bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the surjectivity criterion for Buchsbaum modules
Authors: Goto Shiro 
Published: June 2010

Let

R
R

be a Cohen-Macaulay local ring with maximal ideal

m
m

and suppose that

dim
⁡
R
≥
2

\dim R \geq 2

. Then

R
R

is regular if (and only if) for any Buchsbaum

R
R

-module

M
M

and for any integer

i
,
i
≠

dim
R

M

i,i \ne {\dim _R}M

, the canonical map

Ext

R
i

(

R

/

m
,
M

)

→

H
m
i

(
M
)

:=

lim

→

n

E
x
t

R
i

(
R

/

m
n

,
M
)

{\text {Ext}}_R^i\left ( {R/m,M} \right ) \to H_m^i\left ( M \right ): = \lim _{\substack {\to \\n}} \mathrm {Ext}_R^i \left (R/m^n, M \right )

is surjective. The hypothesis that

R
R

is Cohen-Macaulay is not superfluous. Two examples are given.
The semisimplicity problem for 𝑝-adic group algebras
Authors: Hare Kathryn E. , Shirvani Maziar 
Published: June 2010

For a prime

p
p

let

Ω
=

Ω
p

\Omega = {\Omega _p}

denote the completion of the algebraic closure of the field of

p
p

-adic numbers with

p
p

-adic valuation

|
|

\left | \right |

. Given a group

G
G

consider the ring of formal sums
\[

l
1

(

Ω
,
G

)

=

{

∑

x
∈
G

α
x

x
:

α
x

∈
Ω
,

|

α
x

|

→
0

}

.

{l_1}\left ( {\Omega ,G} \right ) = \left \{ {\sum \limits _{x \in G} {{\alpha _x}x:{\alpha _x} \in \Omega ,\left | {{\alpha _x}} \right |} \to 0} \right \}.

\]
Motivated by the study of group rings and the complex Banach algebras

l
1

(

C

,
G

)

{l_1}\left ( {{\mathbf {C}},G} \right )

, we consider the problem of when this ring is semisimple (semiprimitive). Our main result is that for an Abelian group

G
,

l
1

(

Ω
,
G

)

G,{l_1}\left ( {\Omega ,G} \right )

is semisimple if and only if

G
G

does not contain a

C
p

∞

{C_p}\infty

subgroup. We also prove that

l
1

(

Ω
,
G

)

{l_1}\left ( {\Omega ,G} \right )

is semisimple if

G
G

is a nilpotent

p
′

p’

-group, an ordered group, or a torsion-free solvable group. We use a mixture of algebraic and analytic methods.
On a Dirichlet series associated with a polynomial
Authors: Eie Min King 
Published: June 2010

Let

P
(
x
)
=

∏

j
=
2

k

(
x
+

δ
j

)

P(x) = \prod \nolimits _{j = 2}^k {(x + {\delta _j})}

be a polynomial with real coefficients and

Re
⁡

δ
j

>
−
1
(
j
=
1
,
…
,
k
)

\operatorname {Re} {\delta _j} > - 1(j = 1, \ldots ,k)

. Define the zeta function

Z
p

(
s
)

{Z_p}(s)

associated with the polynomial

P
(
x
)

P(x)

as
\[

Z
P

(
s
)
=

∑

n
=
1

∞

1

P

(
n
)

s

,
Re
⁡
s
>
1

/

k
.

{Z_P}(s) = \sum \limits _{n = 1}^\infty {\frac {1}{{P{{(n)}^s}}}} ,\operatorname {Re} s > 1/k.

\]

Z
P

(
s
)

Z_P(s)

is holomorphic for

Re
⁡
s
>
1

/

k

\operatorname {Re} s > 1/k

and it has an analytic continuation in the whole complex

s
s

-plane with only possible simple poles at

s
=
j

/

k
(
j
=
1
,
0
,
−
1
,
−
2
,
−
3
,
…
)

s = j/k(j = 1,0, - 1, - 2, - 3, \ldots )

other than nonpositive integers. In this paper, we shall obtain the explicit value of

Z
P

(
−
m
)

{Z_P}( - m)

for any non-negative integer

m
m

, the asymptotic formula of

Z
P

(
s
)

{Z_P}(s)

at

s
=
1

/

k

s = 1/k

, the value

Z
P
′

(
0
)

{Z’_P}(0)

and its application to the determinants of elliptic operators.
Cell-like maps that are shape equivalences
Authors: Choi Jung-In K. 
Published: June 2010

Let

f
:

X
′

→
X

f:X’ \to X

be a cell-like map between metric spaces and set

N
f

=
{
x
∈
X
:

f

−
1

(
x
)
≠

point}

{N_f} = \{ x \in X:{f^{ - 1}}(x) \ne {\text {point\} }}

. Even if

N
f

⊂

⋃

n
=
1

∞

B
n

{N_f} \subset \bigcup \nolimits _{n = 1}^\infty {{B_n}}

, where each

B
n

{B_n}

is closed and each

f

|

f

−
1

(

B
n

)
:

f

−
1

(

B
n

)
→

B
n

f|{f^{ - 1}}({B_n}):{f^{ - 1}}({B_n}) \to {B_n}

is hereditary shape equivalence,

f
f

may not be a hereditary shape equivalence. Conditions are placed on the

B
n

{B_n}

’s to assure that

f
f

is a hereditary shape equivalence. For example, if

N
f

⊂

⋃

n
=
1

∞

B
n

{N_f} \subset \bigcup \nolimits _{n = 1}^\infty {{B_n}}

, where

B
n

{B_n}

is closed for each

n
=
1
,
2
,
…
,
f

|

f

−
1

(

B
n

)
:

f

−
1

(

B
n

)
→

B
n

n = 1,2, \ldots ,f|{f^{ - 1}}({B_n}):{f^{ - 1}}({B_n}) \to {B_n}

is a hereditary shape equivalence, and

B
n

{B_n}

has arbitrary small neighborhoods whose boundaries miss

⋃

i
=
1

∞

B
i

\bigcup \nolimits _{i = 1}^\infty {{B_i}}

then

f
f

is a hereditary shape equivalence. An immediate consequence is that if

{

B
n

}

n
=
1

∞

\{ {B_n}\} _{n = 1}^\infty

is a pairwise disjoint null-sequence and each

f

|

f

−
1

(

B
n

)

f|{f^{ - 1}}({B_n})

is a hereditary shape equivalence, then

f
f

is a hereditary shape equivalence. Previously G. Kozlowski showed that if

{

f

−
1

(

B
n

)

}

n
=
1

∞

\{ {f^{ - 1}}({B_n})\} _{n = 1}^\infty

is a pairwise disjoint null-sequence and each

f

|

f

−
1

(

B
n

)

f|{f^{ - 1}}({B_n})

is a hereditary shape equivalence, then

f
f

is a hereditary shape equivalence, which can be obtained as an immediate corollary of one of our results.
Chebyshev-Vandermonde systems
Authors: Reichel Lothar , Opfer Gerhard 
Published: June 2010

A Chebyshev-Vandermonde matrix
\[

V
=
[

p
j

(

z
k

)

]

j
,
k
=
0

n

∈

C

(
n
+
1
)
×
(
n
+
1
)

V = [{p_j}({z_k})]_{j,k = 0}^n \in {\mathbb {C}^{(n + 1) \times (n + 1)}}

\]
is obtained by replacing the monomial entries of a Vandermonde matrix by Chebyshev polynomials

p
j

{p_j}

for an ellipse. The ellipse is also allowed to be a disk or an interval. We present a progressive scheme for allocating distinct nodes

z
k

{z_k}

on the boundary of the ellipse such that the Chebyshev-Vandermonde matrices obtained are reasonably well-conditioned. Fast progressive algorithms for the solution of the Chebyshev-Vandermonde systems are described. These algorithms are closely related to methods recently presented by Higham. We show that the node allocation is such that the solution computed by the progressive algorithms is fairly insensitive to perturbations in the right-hand side vector. Computed examples illustrate the numerical behavior of the schemes. Our analysis can also be used to bound the condition number of the polynomial interpolation operator defined by Newton’s interpolation formula. This extends earlier results of Fischer and the first author.
Runge-Kutta methods for partial differential equations and fractional orders of convergence
Authors: Ostermann A. , Roche M. 
Published: June 2010

We apply Runge-Kutta methods to linear partial differential equations of the form

u
t

(
x
,
t
)
=

L

(
x
,
∂
)
u
(
x
,
t
)
+
f
(
x
,
t
)

{u_t}(x,t) = \mathcal {L}(x,\partial )u(x,t) + f(x,t)

. Under appropriate assumptions on the eigenvalues of the operator

L

\mathcal {L}

and the (generalized) Fourier coefficients of f, we give a sharp lower bound for the order of convergence of these methods. We further show that this order is, in general, fractional and that it depends on the

L
r

{L^r}

-norm used to estimate the global error. The analysis also applies to systems arising from spatial discretization of partial differential equations by finite differences or finite element techniques. Numerical examples illustrate the results.
On the remainder of Gaussian quadrature formulas for Bernstein-Szegő weight functions
Authors: Peherstorfer F. 
Published: June 2010

We give an explicit expression for the kernel of the error functional for Gaussian quadrature formulas with respect to weight functions of Bernstein-Szegö type, i.e., weight functions of the form

(
1
−
x

)
α

(
1
+
x

)
β

/

ρ
(
x
)
,

x
∈
(
−
1
,
1
)

{(1 - x)^\alpha }{(1 + x)^\beta }/\rho (x),\quad x \in ( - 1,1)

, where

α
,
β
∈
{
−

1
2

,

1
2

}

\alpha ,\beta \in \{ - \tfrac {1}{2},\tfrac {1}{2}\}

and

ρ
\rho

is a polynomial of arbitrary degree which is positive on

[
−
1
,
1
]

[ - 1,1]

. With the help of this result the norm of the error functional can easily be calculated explicitly for a wide subclass of these weight functions.
On Fourier coefficients of Maass waveforms for 𝑃𝑆𝐿(2,𝑍)
Authors: Hejhal D. A. , Arno S. 
Published: June 2010

In this paper, we use machine experiments to test the validity of the Sato-Tate conjecture for Maass waveforms on

P
S
L

(
2
,

m
a
t
h
b
b

Z

)
∖
H

\mathrm {PSL}(2,\ mathbb{Z})\backslash H

. We also elaborate on Stark’s iterative method for calculating the Fourier coefficients of such forms.
On computing factors of cyclotomic polynomials
Authors: Brent Richard P. 
Published: June 2010

For odd square-free

n
>
1

n > 1

the cyclotomic polynomial

Φ
n

(
x
)

{\Phi _n}(x)

satisfies the identity of Gauss,
\[

4

Φ
n

(
x
)
=

A
n
2

−

(
−
1

)

(
n
−
1
)

/

2

n

B
n
2

.

4{\Phi _n}(x) = A_n^2 - {( - 1)^{(n - 1)/2}}nB_n^2.

\]
A similar identity of Aurifeuille, Le Lasseur, and Lucas is
\[

Φ
n

(

(
−
1

)

(
n
−
1
)

/

2

x
)
=

C
n
2

−
n
x

D
n
2

{\Phi _n}({( - 1)^{(n - 1)/2}}x) = C_n^2 - nxD_n^2

\]
or, in the case that n is even and square-free,
\[

±

Φ

n

/

2

(
−

x
2

)
=

C
n
2

−
n
x

D
n
2

.

\pm {\Phi _{n/2}}( - {x^2}) = C_n^2 - nxD_n^2.

\]
Here,

A
n

(
x
)
,
…
,

D
n

(
x
)

{A_n}(x), \ldots ,{D_n}(x)

are polynomials with integer coefficients. We show how these coefficients can be computed by simple algorithms which require

O
(

n
2

)

O({n^2})

arithmetic operations and work over the integers. We also give explicit formulae and generating functions for

A
n

(
x
)
,
…
,

D
n

(
x
)

{A_n}(x), \ldots ,{D_n}(x)

, and illustrate the application to integer factorization with some numerical examples.
On Faber polynomials generated by an 𝑚-star
Authors: Bartolomeo J. , He Matthew 
Published: June 2010

In this paper, we study the Faber polynomials

F
n

(
z
)

{F_n}(z)

generated by a regular m-star

(
m
=
3
,
4
,
…
)

(m = 3,4, \ldots )

\[

S
m

=
{

x

ω
k

;
0
≤
x
≤

4

1

/

m

,
k
=
0
,
1
,
…
,
m
−
1
,

ω
m

=
1

}
.

{S_m} = \{ {x{\omega ^k};0 \leq x \leq {4^{1/m}},k = 0,1, \ldots ,m - 1,{\omega ^m} = 1} \}.

\]
An explicit and precise expression for

F
n

(
z
)

{F_n}(z)

is obtained by computing the coefficients via a Cauchy integral formula. The location and limiting distribution of zeros of

F
n

(
z
)

{F_n}(z)

are explored. We also find a class of second-order hypergeometric differential equations satisfied by

F
n

(
z
)

{F_n}(z)

. Our results extend some classical results of Chebyshev polynomials for a segment

[
−
2
,
2
]

[ - 2,2]

in the case when

m
=
2

m = 2

.
Quadratic residue covers for certain real quadratic fields
Authors: Mollin R. A. , Williams H. C. 
Published: June 2010

Let

Δ
n

(
a
,
b
)
=

(
b

a
n

+
(
a
−
1
)

/

b

)
2

+
4

a
n

{\Delta _n}(a,b) = {(b{a^n} + (a - 1)/b)^2} + 4{a^n}

with

n
≥
1

n \geq 1

and

b

|

a
−
1

b|a - 1

. If

C

\mathcal {C}

is a finite set of primes such that for each

n
≥
1

n \geq 1

there exists some

q
∈

C

q \in \mathcal {C}

for which the Legendre symbol

(

Δ
n

(
a
,
b
)

/

q
)
≠
−
1

({\Delta _n}(a,b)/q) \ne - 1

, we call

C

\mathcal {C}

a quadratic residue cover (QRC) for the quadratic fields

K
n

(
a
,
b
)
=
Q
(

Δ
n

(
a
,
b
)
)

{K_n}(a,b) = Q(\sqrt {{\Delta _n}(a,b))}

. It is shown how the existence of a QRC for any a, b can be used to determine lower bounds on the class number of

K
n

(
a
,
b
)

{K_n}(a,b)

when

Δ
n

(
a
,
b
)

{\Delta _n}(a,b)

is the discriminant of

K
n

(
a
,
b
)

{K_n}(a,b)

. Also, QRCs are computed for all

1
≤
a
,
b
≤
10000

1 \leq a,b \leq 10000

.
Conjugacy classes of Γ(2) and spectral rigidity
Authors: Phillips Ralph 
Published: June 2010

The free groupΓ(2)\Gamma (2)is generated byA=(12,01)A = (1\;2,0\;1)andB=(10,−21)B = (1\;0, - 2\;1), and settingχ(ξ,η)(A)=exp⁡(2πiξ),χ(ξ,η)(B)=exp⁡(2πiη){\chi _{(\xi ,\eta )}}(A) = \exp (2\pi i\xi ),{\chi _{(\xi ,\eta )}}(B) = \exp (2\pi i\eta )defines a unitary character onΓ(2)\Gamma (2)for0≤ξ,η>10 \leq \xi ,\eta > 1. A program is devised to compute\[μ(tr)=∑χ(ξ,η)(conj.class),\mu ({\text {tr}}) = \sum {{\chi _{(\xi ,\eta )}}({\text {conj}}. {\text {class}}),}\]summed over all primitive conjugacy classes ofΓ(2)\Gamma (2)of trace tr. Combined with a Luo-Sarnak theorem, this yields lower bounds for the spectral variance for a large sampling of characters in the range0>ξ,η>10 > \xi ,\eta > 1. The results indicate that the Berry conjecture for spectral rigidity does not hold for this set of classically chaotic systems. The program is also used to compute\[θ(x)=∑ln⁡(N({γ})),\theta (x) = \sum {\ln (N(\{ \gamma \} )),}\]summed over all primitive conjugacy classes ofΓ(2)\Gamma (2)of normN({γ})≤xN(\{ \gamma \} ) \leq x. The functionθ(x)\theta (x)is asymptotic tox, and the remainder can be written as|θ(x)−x|=xβ|\theta (x) - x| = {x^\beta }. The values ofβ(x)\beta (x)are computed for all traces between 3202 and 4802 (herex=tr2−2x = {\text {tr}^2} - 2). Theβ\beta’s cluster around 0.6, attaining a maximum of2/32/3. Finally, it is proved that the remainderθ(x)−x\theta (x) - xhas a negative bias by showing that the mean normalized remainder converges to a negative limit.
Leptospira: a spirochaete with a hybrid outer membrane
Authors: Haake David A. , Matsunaga James 
Published: June 2010

Summary Leptospira is a genus of spirochaetes that includes organisms with a variety of lifestyles ranging from aquatic saprophytes to invasive pathogens. Adaptation to a wide variety of environmental conditions has required leptospires to acquire a large genome and a complex outer membrane with features that are unique among bacteria. The most abundant surface‐exposed outer membrane proteins are lipoproteins that are integrated into the lipid bilayer by amino‐terminal fatty acids. In contrast to many spirochaetes, the leptospiral outer membrane also includes lipopolysaccharide and many homologues of well‐known beta‐barrel transmembrane outer membrane proteins. Research on leptospiral transmembrane outer membrane proteins has lagged behind studies of lipoproteins because of their aberrant behaviour by Triton X‐114 detergent fractionation. For this reason, transmembrane outer membrane proteins are best characterized by assessing membrane integration and surface exposure. Not surprisingly, some outer membrane proteins that mediate host–pathogen interactions are strongly regulated by conditions found in mammalian host tissues. For example, the leptospiral immunoglobulin‐like (Lig) repeat proteins are dramatically induced by osmolarity and mediate interactions with host extracellular matrix proteins. Development of molecular genetic tools are making it possible to finally understand the roles of these and other outer membrane proteins in mechanisms of leptospiral pathogenesis.
Serum uric acid level is associated with cardiac hypertrophy in renal transplant recipients
Authors: Caliskan Yasar , Gorgulu Numan , Yelken Berna , Akturk Faruk , Yazici Halil , Turkmen Aydin , Sever Mehmet Sukru 
Published: June 2010

Caliskan Y, Gorgulu N, Yelken B, Akturk F, Yazici H, Turkmen A, Sever MS. Serum uric acid level is associated with cardiac hypertrophy in renal transplant recipients. Clin Transplant 2011: 25: 368–374. © 2010 John Wiley & Sons A/S.Abstract:  Background:  Serum uric acid (UA) level as a significant and independent risk factor for cardiovascular disease, and the link between this marker and left ventricular hypertrophy (LVH) in renal transplant recipients remains to be clarified.Methods:  A total of 141 renal transplant recipients (83 men), between ages of 18 and 69 (mean age 37 ± 11), were included in this single center study. In addition to demographic, clinical, and laboratory parameters, serum UA concentrations were evaluated. LVH was determined by two‐dimensional and M‐mode echocardiography.Results:  Serum UA levels were significantly higher (6.14 ± 1.15 mg/dL) in patients with LVH (n = 54) when compared to patients (n = 87) who did not have this abnormality (5.29 ± 1.43 mg/dL) (p = 0.006). Serum UA levels were significantly correlated with septal wall thickness, LV posterior wall thickness, LV mass index (LVMI), and pulmonary arterial pressure. Multiple linear regression analysis revealed that UA predicted LVMI (r2 = 0.150, β = 0.369, p = 0.001). However, serum creatinine (β = 0.060, p = 0.593) and age (β = 0.146, p = 0.175) were not predictors of LVMI.Conclusion:  High serum UA levels are associated with LVH in renal transplant recipients, which underlines the importance of treating hyperuricemia.
Type 1 and type IV hypersensitivity to nickel
Authors: Walsh Maeve L , Smith Victoria H , King Clodagh M 
Published: June 2010

ABSTRACTWe report a case of type 1 and type IV contact hypersensitivity to nickel. Very few cases of immediate contact urticaria to nickel have been reported. The mechanism behind this is not fully understood, although it has been postulated that nickel may act as a mast cell discharger on a non‐immunological basis. Nickel is found in varying concentrations in stainless steels; its biological availability varies depending on the alloy composition. Our patient has adapted her lifestyle to minimize her contact with household appliances containing nickel. If medical or dental treatment using stainless steel equipment is required, we recommend a short course of oral corticosteroids and antihistamines.
Sustained low hepatitis B viral load predicts good outcome after curative resection in patients with hepatocellular carcinoma
Authors: An Ho Jung , Jang Jeong Won , Bae Si Hyun , Choi Jong Young , Cho Se Hyun , Yoon Seung Kew , Han June Yeol , Lee Keun Ho , Kim Dong Goo , Jung Eun Sun 
Published: June 2010

AbstractBackground and Aim:  Little is known about the role of hepatitis B virus (HBV) factors in the long‐term prognosis of hepatocellular carcinoma (HCC) after resection. The objective of the present study was to identify the changing patterns of HBV levels and its effect on outcome after resection.Methods:  This study recruited 188 patients with HBV‐related HCC who underwent curative resection. Among the 188 patients, 115 were alive without recurrence at 12 months, and had serial measurements of viral levels.Results:  The mean age was 53 years and the mean follow‐up period was 48.5 months. With multivariate analysis, tumor size > 5 cm (P = 0.047), Child‐Pugh class B (P = 0.017), vascular invasion (P = 0.028), and HBV DNA > 104 copies/mL at the time of resection (P = 0.003) were independently predictive of HCC recurrence for the entire population. For the 115 patients with serial measurements of viral levels, tumor size > 5 cm, HBV DNA > 104 copies/mL at resection, and the absence of sustained HBV DNA level < 104 copies/mL, the presence of cirrhosis, and elevated aminotransferase levels (> 40 IU/L) were marginally or significantly associated with HCC recurrence and overall survival. However, on multivariate analysis, sustained HBV DNA level < 104 copies/mL was the only factor for both low recurrence (P = 0.002; odds ratio [OR] 3.13; 95% confidence interval [CI] 1.55–6.35) and longer survival (P = 0.002; OR 3.76; 95% CI 1.61–8.78).Conclusions:  A high HBV replication state is among the most important predictors of adverse outcome after resection of HBV‐related HCC. The sustained suppression of HBV below 104 copies/mL is a strong protective factor for long‐term recurrence‐free and overall survival.
Father involvement and child well‐being
Authors: Wilson Katherine R , Prior Margot R 
Published: June 2010

AbstractChildren's development is influenced by the quantity and quality of father involvement (FI) in their care. High levels of FI are associated with significant and highly desirable outcomes for children and families. In order to foster increased positive FI, dissemination of evidence‐based knowledge regarding its importance and value is needed. Evidence summarised here suggests that fathers and mothers alike need to be educated about the fact that positive paternal involvement is highly beneficial to children.
Differing causal roles for lateral occipital cortex and occipital face area in invariant shape recognition
Authors: Silvanto J. , Schwarzkopf D. S. , Gilaie‐Dotan S. , Rees G. 
Published: June 2010

AbstractThe human extrastriate visual cortex contains functionally distinct regions where neuronal populations exhibit signals that are selective for objects. How such regions might play a causal role in underpinning our ability to recognize objects across different viewpoints remains uncertain. Here, we tested whether two extrastriate areas, the lateral occipital (LO) region and occipital face area (OFA), contained neuronal populations that play a causal role in recognizing two‐dimensional shapes across different rotations. We used visual priming to modulate the rotation‐sensitive activity of neuronal populations in these areas. State‐dependent transcranial magnetic stimulation (TMS) was applied after the presentation of a shape and immediately before a subsequent probe shape to which participants had to respond. We found that TMS applied to both the LO region and OFA modulated rotation‐invariant shape priming but, whereas the LO region was modulated by TMS for small rotations, the OFA was modulated for larger rotations. Importantly, our results demonstrate that a node in the face‐sensitive network, the OFA, participates in causally relevant encoding of non‐face stimuli.
Girard's Use of Mimetic Theory Girard and Theology – By Michael Kirwan
Authors: Avery‐Wall Vanessa 
Published: June 2010

AbstractWith the advent of Rene Girard's Violence and the Sacred, mimetic theory has become relevant as a vehicle for looking at religion and its origins. In later works, Girard uses mimetic theory specifically as an interpretive principle for scripture, and in doing so, arrives at a theology that provides for the existence of a sacred free of violence and violent agency. How, though, does Girard's theory correlate with other theological paradigms? Where does Girard fit in? And is Girard's theory able to further the possibilities of theological discourse? These are the aims of Kirwan's book, which provides an excellent overview of various branches of theology, the prevailing paradigms in each area, and how Girard might be located within those frames. Kirwan also gives ample space to the criticisms that have been voiced concerning Girard and his theory. Overall, this book is a convincing exposition of the versatility of mimetic theory, and how it may indeed contribute across the wide spectrum theological thought.
The frequency‐dependence of the nicotine‐induced inhibition of dopamine is controlled by the α7 nicotinic receptor
Authors: Seipel Andrew T. , Yakel Jerrel L. 
Published: June 2010

J. Neurochem. (2010) 114, 1659–1666.AbstractVoltammetric analyses show that low (100–500 nM) doses of nicotine regulate striatal dopamine by inhibiting release evoked by a single stimulation to a greater extent than release evoked by high frequency stimulations. This frequency‐dependent inhibition is because of nicotine desensitizing heteromeric β2 subunit‐containing nicotinic acetylcholine receptor (nAChR) subtypes. Surprisingly, a high dose of nicotine (2 μM; capable of interacting with additional nAChR subtypes) produced an inhibition of dopamine evoked by high frequency stimulation, an effect that was not seen with the low dose of nicotine or the β2 antagonist, dihydro‐β‐erythroidine hydrobromide. This inhibition was replicated by application of α7 nAChR antagonists methyllcaconitine citrate or α‐bungarotoxin in conjunction with the low dose of nicotine or dihydro‐β‐erythroidine hydrobromide. Blocking α7 receptor function alone produced a modest increase in dopamine evoked by single pulse stimulation while not affecting dopamine evoked by high frequency stimulation. The antagonist results were mimicked using selective α7 agonists PHA 543613 and PNU 282987. The frequency dependence of the low dose nicotine inhibition therefore requires functional α7 nAChRs, and may arise from differing levels of endogenous acetylcholine evoked by the stimulation.