Within days after birth, rapid surface colonization of infant skin coincides with significant functional changes. Gradual maturation of skin function, structure, and composition continues throughout ...the first years of life. Recent reports have revealed topographical and temporal variations in the adult skin microbiome. Here we address the question of how the human skin microbiome develops early in life. We show that the composition of cutaneous microbial communities evolves over the first year of life, showing increasing diversity with age. Although early colonization is dominated by Staphylococci, their significant decline contributes to increased population evenness by the end of the first year. Similar to what has been shown in adults, the composition of infant skin microflora appears to be site specific. In contrast to adults, we find that Firmicutes predominate on infant skin. Timely and proper establishment of healthy skin microbiome during this early period might have a pivotal role in denying access to potentially infectious microbes and could affect microbiome composition and stability extending into adulthood. Bacterial communities contribute to the establishment of cutaneous homeostasis and modulate inflammatory responses. Early microbial colonization is therefore expected to critically affect the development of the skin immune function.
We study the Laminar Separation Bubble (LSB) which develops on the suction side of a NACA 0015 hydrofoil by means of a Temperature-Sensitive Paint (TSP), at a Reynolds number of
1.8
×
10
5
and angles ...of attack
AoA
=
3
∘
,
5
∘
,
7
∘
,
10
∘
. The thermal footprints
T
w
(
x
,
y
,
t
)
of the fluid unveil three different flow regimes whose complexity in time and space decreases when
AoA
increases, up to
10
∘
where the LSB-induced spatial gradients are linked to quasi-steady positions in time. At
AoA
=
7
∘
the LSB system undergoes a 3
D
destabilization, that induces
C
-shaped arcs at separation and weak bubble-flapping at reattachment. Structural changes occur at
A
o
A
=
5
∘
and
3
∘
: bubble-flapping raises homogeneously at reattachment while intermittent, wedge-shaped events alter the LSB shape. The relative skin-friction vector fields
τ
w
(
x
,
y
,
t
)
, extracted from
T
w
(
x
,
y
,
t
)
by means of an optical-flow-based algorithm, provide the topology of the flow at the wall and feed a physics-based criterion for the identification of flow separation
S
(
y
,
t
)
and reattachment
R
(
y
,
t
)
. This criterion fulfills, in average, a novel skin-friction ground-truth estimation grounded on the determination of the propagation velocity of temperature fluctuations. The obtained
S
(
y
,
t
)
is composed of several manifolds that extend spanwise from saddle points to converging nodes via the saddles unstable manifold, while, at least at higher AoA, manifolds that compose
R
(
y
,
t
)
move from diverging nodes to saddle points via the saddles stable manifolds. The triggering of a wedge-shaped event by a rising
Ω
-shaped vortex in the reverse LSB flow is captured and described in analogy to a simplified model.
Graphical Abstract
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•Optimized PFBHA reaction and selective solid phase extraction conditions.•Matrix effects controlled by well equilibrated adequate internal standards.•Satisfactory limits of ...detection, linearities, reproducibilities and recoveries.•Between 48 and 65% of wines contain total SAs at levels of sensory concern.
Strecker aldehydes (SAs) are key determinants of wine shelf-life and can be present in unoxidized wines in odorless forms, such as hydroxyalkylsulfonates, imines or acetals. A robust and accurate method for the determination of total forms of SAs, based on the classical derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and in the selective solid phase extraction of derivatives has been optimized and validated. Matrix effects have been solved by the use of adequate internal standards and by large-enough equilibration times under anoxic conditions. Method figures of merit are highly satisfactory in terms of detection limits (<0.1 μg/L), linearity (R2 > 0.997), reproducibility (5–13%) and recoveries (RSDs, between 2 and 10%, for 3-methylbutanal, 14%). The analysis of total SAs in 108 Spanish wines revealed that between 52% and 70% of unoxidized red wines and likely a similar fraction of white wines, contain levels of SAs high enough to cause oxidative aromas if bound forms of SAs cleave.
Carbapenem-resistant Klebsiella pneumoniae (CR-KP) is becoming a common cause of healthcare-associated infection in Italy, with high morbidity and mortality. Prevalent CR-KP clones and resistance ...mechanisms vary between regions and over time. Therapeutic approaches and their impact on mortality have to be investigated. We performed a prospective study of patients with CR-KP isolation, hospitalized in nine hospitals of Rome, Italy, from December 2010 to May 2011, to describe the molecular epidemiology, antibiotic treatment and risk factors for mortality. Overall, 97 patients (60% male, median age 69 years) were enrolled. Strains producing blaKPC-3 were identified in 89 patients, blaVIM in three patients and blaCTX-M-15 plus porin defects in the remaining five patients. Inter-hospital spread of two major clones, ST512 and ST258, was found. Overall, 36.1% and 20.4% of strains were also resistant to colistin and tigecycline, respectively. Infection was diagnosed in 91 patients who received appropriate antibiotic treatment, combination therapy and removal of the infectious source in 73.6%, 59.3% and 28.5% of cases, respectively. Overall, 23 different antibiotic regimens were prescribed. In-hospital mortality was 25.8%. Multivariate analysis adjusted for appropriate treatment, combination therapy and infectious-source removal, showed that Charlson comorbidity score, intensive-care unit onset of infection, bacteraemia and infection due to a colistin-resistant CR-KP strain were independent risk factors for mortality. The spread of clones producing K. pneumoniae carbapenemases, mainly ST258, is currently the major cause of CR-KP infection in central Italy. We observed a high rate of resistance to colistin that is independently associated with worse outcome.
In this paper novel optimization models are proposed for planning Wireless Mesh Networks (WMNs), where the objective is to minimize the network installation cost while providing full coverage to ...wireless mesh clients. Our mixed integer linear programming models allow to select the number and positions of mesh routers and access points, while accurately taking into account traffic routing, interference, rate adaptation, and channel assignment. We provide the optimal solutions of three problem formulations for a set of realistic-size instances (with up to 60 mesh devices) and discuss the effect of different parameters on the characteristics of the planned networks. Moreover, we propose and evaluate a relaxation-based heuristic for large-sized network instances which jointly solves the topology/coverage planning and channel assignment problems. Finally, the quality of the planned networks is evaluated under different traffic conditions through detailed system level simulations.
Classical coverage models, adopted for second-generation cellular systems, are not suited for planning Universal Mobile Telecommunication System (UMTS) base station (BS) location because they are ...only based on signal predictions and do not consider the traffic distribution, the signal quality requirements, and the power control (PC) mechanism. We propose discrete optimization models and algorithms aimed at supporting the decisions in the process of planning where to locate new BSs. These models consider the signal-to-interference ratio as quality measure and capture at different levels of detail the signal quality requirements and the specific PC mechanism of the wideband CDMA air interface. Given that these UMTS BS location models are nonpolynomial (NP)-hard, we propose two randomized greedy procedures and a tabu search algorithm for the uplink (mobile to BS) direction which is the most stringent one from the traffic point of view in the presence of balanced connections such as voice calls. The different models, which take into account installation costs, signal quality and traffic coverage, and the corresponding algorithms, are compared on families of small to large-size instances generated by using classical propagation models.
Ad-hoc networking, though an attractive solution for many applications, still has many unsolved issues, such as the hidden-terminal problem, flexible and prompt access, QoS provisioning, and ...efficient broadcast service. In this paper we present a MAC architecture able to solve the above issues in environments with no power consumption limitations, such as networks for inter-vehicle communications. This new architecture is based on a completely distributed access technique, RR-ALOHA, capable of dynamically establishing, for each active terminal in the network, a reliable single-hop broadcast channel on a slotted/framed structure. Though the proposed architecture uses a slotted channel it can be adapted to operate on the physical layer of different standards, including the UMTS Terrestrial Radio Access TDD, and IEEE 802.11. The paper presents the mechanisms that compose the new MAC: the basic RR-ALOHA protocol, an efficient broadcast service and the reservation of point-to-point channels that exploit parallel transmissions. Some basic performance figures are discussed to prove the effectiveness of the protocol. PUBLICATION ABSTRACT
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