A Steiner quadruple system of order
v
+
1
with resolvable derived designs (every derived Steiner triple system of order
v
at a point is resolvable), abbreviated as RDSQS
(
v
+
1
)
, has been used to ...construct a large set of Kirkman triple systems of order 3
v
. In this paper, an RDSQS
(
v
+
1
)
is reduced to an overlarge set of Kirkman triple systems of order
v
with an additional property (OLKTS
+
(
v
)
), which plays the same role in constructing an LKTS(3
v
) as an RDSQS
(
v
+
1
)
. Some recursive constructions of OLKTS
+
s are also established. As a result, some infinite classes of OLKTS
+
s and LKTSs are obtained.
High temperatures have dramatic negative effects on interconnect performance. In a bus, whenever the state transitions from “0” to “1”, or “0” to “1”, joule heating causes the temperature to rise. A ...low-power error-correcting cooling (LPECC) code, introduced in Chee et al. (IEEE Trans Inf Theory 64:3062–3085, 2018), is a coding scheme which can be used to control the peak temperature, the average power consumption of on-chip buses and error-correction for the transmitted information, simultaneously. In this paper, we show upper bounds and some lower bounds of LPECC codes by some combinatorial configurations, and also present several families of optimal LPECC codes.
Frequency hopping sequences (FHSs) with favorable partial Hamming correlation properties have important applications in many synchronization and multiple-access systems. In this paper, we investigate ...constructions of FHSs and FHS sets with optimal partial Hamming correlation. We first establish a correspondence between FHS sets with optimal partial Hamming correlation and multiple partition-type balanced nested cyclic difference packings with a special property. By virtue of this correspondence, some FHSs and FHS sets with optimal partial Hamming correlation are constructed from various combinatorial structures, such as cyclic difference packings and cyclic relative difference families. As a consequence, our constructions yield new FHSs and FHS sets with optimal partial Hamming correlation.
Ag@C fibres with porous silver structure were synthesized with a surface-hydrolyzed polyacrylonitrile (PAN) fibre as a template and by a hydrazine hydrate reduction and carbonization process. The ...composition and structure of the Ag@C fibres were characterized with a scanning electron microscope, an X-ray diffractometer, a Fourier transform infrared spectrometer, an X-ray photoelectron spectrometer, a Raman spectrometer, and a thermogravimetric analyser. The porous structure of the silver shell combined with carbon was conducive to the release of silver ions and suppressed the loss of silver nanoparticles from the surface of the carbon fibres. The Ag@C fibres showed excellent antibacterial performance. When the dosage of Ag@C fibres prepared with a silver nitrate solution of 0.5 mol/L was 1 mg, 2 mg, 4 mg and 8 mg, the bacterial inactivation rate to
Staphylococcus aureus
was 97.98%, 99.89%, 99.99%, and 99.99% in 12 h, respectively. The loss of viability only decreased to 80% when 1 mg of Ag@C fibres were used for antimicrobial activity test after five times of recycling. The Ag@C fibres have a broad application prospect in producing fabric products of antibacterial fields.
Graphical abstract
A
t
-
(
n
,
k
,
λ
)
q
design is a set of
k
-dimensional subspaces, called blocks, of an
n
-dimensional vector space
V
over the finite field
F
q
with
q
elements such that each
t
-dimensional subspace ...is contained in exactly
λ
blocks. A partition of the complete set of
k
-dimensional subspaces of
V
into
l
disjoint
t
-
(
n
,
k
,
λ
)
q
designs is called a large set of
t
-designs over
F
q
and denoted by
L
S
q
l
(
t
,
k
,
n
)
. Large sets of
t
-designs over finite fields with
t
≥
2
are currently known to exist only for
L
S
2
3
(
2
,
3
,
8
)
,
L
S
3
2
(
2
,
k
,
n
)
and
L
S
5
2
(
2
,
k
,
n
)
with integers
n
≥
6
,
n
≡
2
(
mod
4
)
and
3
≤
k
≤
n
-
3
,
k
≡
3
(
mod
4
)
. In this article, we use the KLP theorem to prove that an
L
S
q
l
(
t
,
k
,
n
)
exists for all
t
and
q
, provided that
k
>
6.1
(
t
+
1
)
and
n
is sufficiently large and
n
-
s
k
-
s
q
≡
0
(
mod
l
)
for
0
≤
s
≤
t
.
Frequency hopping sequences (FHSs) are employed to mitigate the interferences caused by the hits of frequencies in frequency hopping spread spectrum systems. In this paper, we present combinatorial ...constructions for FHS sets, including direct constructions by using cyclotomic classes, recursive constructions based on cyclic difference matrices, merging blocks, and discrete logarithm. By these constructions, a number of series of new FHS sets are then produced. These FHS sets are optimal with respect to the Peng-Fan bounds.
This study aimed to investigate the effect of Ru (Rut) on angiogenesis, and the underlying regulation mechanism of signal transduction. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium ...bromide (MTT) assay, adhesion inhibition experiment, migration inhibition experiment, and chick embryo chorioallantoic membrane (CAM) assays were performed on models of angiogenesis. The potential targets of rutaecarpine (Ru) were reverse screened with Discovery Studio 2017. The interaction between the compound and target were detected by surface plasmon resonance (SPR), enzyme-activity experiment, and Western blot assay. The obtained results confirmed that Ru exhibited modest inhibitory activity against human umbilical vein endothelial cells (HUVECs) (IC
=16.54 ± 2.4 μM) and remarkable inhibitive effect against the migration and adhesion of HUVECs, as well as significant anti-angiogenesis activities in the CAM assay. The possible targets of vascular endothelial growth factor receptor 2 (VEGFR2) were identified by computer-aided simulation. Results showed a good binding relationship between the ligand and target through molecular docking, and this relationship was confirmed by SPR analysis. Furthermore, enzyme-activity experiment and western blot assay showed that Ru remarkably inhibited the activity of VEGFR2 and blocked the VEGFR2-mediated Akt/ (mTOR)/p70s6k signaling pathway in vitro. Ru can be a potential drug candidate for cancer prevention and cancer therapy.
Splitting authentication codes were first introduced by Simmons in 1982. Ogata et al. introduced
(
v
,
u
×
c
,
1
)
-splitting balanced incomplete block designs in 2006 in order to construct twofold ...optimal
c
-splitting authentication codes. In 2020, Paterson and Stinson showed that there exists an authentication code with perfect secrecy for
u
uniformly distributed source states that is
ϵ
-secure against message-substitution and key-substitution attacks if and only if there exists an
ϵ
-secure robust (2, 2)-threshold scheme for
u
uniformly distributed secrets, and they used an equitably ordered
(
v
,
u
×
c
,
1
)
-splitting balanced incomplete block design (briefly a
(
v
,
u
×
c
,
1
)
-ESBIBD) to construct a (1/
cu
)-secure robust (2, 2)-threshold scheme for
u
equiprobable secrets. Note that
v
≡
1
(
mod
u
(
u
-
1
)
c
)
and
v
(
v
-
1
)
≡
0
(
mod
u
(
u
-
1
)
c
2
)
if there is a
(
v
,
u
×
c
,
1
)
-ESBIBD. In order to consider other orders
v
, we generalize the concept of a
(
v
,
u
×
c
,
1
)
-ESBIBD to an equitably ordered
(
v
,
u
×
c
,
1
)
-splitting packing design (briefly a
(
v
,
u
×
c
,
1
)
-ESPD), which can also be used to construct a (1/
cu
)-secure robust (2, 2)-threshold scheme for
u
equiprobable secrets. In this paper, we study combinatorial constructions of
(
v
,
u
×
c
,
1
)
-ESPDs and determine the existence of an optimal
(
v
,
u
×
c
,
1
)
-ESPD for
(
u
,
c
)
∈
{
(
2
,
k
)
:
k
is
a
positive
integer
}
∪
{
(
3
,
1
)
,
(
4
,
1
)
,
(
3
,
2
)
}
. Consequently, we obtain some new infinite classes of authentication codes with perfect secrecy and (1/
cu
)-secure robust (2, 2)-threshold schemes.
Transparent TiO
2
/polymer nanocomposites (PSEM) with excellent anti-UV light property and antibacterial activity against
Staphylococcus aureus
were designed and prepared successfully by the ...copolymerization of styrene monomers with dispersed TiO
2
nanoparticles, polyethylene glycol (600) dimethacrylate and ethoxylated trimethylolpropane. PSEM nanocomposites could shield ultraviolet light in the wavelength range of 200–368 nm, reducing the transmittance of blue and violet light in the range of 368–500 nm and having a light transmittance of about 91% in the visible light region of 600–800 nm. The results suggested that the interaction between PEG chains and TiO
2
nanoparticles could promote the stable dispersion of TiO
2
nanoparticles, which was a key for the outstanding transparent performance and highly efficient UV light absorbance. The maximum inhibition zone against
Staphylococcus aureus
was 28.0 mm. PEG chains in polyethylene glycol (600) dimethacrylate provided soft segments for PSEM nanocomposites, styrene monomers provided hard segments, while ethoxylated trimethylolpropane trimethacrylate enhanced the crosslinking density. The molecular structure design ensured PSEM nanocomposites had tailored mechanical properties and stable thermal properties. The maximum unnotched impact strength, tensile strength, bending stress and hardness reached 56.11 kJ/m
2
, 54 MPa, 88.02 MPa, and 74 HRR, respectively. This research provided a meaningful strategy for designing highly transparent and self-sterilizing composite materials used in medical industry.
Nanoscale bioactive glass particles have greater bioactivity than microscale bioactive glass particles, due to their high-specific surface area and fast ion release rate in body fluid. However, ...preparation of bioactive glass nanoparticles (BGNPs) is difficult since calcium is not easy to be highly doped into the forming silica atom network, leading to an uneven distribution and a low content of calcium. In addition, BGNPs are usually prepared in a dilute solution to avoid agglomeration of the nanoparticles, which decreases the production efficiency and increases the cost. In this work, BGNPs are prepared by a method of the reactive flash nanoprecipitation (RFNP) as well as a traditional sol–gel method. The results indicate that the BGNPs by the RFNP present a smaller size, narrower size distribution, more uniform composition, and better bioactivity than those by the traditional sol–gel method. The obtained BGNPs have uniform compositions close to the feed values. The high and even doping of calcium in the BGNPs is achieved. This successful doping of calcium into nanoparticles by the RFNP demonstrates a promising way to effectively generate high-quality BGNPs for bone repairs.
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