The treatment of massive bone defects is still a significant challenge for orthopedists. Here we have engineered synthetic porous AuPd alloy nanoparticles (pAuPds) as a hyperthermia agent for in situ bone regeneration through photothermal therapy (PTT). After being swallowed by cells, pAuPds produced a mild localized heat (MLH) (40−43 °C) under the irradiation of a nearinfrared laser, which can greatly accelerate cell proliferation and bone regeneration. Almost 97% of the cranial defect area (8 mm in diameter) was covered by the newly formed bone after 6 weeks of PTT. RNA sequencing analysis was used to obtain insight into the molecular mechanism of the MLH on cell proliferation and bone formation. These results demonstrated that the Wnt signaling pathway was involved in the MLH. This Letter provides a unique strategy with mild heat stimulation and high efficiency for in situ bone regeneration.

In this paper, we propose a novel secure multi-party quantum summation protocol based on quantum Fourier transform, where the traveling particles are transmitted in a tree-type mode. The party who prepares the initial quantum states is assumed to be semi-honest, which means that she may misbehave on her own but will not conspire with anyone. The proposed protocol can resist both the outside attacks and the participant attacks. Especially, one party cannot obtain other parties' private integer strings; and it is secure for the colluding attack performed by at most 2 n − parties, where n is the number of parties. In addition, the proposed protocol calculates the addition of modulo d and implements the calculation of addition in a secret-by-secret way rather than a bit-by-bit way.

Most recently, Liu and Chen [Chin. Phys. Lett. 30 (2013) 079901] used the tool of information theory to analyze the security of our two improved versions of the MX protocol [Chin. Phys. Lett. 30 (2013) 040305], and they found out that our two improved versions still have the information leakage problem. After revisiting them with the tool of information theory again, with respect to the security, we draw the same conclusion as Liu and Chen. In addition, we point out that how to use a single quantum state as the sole quantum resource to design a bidirectional quantum secure direct communication protocol without information leakage is still a big challenge that needs to be solved.

In order to avoid the risk of information leakage during the information mutual transmission between two authorized participants, i.e., Alice and Bob, a quantum dialogue protocol based on the entanglement swapping between any two Bell states and the shared secret Bell state is proposed. The proposed protocol integrates the ideas of block transmission, two-step transmission and unitary operation encoding together using the Bell states as the information carriers. Besides the entanglement swapping between any two Bell states, a shared secret Bell state is also used to overcome the information leakage problem, which not only makes Bob aware of the prepared initial state but also is used for Bob's encoding and entanglement swapping. Security analysis shows that the proposed protocol can resist the general active attacks from an outside eavesdropper Eve. Moreover, the relation between the maximal amount of information Eve can gain and the detection probability is derived.

The security of controlled bidirectional quantum direct communication using a GHZ state [Chin. Phys. Lett. 23 (2006) 1680] is analyzed. It turns out that the MX protocol has the problem of definite information leakage, i.e., the first bit of a secret message from any communication party is always leaked out without any active attack after the controller's announcement of measurement results. We put forward two approaches to improve this. The first is to merely modify the encoding rule of the MX protocol, while the second is to use a Bell state as the quantum resource instead of a GHZ state. Both our approaches can ensure that all the bits of secret messages from two communication parties are not leaked out after the controller's announcement of measurement results. Moreover, the controlled bidirectional quantum secure direct communication protocol based on the second approach is more convenient to implement than the MX protocol, since it merely uses a Bell state as the quantum resource and only needs to perform the Bell-basis measurement.