Exactly solvable models are very important in physics. They are important not just from a theoretical point of view but also from the experimentalist's perspective because in such cases theoretical results and experimental results can be compared without ambiguity. This 1999 book is about an important class of exactly solvable models in physics. The subject area is the Bethe-ansatz approach for a number of one-dimensional models, and the setting up of equations within this approach to determine the thermodynamics of these systems. It is a topic that crosses the boundaries between condensed matter physics, mathematics and field theory. The derivation and application of thermodynamic Bethe-ansatz equations for one-dimensional models are explained in detail. This technique is indispensable for physicists studying the low-temperature properties of one-dimensional substances. This book, written by one of the top physicists in this field, and the originator of much of the work in the subject, will be of great interest to theoretical condensed matter physicists.

No abstract

No abstract

No abstract

No abstract

Highly accurate results are presented for the susceptibility, χ(T ) of the s = 1/2 Heisenberg antiferromagnetic chain for all temperatures, using the Bethe ansatz and field theory methods. After going through a rounded peak, χ(T ) approaches its asympotic zero-temperature value with infinite slope. 75.10.JmTypeset using REVT E X 1 In a pioneering work in 1964, Bonner and Fisher estimated numerically 1 the susceptibility, χ(T ) for the s = 1/2 Heisenberg antiferromagnetic chain, using chain lengths of up to 11. The exact value at T = 0 was obtained using the Bethe ansatz 2,3 . Since that time, the Bonner-Fisher curve has frequently been used by experimentalists to determine the value of the exchange coupling, J, and to determine whether or not a given material has sufficiently small anisotropic exchange and inter-chain couplings to be approximated by this model. Recently it has become possible to calculate this curve much more accurately, using the Bethe ansatz. 4 This method easily gives very accurate results for T not too small, but becomes increasingly difficult as T → 0. On the other hand, an analytic formula can be derived for χ(T ) at small T , from conformal field theory methods. Perhaps surprisingly, this formula predicts, due to the marginally irrelevant operator, that the susceptibility has infinite slope at T = 0. Here we present results for χ(T ) obtained using the Bethe ansatz for T ≥ .003J and compare them to the conformal field theory prediction, obtaining excellent agreement. The field theory prediction for the general xxz model is also given. Figure (1) shows the susceptibility obtained from the Bethe ansatz and Figure (2) compares this result to the field theory prediction at low T . Note that, with decreasing T , after passing through the maximum, χ ≈ .147/J, at T ≈ .640824J, the slope of χ starts to increase below the inflection point at T ≈ .087J, approaching ∞ as T → 0.The Heisenberg Hamiltonian is written:

No abstract

Hepatic transdifferentiation of bone marrow cells has been previously demonstrated by intravenous administration of donor cells, which may recirculate to the liver after undergoing proliferation and differentiation in the recipient's bone marrow. In the present study, to elucidate which cellular components of human bone marrow more potently differentiate into hepatocytes, we fractionated human bone marrow cells into mesenchymal stem cells (MSCs) Schwartz et al 1 demonstrated that multipotent adult progenitor cells (MAPCs) 2,3 from the bone marrow of humans as well as mice and rats, when cultured with fibroblast growth factor-4 (FGF-4) and hepatocyte growth factor (HGF) in matrigel, secreted albumin, expressed P450, took up low-density lipoprotein (LDL), and stored glycogen. 3 Lee et al reported that mesenchymal stem cells (MSCs) from human bone marrow and umbilical cord blood differentiated into hepatocyte-like cells with the use of HGF and oncostatin M. 4,5 Most recently, Jang et al reported that hematopoietic stem cells (HSCs) from mice devoid of progenitors and selected for unique properties displayed a plasticity by which they became liver cells when cocultured with injured liver separated by a barrier. 6 Thus, the origin of cells which may undergo hepatic differentiation as revealed by in vitro experiments were quite diverse, reflecting the sources, human or rodent, and methods of isolation.,The differentiation of bone marrow or umbilical cord blood derived cells into hepatocytes has also been demonstrated by in vivo transplantation procedures. In most of these transplantation studies, either isolated 7-12 or clonally defined [13][14][15][16][17][18][19][20][21] HSCs of donor origin, though their characteristics were not equally specified in each study, were found to induce hepatocytes in recipient liver, suggesting the differentiation potency of HSCs.However, in these studies HSCs were generally introduced intravenously and were surmised to reside once in bone marrow where they may undergo proliferation and differentiation. Therefore, the cells distributed to the liver via bone marrow may not necessarily represent the original HSCs themselves.In fact, some recent studies have disclosed that hepatocytes with apparent donor characters were the result of fusion of donor myelomonocytic cells differentiated from HSCs with host hepatocytes. 20,22 Further, the results of these studies with HSCs do not exclude the possibility that other cell types in bone marrow such as MSCs are also capable of undergoing hepatic differentiation. Thus, issues still remained to be clarified as to which cellular component of bone marrow is most suitable to bring about hepatic regeneration in consideration of future clinical application. It also remains to be solved if any bone marrow components indeed differentiate in vivo without fusion.In the present investigation, we attempted to examine the differentiation ability of fractionated human bone marrow components-MSCs, CD34 ϩ cells, and non-MSCs/CD34 Ϫ cells-into hepatocytes in vivo ...