bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of temperature and/or pressure on lactoperoxidase activity in bovine milk and acid whey
Authors: LUDIKHUYZE LINDA R. , CLAEYS WENDIE L. , HENDRICKX MARC E. 
Published: July 2002

At atmospheric pressure, inactivation of lactoperoxidase (LPO) in milk and whey was studied in a temperature range of 69–73 °C and followed first order kinetics. Temperature dependence of the first order inactivation rate constants could be accurately described by the Arrhenius equation, with an activation energy of 635·3±70·7 kJ/mol for raw bovine milk and 736·9±40·9 kJ/mol for diluted whey, indicating a very high temperature sensitivity. On the other hand, LPO is very pressure resistant and not or only slightly affected by treatment at pressure up to 700 MPa combined with temperatures between 20 and 65 °C. Both for thermal and pressure treatment, stability of LPO was higher in milk than in diluted whey. Besides, a very pronounced antagonistic effect between high temperature and pressure was observed, i.e. at 73 °C, a temperature where thermal inactivation at atmospheric pressure occurs rapidly, application of pressure up to 700 MPa exerted a protective effect. At atmospheric pressure, LPO in diluted whey was optimally active at a temperature of about 50 °C. At all temperatures studied (20–60 °C), LPO remained active during pressure treatment up to 300 MPa, although the activity was significantly reduced at pressures higher than 100 MPa. The optimal temperature was found to shift to lower values (30–40 °C) with increasing pressure.
In vitro digestion of caseinophosphopeptide–iron complex
Authors: AÎT-OUKHATAR NABIL , BOUHALLAB SAÏD , BUREAU FRANÇOIS , ARHAN PIERRE , MAUBOIS JEAN-LOUIS , BOUGLÉ DOMINIQUE L. 
Published: July 2002

Caseins bind strongly to Fe by their phosphoseryl residues (Hegenauer et al. 1979;
Brulé & Fauquant, 1982; Bouhallab et al. 1991; Emery, 1992) and keep it soluble at
the alkaline pH of the duodenum (Manson & Annan, 1971; Bouhallab et al. 1991). It
has been suggested that this strong binding prevents the release of free Fe during
digestion and impairs its absorption (West, 1986; Hurrell, 1997), but in human
studies hydrolysis by digestive enzymes to give low molecular mass peptides
improves Fe absorption (Hurrell et al. 1988, 1989).β-Casein peptide 1–25 (β-CN(1–25)) is the phosphorylated N-terminal fragment
of β-CN. Its molecular mass is 3124 Da and it contains four phosphoseryl residues
that bind four Fe atoms and keep them soluble (Bouhallab et al. 1991).Preliminary results showed that binding Fe to β-CN(1–25) enhances its
bioavailability in the rat (Aît-Oukhatar et al. 1997) and its absorption by the
duodenal rat loop model (Pérès et al. 1997). We recently showed that the β-
CN(1–25)–Fe complex is hydrolysed to a lesser extent than free β-CN(1–25) during
duodenal digestion, and that the phosphorylated region of the peptide to which Fe
is bound, β-CN(15–24), cannot be detected in the digestive lumen (our unpublished
results).These previous studies did not examine the effect of luminal digestion that could
release free inorganic Fe. We considered the possibility that Fe bound to β-CN(1–25)
is not released in the digestive lumen, and that it reaches the absorbing surface of the
small intestine brush border membrane as a complex. To test this hypothesis we
examined in vitro the influence of pH and digestive enzymes on the dialysability of
the β-CN(1–25)–Fe complex.
Turbulent mixing in a sloping benthic boundary layer energized by internal waves
Authors: IVEY G. N. , WINTERS K. B. , DE SILVA I. P. D. 
Published: July 2002

A laboratory study was carried out to directly measure the turbulence properties
in a benthic boundary layer (BBL) above a uniformly sloping bottom where the
BBL is energized by internal waves. The ambient fluid was continuously stratified
and the steadily forced incoming wave field consisted of a confined beam, restricting
the turbulent activity to a finite region along the bottom slope. Measurements of
dissipation showed some variation over the wave phase, but cycle-averaged values
indicated that the dissipation was nearly constant with height within the BBL.
Dissipation levels were up to three orders of magnitude larger than background
laminar values and the thickness of the BBL could be defined in terms of the
observed dissipation variation with height. Assuming that most of the incoming wave
energy was dissipated within the BBL, predicted levels of dissipation were in good
agreement with the observations.Measurements were also made of density and two orthogonal components of the
velocity fluctuations at discrete heights above the bottom. Cospectral estimates of
density and velocity fluctuations showed that the major contributions to both the
vertical density flux and the momentum flux resulted from frequencies near the
wave forcing frequency, rather than super-buoyancy frequencies, suggesting a strong
nonlinear interaction between the incident and reflected waves close to the bottom.
Within the turbulent BBL, time-averaged density fluxes were significant and negative
near the wave frequencies but negligible at frequencies greater than the buoyancy
frequency N. While dissipation rates were high compared to background laminar
values, they were low compared to the value of
εtr ≈ 15vN2, the transition value
often used to assess the capacity of a stratified flow to produce mixing. Existing
models relating mixing to dissipation rate rely on the existence of a positive-definite
density flux at frequencies greater than N as a signature of fluid mixing and therefore
cannot apply to these experiments. We therefore introduce a simple model, based
on the concept of diascalar fluxes, to interpret the mixing in the stratified fluid in
the BBL and suggest that this may have wider application than to the particular
configuration studied here.
Perturbation of low-frequency underwater acoustics by gravity waves
Authors: CHAMPY-DOUTRELEAU I. , EUVRARD D. , HAZARD C. 
Published: July 2002

A body immersed in an ocean of large depth is assumed to vibrate and to radiate a
time-harmonic acoustic field of small amplitude in the presence of gravity waves of
small amplitude. Assuming both waves to have lengths of the same order (which in
practice corresponds to very low acoustic frequencies) it is shown that the diffraction
of acoustic waves by the corrugated free surface generates a second-order acoustic
pressure field p2. The computation of p2 involves a difficulty: a non-homogeneous
Dirichlet condition to be satisfied on the mean free surface up to infinity which implies
the absence of any clear indication about the condition that should be imposed at
infinity to have a well-posed problem. In order to get an insight into this difficult
problem the simple case of a point source is studied. We first judiciously choose one
solution and then show it is the physical solution using a limiting-amplitude procedure.
Coming back to the general case of a vibrating body the calculation of p2 is split
into two successive steps: the first one consists in computing an explicit convolution
product via numerical methods of integration, the second one is a standard radiation
problem that is solved using a method coupling a Green integral representation and
finite elements. A peak of the second-order pressure appears just above the vibrating
body.The same concepts also apply to other second-order scattering problems, such as
the sea-keeping of weakly immersed submarines.
Life events, difficulties and onset of depressive episodes in later life
Authors: I. BRILMAN ELS , ORMEL JOHAN 
Published: July 2002

Background. The importance of stressful life events and long-term difficulties in the onset of episodes of unipolar depression is well established for young and middle-aged persons, but less so for older people.Method. A prospective case–control study was nested in a large community survey of older people. We recruited 83 onset cases during a 2-year period starting 2½ years after the survey, via screening (N = 59) and GP monitoring (N = 24), and 83 controls, a random sample from the same survey population. We assessed depression with the PSE-10 and life stress exposure with the LEDS.Results. Risk of onset was increased 22-fold by severe events and three-fold by ongoing difficulties of at least moderate severity. Severe events accounted for 21% of all episodes but ongoing difficulties for 45%. The association of onset with life stress, often health-related such as death, major disability and hospitalization of subject or someone close, was most pronounced in the cases identified by screening. While a clear risk threshold for events was found between threat 2 and 3 (on a scale of 1–4), the risk associated with difficulties increased more gradually with severity of difficulty. Compared with controls, severe events involved a larger risk for cases without a prior history of depression (OR = 39·48) than for cases with (OR = 8·86). The opposite was found for mild events (OR = 2·94 in recurrent episodes; OR = 1·09 in first episodes). The impact of ongoing difficulties was independent of severity of episode and history of depression.Conclusion. Although the nature of life stress in later life, in particular health-related disability and loss of (close) social contacts, is rather different from that in younger persons, it is a potent risk factor for onset of a depressive episode in old age. Severe events show the largest relative risk, but ongoing difficulties account for most episodes. The association of severe events with onset tends to be stronger in first than in recurrent episodes. Mild events can trigger a recurrent episode but not a first one.
A validation study of the Hospital Anxiety and Depression Scale
(HADS) in different groups of Dutch subjects
Authors: SPINHOVEN PH. , ORMEL J. , SLOEKERS P. P. A. , KEMPEN G. I. J. M. , SPECKENS A. E. M. , HEMERT A. M. VAN 
Published: July 2002

Background. Research on the dimensional structure and
reliability of the Hospital Anxiety and Depression Scale (HADS) and
its relationship with age is scarce. Moreover, its efficacy in
determining the presence of depression in different patient groups has
been questioned.Methods. Psychometric properties of the HADS were assessed
in six different groups of Dutch subjects (N = 6165): (1) a
random sample of younger adults (age 18–65 years) (N =
199); (2) a random sample of elderly subjects of 57 to 65 years of age
(N = 1901); (3) a random sample of elderly subjects of 66
years or older (N = 3293); (4) a sample of consecutive
general practice patients (N = 112); (5) a sample of
consecutive general medical out-patients with unexplained somatic
symptoms (N = 169); and (6) a sample of consecutive
psychiatric out-patients (N = 491).Results. Evidence for a two-factor solution corresponding
to the original two subscales of the HADS was found, although anxiety
and depression subscales were strongly correlated. Homogeneity and
test–retest reliability of the total scale and the subscales
were good. The dimensional structure and reliability of the HADS was
stable across medical settings and age groups. The correlations
between HADS scores and age were small. The total HADS scale showed a
better balance between sensitivity and positive predictive value (PPV)
in identifying cases of psychiatric disorder as defined by the Present
State Examination than the depression subscale in identifying cases of
unipolar depression as defined by ICD-8.Conclusions. The moderate PPV suggests that the HADS is
best used as a screening questionnaire and not as a
‘case-identifier’ for psychiatric disorder or
depression.
Qualitative and quantitative analyses of a ‘lock and
key’ hypothesis of depression
Authors: PARKER G. , GLADSTONE G. , ROUSSOS J. , WILHELM K. , MITCHELL P. , HADZI-PAVLOVIC D. , AUSTIN M.-P. , HICKIE I. 
Published: July 2002

Background. We examine a ‘lock and key’
(‘L–K’) hypothesis to depression which posits that early

adverse experiences establish locks that are activated by keys mirroring
the earlier adverse
experience to induce depression.Methods. Two-hundred and seventy clinically depressed patients
were examined with open-ended
and pre-coded interview questions to ascertain both early adverse experiences
and precipitating life
events. Qualitative and quantitative data analyses examined for any associations
between
developmental ‘locks’ and precipitating ‘keys’.Results. Qualitative assessment suggested ‘L–K’
links in almost one-third of the sample, and
examples are provided. While quantitative analyses indicated significant
associations between
several identical ‘lock’ and ‘key’ constructs,
evidence of specificity was rare. When individual
‘locks’ and ‘keys’ were consolidated into three
higher-order constructs, variable models were
suggested, including a non-specific link, a specific link and absence of
any link. ‘L–K’ links
appeared more likely in those with ‘non-melancholic’ (versus
‘melancholic’) depression, with the
seemingly greater relevance to ‘reactive’ (versus
‘neurotic’) depression in the quantitative analyses
inviting speculation that that ‘disorder’ may be more a reaction
to a salient rather than a severe
stressor.Conclusions. This exploratory study suggests that early adverse
experiences may variably establish
specific and non-specific patterns of vulnerability to having depression
triggered by exposure to
salient mirroring life event stressors.
The Thought Control Questionnaire – psychometric
properties in a clinical sample, and relationships with
PTSD and depression
Authors: REYNOLDS MARTINA , WELLS ADRIAN 
Published: July 2002

Background. Recent developments in research suggest that particular attempts to control thoughts
may contribute to the problem of intrusion. An instrument capable of identifying strategies for
dealing with unwanted intrusions in clinical populations may be used for differentiating between
thought control strategies that may or may not be helpful.Methods. The Thought Control Questionnaire (TCQ) (Wells & Davies, 1994) developed and
validated on a normal sample, was administered to a clinical sample in order to investigate the
consistency of the original factor structure and its psychometric properties. The sensitivity of the
scale to change associated with recovery was also examined. Relationships between individual
differences in thought control strategies and psychiatric symptoms in patients with DSM-IV major
depression, and PTSD with or without major depression were investigated.Results. The Scree Test suggested a six-factor solution which was rotated. This solution split the
original distraction subscale into separate behavioural and cognitive distraction, otherwise the
subscales were almost identical to those obtained in non-clinical subjects. As this split has been
shown to be unreliable, further analyses in this study were based on the five-factor version of the
TCQ obtained by Wells & Davies (1994). Predictors of recovery and of symptoms in PTSD and
depression were explored.Conclusions. Correlations between the TCQ subscales and other measures suggest that particular
thought control strategies may be associated with the symptoms of PTSD and depression. The TCQ
scales appear to be sensitive to changes associated with recovery. Significant differences emerged
in thought control strategies between depressed and PTSD patients. Hierarchical regression
analysis showed distraction, punishment and reappraisal control strategies predicted depression
scores in depressed patients while use of distraction predicted intrusions in PTSD.
Schizophrenia among Surinamese in the Netherlands: high admission rates not explained by high emigration rates
Authors: BOGERS J. P. A. M. , DE JONG J. T. V. M. , KOMPROE I. H. 
Published: July 2002

Background. A high risk of schizophrenia has been found among Caribbean immigrants in the
Netherlands and Great Britain. One hypothesis to explain these findings is that patients with a
diagnosis of schizophrenia or patients with symptoms of psychosis not specifically diagnosed,
emigrate more than the general population. Such selection might account for high rates of
Surinamese patients with a diagnosis of schizophrenia in Netherlands psychiatric hospitals. We
examined this hypothesis.Methods. The files of patients with schizophrenia or patients suffering from unspecified psychosis
were selected from the archives of the National Psychiatric Hospital in Surinam. These patients were
traced to investigate patterns of emigration. Data from the Central Bureau for Statistics in the
Netherlands and from the Central Population Bureau in Surinam provided the percentage of the
general Surinamese population that emigrated to the Netherlands. The difference between the two
percentages was evaluated using the chi-squared test. Using the same method the percentage of
remigration from the Netherlands among Surinamese patients was compared with the percentage
of remigration among the general Surinamese population.Results. Surinamese patients with schizophrenia or unspecified psychosis did not emigrate more
frequently to the Netherlands compared with the general Surinamese population. They did
remigrate significantly more frequently.Conclusion. High migration rates do not explain the high hospital admission rates for schizophrenia
among Surinamese in the Netherlands.
Cognitive reserve and mortality in dementia: the role
of cognition, functional ability and depression
Authors: GEERLINGS M. I. , DEEG D. J. H. , PENNINX B. W. J. H. , SCHMAND B. , JONKER C. , BOUTER L. M. , VAN TILBURG W. 
Published: July 2002

Objective. This study examined whether dementia patients with greater cognitive reserve had
increased mortality rates, and whether this association was different across strata of cognition,
functional ability and depression.Methods. In the community-based Amsterdam Study of the Elderly, 261 non-institutionalized
dementia patients, identified using the Geriatric Mental State Schedule (GMS), were followed for an
average of 55·5 months after which mortality data were obtained. Cognitive reserve was indicated
by years of education and pre-morbid intelligence (measured using the Dutch Adult Reading
Test). Cognition, functional ability and depression were indicated by Mini-Mental State scores,
ADL and IADL measurements and GMS depressive syndrome, respectively.Results. During the follow-up 146 persons (55·9%) died. Cox regression analyses showed that more
highly educated dementia patients had higher mortality rates, only if they had low MMSE scores
or if they had a concurrent depression. Pre-morbid intelligence was associated with a higher
mortality rate, independent of cognition, but this association was much stronger among patients
with depression. The positive association between education or intelligence and mortality was not
modified by functional disabilities.Conclusions. The results suggest that dementia patients with greater cognitive reserve have
increased mortality rates, only if the disease has progressed to such an extent that clinical symptoms
are more severe. In this respect, the reserve hypothesis needs a modification. Depression in
dementia patients with greater cognitive reserve may reflect a subgroup of patients with poor
prognosis.
CCD detectors in high-resolution biological electron microscopy
Authors: Faruqi A. R. , Subramaniam Sriram 
Published: July 2002

1. Introduction 11.1 The ‘band gap’ in silicon 22. Principles of CCD detector operation 32.1 Direct detection 32.2 Electron energy conversion into light 42.3 Optical coupling: lens or fibre optics? 62.4 Readout speed and comparison with film 83. Practical considerations for electron microscopic applications 93.1 Sources of noise 93.1.1 Dark current noise 93.1.2 Readout noise 93.1.3 Spurious events due to X-rays or cosmic rays 103.2 Efficiency of detection 113.3 Spatial resolution and modulation transfer function 123.4 Interface to electron microscope 143.5 Electron diffraction applications 154. Prospects for high-resolution imaging with CCD detectors 185. Alternative technologies for electronic detection 235.1 Image plates 235.2 Hybrid pixel detectors 246. References 26During the past decade charge-coupled device (CCD) detectors have increasingly become the
preferred choice of medium for recording data in the electron microscope. The CCD detector
itself can be likened to a new type of television camera with superior properties, which makes
it an ideal detector for recording very low exposure images. The success of CCD detectors
for electron microscopy, however, also relies on a number of other factors, which include its
fast response, low noise electronics, the ease of interfacing them to the electron microscope,
and the improvements in computing that have made possible the storage and processing of
large images.CCD detectors have already begun to be routinely used in a number of important
biological applications such as tomography of cellular organelles (reviewed by Baumeister,
1999), where the resolution requirements are relatively modest. However, in most high-
resolution microscopic applications, especially where the goal of the microscopy is to obtain
structural information at near-atomic resolution, photographic film has continued to remain
the medium of choice. With the increasing interest and demand for high-throughput structure
determination of important macromolecular assemblies, it is clearly important to have tools
for electronic data collection that bypass the slow and tedious process of processing images
recorded on photographic film.In this review, we present an analysis of the potential of CCD-based detectors to fully
replace photographic film for high-resolution electron crystallographic applications.
A NEW METHOD FOR OBTAINING THE AUTOCOVARIANCE OF AN ARMA
MODEL: AN EXACT FORM SOLUTION
Authors: Karanasos Menelaos 
Published: July 2002

Karanasos (1998) presented a new method for computing
the theoretical autocovariance function (acf) of the following
univariate autoregressive moving average (ARMA) model:Φ(L)yt =
Θ(L)εtwhereΦ(L) = 1 − φ1L −
… − φpLp,
Θ(L) = 1 − θ1L −
… − θqLq
Systoles of hyperbolic 3-manifolds
Authors: ADAMS COLIN C. , REID ALAN W. 
Published: July 2002

Let M be a complete hyperbolic n-manifold of finite
volume. By a systole of M we
mean a shortest closed geodesic in M. By the systole length of M we mean the length
of a systole. We denote this by sl (M). In the case when M is closed, the systole length
is simply twice the injectivity radius of M. In the presence of cusps, injectivity radius
becomes arbitrarily small and it is for this reason we use the language of ‘systole
length’.In the context of hyperbolic surfaces of finite volume, much work has been done
on systoles; we refer the reader to [2, 10–12]
for some results. In dimension 3, little seems known about systoles. The main result in
this paper is the following (see below for definitions):