhibits transcriptional activity of platelet-derived growth factor A-chain promoter

Expression of the platelet-derived growth factor (PDGF) A-chain gene is temporally and spatially restricted in development and highly regulated in selected normal and tumor cell lines. Because DNA methylation appears to be important in regulating tissue specific gene expression, we tested the influence of in vitro methylation of the human PDGF A-chain promotor on its activity in vivo in transient transfection assays. We now report that PDGF A-chain promoter activity is strongly repressed by DNA methylation in a DNA sequence-specific manner and that the repression of promoter activity by methylation requires a methyl CpG-binding protein(s). We also report that incubation of HeLa cells with 5-azacytidine sharply increases levels of endogenous PDGF A-chain gene transcripts. These results indicate that the promoter activity of the PDGF A-chain gene is sharply and selectively reduced by in vitro DNA methylation and that DNA methylation in vivo also may reduce its function in selected cell lines.

Identification of a novel tyrosine kinase receptor-like molecule in neuroblastomas

Growth factor receptors are important determinants of both normal and abnormal cell growth. We have now used degenerate primers designed from conserved tyrosine kinase domains to identify and clone a novel receptor-like molecule (designated Nbtk-1) from a NB41 mouse neuroblastoma cell line. Nbtk-1 is related to the met proto-oncogene family of tyrosine kinase receptors. Transcripts of approximately 2.1 and 2.6 kb have been found in mouse cell lines and one transcript of approximately 3 kb in human cell lines and in a wide range of primary human tumors, such as neuroblastomas, primitive neuroectodermal tumors (PNETs), Wilms' tumors, and melanomas and in the corresponding normal human tissues. These observations suggest that Nbtk-1 may have important roles in normal and tumor cell growth.

Analysis of Fluid Flow through the Grinding Zone

A theoretical model of fluid flow in grinding has been developed by an analysis of fluid flow through a porous medium. Fluid tangential velocity, radial velocity, depth of penetration into the wheel, and the useful flow rate through the grinding zone are predicted by using this model. The analysis indicates that the nozzle position, nozzle velocity (or flow rate), and the effective wheel porosity are the three main factors which most significantly influence the useful flow rate through the grinding zone. A dimensionless effective wheel porosity parameter is introduced which is the ratio of the effective wheel porosity to its bulk porosity. By fitting the theoretical analysis to available experimental results, creep feed wheels were found to have much bigger dimensionless effective porosities than conventional wheels, which enhances their ability to more effectively pump fluid through the grinding zone.

Ambulatory blood pressure monitoring in elderly patients with isolated systolic hypertension

OBJECTIVES

This study compared clinic and ambulatory blood pressure measurement and the reproducibility of these measurements in older patients with isolated systolic hypertension (ISH).

PATIENTS

Eighty-seven patients aged greater than or equal to 60 years with ISH on clinic measurement were followed in the placebo run-in phase of the Syst-Eur trial.

METHODS

Clinic blood pressure was defined as the mean of two blood pressure readings on each of three clinic visits (six readings in total). Ambulatory blood pressure was measured over 24 h using non-invasive ambulatory blood pressure monitors.

RESULTS

Daytime ambulatory systolic pressure was, on average, 21 mmHg lower than the clinic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. In the 42 patients who had repeat measurements, clinic blood pressure levels nad the amplitude of the diurnal blood pressure profile (fitted by Fourier analysis) were equally reproducible. However, both were less reproducible than ambulatory blood pressure levels. The repeatability coefficients, expressed as per cent of near maximum variation (four times the standard deviation of a given measurement), were 52% and 45% for the clinic systolic and diastolic pressures, 56% and 42% for the amplitude of the diurnal profile, and 29% and 26% for mean 24-h pressures.

CONCLUSIONS

In older patients with ISH, clinic and ambulatory systolic blood pressure measurements may differ largely: the prognostic significance of this difference remains to be elucidated. Furthermore, in these patients the level of pressure is more reproducible by daytime ambulatory blood pressure measurement than by clinic measurement.

[Pharmacological study on Cordyceps sinensis (Berk.) Sacc. and ze-e Cordyceps]

The Ze-e Cordyceps is similar to the Cordyceps sinensis in such pharmacological actions as calming, enduring hypoxia, dilating trachea, male sex hormone action, antiphlogistic and toxicity, etc. It is thus suggested that the Ze-e Cordyceps may be used place of the Cordyceps sinensis in clinical practice.

Trials in elderly patients with isolated systolic hypertension

The hypothesis that antihypertensive drugs should be prescribed to elderly patients with isolated systolic hypertension is being addressed in at least 3 trials: the Systolic Hypertension in the Elderly Program (SHEP) in the United States, a trial in China, and the Syst-Eur study in Europe. The SHEP trial has recently reported its final morbidity and mortality results. This article summarizes the protocol of the European study. To be eligible for the Syst-Eur trial, patients must be at least 60 years old and have a systolic blood pressure averaging 160-219 mmHg with a diastolic pressure less than 95 mmHg. Patients must give their informed consent and be free of major cardiovascular and non-cardiovascular diseases at entry. The patients are randomized into active treatment or placebo. Active treatment consists of nitrendipine (10-40 mg/d), combined with enalapril (5-20 mg/d) and hydrochlorothiazide (12.5-25 mg/d), as necessary. The control group received matching placebos. The drugs (or matching placebos) are stepwise titrated and combined in order to reduce systolic blood pressure by 20 mmHg at least to a level below 150 mmHg. Morbidity and mortality are monitored to enable an intention-to-treat and per protocol comparison of the outcome in the two treatment groups.

Mean and range of the ambulatory pressure in normotensive subjects

To perform a meta-analysis of published reports in an attempt to determine the mean and range of normal ambulatory blood pressure (BP), 23 studies including a total of 3,476 normal subjects were reviewed. Most studies were compatible with a mean 24-h BP in the range of 115-120/70-75 mmHg, a mean day time BP of 120-125/75-80 mmHg, and a mean night time BP of 105 to 110/60 to 65 mmHg. With weighting for the number of subjects included in the individual studies, the 24-h BP averaged 118/72 mmHg, the day time BP 123/76 mmHg, and the night time BP 106/64 mmHg. The night/day pressure ratio averaged 0.87 for systolic and 0.83 for diastolic BP, with ranges across the individual studies from 0.79 to 0.92 and from 0.75 to 0.90, respectively. If the mean +/- 2 standard deviation interval in the various studies was considered normal, the range of normality was on average 97 to 139/57 to 87 mmHg for the 24-h BP, 101 to 146/61 to 91 mmHg for the day time BP, and 86 to 127/48 to 79 mmHg for the night time BP. Until the results of prospective studies on the relation between the ambulatory BP and the incidence of cardiovascular morbidity and mortality become available, the aforementioned intervals, which summarize the experience of 23 investigators, could serve as a temporary reference for clinical practice.